From b91fce01a05af108ffb8dde94bb4cbcaacdc46c8 Mon Sep 17 00:00:00 2001
From: Lauren Budorick <lauren@mapbox.com>
Date: Wed, 22 Nov 2017 16:31:11 -0800
Subject: [PATCH 1/7] Create Framebuffer class, remove RenderTexture

---
 flow-typed/window.js                          |  3 +-
 src/gl/context.js                             | 16 +++++
 src/gl/framebuffer.js                         | 23 +++++++
 src/gl/state.js                               | 10 ++-
 src/gl/value.js                               | 52 +++++++++++++++-
 src/render/draw_fill_extrusion.js             |  4 +-
 src/render/draw_heatmap.js                    | 10 +--
 src/render/draw_hillshade.js                  | 18 +++---
 src/render/painter.js                         | 40 ++++++------
 src/render/render_texture.js                  | 61 -------------------
 src/render/texture.js                         |  9 ++-
 src/style/style_layer.js                      |  4 +-
 .../style_layer/fill_extrusion_style_layer.js |  6 +-
 src/style/style_layer/heatmap_style_layer.js  |  5 +-
 src/util/window.js                            |  1 +
 15 files changed, 155 insertions(+), 107 deletions(-)
 create mode 100644 src/gl/framebuffer.js
 delete mode 100644 src/render/render_texture.js

diff --git a/flow-typed/window.js b/flow-typed/window.js
index 82e7e2522c6..33dcf650154 100644
--- a/flow-typed/window.js
+++ b/flow-typed/window.js
@@ -121,8 +121,9 @@ declare interface Window extends EventTarget, IDBEnvironment {
     Image: typeof Image;
     ImageData: typeof ImageData;
     URL: typeof URL;
-    webkitURL: typeof URL;
     URLSearchParams: typeof URLSearchParams;
+    WebGLFramebuffer: typeof WebGLFramebuffer;
+    webkitURL: typeof URL;
     WheelEvent: typeof WheelEvent;
     Worker: typeof Worker;
     XMLHttpRequest: typeof XMLHttpRequest;
diff --git a/src/gl/context.js b/src/gl/context.js
index 2afe6605a2c..876d8a4ece1 100644
--- a/src/gl/context.js
+++ b/src/gl/context.js
@@ -1,6 +1,7 @@
 // @flow
 const IndexBuffer = require('./index_buffer');
 const VertexBuffer = require('./vertex_buffer');
+const Framebuffer = require('./framebuffer');
 const State = require('./state');
 const {
     ClearColor,
@@ -128,6 +129,21 @@ class Context {
         return new VertexBuffer(this, array, dynamicDraw);
     }
 
+    createRenderbuffer(storageFormat: number, width: number, height: number) {
+        const gl = this.gl;
+
+        const rbo = gl.createRenderbuffer();
+        this.bindRenderbuffer.set(rbo);
+        gl.renderbufferStorage(gl.RENDERBUFFER, storageFormat, width, height);
+        this.bindRenderbuffer.set(null);
+
+        return rbo;
+    }
+
+    createFramebuffer() {
+        return new Framebuffer(this);
+    }
+
     clear({color, depth}: ClearArgs) {
         const gl = this.gl;
         let mask = 0;
diff --git a/src/gl/framebuffer.js b/src/gl/framebuffer.js
new file mode 100644
index 00000000000..93941c45a2a
--- /dev/null
+++ b/src/gl/framebuffer.js
@@ -0,0 +1,23 @@
+// @flow
+const State = require('./state');
+const { ColorAttachment, DepthAttachment } = require('./value');
+
+import type Context from './context';
+
+class Framebuffer {
+    context: Context;
+    framebuffer: WebGLFramebuffer;
+    colorAttachment: State<?WebGLTexture>;
+    depthAttachment: State<?WebGLRenderbuffer>;
+
+    constructor(context: Context) {
+        this.context = context;
+        const gl = context.gl;
+        const fbo = this.framebuffer = gl.createFramebuffer();
+
+        this.colorAttachment = new State(new ColorAttachment(context, fbo));
+        this.depthAttachment = new State(new DepthAttachment(context, fbo));
+    }
+}
+
+module.exports = Framebuffer;
diff --git a/src/gl/state.js b/src/gl/state.js
index cd591991c79..0a83042887d 100644
--- a/src/gl/state.js
+++ b/src/gl/state.js
@@ -17,11 +17,19 @@ class State<T> {
     }
 
     set(t: T) {
-        if (!this.value.constructor.equal(this.current, t)) {
+        if (this.dirty || !this.value.constructor.equal(this.current, t)) {
             this.current = t;
             this.value.set(t);
         }
     }
+
+    isDirty(): boolean {
+        return this.dirty;
+    }
+
+    setDirty(): void {
+        this.dirty = true;
+    }
 }
 
 module.exports = State;
diff --git a/src/gl/value.js b/src/gl/value.js
index fb15aad3843..1f6751b8ea7 100644
--- a/src/gl/value.js
+++ b/src/gl/value.js
@@ -1,7 +1,9 @@
 // @flow
+const assert = require('assert');
 
 const Color = require('../style-spec/util/color');
 const util = require('../util/util');
+const window = require('../util/window');
 
 import type Context from './context';
 import type {
@@ -15,7 +17,6 @@ import type {
     ViewportType,
 } from './types';
 
-
 export interface Value<T> {
     context: Context;
     static default(context?: Context): T;
@@ -25,9 +26,13 @@ export interface Value<T> {
 
 class ContextValue {
     context: Context;
+    parent: ?any;
 
-    constructor(context: Context) {
+    constructor(context: Context, parent: ?any) {
         this.context = context;
+        if (parent) {
+            this.parent = parent;
+        }
     }
 
     static equal(a, b): boolean {
@@ -324,6 +329,46 @@ class PixelStoreUnpackPremultiplyAlpha extends ContextValue implements Value<boo
     }
 }
 
+/**
+ * Framebuffer values
+ */
+
+class ColorAttachment extends ContextValue implements Value<?WebGLTexture> {
+    static default() { return null; }
+
+    set(v: ?WebGLTexture): void {
+        assert(this.parent && this.parent instanceof window.WebGLFramebuffer);
+
+        const gl = this.context.gl;
+        this.context.bindFramebuffer.set(this.parent);
+        // note: it's possible to attach a renderbuffer to the color
+        // attachment point, but thus far MBGL only uses textures for color
+        gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, v, 0);
+    }
+
+    static equal(a, b): boolean {
+        return a === b;
+    }
+}
+
+class DepthAttachment extends ContextValue implements Value<?WebGLRenderbuffer> {
+    static default() { return null; }
+
+    set(v: ?WebGLRenderbuffer): void {
+        assert(this.parent && this.parent instanceof window.WebGLFramebuffer);
+
+        const gl = this.context.gl;
+        this.context.bindFramebuffer.set(this.parent);
+        // note: it's possible to attach a texture to the depth attachment
+        // point, but thus far MBGL only uses renderbuffers for depth
+        gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, v);
+    }
+
+    static equal(a, b): boolean {
+        return a === b;
+    }
+}
+
 module.exports = {
     ClearColor,
     ClearDepth,
@@ -352,4 +397,7 @@ module.exports = {
     BindVertexArrayOES,
     PixelStoreUnpack,
     PixelStoreUnpackPremultiplyAlpha,
+
+    ColorAttachment,
+    DepthAttachment,
 };
diff --git a/src/render/draw_fill_extrusion.js b/src/render/draw_fill_extrusion.js
index b001182157b..0dedaced459 100644
--- a/src/render/draw_fill_extrusion.js
+++ b/src/render/draw_fill_extrusion.js
@@ -48,8 +48,8 @@ function drawExtrusionTexture(painter, layer) {
     context.stencilTest.set(false);
     context.depthTest.set(false);
 
-    gl.activeTexture(gl.TEXTURE0);
-    gl.bindTexture(gl.TEXTURE_2D, renderedTexture.texture);
+    context.activeTexture.set(gl.TEXTURE0);
+    gl.bindTexture(gl.TEXTURE_2D, renderedTexture.colorAttachment.get());
 
     gl.uniform1f(program.uniforms.u_opacity, layer.paint.get('fill-extrusion-opacity'));
     gl.uniform1i(program.uniforms.u_image, 0);
diff --git a/src/render/draw_heatmap.js b/src/render/draw_heatmap.js
index 0f1498c166a..537d3339480 100644
--- a/src/render/draw_heatmap.js
+++ b/src/render/draw_heatmap.js
@@ -82,7 +82,7 @@ function renderToTexture(context, painter, layer) {
     let texture = layer.heatmapTexture;
     let fbo = layer.heatmapFbo;
 
-    if (!texture) {
+    if (!texture || !fbo) {
         texture = layer.heatmapTexture = gl.createTexture();
         gl.bindTexture(gl.TEXTURE_2D, texture);
         gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
@@ -90,13 +90,13 @@ function renderToTexture(context, painter, layer) {
         gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
         gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
 
-        fbo = layer.heatmapFbo = gl.createFramebuffer();
+        fbo = layer.heatmapFbo = context.createFramebuffer();
 
         bindTextureFramebuffer(context, painter, texture, fbo);
 
     } else {
         gl.bindTexture(gl.TEXTURE_2D, texture);
-        context.bindFramebuffer.set(fbo);
+        context.bindFramebuffer.set(fbo.framebuffer);
     }
 }
 
