Debug Draw

Cargo.toml

@@ -51,6 +51,7 @@ bevy_winit = ["bevy_internal/bevy_winit"]
 trace_chrome = ["bevy_internal/trace_chrome"]
 trace = ["bevy_internal/trace"]
 wgpu_trace = ["bevy_internal/wgpu_trace"]
+debug_draw = ["bevy_internal/bevy_debug_draw"]
 
 # Image format support for texture loading (PNG and HDR are enabled by default)
 hdr = ["bevy_internal/hdr"]
@@ -119,6 +120,11 @@ path = "examples/2d/texture_atlas.rs"
 name = "3d_scene"
 path = "examples/3d/3d_scene.rs"
 
+[[example]]
+name = "debug_draw_3d"
+path = "examples/3d/debug_draw_3d.rs"
+required-features = ["debug_draw"]
+
 [[example]]
 name = "load_gltf"
 path = "examples/3d/load_gltf.rs"

crates/bevy_debug_draw/Cargo.toml

@@ -0,0 +1,28 @@
+[package]
+name = "bevy_debug_draw"
+version = "0.4.0"
+edition = "2018"
+authors = [
+    "Bevy Contributors <bevyengine@gmail.com>",
+    "Fabian Krauser <The5_1@outlook.com>",
+]
+description = "Provides immediate mode debug drawing for the Bevy Engine"
+homepage = "https://bevyengine.org"
+repository = "https://github.com/bevyengine/bevy"
+license = "MIT"
+keywords = ["bevy"]
+
+
+[dependencies]
+# bevy
+bevy_render = { path = "../bevy_render", version = "0.4.0" }
+bevy_app = { path = "../bevy_app", version = "0.4.0" }
+bevy_asset = { path = "../bevy_asset", version = "0.4.0" }
+bevy_core = { path = "../bevy_core", version = "0.4.0" }
+bevy_log = { path = "../bevy_log", version = "0.4.0" }
+bevy_derive = { path = "../bevy_derive", version = "0.4.0" }
+bevy_ecs = { path = "../bevy_ecs", version = "0.4.0" }
+bevy_math = { path = "../bevy_math", version = "0.4.0" }
+bevy_reflect = { path = "../bevy_reflect", version = "0.4.0", features = ["bevy"] }
+bevy_transform = { path = "../bevy_transform", version = "0.4.0" }
+bevy_utils = { path = "../bevy_utils", version = "0.4.0" }

