WebGPUBackend: Fix Depth Buffer (#26395)

* WebGPUBackend: Fix depthBuffer

* cleanup

* revision

examples/jsm/renderers/common/RenderContexts.js

@@ -38,7 +38,7 @@ class RenderContexts {
 
 	dispose() {
 
-		this.renderStates = new ChainMap();
+		this.chainMaps = {};
 
 	}
 

examples/jsm/renderers/webgpu/WebGPUBackend.js

@@ -54,7 +54,8 @@ class WebGPUBackend extends Backend {
 		this.context = null;
 		this.colorBuffer = null;
 
-		this.depthBuffers = new WeakMap();
+		this.defaultDepthTexture = new DepthTexture();
+		this.defaultDepthTexture.name = 'depthBuffer';
 
 		this.utils = new WebGPUUtils( this );
 		this.attributeUtils = new WebGPUAttributeUtils( this );
@@ -753,63 +754,49 @@ class WebGPUBackend extends Backend {
 
 	_getDepthBufferGPU( renderContext ) {
 
-		const { depthBuffers } = this;
 		const { width, height } = this.getDrawingBufferSize();
 
-		let depthTexture = depthBuffers.get( renderContext );
+		const depthTexture = this.defaultDepthTexture;
+		const depthTextureGPU = this.get( depthTexture ).texture;
 
-		if ( depthTexture !== undefined && depthTexture.image.width === width && depthTexture.image.height === height ) {
+		let format, type;
 
-			return this.get( depthTexture ).texture;
+		if ( renderContext.stencil ) {
 
-		}
+			format = DepthStencilFormat;
+			type = UnsignedInt248Type;
 
-		this._destroyDepthBufferGPU( renderContext );
+		} else if ( renderContext.depth ) {
 
-		depthTexture = new DepthTexture();
-		depthTexture.name = 'depthBuffer';
+			format = DepthFormat;
+			type = UnsignedIntType;
 
-		if ( renderContext.stencil  ) {
+		}
 
-			depthTexture = new DepthTexture();
-			depthTexture.format = DepthStencilFormat;
-			depthTexture.type = UnsignedInt248Type;
+		if ( depthTextureGPU !== undefined ) {
 
-		} else if ( renderContext.depth ) {
+			if ( depthTexture.image.width === width && depthTexture.image.height === height && depthTexture.format === format && depthTexture.type === type ) {
 
-			depthTexture = new DepthTexture();
-			depthTexture.format = DepthFormat;
-			depthTexture.type = UnsignedIntType;
+				return depthTextureGPU;
+
+			}
+
+			this.textureUtils.destroyTexture( depthTexture );
 
 		}
 
+		depthTexture.name = 'depthBuffer';
+		depthTexture.format = format;
+		depthTexture.type = type;
 		depthTexture.image.width = width;
 		depthTexture.image.height = height;
 
 		this.textureUtils.createTexture( depthTexture, { sampleCount: this.parameters.sampleCount } );
 
-		depthBuffers.set( renderContext, depthTexture );
-
 		return this.get( depthTexture ).texture;
 
 	}
 
-	_destroyDepthBufferGPU( renderContext ) {
-
-		const { depthBuffers } = this;
-
-		const depthTexture = depthBuffers.get( renderContext );
-
-		if ( depthTexture !== undefined ) {
-
-			this.textureUtils.destroyTexture( depthTexture );
-
-			depthBuffers.delete( renderContext );
-
-		}
-
-	}
-
 	_configureContext() {
 
 		this.context.configure( {