@@ -106,12 +106,12 @@ function bindTextureFramebuffer(context, painter, texture, fbo) {
     gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, painter.width / 4, painter.height / 4, 0, gl.RGBA,
         painter.extTextureHalfFloat ? painter.extTextureHalfFloat.HALF_FLOAT_OES : gl.UNSIGNED_BYTE, null);
 
-    context.bindFramebuffer.set(fbo);
-    gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
+    fbo.colorAttachment.set(texture);
 
     // If using half-float texture as a render target is not supported, fall back to a low precision texture
     if (painter.extTextureHalfFloat && gl.checkFramebufferStatus(gl.FRAMEBUFFER) !== gl.FRAMEBUFFER_COMPLETE) {
         painter.extTextureHalfFloat = null;
+        fbo.colorAttachment.setDirty();
         bindTextureFramebuffer(context, painter, texture, fbo);
     }
 }
diff --git a/src/render/draw_hillshade.js b/src/render/draw_hillshade.js
index b2144a02219..c356e3fe89a 100644
--- a/src/render/draw_hillshade.js
+++ b/src/render/draw_hillshade.js
@@ -1,7 +1,6 @@
 // @flow
 const Coordinate = require('../geo/coordinate');
 const Texture = require('./texture');
-const RenderTexture = require('./render_texture');
 const EXTENT = require('../data/extent');
 const mat4 = require('@mapbox/gl-matrix').mat4;
 
@@ -30,6 +29,8 @@ function drawHillshade(painter: Painter, sourceCache: SourceCache, layer: Hillsh
         }
     }
 
+    context.viewport.set([0, 0, painter.width, painter.height]);
+    context.bindFramebuffer.set(null);
 }
 
 function setLight(program, painter, layer) {
@@ -57,7 +58,8 @@ function renderHillshade(painter, tile, layer) {
     // for scaling the magnitude of a points slope by its latitude
     const latRange = getTileLatRange(painter, tile.tileID);
     context.activeTexture.set(gl.TEXTURE0);
-    gl.bindTexture(gl.TEXTURE_2D, tile.texture.texture);
+
+    gl.bindTexture(gl.TEXTURE_2D, tile.texture.colorAttachment.get());
 
     gl.uniformMatrix4fv(program.uniforms.u_matrix, false, posMatrix);
     gl.uniform2fv(program.uniforms.u_latrange, latRange);
@@ -125,10 +127,14 @@ function prepareHillshade(painter, tile) {
 
         context.activeTexture.set(gl.TEXTURE0);
         if (!tile.texture) {
-            tile.texture = new RenderTexture(painter, tileSize, tileSize);
-        } else {
-            tile.texture.bindFbo();
+            const _texture = new Texture(context, {width: tileSize, height: tileSize, data: null}, gl.RGBA);
+            _texture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
+
+            tile.texture = context.createFramebuffer();
+            tile.texture.colorAttachment.set(_texture.texture);
         }
+
+        context.bindFramebuffer.set(tile.texture.framebuffer);
         context.viewport.set([0, 0, tileSize, tileSize]);
 
         const matrix = mat4.create();
@@ -149,8 +155,6 @@ function prepareHillshade(painter, tile) {
         vao.bind(context, program, buffer);
         gl.drawArrays(gl.TRIANGLE_STRIP, 0, buffer.length);
 
-        tile.texture.unbind();
-        context.viewport.set([0, 0, painter.width, painter.height]);
         tile.needsHillshadePrepare = false;
     }
 }
diff --git a/src/render/painter.js b/src/render/painter.js
index 38b651f97f7..0f2c4e2bfed 100644
--- a/src/render/painter.js
+++ b/src/render/painter.js
@@ -14,7 +14,7 @@ const CrossTileSymbolIndex = require('../symbol/cross_tile_symbol_index');
 const shaders = require('../shaders');
 const Program = require('./program');
 const Context = require('../gl/context');
-const RenderTexture = require('./render_texture');
+const Texture = require('./texture');
 const updateTileMasks = require('./tile_mask');
 const Color = require('../style-spec/util/color');
 
@@ -37,7 +37,6 @@ import type {OverscaledTileID} from '../source/tile_id';
 import type Style from '../style/style';
 import type StyleLayer from '../style/style_layer';
 import type LineAtlas from './line_atlas';
-import type Texture from './texture';
 import type ImageManager from './image_manager';
 import type GlyphManager from './glyph_manager';
 import type VertexBuffer from '../gl/vertex_buffer';
@@ -69,7 +68,6 @@ class Painter {
     width: number;
     height: number;
     depthRbo: WebGLRenderbuffer;
-    depthRboAttached: boolean;
     tileExtentBuffer: VertexBuffer;
     tileExtentVAO: VertexArrayObject;
     tileExtentPatternVAO: VertexArrayObject;
@@ -292,7 +290,7 @@ class Painter {
         this.imageManager = style.imageManager;
         this.glyphManager = style.glyphManager;
 
-        const context = this.context;
+        const gl = this.context.gl;
 
         for (const id in style.sourceCaches) {
             const sourceCache = this.style.sourceCaches[id];
@@ -351,19 +349,28 @@ class Painter {
 
                 this._setup3DRenderbuffer();
 
-                const renderTarget = layer.viewportFrame || new RenderTexture(this);
-                layer.viewportFrame = renderTarget;
-                renderTarget.bindWithDepth(this.depthRbo);
+                let renderTarget = layer.viewportFrame;
+                if (!renderTarget) {
+                    const texture = new Texture(this.context, {width: this.width, height: this.height, data: null}, gl.RGBA);
+                    texture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
+
+                    renderTarget = this.context.createFramebuffer();
+                    renderTarget.colorAttachment.set(texture.texture);
+                    layer.viewportFrame = renderTarget;
+                }
+
+                this.context.bindFramebuffer.set(renderTarget.framebuffer);
+                renderTarget.depthAttachment.set(this.depthRbo);
 
                 if (first) {
-                    context.clear({ depth: 1 });
+                    this.context.clear({ depth: 1 });
                     first = false;
                 }
 
                 this.renderLayer(this, (sourceCache: any), layer, coords);
-
-                renderTarget.unbind();
             }
+
+            this.context.bindFramebuffer.set(null);
         }
 
 
@@ -397,7 +404,7 @@ class Painter {
 
 
         // Clear buffers in preparation for drawing to the main framebuffer
-        context.clear({ color: Color.transparent, depth: 1 });
+        this.context.clear({ color: Color.transparent, depth: 1 });
 
         this.showOverdrawInspector(options.showOverdrawInspector);
 
@@ -477,19 +484,12 @@ class Painter {
         }
     }
 
-    _setup3DRenderbuffer() {
+    _setup3DRenderbuffer(): void {
         const context = this.context;
         // All of the 3D textures will use the same depth renderbuffer.
         if (!this.depthRbo) {
-            const gl = this.context.gl;
-            this.depthRbo = gl.createRenderbuffer();
-
-            context.bindRenderbuffer.set(this.depthRbo);
-            gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, this.width, this.height);
-            context.bindRenderbuffer.set(null);
+            this.depthRbo = context.createRenderbuffer(context.gl.DEPTH_COMPONENT16, this.width, this.height);
         }
-
-        this.depthRboAttached = true;
     }
 
     renderLayer(painter: Painter, sourceCache: SourceCache, layer: StyleLayer, coords: Array<OverscaledTileID>) {
diff --git a/src/render/render_texture.js b/src/render/render_texture.js
deleted file mode 100644
index 1ff7133fdc0..00000000000
--- a/src/render/render_texture.js
+++ /dev/null
@@ -1,61 +0,0 @@
-// @flow
-
-import type Context from '../gl/context';
-import type VertexBuffer from '../gl/vertex_buffer';
-import type VertexArrayObject from './vertex_array_object';
-
-import type Painter from './painter';
-
-class RenderTexture {
-    context: Context;
-    texture: WebGLTexture;
-    fbo: WebGLFramebuffer;
-    buffer: VertexBuffer;
-    vao: VertexArrayObject;
-    attachedRbo: ?WebGLRenderbuffer;
-
-    constructor(painter: Painter, height: ?number, width: ?number) {
-        const context = this.context = painter.context;
-        const gl = context.gl;
-
-        const texture = this.texture = gl.createTexture();
-        gl.bindTexture(gl.TEXTURE_2D, texture);
-        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
-        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
-        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
-        gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
-        gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, width || painter.width, height || painter.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
-
-        gl.bindTexture(gl.TEXTURE_2D, null);
-
-        const fbo = this.fbo = gl.createFramebuffer();
-        context.bindFramebuffer.set(fbo);
-        gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
-    }
-
-    bindFbo() {
-        const context = this.context;
-        const gl = context.gl;
-
-        gl.bindTexture(gl.TEXTURE_2D, null);
-        context.bindFramebuffer.set(this.fbo);
-        gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, this.texture, 0);
-
-    }
-
-    bindWithDepth(depthRbo: WebGLRenderbuffer) {
-        const context = this.context;
-        const gl = context.gl;
-        context.bindFramebuffer.set(this.fbo);
-        if (this.attachedRbo !== depthRbo) {
-            gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, depthRbo);
-            this.attachedRbo = depthRbo;
-        }
-    }
-
-    unbind() {
-        this.context.bindFramebuffer.set(null);
-    }
-}
-
-module.exports = RenderTexture;
diff --git a/src/render/texture.js b/src/render/texture.js
index d8542b7b52b..7c1eef5db96 100644
--- a/src/render/texture.js
+++ b/src/render/texture.js
@@ -18,10 +18,17 @@ export type TextureWrap =
     | $PropertyType<WebGLRenderingContext, 'CLAMP_TO_EDGE'>
     | $PropertyType<WebGLRenderingContext, 'MIRRORED_REPEAT'>;
 
