Fixed depth texture component support using "depth texture" extension to work with draw buffers extension (WebGL 1)

Fixed SSAO2 post-process shader to use "texture2D"

src/PostProcess/RenderPipeline/Pipelines/babylon.ssao2RenderingPipeline.ts

@@ -120,7 +120,7 @@
         */
         public static get IsSupported(): boolean {
             var engine = Engine.LastCreatedEngine;
-            return engine.webGLVersion > 1;
+            return engine.getCaps().drawBuffersExtension;
         }
 
         private _scene: Scene;

src/Rendering/babylon.geometryBufferRenderer.ts

@@ -123,7 +123,7 @@ module BABYLON {
             var engine = this._scene.getEngine();
             var count = this._enablePosition ? 3 : 2;
 
-            this._multiRenderTarget = new MultiRenderTarget("gBuffer", { width: engine.getRenderWidth() * this._ratio, height: engine.getRenderHeight() * this._ratio }, count, this._scene, { generateMipMaps : false, generateDepthTexture: false });
+            this._multiRenderTarget = new MultiRenderTarget("gBuffer", { width: engine.getRenderWidth() * this._ratio, height: engine.getRenderHeight() * this._ratio }, count, this._scene, { generateMipMaps : false, generateDepthTexture: true });
             if (!this.isSupported) {
                 return null;
             }

src/Shaders/ssao2.fragment.fx

@@ -40,7 +40,7 @@ uniform mat4 projection;
 void main()
 {
 	vec3 random = texture2D(randomSampler, vUV * randTextureTiles).rgb;
-	float depth = abs(texture(textureSampler, vUV).r);
+	float depth = abs(texture2D(textureSampler, vUV).r);
 	vec3 normal = texture2D(normalSampler, vUV).rgb; 
 	float occlusion = 0.0;
 	float correctedRadius = min(radius, minZAspect * depth / near);
@@ -76,7 +76,7 @@ void main()
 	   }
 	  
 		// get sample linearDepth:
-	   float sampleDepth = abs(texture(textureSampler, offset.xy).r);
+	   float sampleDepth = abs(texture2D(textureSampler, offset.xy).r);
 		// range check & accumulate:
 	   float rangeCheck = abs(depth - sampleDepth) < correctedRadius ? 1.0 : 0.0;
 	   difference = samplePosition.z - sampleDepth;

src/babylon.engine.ts

@@ -239,7 +239,8 @@
         public textureHalfFloatLinearFiltering: boolean;
         public textureHalfFloatRender: boolean;
         public textureLOD: boolean;
-        public drawBuffersExtension;
+        public drawBuffersExtension: boolean;
+        public depthTextureExtension: boolean;
         public colorBufferFloat: boolean;
     }
 
@@ -1087,6 +1088,17 @@
                 }
             }
 
+            // Depth Texture
+            if (this._webGLVersion > 1) {
+                this._caps.depthTextureExtension = true;
+            } else {
+                var depthTextureExtension = this._gl.getExtension('WEBGL_depth_texture');
+
+                if (depthTextureExtension != null) {
+                    this._caps.depthTextureExtension = true;
+                }
+            }
+
             // Vertex array object
             if (this._webGLVersion > 1) {
                 this._caps.vertexArrayObject = true;
@@ -3275,7 +3287,7 @@
                 this._internalTexturesCache.push(texture);
             }
 
-            if (generateDepthTexture) {
+            if (generateDepthTexture && this._caps.depthTextureExtension) {
                 // Depth texture
                 var depthTexture = new InternalTexture(this, InternalTexture.DATASOURCE_MULTIRENDERTARGET);