feat(WebGPU): Depth only / zbuffer pass support in CellArrayMapper

Author: daker

Sources/Rendering/WebGPU/CellArrayMapper/index.js

@@ -426,20 +426,33 @@ function vtkWebGPUCellArrayMapper(publicAPI, model) {
   };
 
   // Renders myself
+  publicAPI.renderForPass = (renderEncoder, depthOnly = false) => {
+    model.depthOnlyPass = depthOnly;
+    publicAPI.prepareToDraw(renderEncoder);
+    model.renderEncoder.registerDrawCallback(model.pipeline, publicAPI.draw);
+    model.depthOnlyPass = false;
+  };
+
   publicAPI.translucentPass = (prepass) => {
     if (prepass) {
-      publicAPI.prepareToDraw(model.WebGPURenderer.getRenderEncoder());
-      model.renderEncoder.registerDrawCallback(model.pipeline, publicAPI.draw);
+      publicAPI.renderForPass(model.WebGPURenderer.getRenderEncoder());
     }
   };
 
   publicAPI.opaquePass = (prepass) => {
     if (prepass) {
-      publicAPI.prepareToDraw(model.WebGPURenderer.getRenderEncoder());
-      model.renderEncoder.registerDrawCallback(model.pipeline, publicAPI.draw);
+      publicAPI.renderForPass(model.WebGPURenderer.getRenderEncoder());
     }
   };
 
+  publicAPI.zBufferPass = (prepass) => {
+    if (prepass) {
+      publicAPI.renderForPass(model.WebGPURenderer.getRenderEncoder(), true);
+    }
+  };
+
+  publicAPI.opaqueZBufferPass = (prepass) => publicAPI.zBufferPass(prepass);
+
   publicAPI.updateUBO = () => {
     const actor = model.WebGPUActor.getRenderable();
     const ppty = actor.getProperty();
@@ -621,6 +634,18 @@ function vtkWebGPUCellArrayMapper(publicAPI, model) {
     primitive: {
       cullMode: publicAPI.getCullMode(),
     },
+    ...(model.depthOnlyPass
+      ? {
+          fragment: {
+            targets: [
+              {
+                format: 'rgba16float',
+                writeMask: 0,
+              },
+            ],
+          },
+        }
+      : {}),
   });
 
   publicAPI.getCoincidentParameters = () => {
@@ -1545,6 +1570,9 @@ function vtkWebGPUCellArrayMapper(publicAPI, model) {
     let pipelineHash = `pd${model.useRendererMatrix ? 'r' : ''}${
       model.forceZValue ? 'z' : ''
     }`;
+    if (model.depthOnlyPass) {
+      pipelineHash += 'd';
+    }
 
     if (
       model.primitiveType === PrimitiveTypes.TriangleEdges ||
@@ -1622,6 +1650,7 @@ function vtkWebGPUCellArrayMapper(publicAPI, model) {
 // ----------------------------------------------------------------------------
 
 const DEFAULT_VALUES = {
+  depthOnlyPass: false,
   is2D: false,
   cellArray: null,
   currentInput: null,

Sources/Rendering/WebGPU/RenderEncoder/index.js

@@ -50,19 +50,20 @@ function vtkWebGPURenderEncoder(publicAPI, model) {
     }
     model.handle.setPipeline(pl.getHandle());
     const pd = pl.getPipelineDescription();
+    const fragmentTargets = pd.fragment?.targets;
 
     // check attachment state
-    if (model.colorTextureViews.length !== pd.fragment.targets.length) {
+    if (model.colorTextureViews.length !== fragmentTargets.length) {
       console.log(
-        `mismatched attachment counts on pipeline ${pd.fragment.targets.length} while encoder has ${model.colorTextureViews.length}`
+        `mismatched attachment counts on pipeline ${fragmentTargets.length} while encoder has ${model.colorTextureViews.length}`
       );
       console.trace();
     } else {
       for (let i = 0; i < model.colorTextureViews.length; i++) {
         const fmt = model.colorTextureViews[i].getTexture()?.getFormat();
-        if (fmt && fmt !== pd.fragment.targets[i].format) {
+        if (fmt && fmt !== fragmentTargets[i].format) {
           console.log(
-            `mismatched attachments for attachment ${i} on pipeline ${pd.fragment.targets[i].format} while encoder has ${fmt}`
+            `mismatched attachments for attachment ${i} on pipeline ${fragmentTargets[i].format} while encoder has ${fmt}`
           );
           console.trace();
         }

Sources/Rendering/WebGPU/Renderer/index.js

@@ -356,6 +356,19 @@ function vtkWebGPURenderer(publicAPI, model) {
     }
   };
 
+  publicAPI.zBufferPass = (prepass) => {
+    if (prepass) {
+      model.renderEncoder.begin(model._parent.getCommandEncoder());
+      publicAPI.updateUBO();
+      publicAPI.updateSSBO();
+    } else {
+      publicAPI.scissorAndViewport(model.renderEncoder);
+      model.renderEncoder.end();
+    }
+  };
+
+  publicAPI.opaqueZBufferPass = (prepass) => publicAPI.zBufferPass(prepass);
+
   publicAPI.clear = () => {
     if (model.renderable.getTransparent() || model.suppressClear) {
       return;

Sources/Rendering/WebGPU/ShaderDescription/index.js

@@ -77,7 +77,10 @@ function vtkWebGPUShaderDescription(publicAPI, model) {
       ).result;
     }
 
-    if (model.outputNames.length + model.builtinOutputNames.length) {
+    if (
+      model.outputNames.length + model.builtinOutputNames.length ||
+      model.code.includes('//VTK::IOStructs::Output')
+    ) {
       const outputStruct = [`struct ${model.type}Output\n{`];
       for (let i = 0; i < model.outputNames.length; i++) {
         if (model.outputInterpolations[i] !== undefined) {