+type EmptyImage = {
+    width: number,
+    height: number,
+    data: null
+}
+
 export type TextureImage =
     | RGBAImage
     | AlphaImage
-    | ImageTextureSource;
+    | ImageTextureSource
+    | EmptyImage;
 
 class Texture {
     context: Context;
diff --git a/src/style/style_layer.js b/src/style/style_layer.js
index 50f3137e948..b7a4ff65ac1 100644
--- a/src/style/style_layer.js
+++ b/src/style/style_layer.js
@@ -15,7 +15,7 @@ const {
 
 import type {Bucket} from '../data/bucket';
 import type Point from '@mapbox/point-geometry';
-import type RenderTexture from '../render/render_texture';
+import type Framebuffer from '../gl/framebuffer';
 import type {FeatureFilter} from '../style-spec/feature_filter';
 import type {TransitionParameters} from './properties';
 import type EvaluationParameters from './evaluation_parameters';
@@ -42,7 +42,7 @@ class StyleLayer extends Evented {
     _transitioningPaint: Transitioning<any>;
     +paint: mixed;
 
-    viewportFrame: ?RenderTexture;
+    viewportFrame: ?Framebuffer;
     _featureFilter: FeatureFilter;
 
     +queryRadius: (bucket: Bucket) => number;
diff --git a/src/style/style_layer/fill_extrusion_style_layer.js b/src/style/style_layer/fill_extrusion_style_layer.js
index f042aa4095e..112bda15fcc 100644
--- a/src/style/style_layer/fill_extrusion_style_layer.js
+++ b/src/style/style_layer/fill_extrusion_style_layer.js
@@ -52,9 +52,9 @@ class FillExtrusionStyleLayer extends StyleLayer {
 
     resize(gl: WebGLRenderingContext) {
         if (this.viewportFrame) {
-            const {texture, fbo} = this.viewportFrame;
-            gl.deleteTexture(texture);
-            gl.deleteFramebuffer(fbo);
+            const {colorAttachment, framebuffer} = this.viewportFrame;
+            gl.deleteTexture(colorAttachment.get());
+            gl.deleteFramebuffer(framebuffer);
             this.viewportFrame = null;
         }
     }
diff --git a/src/style/style_layer/heatmap_style_layer.js b/src/style/style_layer/heatmap_style_layer.js
index 2ea0fd5b83f..be9d887b7d5 100644
--- a/src/style/style_layer/heatmap_style_layer.js
+++ b/src/style/style_layer/heatmap_style_layer.js
@@ -12,12 +12,13 @@ const {
 } = require('../properties');
 
 import type Texture from '../../render/texture';
+import type Framebuffer from '../../gl/framebuffer';
 import type {PaintProps} from './heatmap_style_layer_properties';
 
 class HeatmapStyleLayer extends StyleLayer {
 
     heatmapTexture: ?WebGLTexture;
-    heatmapFbo: ?WebGLFramebuffer;
+    heatmapFbo: ?Framebuffer;
     colorRamp: RGBAImage;
     colorRampTexture: ?Texture;
 
@@ -66,7 +67,7 @@ class HeatmapStyleLayer extends StyleLayer {
             this.heatmapTexture = null;
         }
         if (this.heatmapFbo) {
-            gl.deleteFramebuffer(this.heatmapFbo);
+            gl.deleteFramebuffer(this.heatmapFbo.framebuffer);
             this.heatmapFbo = null;
         }
     }
diff --git a/src/util/window.js b/src/util/window.js
index 65862db169a..0fed6cfd0b3 100644
--- a/src/util/window.js
+++ b/src/util/window.js
@@ -57,6 +57,7 @@ function restore(): Window {
 
     window.ImageData = window.ImageData || function() { return false; };
     window.ImageBitmap = window.ImageBitmap || function() { return false; };
+    window.WebGLFramebuffer = window.WebGLFramebuffer || Object;
     util.extend(module.exports, window);
 
     return window;

From 6669b08310b5b209fad2585fefa7e2cbf05b7083 Mon Sep 17 00:00:00 2001
From: Lauren Budorick <lauren@mapbox.com>
Date: Mon, 4 Dec 2017 11:45:04 -0800
Subject: [PATCH 2/7] Tweak naming in draw_hillshade

---
 src/render/draw_hillshade.js | 14 +++++++-------
 src/source/tile.js           |  1 +
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/src/render/draw_hillshade.js b/src/render/draw_hillshade.js
index c356e3fe89a..ef466bc6ec4 100644
--- a/src/render/draw_hillshade.js
+++ b/src/render/draw_hillshade.js
@@ -59,7 +59,7 @@ function renderHillshade(painter, tile, layer) {
     const latRange = getTileLatRange(painter, tile.tileID);
     context.activeTexture.set(gl.TEXTURE0);
 
-    gl.bindTexture(gl.TEXTURE_2D, tile.texture.colorAttachment.get());
+    gl.bindTexture(gl.TEXTURE_2D, tile.fbo.colorAttachment.get());
 
     gl.uniformMatrix4fv(program.uniforms.u_matrix, false, posMatrix);
     gl.uniform2fv(program.uniforms.u_latrange, latRange);
@@ -126,15 +126,15 @@ function prepareHillshade(painter, tile) {
         }
 
         context.activeTexture.set(gl.TEXTURE0);
-        if (!tile.texture) {
-            const _texture = new Texture(context, {width: tileSize, height: tileSize, data: null}, gl.RGBA);
-            _texture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
+        if (!tile.fbo) {
+            const renderTexture = new Texture(context, {width: tileSize, height: tileSize, data: null}, gl.RGBA);
+            renderTexture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
 
-            tile.texture = context.createFramebuffer();
-            tile.texture.colorAttachment.set(_texture.texture);
+            tile.fbo = context.createFramebuffer();
+            tile.fbo.colorAttachment.set(renderTexture.texture);
         }
 
-        context.bindFramebuffer.set(tile.texture.framebuffer);
+        context.bindFramebuffer.set(tile.fbo.framebuffer);
         context.viewport.set([0, 0, tileSize, tileSize]);
 
         const matrix = mat4.create();
diff --git a/src/source/tile.js b/src/source/tile.js
index 345c5e72087..cedcdd433b9 100644
--- a/src/source/tile.js
+++ b/src/source/tile.js
@@ -86,6 +86,7 @@ class Tile {
     needsHillshadePrepare: ?boolean
     request: any;
     texture: any;
+    fbo: any;
     demTexture: ?Texture;
     refreshedUponExpiration: boolean;
     reloadCallback: any;

From b8fcd75f67c320c11f1971de968c0a1438c05347 Mon Sep 17 00:00:00 2001
From: Lauren Budorick <lauren@mapbox.com>
Date: Mon, 4 Dec 2017 17:29:33 -0800
Subject: [PATCH 3/7] Refactor all offscreen passes, move painter extensions
 into context, have framebuffers destroy their own attachments

---
 src/gl/context.js                             |  23 ++-
 src/gl/framebuffer.js                         |  21 ++-
 src/gl/value.js                               |  25 ++--
 src/render/draw_fill_extrusion.js             |  33 ++++-
 src/render/draw_heatmap.js                    | 135 +++++++++---------
 src/render/draw_hillshade.js                  |  19 +--
 src/render/painter.js                         | 125 +++++-----------
 src/source/raster_tile_source.js              |   4 +-
 src/source/tile.js                            |   5 +-
 src/style/style_layer.js                      |   4 +-
 .../style_layer/fill_extrusion_style_layer.js |   8 +-
 src/style/style_layer/heatmap_style_layer.js  |  13 +-
 .../style_layer/hillshade_style_layer.js      |   4 +
 13 files changed, 221 insertions(+), 198 deletions(-)

diff --git a/src/gl/context.js b/src/gl/context.js
index 876d8a4ece1..38d6515bd25 100644
--- a/src/gl/context.js
+++ b/src/gl/context.js
@@ -88,6 +88,10 @@ class Context {
     pixelStoreUnpack: State<number>;
     pixelStoreUnpackPremultiplyAlpha: State<boolean>;
 
+    extTextureFilterAnisotropic: any;
+    extTextureFilterAnisotropicMax: any;
+    extTextureHalfFloat: any;
+
     constructor(gl: WebGLRenderingContext) {
         this.gl = gl;
         this.extVertexArrayObject = this.gl.getExtension('OES_vertex_array_object');
@@ -119,6 +123,21 @@ class Context {
         this.bindVertexArrayOES = this.extVertexArrayObject && new State(new BindVertexArrayOES(this));
         this.pixelStoreUnpack = new State(new PixelStoreUnpack(this));
         this.pixelStoreUnpackPremultiplyAlpha = new State(new PixelStoreUnpackPremultiplyAlpha(this));
+
+        this.extTextureFilterAnisotropic = (
+            gl.getExtension('EXT_texture_filter_anisotropic') ||
+            gl.getExtension('MOZ_EXT_texture_filter_anisotropic') ||
+            gl.getExtension('WEBKIT_EXT_texture_filter_anisotropic')
+        );
+        if (this.extTextureFilterAnisotropic) {
+            this.extTextureFilterAnisotropicMax = gl.getParameter(this.extTextureFilterAnisotropic.MAX_TEXTURE_MAX_ANISOTROPY_EXT);
+        }
+
+        this.extTextureHalfFloat = gl.getExtension('OES_texture_half_float');
+        if (this.extTextureHalfFloat) {
+            gl.getExtension('OES_texture_half_float_linear');
+        }
+
     }
 
     createIndexBuffer(array: TriangleIndexArray | LineIndexArray, dynamicDraw?: boolean) {
@@ -140,8 +159,8 @@ class Context {
         return rbo;
     }
 
