Merge pull request #13150 from mike-000/heatmap-opacity

Include layer opacity in Heatmap shader

src/ol/layer/Heatmap.js

@@ -285,12 +285,13 @@ class Heatmap extends BaseVector {
 
             uniform sampler2D u_image;
             uniform sampler2D u_gradientTexture;
+            uniform float u_opacity;
 
             varying vec2 v_texCoord;
 
             void main() {
               vec4 color = texture2D(u_image, v_texCoord);
-              gl_FragColor.a = color.a;
+              gl_FragColor.a = color.a * u_opacity;
               gl_FragColor.rgb = texture2D(u_gradientTexture, vec2(0.5, color.a)).rgb;
               gl_FragColor.rgb *= gl_FragColor.a;
             }`,
@@ -298,6 +299,9 @@ class Heatmap extends BaseVector {
             u_gradientTexture: function () {
               return this.gradient_;
             }.bind(this),
+            u_opacity: function () {
+              return this.getOpacity();
+            }.bind(this),
           },
         },
       ],

src/ol/renderer/webgl/PointsLayer.js

@@ -55,7 +55,7 @@ import {listen, unlistenByKey} from '../../events.js';
  * @property {string} [hitVertexShader] Vertex shader source for hit detection rendering.
  * @property {string} [hitFragmentShader] Fragment shader source for hit detection rendering.
  * @property {Object<string,import("../../webgl/Helper").UniformValue>} [uniforms] Uniform definitions for the post process steps
- * Please note that `u_texture` is reserved for the main texture slot.
+ * Please note that `u_texture` is reserved for the main texture slot and `u_opacity` is reserved for the layer opacity.
  * @property {Array<import("./Layer").PostProcessesOptions>} [postProcesses] Post-processes definitions
  */
 
@@ -99,6 +99,7 @@ import {listen, unlistenByKey} from '../../events.js';
  * the final color that will have to be output for hit detection to work.
  *
  * The following uniform is used for the main texture: `u_texture`.
+ * The following uniform is used for the layer opacity: `u_opacity`.
  *
  * Please note that the main shader output should have premultiplied alpha, otherwise visual anomalies may occur.
  *

test/rendering/cases/heatmap-layer-opacity/main.js

@@ -0,0 +1,45 @@
+import KML from '../../../../src/ol/format/KML.js';
+import Map from '../../../../src/ol/Map.js';
+import TileLayer from '../../../../src/ol/layer/Tile.js';
+import VectorSource from '../../../../src/ol/source/Vector.js';
+import View from '../../../../src/ol/View.js';
+import XYZ from '../../../../src/ol/source/XYZ.js';
+import {Heatmap as HeatmapLayer} from '../../../../src/ol/layer.js';
+
+const vector = new HeatmapLayer({
+  source: new VectorSource({
+    url: '/data/2012_Earthquakes_Mag5.kml',
+    format: new KML({
+      extractStyles: false,
+    }),
+  }),
+  blur: 3,
+  radius: 3,
+  opacity: 0.5,
+});
+
+vector.getSource().on('addfeature', function (event) {
+  const name = event.feature.get('name');
+  const magnitude = parseFloat(name.substr(2));
+  event.feature.set('weight', magnitude - 5);
+});
+
+const raster = new TileLayer({
+  source: new XYZ({
+    url: '/data/tiles/satellite/{z}/{x}/{y}.jpg',
+    transition: 0,
+  }),
+});
+
+new Map({
+  layers: [raster, vector],
+  target: 'map',
+  view: new View({
+    center: [0, 0],
+    zoom: 0,
+  }),
+});
+
+render({
+  message: 'Heatmap layer with opacity renders properly using webgl',
+});