crates/bevy_debug_draw/src/debug_draw_3d.rs

@@ -0,0 +1,211 @@
+use bevy_app::{AppBuilder, CoreStage, Plugin};
+use bevy_asset::{AddAsset, Assets, Handle};
+use bevy_ecs::{
+    prelude::{Commands, Query, ResMut, With},
+    schedule::*,
+    system::*,
+};
+use bevy_log::info;
+use bevy_math::*;
+use bevy_reflect::TypeUuid;
+use bevy_render::{
+    mesh::*,
+    pipeline::{CullMode, PipelineDescriptor, PrimitiveTopology, RenderPipeline},
+    prelude::{Color, MeshBundle, RenderPipelines},
+    render_graph::{base, AssetRenderResourcesNode, RenderGraph},
+    renderer::RenderResources,
+    shader::{Shader, ShaderStage, ShaderStages},
+};
+use bevy_transform::{
+    components::{GlobalTransform, Transform},
+    TransformSystem,
+};
+
+use crate::gizmo::CoordinateGizmo;
+/// Bevy immediate mode debug drawing:
+/// This crate introduces a DebugDraw3D resource which provides functions such as `draw_line(start, end, color)`
+/// Whenever such a draw_line function is called, a set of vertices is added to the DebugDraw3D objects data.
+/// At the end of the frame the internal data is copied into a mesh entity for drawing and then cleared from the DebugDraw3D object.
+/// With this, no persistent line drawing is possible and lines have to be added every frame (hence immediate mode).
+/// For convenience a system called `debug_draw_all_gizmos` is provided that draws a coordinate gizmo for any `GlobalTransform`.
+///
+/// ToDo:
+/// * Add more convenience functions such as `draw_arrow(start, end, head_size, color)`, `draw_circle(origin, radius, axis, color)`, `draw_aabb(min,max,color)`.
+/// * Modify the shader and access the depth buffer and perform hidden-line rendering rather than a binary depth test for better line visualization.
+/// * Add the `debug_draw_all_gizmos` system to the plugin, using a parameter to turn it on or off.
+/// * Add transparent triangle drawing (useful to visually project a line down on a plane) and matching utility functions.
+/// * Add timed or persistent drawing: This requires storing `Line` structs containing a lifetime rather than directly pushing to an array.
+/// * Even though this is a debug feature, there current approach may likely not be the most performant solution and optimizations/refactoring should be applied.
+
+pub struct DebugDrawPlugin;
+impl Plugin for DebugDrawPlugin {
+    fn build(&self, app: &mut AppBuilder) {
+        app.add_asset::<DebugDraw3DMaterial>()
+            .init_resource::<DebugDraw3D>()
+            .add_startup_system(setup_debug_draw_3d.system())
+            .add_system_to_stage(
+                CoreStage::PostUpdate,
+                update_debug_draw_3d
+                    .system()
+                    .after(TransformSystem::TransformPropagate),
+            );
+    }
+}
+
+/// DebugDraw3D Resource providing functions for immediate mode drawing
+pub struct DebugDraw3D {
+    // The mesh data is held as plain arrays here
+    // If we wish to extend to more than just lines we may need multiple pairs that will later be ass, e.g. vertices_line and vertices_triangle
+    vertices: Vec<[f32; 3]>,
+    colors: Vec<[f32; 4]>,
+    dirty: bool,
+    clear: bool,
+}
+
+impl Default for DebugDraw3D {
+    fn default() -> Self {
+        DebugDraw3D {
+            vertices: Default::default(),
+            colors: Default::default(),
+            dirty: true,
+            clear: true,
+        }
+    }
+}
+
+impl DebugDraw3D {
+    pub fn draw_line(&mut self, start: Vec3, end: Vec3, color: Color) {
+        self.vertices.push(start.into());
+        self.vertices.push(end.into());
+        self.colors.push(color.into());
+        self.colors.push(color.into());
+        self.set_dirty();
+    }
+
+    /// Turning this off results in lines not being cleared anymore.
+    /// You will have to use clear() manually.
+    pub fn automatic(&mut self, clear: bool) {
+        self.clear = clear;
+    }
+
+    /// You do not have to call this in automatic mode.
+    pub fn clear(&mut self) {
+        self.vertices.clear();
+        self.colors.clear();
+    }
+
+    fn set_dirty(&mut self) {
+        self.dirty = true;
+    }
+
+    fn reset(&mut self) {
+        if self.clear {
+            self.clear();
+        }
+        self.dirty = false;
+    }
+}
+/// This component marks the internal entity that does the mesh drawing.
+#[derive(Default)]
+struct DebugDraw3DComponent;
+
+/// The Material holding the shader for debug drawing
+#[derive(RenderResources, Default, TypeUuid)]
+#[uuid = "188f0f97-60b2-476a-a749-7a0103adeeba"]
+pub struct DebugDraw3DMaterial;
+
+///This system sets up the entity holding the actual mesh for drawing as well as the render pipeline step for the shader.
+fn setup_debug_draw_3d(
+    mut commands: Commands,
+    mut pipelines: ResMut<Assets<PipelineDescriptor>>,
+    mut shaders: ResMut<Assets<Shader>>,
+    mut meshes: ResMut<Assets<Mesh>>,
+    mut materials: ResMut<Assets<DebugDraw3DMaterial>>,
+    mut render_graph: ResMut<RenderGraph>,
+) {
+    // Crate a shader Pipeline
+    let mut p = PipelineDescriptor::default_config(ShaderStages {
+        vertex: shaders.add(Shader::from_glsl(
+            ShaderStage::Vertex,
+            include_str!("shaders/debugDrawLine.vert"),
+        )),
+        fragment: Some(shaders.add(Shader::from_glsl(
+            ShaderStage::Fragment,
+            include_str!("shaders/debugDrawLine.frag"),
+        ))),
+    });
+    p.primitive.topology = PrimitiveTopology::LineList;
+    p.primitive.cull_mode = CullMode::None;
+    let pipeline_handle = pipelines.add(p);
+    let pipeline = RenderPipelines::from_pipelines(vec![RenderPipeline::new(pipeline_handle)]);
+
+    // add the material to the pipeline
+    render_graph.add_system_node(
+        "debug_draw_3d",
+        AssetRenderResourcesNode::<DebugDraw3DMaterial>::new(false),
+    );
+    // connect that node stage the MAIN_PASS node
+    render_graph
+        .add_node_edge("debug_draw_3d", base::node::MAIN_PASS)
+        .unwrap();
+
+    let material_instance = materials.add(DebugDraw3DMaterial {});
+
+    // Spawn a entity that will do the debug drawing with its mesh
+    commands
+        .spawn(MeshBundle {
+            mesh: meshes.add(Mesh::from(CoordinateGizmo { size: 1.0 })),
+            render_pipelines: pipeline, //we have to tell our mesh what pipeline to render in...
+            transform: Transform::from_translation(Vec3::ZERO),
+            ..Default::default()
+        })
+        .with(material_instance)
+        .with(DebugDraw3DComponent::default());
+
+    info!("Loaded debug lines plugin.");
+}
+
+/// This system updates the debug draw Entity with the data from
+fn update_debug_draw_3d(
+    mut debug_draw: ResMut<DebugDraw3D>,
+    mut meshes: ResMut<Assets<Mesh>>,
+    query: Query<&Handle<Mesh>, With<DebugDraw3DComponent>>,
+) {
+    if !debug_draw.dirty {
+        return;
+    } else {
+        for mesh in query.iter() {
+            if let Some(mesh) = meshes.get_mut(mesh) {
+                mesh.set_attribute(
+                    Mesh::ATTRIBUTE_POSITION,
+                    VertexAttributeValues::Float3(debug_draw.vertices.clone()),
+                );
+                mesh.set_attribute(
+                    "Vertex_Color",
+                    VertexAttributeValues::Float4(debug_draw.colors.clone()),
+                );
+            }
+        }
+    }
+    debug_draw.reset();
+}
+
+pub fn debug_draw_all_gizmos(mut debug_draw: ResMut<DebugDraw3D>, query: Query<&GlobalTransform>) {
+    for transform in query.iter() {
+        debug_draw.draw_line(
+            transform.translation,
+            transform.translation + transform.local_x(),
+            Color::RED,
+        );
+        debug_draw.draw_line(
+            transform.translation,
+            transform.translation + transform.local_y(),
+            Color::GREEN,
+        );
+        debug_draw.draw_line(
+            transform.translation,
+            transform.translation + transform.local_z(),
+            Color::BLUE,
+        );
+    }
+}