-    createFramebuffer() {
-        return new Framebuffer(this);
+    createFramebuffer(width: number, height: number) {
+        return new Framebuffer(this, width, height);
     }
 
     clear({color, depth}: ClearArgs) {
diff --git a/src/gl/framebuffer.js b/src/gl/framebuffer.js
index 93941c45a2a..7ed0b36c156 100644
--- a/src/gl/framebuffer.js
+++ b/src/gl/framebuffer.js
@@ -6,18 +6,37 @@ import type Context from './context';
 
 class Framebuffer {
     context: Context;
+    width: number;
+    height: number;
     framebuffer: WebGLFramebuffer;
     colorAttachment: State<?WebGLTexture>;
     depthAttachment: State<?WebGLRenderbuffer>;
 
-    constructor(context: Context) {
+    constructor(context: Context, width: number, height: number) {
         this.context = context;
+        this.width = width;
+        this.height = height;
         const gl = context.gl;
         const fbo = this.framebuffer = gl.createFramebuffer();
 
         this.colorAttachment = new State(new ColorAttachment(context, fbo));
         this.depthAttachment = new State(new DepthAttachment(context, fbo));
     }
+
+    destroy() {
+        const gl = this.context.gl;
+
+        const texture = this.colorAttachment.get();
+        if (texture) gl.deleteTexture(texture);
+
+        const renderbuffer = this.depthAttachment.get();
+        if (renderbuffer) gl.deleteRenderbuffer(renderbuffer);
+
+        gl.deleteFramebuffer(this.framebuffer);
+
+        // TODO we could actually preserve framebuffer on resize since it
+        // has no inherent size-dependent storage, and just destroy attachments...
+    }
 }
 
 module.exports = Framebuffer;
diff --git a/src/gl/value.js b/src/gl/value.js
index 1f6751b8ea7..f3066a249d3 100644
--- a/src/gl/value.js
+++ b/src/gl/value.js
@@ -1,9 +1,7 @@
 // @flow
-const assert = require('assert');
 
 const Color = require('../style-spec/util/color');
 const util = require('../util/util');
-const window = require('../util/window');
 
 import type Context from './context';
 import type {
@@ -26,13 +24,9 @@ export interface Value<T> {
 
 class ContextValue {
     context: Context;
-    parent: ?any;
 
-    constructor(context: Context, parent: ?any) {
+    constructor(context: Context) {
         this.context = context;
-        if (parent) {
-            this.parent = parent;
-        }
     }
 
     static equal(a, b): boolean {
@@ -332,13 +326,20 @@ class PixelStoreUnpackPremultiplyAlpha extends ContextValue implements Value<boo
 /**
  * Framebuffer values
  */
+class FramebufferValue extends ContextValue {
+    context: Context;
+    parent: WebGLFramebuffer;
 
-class ColorAttachment extends ContextValue implements Value<?WebGLTexture> {
+    constructor(context: Context, parent: WebGLFramebuffer) {
+        super(context);
+        this.parent = parent;
+    }
+}
+
+class ColorAttachment extends FramebufferValue implements Value<?WebGLTexture> {
     static default() { return null; }
 
     set(v: ?WebGLTexture): void {
-        assert(this.parent && this.parent instanceof window.WebGLFramebuffer);
-
         const gl = this.context.gl;
         this.context.bindFramebuffer.set(this.parent);
         // note: it's possible to attach a renderbuffer to the color
@@ -351,12 +352,10 @@ class ColorAttachment extends ContextValue implements Value<?WebGLTexture> {
     }
 }
 
-class DepthAttachment extends ContextValue implements Value<?WebGLRenderbuffer> {
+class DepthAttachment extends FramebufferValue implements Value<?WebGLRenderbuffer> {
     static default() { return null; }
 
     set(v: ?WebGLRenderbuffer): void {
-        assert(this.parent && this.parent instanceof window.WebGLFramebuffer);
-
         const gl = this.context.gl;
         this.context.bindFramebuffer.set(this.parent);
         // note: it's possible to attach a texture to the depth attachment
diff --git a/src/render/draw_fill_extrusion.js b/src/render/draw_fill_extrusion.js
index 0dedaced459..ff762720b44 100644
--- a/src/render/draw_fill_extrusion.js
+++ b/src/render/draw_fill_extrusion.js
@@ -2,6 +2,7 @@
 
 const glMatrix = require('@mapbox/gl-matrix');
 const pattern = require('./pattern');
+const Texture = require('./texture');
 const Color = require('../style-spec/util/color');
 const mat3 = glMatrix.mat3;
 const mat4 = glMatrix.mat4;
@@ -20,9 +21,11 @@ function draw(painter: Painter, source: SourceCache, layer: FillExtrusionStyleLa
         return;
     }
 
-    if (painter.renderPass === '3d') {
+    if (painter.renderPass === 'offscreen') {
         const context = painter.context;
 
+        setupFramebuffer(painter, layer);
+
         context.stencilTest.set(false);
         context.depthTest.set(true);
 
@@ -37,6 +40,34 @@ function draw(painter: Painter, source: SourceCache, layer: FillExtrusionStyleLa
     }
 }
 
+function setupFramebuffer(painter, layer) {
+    const context = painter.context;
+    const gl = context.gl;
+
+    let renderTarget = layer.viewportFrame;
+
+    if (painter.depthRboNeedsClear) {
+        painter.setupOffscreenDepthRenderbuffer();
+    }
+
+    if (!renderTarget) {
+        const texture = new Texture(context, {width: painter.width, height: painter.height, data: null}, gl.RGBA);
+        texture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
+
+        renderTarget = layer.viewportFrame = context.createFramebuffer(painter.width, painter.height);
+        renderTarget.colorAttachment.set(texture.texture);
+    }
+
+    context.bindFramebuffer.set(renderTarget.framebuffer);
+    renderTarget.depthAttachment.set(painter.depthRbo);
+
+    if (painter.depthRboNeedsClear) {
+        context.clear({ depth: 1 });
+        painter.depthRboNeedsClear = false;
+    }
+
+}
+
 function drawExtrusionTexture(painter, layer) {
     const renderedTexture = layer.viewportFrame;
     if (!renderedTexture) return;
diff --git a/src/render/draw_heatmap.js b/src/render/draw_heatmap.js
index 537d3339480..054b7d6ae2c 100644
--- a/src/render/draw_heatmap.js
+++ b/src/render/draw_heatmap.js
@@ -14,141 +14,148 @@ import type {OverscaledTileID} from '../source/tile_id';
 module.exports = drawHeatmap;
 
 function drawHeatmap(painter: Painter, sourceCache: SourceCache, layer: HeatmapStyleLayer, coords: Array<OverscaledTileID>) {
-    if (painter.isOpaquePass) return;
     if (layer.paint.get('heatmap-opacity') === 0) {
         return;
     }
 
-    const context = painter.context;
-    const gl = context.gl;
+    if (painter.renderPass === 'offscreen') {
+        const context = painter.context;
+        const gl = context.gl;
 
-    painter.setDepthSublayer(0);
-    context.depthMask.set(false);
+        painter.setDepthSublayer(0);
+        context.depthMask.set(false);
 
-    // Allow kernels to be drawn across boundaries, so that
-    // large kernels are not clipped to tiles
-    context.stencilTest.set(false);
+        // Allow kernels to be drawn across boundaries, so that
+        // large kernels are not clipped to tiles
+        context.stencilTest.set(false);
 
-    renderToTexture(context, painter, layer);
+        bindFramebuffer(context, painter, layer);
 
-    context.clear({ color: Color.transparent });
+        context.clear({ color: Color.transparent });
 
-    // Turn on additive blending for kernels, which is a key aspect of kernel density estimation formula
-    context.blendFunc.set([gl.ONE, gl.ONE]);
+        // Turn on additive blending for kernels, which is a key aspect of kernel density estimation formula
+        context.blendFunc.set([gl.ONE, gl.ONE]);
 
-    for (let i = 0; i < coords.length; i++) {
-        const coord = coords[i];
+        for (let i = 0; i < coords.length; i++) {
+            const coord = coords[i];
 
-        // Skip tiles that have uncovered parents to avoid flickering; we don't need
-        // to use complex tile masking here because the change between zoom levels is subtle,
-        // so it's fine to simply render the parent until all its 4 children are loaded
-        if (sourceCache.hasRenderableParent(coord)) continue;
+            // Skip tiles that have uncovered parents to avoid flickering; we don't need
+            // to use complex tile masking here because the change between zoom levels is subtle,
+            // so it's fine to simply render the parent until all its 4 children are loaded
+            if (sourceCache.hasRenderableParent(coord)) continue;
 
-        const tile = sourceCache.getTile(coord);
-        const bucket: ?HeatmapBucket = (tile.getBucket(layer): any);
-        if (!bucket) continue;
+            const tile = sourceCache.getTile(coord);
+            const bucket: ?HeatmapBucket = (tile.getBucket(layer): any);
+            if (!bucket) continue;
 
