Fix object returns in p5.strands hooks

src/strands/ir_builders.js

@@ -344,38 +344,24 @@ export function castToFloat(strandsContext, dep) {
   return createStrandsNode(id, dimension, strandsContext);
 }
 
-export function structConstructorNode(strandsContext, structTypeInfo, rawUserArgs) {
+export function structConstructorNode(strandsContext, structTypeInfo, dependsOn) {
   const { cfg, dag } = strandsContext;
-  const { identifer, properties } = structTypeInfo;
+  const { properties } = structTypeInfo;
 
-  if (!(rawUserArgs.length === properties.length)) {
+  if (dependsOn.length !== properties.length) {
     FES.userError('type error',
-      `You've tried to construct a ${structTypeInfo.typeName} struct with ${rawUserArgs.length} properties, but it expects ${properties.length} properties.\n` +
+      `You've tried to construct a ${structTypeInfo.typeName} struct with ${dependsOn.length} properties, but it expects ${properties.length} properties.\n` +
       `The properties it expects are:\n` +
-      `${properties.map(prop => prop.name + ' ' + prop.DataType.baseType + prop.DataType.dimension)}`
+      `${properties.map(prop => `${prop.name}: ${prop.dataType.baseType}${prop.dataType.dimension}`).join(', ')}`
     );
   }
 
-  const dependsOn = [];
-  for (let i = 0; i < properties.length; i++) {
-    const expectedProperty = properties[i];
-    const { originalNodeID, mappedDependencies } = mapPrimitiveDepsToIDs(strandsContext, expectedProperty.dataType, rawUserArgs[i]);
-    if (originalNodeID) {
-      dependsOn.push(originalNodeID);
-    }
-    else {
-      dependsOn.push(
-        constructTypeFromIDs(strandsContext, expectedProperty.dataType, mappedDependencies)
-      );
-    }
-  }
-
   const nodeData = DAG.createNodeData({
     nodeType: NodeType.OPERATION,
     opCode: OpCode.Nary.CONSTRUCTOR,
     dimension: properties.length,
-    baseType: structTypeInfo.typeName ,
-    dependsOn
+    baseType: structTypeInfo.typeName,
+    dependsOn,
   });
   const id = DAG.getOrCreateNode(dag, nodeData);
   CFG.recordInBasicBlock(cfg, cfg.currentBlock, id);

src/webgl/strands_glslBackend.js

@@ -249,7 +249,7 @@ export const glslBackend = {
     }
     const dag = strandsContext.dag;
     const rootNode = getNodeDataFromID(dag, rootNodeID);
-    if (isStructType(returnType)) {
+    if (isStructType(returnType) && rootNode.identifier) {
       const structTypeInfo = returnType;
       for (let i = 0; i < structTypeInfo.properties.length; i++) {
         const prop = structTypeInfo.properties[i];

src/webgpu/strands_wgslBackend.js

@@ -410,7 +410,7 @@ export const wgslBackend = {
     }
     const dag = strandsContext.dag;
     const rootNode = getNodeDataFromID(dag, rootNodeID);
-    if (isStructType(returnType)) {
+    if (isStructType(returnType) && rootNode.identifier) {
       const structTypeInfo = returnType;
       for (let i = 0; i < structTypeInfo.properties.length; i++) {
         const prop = structTypeInfo.properties[i];

test/unit/visual/cases/webgl.js

@@ -1500,6 +1500,25 @@ visualTest('randomGaussian() in a fragment loop averages to the mean', (p5, scre
       p5.circle(0, 0, 30);
       screenshot();
     });
+
+    visualTest('hook returning a fresh struct (not the struct argument) applies modifications', (p5, screenshot) => {
+      p5.createCanvas(50, 50, p5.WEBGL);
+      const shader = p5.baseMaterialShader().modify(() => {
+        p5.worldInputs.begin();
+        p5.worldInputs.set({
+          position: p5.worldInputs.position.add([10, 0, 0]),
+          normal: p5.worldInputs.normal,
+          texCoord: p5.worldInputs.texCoord,
+          color: [1, 0, 0, 1],
+        });
+        p5.worldInputs.end();
+      }, { p5 });
+      p5.background(0);
+      p5.noStroke();
+      p5.shader(shader);
+      p5.plane(20, 20);
+      screenshot();
+    });
   });
 
   visualSuite('background()', function () {

test/unit/visual/cases/webgpu.js

@@ -364,6 +364,25 @@ visualSuite("WebGPU", function () {
       p5.plane(50, 50);
       await screenshot();
     });
+
+    visualTest('hook returning a fresh struct (not the struct argument) applies modifications', async function(p5, screenshot) {
+      await p5.createCanvas(50, 50, p5.WEBGPU);
+      const shader = p5.baseMaterialShader().modify(() => {
+        p5.worldInputs.begin();
+        p5.worldInputs.set({
+          position: p5.worldInputs.position.add([10, 0, 0]),
+          normal: p5.worldInputs.normal,
+          texCoord: p5.worldInputs.texCoord,
+          color: [1, 0, 0, 1],
+        });
+        p5.worldInputs.end();
+      }, { p5 });
+      p5.background(0);
+      p5.noStroke();
+      p5.shader(shader);
+      p5.plane(20, 20);
+      await screenshot();
+    }, { focus: true });
   });
 
   visualTest('randomGaussian() colors a basic shader (WebGPU)', async function(p5, screenshot) {

test/unit/visual/screenshots/WebGL/p5.strands/hook returning a fresh struct (not the struct argument) applies modifications/metadata.json

@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}

test/unit/visual/screenshots/WebGPU/Shaders/hook returning a fresh struct (not the struct argument) applies modifications/metadata.json

@@ -0,0 +1,3 @@
+{
+  "numScreenshots": 1
+}