Do not clear when rendering to target in PostProcessEffect (#8705)

visgl · Mar 27, 2024 · db26ab6 · db26ab6
1 parent 51a3a3c
commit db26ab6
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Showing 3 changed files with 8 additions and 4 deletions.
diff --git a/modules/core/src/effects/post-process-effect.ts b/modules/core/src/effects/post-process-effect.ts
@@ -38,12 +38,14 @@ export default class PostProcessEffect<ShaderPassT extends ShaderPass> implement
 
     for (let index = 0; index < passes.length; index++) {
       const isLastPass = index === passes.length - 1;
-      if (target !== undefined && isLastPass) {
+      const renderToTarget = target !== undefined && isLastPass;
+      if (renderToTarget) {
         outputBuffer = target;
       }
+      const clearCanvas = !renderToTarget || Boolean(params.clearCanvas);
       const moduleSettings = {};
       moduleSettings[this.module.name] = this.props;
-      passes[index].render({inputBuffer, outputBuffer, moduleSettings});
+      passes[index].render({clearCanvas, inputBuffer, outputBuffer, moduleSettings});
 
       const switchBuffer = outputBuffer as Framebuffer;
       outputBuffer = inputBuffer;

diff --git a/modules/core/src/lib/deck-renderer.ts b/modules/core/src/lib/deck-renderer.ts
@@ -84,6 +84,7 @@ export default class DeckRenderer {
     const outputBuffer = this.lastPostProcessEffect ? this.renderBuffers[0] : renderOpts.target;
     if (this.lastPostProcessEffect) {
       renderOpts.clearColor = [0, 0, 0, 0];
+      renderOpts.clearCanvas = true;
     }
     const renderStats = layerPass.render({...renderOpts, target: outputBuffer});
 

diff --git a/modules/core/src/passes/screen-pass.ts b/modules/core/src/passes/screen-pass.ts
@@ -13,6 +13,7 @@ type ScreenPassProps = {
 };
 
 type ScreenPassRenderOptions = {
+  clearCanvas?: boolean;
   inputBuffer: Framebuffer;
   outputBuffer: Framebuffer | null;
   moduleSettings: any;
@@ -47,15 +48,15 @@ export default class ScreenPass extends Pass {
    * @param outputBuffer - Frame buffer that serves as the output render target
    */
   protected _renderPass(device: Device, options: ScreenPassRenderOptions) {
-    const {inputBuffer, outputBuffer} = options;
+    const {clearCanvas, inputBuffer, outputBuffer} = options;
     const texSize = [inputBuffer.width, inputBuffer.height];
     this.model.shaderInputs.setProps(options.moduleSettings);
     this.model.setBindings({texSrc: inputBuffer.colorAttachments[0]});
     this.model.setUniforms({texSize});
     const renderPass = this.device.beginRenderPass({
       framebuffer: outputBuffer,
       parameters: {viewport: [0, 0, ...texSize]},
-      clearColor: [0, 0, 0, 0],
+      clearColor: clearCanvas ? [0, 0, 0, 0] : false,
       clearDepth: 1
     });