-        const programConfiguration = bucket.programConfigurations.get(layer.id);
-        const program = painter.useProgram('heatmap', programConfiguration);
-        const {zoom} = painter.transform;
-        programConfiguration.setUniforms(painter.context, program, layer.paint, {zoom});
-        gl.uniform1f(program.uniforms.u_radius, layer.paint.get('heatmap-radius'));
+            const programConfiguration = bucket.programConfigurations.get(layer.id);
+            const program = painter.useProgram('heatmap', programConfiguration);
+            const {zoom} = painter.transform;
+            programConfiguration.setUniforms(painter.context, program, layer.paint, {zoom});
+            gl.uniform1f(program.uniforms.u_radius, layer.paint.get('heatmap-radius'));
 
-        gl.uniform1f(program.uniforms.u_extrude_scale, pixelsToTileUnits(tile, 1, zoom));
+            gl.uniform1f(program.uniforms.u_extrude_scale, pixelsToTileUnits(tile, 1, zoom));
 
-        gl.uniform1f(program.uniforms.u_intensity, layer.paint.get('heatmap-intensity'));
-        gl.uniformMatrix4fv(program.uniforms.u_matrix, false, coord.posMatrix);
+            gl.uniform1f(program.uniforms.u_intensity, layer.paint.get('heatmap-intensity'));
+            gl.uniformMatrix4fv(program.uniforms.u_matrix, false, coord.posMatrix);
 
-        program.draw(
-            context,
-            gl.TRIANGLES,
-            layer.id,
-            bucket.layoutVertexBuffer,
-            bucket.indexBuffer,
-            bucket.segments,
-            programConfiguration);
-    }
+            program.draw(
+                context,
+                gl.TRIANGLES,
+                layer.id,
+                bucket.layoutVertexBuffer,
+                bucket.indexBuffer,
+                bucket.segments,
+                programConfiguration);
+        }
 
-    renderTextureToMap(context, painter, layer);
+        context.viewport.set([0, 0, painter.width, painter.height]);
+        context.blendFunc.set(painter._showOverdrawInspector ? [gl.CONSTANT_COLOR, gl.ONE] : [gl.ONE, gl.ONE_MINUS_SRC_ALPHA]);
+
+    } else if (painter.renderPass === 'translucent') {
+        renderTextureToMap(painter, layer);
+    }
 }
 
-function renderToTexture(context, painter, layer) {
+function bindFramebuffer(context, painter, layer) {
     const gl = context.gl;
     context.activeTexture.set(gl.TEXTURE1);
 
     // Use a 4x downscaled screen texture for better performance
     context.viewport.set([0, 0, painter.width / 4, painter.height / 4]);
 
-    let texture = layer.heatmapTexture;
     let fbo = layer.heatmapFbo;
 
-    if (!texture || !fbo) {
-        texture = layer.heatmapTexture = gl.createTexture();
+    if (!fbo) {
+        const texture = gl.createTexture();
         gl.bindTexture(gl.TEXTURE_2D, texture);
         gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
         gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
         gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
         gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
 
-        fbo = layer.heatmapFbo = context.createFramebuffer();
+        fbo = layer.heatmapFbo = context.createFramebuffer(painter.width / 4, painter.height / 4);
 
-        bindTextureFramebuffer(context, painter, texture, fbo);
+        bindTextureToFramebuffer(context, painter, texture, fbo);
 
     } else {
-        gl.bindTexture(gl.TEXTURE_2D, texture);
+        gl.bindTexture(gl.TEXTURE_2D, fbo.colorAttachment.get());
         context.bindFramebuffer.set(fbo.framebuffer);
     }
 }
 
-function bindTextureFramebuffer(context, painter, texture, fbo) {
+function bindTextureToFramebuffer(context, painter, texture, fbo) {
     const gl = context.gl;
     // Use the higher precision half-float texture where available (producing much smoother looking heatmaps);
     gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, painter.width / 4, painter.height / 4, 0, gl.RGBA,
-        painter.extTextureHalfFloat ? painter.extTextureHalfFloat.HALF_FLOAT_OES : gl.UNSIGNED_BYTE, null);
+        context.extTextureHalfFloat ? context.extTextureHalfFloat.HALF_FLOAT_OES : gl.UNSIGNED_BYTE, null);
 
     fbo.colorAttachment.set(texture);
 
     // If using half-float texture as a render target is not supported, fall back to a low precision texture
-    if (painter.extTextureHalfFloat && gl.checkFramebufferStatus(gl.FRAMEBUFFER) !== gl.FRAMEBUFFER_COMPLETE) {
-        painter.extTextureHalfFloat = null;
+    if (context.extTextureHalfFloat && gl.checkFramebufferStatus(gl.FRAMEBUFFER) !== gl.FRAMEBUFFER_COMPLETE) {
+        context.extTextureHalfFloat = null;
         fbo.colorAttachment.setDirty();
-        bindTextureFramebuffer(context, painter, texture, fbo);
+        bindTextureToFramebuffer(context, painter, texture, fbo);
     }
 }
 
-function renderTextureToMap(context, painter, layer) {
+function renderTextureToMap(painter, layer) {
+    const context = painter.context;
     const gl = context.gl;
-    context.bindFramebuffer.set(null);
 
-    context.activeTexture.set(gl.TEXTURE2);
+
+    // Here we bind two different textures from which we'll sample in drawing
+    // heatmaps: the kernel texture, prepared in the offscreen pass, and a
+    // color ramp texture.
+    const fbo = layer.heatmapFbo;
+    if (!fbo) return;
+    context.activeTexture.set(gl.TEXTURE0);
+    gl.bindTexture(gl.TEXTURE_2D, fbo.colorAttachment.get());
+
+    context.activeTexture.set(gl.TEXTURE1);
     let colorRampTexture = layer.colorRampTexture;
     if (!colorRampTexture) {
         colorRampTexture = layer.colorRampTexture = new Texture(context, layer.colorRamp, gl.RGBA);
     }
     colorRampTexture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
 
-    context.blendFunc.set(painter._showOverdrawInspector ? [gl.CONSTANT_COLOR, gl.ONE] : [gl.ONE, gl.ONE_MINUS_SRC_ALPHA]);
+    context.depthTest.set(false);
 
     const program = painter.useProgram('heatmapTexture');
 
-    context.viewport.set([0, 0, painter.width, painter.height]);
-
-    context.activeTexture.set(gl.TEXTURE0);
-    gl.bindTexture(gl.TEXTURE_2D, layer.heatmapTexture);
-
     const opacity = layer.paint.get('heatmap-opacity');
     gl.uniform1f(program.uniforms.u_opacity, opacity);
-    gl.uniform1i(program.uniforms.u_image, 1);
-    gl.uniform1i(program.uniforms.u_color_ramp, 2);
+    gl.uniform1i(program.uniforms.u_image, 0);
+    gl.uniform1i(program.uniforms.u_color_ramp, 1);
 
     const matrix = mat4.create();
     mat4.ortho(matrix, 0, painter.width, painter.height, 0, 0, 1);
     gl.uniformMatrix4fv(program.uniforms.u_matrix, false, matrix);
 
-    context.depthTest.set(false);
-
     gl.uniform2f(program.uniforms.u_world, gl.drawingBufferWidth, gl.drawingBufferHeight);
 
+
     painter.viewportVAO.bind(painter.context, program, painter.viewportBuffer);
     gl.drawArrays(gl.TRIANGLE_STRIP, 0, 4);
 
diff --git a/src/render/draw_hillshade.js b/src/render/draw_hillshade.js
index ef466bc6ec4..2646a537809 100644
--- a/src/render/draw_hillshade.js
+++ b/src/render/draw_hillshade.js
@@ -12,7 +12,7 @@ import type {OverscaledTileID} from '../source/tile_id';
 module.exports = drawHillshade;
 
 function drawHillshade(painter: Painter, sourceCache: SourceCache, layer: HillshadeStyleLayer, tileIDs: Array<OverscaledTileID>) {
-    if (painter.renderPass !== 'hillshadeprepare' && painter.renderPass !== 'translucent') return;
+    if (painter.renderPass !== 'offscreen' && painter.renderPass !== 'translucent') return;
 
     const context = painter.context;
 
@@ -21,7 +21,7 @@ function drawHillshade(painter: Painter, sourceCache: SourceCache, layer: Hillsh
 
     for (const tileID of tileIDs) {
         const tile = sourceCache.getTile(tileID);
-        if (tile.needsHillshadePrepare && painter.renderPass === 'hillshadeprepare') {
+        if (tile.needsHillshadePrepare && painter.renderPass === 'offscreen') {
             prepareHillshade(painter, tile);
             continue;
         } else if (painter.renderPass === 'translucent') {
@@ -30,7 +30,6 @@ function drawHillshade(painter: Painter, sourceCache: SourceCache, layer: Hillsh
     }
 
     context.viewport.set([0, 0, painter.width, painter.height]);
-    context.bindFramebuffer.set(null);
 }
 
 function setLight(program, painter, layer) {
@@ -51,6 +50,8 @@ function getTileLatRange(painter, tileID: OverscaledTileID) {
 function renderHillshade(painter, tile, layer) {
     const context = painter.context;
     const gl = context.gl;
+    const fbo = tile.fbo;
+    if (!fbo) return;
 
     const program = painter.useProgram('hillshade');
     const posMatrix = painter.transform.calculatePosMatrix(tile.tileID.toUnwrapped());
@@ -59,7 +60,7 @@ function renderHillshade(painter, tile, layer) {
     const latRange = getTileLatRange(painter, tile.tileID);
     context.activeTexture.set(gl.TEXTURE0);
 