crates/bevy_debug_draw/src/gizmo.rs

@@ -0,0 +1,45 @@
+use bevy_render::{mesh::*, pipeline::PrimitiveTopology};
+
+pub struct CoordinateGizmo {
+    pub size: f32,
+}
+
+impl CoordinateGizmo {
+    pub fn new(size: f32) -> CoordinateGizmo {
+        CoordinateGizmo { size }
+    }
+}
+
+impl Default for CoordinateGizmo {
+    fn default() -> Self {
+        CoordinateGizmo { size: 1.0 }
+    }
+}
+
+impl From<CoordinateGizmo> for Mesh {
+    fn from(shape: CoordinateGizmo) -> Self {
+        let mut mesh = Mesh::new(PrimitiveTopology::LineList);
+        let vertices = vec![
+            [0.0, 0.0, 0.0],
+            [shape.size, 0.0, 0.0],
+            [0.0, 0.0, 0.0],
+            [0.0, shape.size, 0.0],
+            [0.0, 0.0, 0.0],
+            [0.0, 0.0, shape.size],
+        ];
+        mesh.set_attribute(
+            Mesh::ATTRIBUTE_POSITION,
+            VertexAttributeValues::Float3(vertices),
+        );
+        let colors = vec![
+            [1.0, 0.0, 0.0, 1.0],
+            [1.0, 0.0, 0.0, 1.0],
+            [0.0, 1.0, 0.0, 1.0],
+            [0.0, 1.0, 0.0, 1.0],
+            [0.0, 0.0, 1.0, 1.0],
+            [0.0, 0.0, 1.0, 1.0],
+        ];
+        mesh.set_attribute("Vertex_Color", VertexAttributeValues::Float4(colors));
+        mesh
+    }
+}

crates/bevy_debug_draw/src/lib.rs

@@ -0,0 +1,2 @@
+pub mod debug_draw_3d;
+pub mod gizmo;

crates/bevy_debug_draw/src/shaders/debugDrawLine.frag

@@ -0,0 +1,6 @@
+#version 450
+layout(location = 0) in vec4 vColor;
+layout(location = 0) out vec4 o_Target;
+void main() {
+    o_Target = vColor;
+}

crates/bevy_debug_draw/src/shaders/debugDrawLine.vert

@@ -0,0 +1,15 @@
+#version 450
+layout(location = 0) in vec3 Vertex_Position;
+layout(location = 1) in vec4 Vertex_Color;
+layout(location = 0) out vec4 vColor;
+
+layout(set = 0, binding = 0) uniform Camera {
+    mat4 ViewProj;
+};
+layout(set = 1, binding = 0) uniform Transform {
+    mat4 Model;
+};
+void main() {
+    vColor = Vertex_Color;
+    gl_Position = ViewProj * Model * vec4(Vertex_Position, 1.0);
+}

crates/bevy_internal/Cargo.toml

@@ -63,6 +63,7 @@ bevy_audio = { path = "../bevy_audio", optional = true, version = "0.4.0" }
 bevy_gltf = { path = "../bevy_gltf", optional = true, version = "0.4.0" }
 bevy_pbr = { path = "../bevy_pbr", optional = true, version = "0.4.0" }
 bevy_render = { path = "../bevy_render", optional = true, version = "0.4.0" }
+bevy_debug_draw = { path = "../bevy_debug_draw", optional = true, version = "0.4.0" }
 bevy_dynamic_plugin = { path = "../bevy_dynamic_plugin", optional = true, version = "0.4.0" }
 bevy_sprite = { path = "../bevy_sprite", optional = true, version = "0.4.0" }
 bevy_text = { path = "../bevy_text", optional = true, version = "0.4.0" }

crates/bevy_internal/src/lib.rs

@@ -106,6 +106,12 @@ pub mod render {
     pub use bevy_render::*;
 }
 
+#[cfg(feature = "bevy_debug_draw")]
+pub mod debug_draw {
+    //! Immediate mode debug drawing, like a visual println.
+    pub use bevy_debug_draw::*;
+}
+
 #[cfg(feature = "bevy_sprite")]
 pub mod sprite {
     //! Items for sprites, rects, texture atlases, etc.