Add needsDepthBlit flag

Author: vanruesc

src/core/EffectComposer.js

@@ -14,7 +14,6 @@ import { ClearMaskPass } from "../passes/ClearMaskPass.js";
 import { CopyPass } from "../passes/CopyPass.js";
 import { MaskPass } from "../passes/MaskPass.js";
 import { Pass } from "../passes/Pass.js";
-import { RenderPass } from "../passes/RenderPass.js";
 import { Timer } from "./Timer.js"; // TODO Replace with Timer from three, requires r179.
 
 /**
@@ -669,7 +668,7 @@ export class EffectComposer {
 
 			pass.render(renderer, inputBuffer, outputBuffer, deltaTime, stencilTest);
 
-			if(pass instanceof RenderPass) {
+			if(pass.needsDepthBlit) {
 
 				// Copy depth to the stable depth texture.
 				if(this.depthRenderTarget !== null) {

src/passes/Pass.js

@@ -116,9 +116,9 @@ export class Pass {
 		/**
 		 * Only relevant for subclassing.
 		 *
-		 * Indicates whether the {@link EffectComposer} should swap the frame buffers after this pass has finished
-		 * rendering. Set this to `false` if this pass doesn't render to the output buffer or the screen. Otherwise, the
-		 * contents of the input buffer will be lost.
+		 * Controls whether the {@link EffectComposer} should swap the frame buffers after this pass has finished rendering.
+		 * Set this to `false` if this pass doesn't render to the output buffer or the screen. Otherwise, the contents of
+		 * the input buffer will be lost.
 		 *
 		 * @type {Boolean}
 		 */
@@ -128,7 +128,18 @@ export class Pass {
 		/**
 		 * Only relevant for subclassing.
 		 *
-		 * Indicates whether the {@link EffectComposer} should prepare a depth texture for this pass.
+		 * Controls whether the {@link EffectComposer} should copy the depth buffer after this pass has finished rendering.
+		 * Default is `false`.
+		 *
+		 * @type {Boolean}
+		 */
+
+		this.needsDepthBlit = false;
+
+		/**
+		 * Only relevant for subclassing.
+		 *
+		 * Controls whether the {@link EffectComposer} should prepare a depth texture for this pass.
 		 * Set this to `true` if this pass relies on depth information from a preceding {@link RenderPass}.
 		 *
 		 * @type {Boolean}

src/passes/RenderPass.js

@@ -23,6 +23,7 @@ export class RenderPass extends Pass {
 		super("RenderPass", scene, camera);
 
 		this.needsSwap = false;
+		this.needsDepthBlit = true;
 
 		/**
 		 * A clear pass.

types/index.d.ts

@@ -2815,6 +2815,15 @@ export class Pass implements Initializable, Resizable, Disposable {
 	 * @type {Boolean}
 	 */
 	needsSwap: boolean;
+	/**
+	 * Only relevant for subclassing.
+	 *
+	 * Controls whether the {@link EffectComposer} should copy the depth buffer after this pass has finished rendering.
+	 * Default is `false`.
+	 *
+	 * @type {Boolean}
+	 */
+	needsDepthBlit: boolean;
 	/**
 	 * Only relevant for subclassing.
 	 *