-    gl.bindTexture(gl.TEXTURE_2D, tile.fbo.colorAttachment.get());
+    gl.bindTexture(gl.TEXTURE_2D, fbo.colorAttachment.get());
 
     gl.uniformMatrix4fv(program.uniforms.u_matrix, false, posMatrix);
     gl.uniform2fv(program.uniforms.u_latrange, latRange);
@@ -126,15 +127,17 @@ function prepareHillshade(painter, tile) {
         }
 
         context.activeTexture.set(gl.TEXTURE0);
-        if (!tile.fbo) {
+        let fbo = tile.fbo;
+
+        if (!fbo) {
             const renderTexture = new Texture(context, {width: tileSize, height: tileSize, data: null}, gl.RGBA);
             renderTexture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
 
-            tile.fbo = context.createFramebuffer();
-            tile.fbo.colorAttachment.set(renderTexture.texture);
+            fbo = tile.fbo = context.createFramebuffer(tileSize, tileSize);
+            fbo.colorAttachment.set(renderTexture.texture);
         }
 
-        context.bindFramebuffer.set(tile.fbo.framebuffer);
+        context.bindFramebuffer.set(fbo.framebuffer);
         context.viewport.set([0, 0, tileSize, tileSize]);
 
         const matrix = mat4.create();
diff --git a/src/render/painter.js b/src/render/painter.js
index 0f2c4e2bfed..af29c8f5837 100644
--- a/src/render/painter.js
+++ b/src/render/painter.js
@@ -40,8 +40,9 @@ import type LineAtlas from './line_atlas';
 import type ImageManager from './image_manager';
 import type GlyphManager from './glyph_manager';
 import type VertexBuffer from '../gl/vertex_buffer';
+import type Framebuffer from '../gl/framebuffer';
 
-export type RenderPass = '3d' | 'hillshadeprepare' | 'opaque' | 'translucent';
+export type RenderPass = 'offscreen' | 'opaque' | 'translucent';
 
 type PainterOptions = {
     showOverdrawInspector: boolean,
@@ -61,6 +62,7 @@ class Painter {
     context: Context;
     transform: Transform;
     _tileTextures: { [number]: Array<Texture> };
+    _tileFramebuffers: { [number]: Array<Framebuffer> };
     numSublayers: number;
     depthEpsilon: number;
     lineWidthRange: [number, number];
@@ -68,6 +70,7 @@ class Painter {
     width: number;
     height: number;
     depthRbo: WebGLRenderbuffer;
+    depthRboNeedsClear: boolean;
     tileExtentBuffer: VertexBuffer;
     tileExtentVAO: VertexArrayObject;
     tileExtentPatternVAO: VertexArrayObject;
@@ -77,9 +80,6 @@ class Painter {
     rasterBoundsVAO: VertexArrayObject;
     viewportBuffer: VertexBuffer;
     viewportVAO: VertexArrayObject;
-    extTextureFilterAnisotropic: any;
-    extTextureFilterAnisotropicMax: any;
-    extTextureHalfFloat: any;
     _tileClippingMaskIDs: { [number]: number };
     style: Style;
     options: PainterOptions;
@@ -99,6 +99,7 @@ class Painter {
         this.context = new Context(gl);
         this.transform = transform;
         this._tileTextures = {};
+        this._tileFramebuffers = {};
 
         this.setup();
 
@@ -107,6 +108,8 @@ class Painter {
         this.numSublayers = SourceCache.maxUnderzooming + SourceCache.maxOverzooming + 1;
         this.depthEpsilon = 1 / Math.pow(2, 16);
 
+        this.depthRboNeedsClear = true;
+
         this.lineWidthRange = gl.getParameter(gl.ALIASED_LINE_WIDTH_RANGE);
 
         this.emptyProgramConfiguration = new ProgramConfiguration();
@@ -127,7 +130,7 @@ class Painter {
 
         if (this.style) {
             for (const layerId of this.style._order) {
-                this.style._layers[layerId].resize(gl);
+                this.style._layers[layerId].resize();
             }
         }
 
@@ -186,20 +189,6 @@ class Painter {
         viewportArray.emplaceBack(1, 1);
         this.viewportBuffer = context.createVertexBuffer(viewportArray);
         this.viewportVAO = new VertexArrayObject();
-
-        this.extTextureFilterAnisotropic = (
-            gl.getExtension('EXT_texture_filter_anisotropic') ||
-            gl.getExtension('MOZ_EXT_texture_filter_anisotropic') ||
-            gl.getExtension('WEBKIT_EXT_texture_filter_anisotropic')
-        );
-        if (this.extTextureFilterAnisotropic) {
-            this.extTextureFilterAnisotropicMax = gl.getParameter(this.extTextureFilterAnisotropic.MAX_TEXTURE_MAX_ANISOTROPY_EXT);
-        }
-
-        this.extTextureHalfFloat = gl.getExtension('OES_texture_half_float');
-        if (this.extTextureHalfFloat) {
-            gl.getExtension('OES_texture_half_float_linear');
-        }
     }
 
     /*
@@ -290,8 +279,6 @@ class Painter {
         this.imageManager = style.imageManager;
         this.glyphManager = style.glyphManager;
 
-        const gl = this.context.gl;
-
         for (const id in style.sourceCaches) {
             const sourceCache = this.style.sourceCaches[id];
             if (sourceCache.used) {
@@ -309,100 +296,41 @@ class Painter {
             updateTileMasks(visibleTiles, this.context);
         }
 
-        // 3D pass
-        // We first create a renderbuffer that we'll use to preserve depth
-        // results across 3D layers, then render each 3D layer to its own
-        // framebuffer/texture, which we'll use later in the translucent pass
-        // to render to the main framebuffer. By doing this before we render to
-        // the main framebuffer we won't have to do an expensive framebuffer
-        // restore mid-render pass.
-        // The most important distinction of the 3D pass is that we use the
-        // depth buffer in an entirely different way (to represent 3D space)
-        // than we do in the 2D pass (to preserve layer order).
-        this.renderPass = '3d';
+        // Offscreen pass
+        // We first do all rendering that requires rendering to a separate
+        // framebuffer, and then save those for rendering back to the map
+        // later: in doing this we avoid doing expensive framebuffer restores.
+        this.renderPass = 'offscreen';
         {
-            // We'll wait and only attach the depth renderbuffer if we think we're
-            // rendering something.
-            let first = true;
-
             let sourceCache;
             let coords = [];
+            this.depthRboNeedsClear = true;
 
             for (let i = 0; i < layerIds.length; i++) {
                 const layer = this.style._layers[layerIds[i]];
 
-                if (!layer.has3DPass() || layer.isHidden(this.transform.zoom)) continue;
+                if (!layer.hasOffscreenPass() || layer.isHidden(this.transform.zoom)) continue;
 
                 if (layer.source !== (sourceCache && sourceCache.id)) {
                     sourceCache = this.style.sourceCaches[layer.source];
                     coords = [];
 
                     if (sourceCache) {
-                        this.clearStencil();
                         coords = sourceCache.getVisibleCoordinates();
+                        coords.reverse();
                     }
-
-                    coords.reverse();
                 }
 
                 if (!coords.length) continue;
 
-                this._setup3DRenderbuffer();
-
-                let renderTarget = layer.viewportFrame;
-                if (!renderTarget) {
-                    const texture = new Texture(this.context, {width: this.width, height: this.height, data: null}, gl.RGBA);
-                    texture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE);
-
-                    renderTarget = this.context.createFramebuffer();
-                    renderTarget.colorAttachment.set(texture.texture);
-                    layer.viewportFrame = renderTarget;
-                }
-
-                this.context.bindFramebuffer.set(renderTarget.framebuffer);
-                renderTarget.depthAttachment.set(this.depthRbo);
-
-                if (first) {
-                    this.context.clear({ depth: 1 });
-                    first = false;
-                }
-
                 this.renderLayer(this, (sourceCache: any), layer, coords);
             }
 
+            // Rebind the main framebuffer now that all offscreen layers
+            // have been rendered:
             this.context.bindFramebuffer.set(null);
         }
 
-
-
-        this.renderPass = 'hillshadeprepare';
-
-        {
-            let sourceCache;
-            let coords = [];
-
-            for (let i = 0; i < layerIds.length; i++) {
-                const layer = this.style._layers[layerIds[i]];
-
-                if (layer.type !== 'hillshade' || layer.isHidden(this.transform.zoom)) continue;
-
-                if (layer.source !== (sourceCache && sourceCache.id)) {
-                    sourceCache = this.style.sourceCaches[layer.source];
-                    coords = [];
-
-                    if (sourceCache) {
-                        this.clearStencil();
-                        coords = sourceCache.getVisibleCoordinates();
-                    }
-
-                    coords.reverse();
-                }
-
-                this.renderLayer(this, (sourceCache: any), layer, coords);
-            }
-        }
-
-
         // Clear buffers in preparation for drawing to the main framebuffer
         this.context.clear({ color: Color.transparent, depth: 1 });
 
