diff --git a/js/render/draw_circle.js b/js/render/draw_circle.js
index f6dbf80227d..57317cf5b94 100644
--- a/js/render/draw_circle.js
+++ b/js/render/draw_circle.js
@@ -27,7 +27,9 @@ function drawCircles(painter, source, layer, coords) {
 
         var program = painter.useProgram('circle', bucket.getProgramMacros('circle', layer));
 
-        gl.uniform2fv(program.u_extrude_scale, painter.transform.pixelsToGLUnits);
+        gl.uniform2f(program.u_extrude_scale,
+                painter.transform.pixelsToGLUnits[0] * painter.transform.altitude,
+                painter.transform.pixelsToGLUnits[1] * painter.transform.altitude);
         gl.uniform1f(program.u_blur, layer.paint['circle-blur']);
         gl.uniform1f(program.u_devicepixelratio, browser.devicePixelRatio);
         gl.uniform1f(program.u_opacity, layer.paint['circle-opacity']);
diff --git a/shaders/circle.vertex.glsl b/shaders/circle.vertex.glsl
index 5574aa28ccb..eda02b993aa 100644
--- a/shaders/circle.vertex.glsl
+++ b/shaders/circle.vertex.glsl
@@ -69,9 +69,7 @@ void main(void) {
     // in extrusion data
     gl_Position = u_matrix * vec4(floor(a_pos * 0.5), 0, 1);
 
-    // gl_Position is divided by gl_Position.w after this shader runs.
-    // Multiply the extrude by it so that it isn't affected by it.
-    gl_Position.xy += extrude * gl_Position.w;
+    gl_Position.xy += extrude;
 
 #ifdef ATTRIBUTE_A_COLOR
     v_color = a_color / 255.0;