@@ -484,7 +412,7 @@ class Painter {
         }
     }
 
-    _setup3DRenderbuffer(): void {
+    setupOffscreenDepthRenderbuffer(): void {
         const context = this.context;
         // All of the 3D textures will use the same depth renderbuffer.
         if (!this.depthRbo) {
@@ -552,6 +480,21 @@ class Painter {
         return textures && textures.length > 0 ? textures.pop() : null;
     }
 
+    saveTileFramebuffer(fbo: Framebuffer) {
+        const framebuffers = this._tileFramebuffers[fbo.width];
+
+        if (!framebuffers) {
+            this._tileFramebuffers[fbo.width] = [fbo];
+        } else {
+            framebuffers.push(fbo);
+        }
+    }
+
+    getTileFramebuffer(size: number) {
+        const framebuffers = this._tileFramebuffers[size];
+        return framebuffers && framebuffers.length > 0 ? framebuffers.pop() : null;
+    }
+
     lineWidth(width: number) {
         this.context.lineWidth.set(util.clamp(width, this.lineWidthRange[0], this.lineWidthRange[1]));
     }
diff --git a/src/source/raster_tile_source.js b/src/source/raster_tile_source.js
index e2e1c0a5cae..c2764fcc068 100644
--- a/src/source/raster_tile_source.js
+++ b/src/source/raster_tile_source.js
@@ -109,8 +109,8 @@ class RasterTileSource extends Evented implements Source {
                     tile.texture = new Texture(context, img, gl.RGBA);
                     tile.texture.bind(gl.LINEAR, gl.CLAMP_TO_EDGE, gl.LINEAR_MIPMAP_NEAREST);
 
-                    if (this.map.painter.extTextureFilterAnisotropic) {
-                        gl.texParameterf(gl.TEXTURE_2D, this.map.painter.extTextureFilterAnisotropic.TEXTURE_MAX_ANISOTROPY_EXT, this.map.painter.extTextureFilterAnisotropicMax);
+                    if (context.extTextureFilterAnisotropic) {
+                        gl.texParameterf(gl.TEXTURE_2D, context.extTextureFilterAnisotropic.TEXTURE_MAX_ANISOTROPY_EXT, context.extTextureFilterAnisotropicMax);
                     }
                 }
                 gl.generateMipmap(gl.TEXTURE_2D);
diff --git a/src/source/tile.js b/src/source/tile.js
index cedcdd433b9..06219620845 100644
--- a/src/source/tile.js
+++ b/src/source/tile.js
@@ -35,6 +35,7 @@ import type Context from '../gl/context';
 import type IndexBuffer from '../gl/index_buffer';
 import type VertexBuffer from '../gl/vertex_buffer';
 import type {OverscaledTileID} from './tile_id';
+import type Framebuffer from '../gl/framebuffer';
 
 export type TileState =
     | 'loading'   // Tile data is in the process of loading.
@@ -86,14 +87,14 @@ class Tile {
     needsHillshadePrepare: ?boolean
     request: any;
     texture: any;
-    fbo: any;
+    fbo: ?Framebuffer;
     demTexture: ?Texture;
     refreshedUponExpiration: boolean;
     reloadCallback: any;
     justReloaded: boolean;
 
     /**
-     * @param {OverscaledTileID} tileID 
+     * @param {OverscaledTileID} tileID
      * @param size
      */
     constructor(tileID: OverscaledTileID, size: number) {
diff --git a/src/style/style_layer.js b/src/style/style_layer.js
index b7a4ff65ac1..40367d8a59d 100644
--- a/src/style/style_layer.js
+++ b/src/style/style_layer.js
@@ -197,11 +197,11 @@ class StyleLayer extends Evented {
         }));
     }
 
-    has3DPass() {
+    hasOffscreenPass() {
         return false;
     }
 
-    resize(gl: WebGLRenderingContext) { // eslint-disable-line
+    resize() { // eslint-disable-line
         // noop
     }
 }
diff --git a/src/style/style_layer/fill_extrusion_style_layer.js b/src/style/style_layer/fill_extrusion_style_layer.js
index 112bda15fcc..5d37f516ecc 100644
--- a/src/style/style_layer/fill_extrusion_style_layer.js
+++ b/src/style/style_layer/fill_extrusion_style_layer.js
@@ -46,15 +46,13 @@ class FillExtrusionStyleLayer extends StyleLayer {
         return multiPolygonIntersectsMultiPolygon(translatedPolygon, geometry);
     }
 
-    has3DPass() {
+    hasOffscreenPass() {
         return this.paint.get('fill-extrusion-opacity') !== 0 && this.visibility !== 'none';
     }
 
-    resize(gl: WebGLRenderingContext) {
+    resize() {
         if (this.viewportFrame) {
-            const {colorAttachment, framebuffer} = this.viewportFrame;
-            gl.deleteTexture(colorAttachment.get());
-            gl.deleteFramebuffer(framebuffer);
+            this.viewportFrame.destroy();
             this.viewportFrame = null;
         }
     }
diff --git a/src/style/style_layer/heatmap_style_layer.js b/src/style/style_layer/heatmap_style_layer.js
index be9d887b7d5..57e3175b97b 100644
--- a/src/style/style_layer/heatmap_style_layer.js
+++ b/src/style/style_layer/heatmap_style_layer.js
@@ -17,7 +17,6 @@ import type {PaintProps} from './heatmap_style_layer_properties';
 
 class HeatmapStyleLayer extends StyleLayer {
 
-    heatmapTexture: ?WebGLTexture;
     heatmapFbo: ?Framebuffer;
     colorRamp: RGBAImage;
     colorRampTexture: ?Texture;
@@ -61,13 +60,9 @@ class HeatmapStyleLayer extends StyleLayer {
         this.colorRampTexture = null;
     }
 
-    resize(gl: WebGLRenderingContext) {
-        if (this.heatmapTexture) {
-            gl.deleteTexture(this.heatmapTexture);
-            this.heatmapTexture = null;
-        }
+    resize() {
         if (this.heatmapFbo) {
-            gl.deleteFramebuffer(this.heatmapFbo.framebuffer);
+            this.heatmapFbo.destroy();
             this.heatmapFbo = null;
         }
     }
@@ -79,6 +74,10 @@ class HeatmapStyleLayer extends StyleLayer {
     queryIntersectsFeature(): boolean  {
         return false;
     }
+
+    hasOffscreenPass() {
+        return this.paint.get('heatmap-opacity') !== 0 && this.visibility !== 'none';
+    }
 }
 
 module.exports = HeatmapStyleLayer;
diff --git a/src/style/style_layer/hillshade_style_layer.js b/src/style/style_layer/hillshade_style_layer.js
index d0920f30a96..1e159202aaa 100644
--- a/src/style/style_layer/hillshade_style_layer.js
+++ b/src/style/style_layer/hillshade_style_layer.js
@@ -19,6 +19,10 @@ class HillshadeStyleLayer extends StyleLayer {
     constructor(layer: LayerSpecification) {
         super(layer, properties);
     }
+
+    hasOffscreenPass() {
+        return this.paint.get('hillshade-exaggeration') !== 0 && this.visibility !== 'none';
+    }
 }
 
 module.exports = HillshadeStyleLayer;

From 98b9169073896e39e94a16fa7bdc3a3d3321f4ed Mon Sep 17 00:00:00 2001
From: Lauren Budorick <lauren@mapbox.com>
Date: Mon, 4 Dec 2017 17:48:13 -0800
Subject: [PATCH 4/7] Use tile framebuffer caching for hillshades

---
 src/render/draw_hillshade.js         | 3 ++-
 src/source/raster_dem_tile_source.js | 4 ++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/src/render/draw_hillshade.js b/src/render/draw_hillshade.js
index 2646a537809..58cc244168e 100644
--- a/src/render/draw_hillshade.js
+++ b/src/render/draw_hillshade.js
@@ -127,7 +127,8 @@ function prepareHillshade(painter, tile) {
         }
 
         context.activeTexture.set(gl.TEXTURE0);
-        let fbo = tile.fbo;
+
+        if (!tile.fbo) tile.fbo = painter.getTileFramebuffer(tile.tileSize);
 
         if (!fbo) {
             const renderTexture = new Texture(context, {width: tileSize, height: tileSize, data: null}, gl.RGBA);
diff --git a/src/source/raster_dem_tile_source.js b/src/source/raster_dem_tile_source.js
index 8e0ce4e7026..7d31c3ab836 100644
--- a/src/source/raster_dem_tile_source.js
+++ b/src/source/raster_dem_tile_source.js
@@ -116,6 +116,10 @@ class RasterDEMTileSource extends RasterTileSource implements Source {
 
     unloadTile(tile: Tile) {
         if (tile.demTexture) this.map.painter.saveTileTexture(tile.demTexture);
+        if (tile.fbo) {
+            this.map.painter.saveTileFramebuffer(tile.fbo);
+            tile.fbo = null;
+        }
         if (tile.dem) delete tile.dem;
         delete tile.neighboringTiles;
 

From a87018b774b49d73eca6c0240ef9fa1191a0b822 Mon Sep 17 00:00:00 2001
From: Lauren Budorick <lauren@mapbox.com>
Date: Tue, 5 Dec 2017 12:06:42 -0800
Subject: [PATCH 5/7] cleanups

---
 src/gl/framebuffer.js        | 3 ---
 src/render/draw_hillshade.js | 1 +
 2 files changed, 1 insertion(+), 3 deletions(-)

diff --git a/src/gl/framebuffer.js b/src/gl/framebuffer.js
index 7ed0b36c156..f63569c0843 100644
--- a/src/gl/framebuffer.js
+++ b/src/gl/framebuffer.js
@@ -33,9 +33,6 @@ class Framebuffer {
         if (renderbuffer) gl.deleteRenderbuffer(renderbuffer);
 
         gl.deleteFramebuffer(this.framebuffer);
-
-        // TODO we could actually preserve framebuffer on resize since it
-        // has no inherent size-dependent storage, and just destroy attachments...
     }
 }
 
diff --git a/src/render/draw_hillshade.js b/src/render/draw_hillshade.js
index 58cc244168e..2b2e562ee77 100644
--- a/src/render/draw_hillshade.js
+++ b/src/render/draw_hillshade.js
@@ -129,6 +129,7 @@ function prepareHillshade(painter, tile) {
         context.activeTexture.set(gl.TEXTURE0);
 
         if (!tile.fbo) tile.fbo = painter.getTileFramebuffer(tile.tileSize);
+        let fbo = tile.fbo;
 
         if (!fbo) {
             const renderTexture = new Texture(context, {width: tileSize, height: tileSize, data: null}, gl.RGBA);

From 6280f133c37a701fdd2ff78e1dbce67909ef1cb7 Mon Sep 17 00:00:00 2001
From: Lauren Budorick <lauren@mapbox.com>
Date: Tue, 5 Dec 2017 12:49:56 -0800
Subject: [PATCH 6/7] Update heatmap test

---
 .../heatmap-radius/antimeridian/expected.png  | Bin 10168 -> 10350 bytes
 1 file changed, 0 insertions(+), 0 deletions(-)

diff --git a/test/integration/render-tests/heatmap-radius/antimeridian/expected.png b/test/integration/render-tests/heatmap-radius/antimeridian/expected.png
index 3644f9211cf5ef80ec2db6cd0b0651e270170769..4f09bd69d72f8182364883624045888eb7bbff60 100644
GIT binary patch
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From 3a5a0aa833f003aa7039775ba0f22adf13ea2128 Mon Sep 17 00:00:00 2001
From: Lauren Budorick <lauren@mapbox.com>
Date: Wed, 6 Dec 2017 17:31:52 -0800
Subject: [PATCH 7/7] Address review comments

---
 src/render/draw_fill_extrusion.js              | 17 +++++++----------
 src/render/draw_hillshade.js                   |  1 -
 src/render/painter.js                          | 18 ------------------
 src/source/raster_dem_tile_source.js           |  4 ++--
 src/style/style_layer.js                       |  4 +---
 .../style_layer/fill_extrusion_style_layer.js  |  2 ++
 6 files changed, 12 insertions(+), 34 deletions(-)

diff --git a/src/render/draw_fill_extrusion.js b/src/render/draw_fill_extrusion.js
index ff762720b44..f52c02244f7 100644
--- a/src/render/draw_fill_extrusion.js
+++ b/src/render/draw_fill_extrusion.js
@@ -22,15 +22,7 @@ function draw(painter: Painter, source: SourceCache, layer: FillExtrusionStyleLa
     }
 
     if (painter.renderPass === 'offscreen') {
-        const context = painter.context;
-
-        setupFramebuffer(painter, layer);
-
-        context.stencilTest.set(false);
-        context.depthTest.set(true);
-
-        context.clear({ color: Color.transparent });
-        context.depthMask.set(true);
+        drawToExtrusionFramebuffer(painter, layer);
 
         for (let i = 0; i < coords.length; i++) {
             drawExtrusion(painter, source, layer, coords[i]);
@@ -40,7 +32,7 @@ function draw(painter: Painter, source: SourceCache, layer: FillExtrusionStyleLa
     }
 }
 
-function setupFramebuffer(painter, layer) {
+function drawToExtrusionFramebuffer(painter, layer) {
     const context = painter.context;
     const gl = context.gl;
 
@@ -66,6 +58,11 @@ function setupFramebuffer(painter, layer) {
         painter.depthRboNeedsClear = false;
     }
 
+    context.stencilTest.set(false);
+    context.depthTest.set(true);
+
+    context.clear({ color: Color.transparent });
+    context.depthMask.set(true);
 }
 
 function drawExtrusionTexture(painter, layer) {
diff --git a/src/render/draw_hillshade.js b/src/render/draw_hillshade.js
index 2b2e562ee77..170fe45bdf4 100644
--- a/src/render/draw_hillshade.js
+++ b/src/render/draw_hillshade.js
@@ -128,7 +128,6 @@ function prepareHillshade(painter, tile) {
 
         context.activeTexture.set(gl.TEXTURE0);
 
-        if (!tile.fbo) tile.fbo = painter.getTileFramebuffer(tile.tileSize);
         let fbo = tile.fbo;
 
         if (!fbo) {
diff --git a/src/render/painter.js b/src/render/painter.js
index af29c8f5837..ea06cc2d1ae 100644
--- a/src/render/painter.js
+++ b/src/render/painter.js
@@ -40,7 +40,6 @@ import type LineAtlas from './line_atlas';
 import type ImageManager from './image_manager';
 import type GlyphManager from './glyph_manager';
 import type VertexBuffer from '../gl/vertex_buffer';
-import type Framebuffer from '../gl/framebuffer';
 
 export type RenderPass = 'offscreen' | 'opaque' | 'translucent';
 
@@ -62,7 +61,6 @@ class Painter {
     context: Context;
     transform: Transform;
     _tileTextures: { [number]: Array<Texture> };
-    _tileFramebuffers: { [number]: Array<Framebuffer> };
     numSublayers: number;
     depthEpsilon: number;
     lineWidthRange: [number, number];
@@ -99,7 +97,6 @@ class Painter {
         this.context = new Context(gl);
         this.transform = transform;
         this._tileTextures = {};
-        this._tileFramebuffers = {};
 
         this.setup();
 
@@ -480,21 +477,6 @@ class Painter {
         return textures && textures.length > 0 ? textures.pop() : null;
     }
 
-    saveTileFramebuffer(fbo: Framebuffer) {
-        const framebuffers = this._tileFramebuffers[fbo.width];
-
-        if (!framebuffers) {
-            this._tileFramebuffers[fbo.width] = [fbo];
-        } else {
-            framebuffers.push(fbo);
-        }
-    }
-
-    getTileFramebuffer(size: number) {
-        const framebuffers = this._tileFramebuffers[size];
-        return framebuffers && framebuffers.length > 0 ? framebuffers.pop() : null;
-    }
-
     lineWidth(width: number) {
         this.context.lineWidth.set(util.clamp(width, this.lineWidthRange[0], this.lineWidthRange[1]));
     }
diff --git a/src/source/raster_dem_tile_source.js b/src/source/raster_dem_tile_source.js
index 7d31c3ab836..225e73faa4f 100644
--- a/src/source/raster_dem_tile_source.js
+++ b/src/source/raster_dem_tile_source.js
@@ -117,8 +117,8 @@ class RasterDEMTileSource extends RasterTileSource implements Source {
     unloadTile(tile: Tile) {
         if (tile.demTexture) this.map.painter.saveTileTexture(tile.demTexture);
         if (tile.fbo) {
-            this.map.painter.saveTileFramebuffer(tile.fbo);
-            tile.fbo = null;
+            tile.fbo.destroy();
+            delete tile.fbo;
         }
         if (tile.dem) delete tile.dem;
         delete tile.neighboringTiles;
diff --git a/src/style/style_layer.js b/src/style/style_layer.js
index 40367d8a59d..fa794c325f2 100644
--- a/src/style/style_layer.js
+++ b/src/style/style_layer.js
@@ -15,7 +15,6 @@ const {
 
 import type {Bucket} from '../data/bucket';
 import type Point from '@mapbox/point-geometry';
-import type Framebuffer from '../gl/framebuffer';
 import type {FeatureFilter} from '../style-spec/feature_filter';
 import type {TransitionParameters} from './properties';
 import type EvaluationParameters from './evaluation_parameters';
@@ -42,7 +41,6 @@ class StyleLayer extends Evented {
     _transitioningPaint: Transitioning<any>;
     +paint: mixed;
 
-    viewportFrame: ?Framebuffer;
     _featureFilter: FeatureFilter;
 
     +queryRadius: (bucket: Bucket) => number;
@@ -201,7 +199,7 @@ class StyleLayer extends Evented {
         return false;
     }
 
-    resize() { // eslint-disable-line
+    resize() {
         // noop
     }
 }
diff --git a/src/style/style_layer/fill_extrusion_style_layer.js b/src/style/style_layer/fill_extrusion_style_layer.js
index 5d37f516ecc..b31c8ac5b64 100644
--- a/src/style/style_layer/fill_extrusion_style_layer.js
+++ b/src/style/style_layer/fill_extrusion_style_layer.js
@@ -15,11 +15,13 @@ const {
 import type {BucketParameters} from '../../data/bucket';
 import type Point from '@mapbox/point-geometry';
 import type {PaintProps} from './fill_extrusion_style_layer_properties';
+import type Framebuffer from '../../gl/framebuffer';
 
 class FillExtrusionStyleLayer extends StyleLayer {
     _transitionablePaint: Transitionable<PaintProps>;
     _transitioningPaint: Transitioning<PaintProps>;
     paint: PossiblyEvaluated<PaintProps>;
+    viewportFrame: ?Framebuffer;
 
     constructor(layer: LayerSpecification) {
         super(layer, properties);