Auto return shader hooks

src/strands/strands_api.js

@@ -404,35 +404,50 @@
       CFG.pushBlock(cfg, entryBlockID);
       const args = createHookArguments(strandsContext, hookType.parameters);
       const userReturned = hookUserCallback(...args);
+
+      // Auto-return input if types match and user didn't return anything
+      let effectiveReturn = userReturned;
+      if (userReturned === undefined) {
+        const expected = hookType.returnType;
+        if (isStructType(expected.typeName)) {
+          if (hookType.parameters.length === 1) {
+            const paramType = hookType.parameters[0].type.typeName;
+            if (paramType === expected.typeName) {
+              effectiveReturn = args[0];
+            }
+          }
+        }
+      }
+
       const expectedReturnType = hookType.returnType;
       let rootNodeID = null;
       if(isStructType(expectedReturnType)) {
         const expectedStructType = structType(expectedReturnType);
-        if (userReturned instanceof StrandsNode) {
-          const returnedNode = getNodeDataFromID(strandsContext.dag, userReturned.id);
+        if (effectiveReturn instanceof StrandsNode) {
+          const returnedNode = getNodeDataFromID(strandsContext.dag, effectiveReturn.id);
           if (returnedNode.baseType !== expectedStructType.typeName) {
-            FES.userError("type error", `You have returned a ${userReturned.baseType} from ${hookType.name} when a ${expectedStructType.typeName} was expected.`);
+            FES.userError("type error", `You have returned a ${effectiveReturn.baseType} from ${hookType.name} when a ${expectedStructType.typeName} was expected.`);
           }
           const newDeps = returnedNode.dependsOn.slice();
           for (let i = 0; i < expectedStructType.properties.length; i++) {
             const expectedType = expectedStructType.properties[i].dataType;
-            const receivedNode = createStrandsNode(returnedNode.dependsOn[i], dag.dependsOn[userReturned.id], strandsContext);
+            const receivedNode = createStrandsNode(returnedNode.dependsOn[i], dag.dependsOn[effectiveReturn.id], strandsContext);
             newDeps[i] = enforceReturnTypeMatch(strandsContext, expectedType, receivedNode, hookType.name);
           }
-          dag.dependsOn[userReturned.id] = newDeps;
-          rootNodeID = userReturned.id;
+          dag.dependsOn[effectiveReturn.id] = newDeps;
+          rootNodeID = effectiveReturn.id;
         }
         else {
           const expectedProperties = expectedStructType.properties;
           const newStructDependencies = [];
           for (let i = 0; i < expectedProperties.length; i++) {
             const expectedProp = expectedProperties[i];
             const propName = expectedProp.name;
-            const receivedValue = userReturned[propName];
+            const receivedValue = effectiveReturn[propName];
             if (receivedValue === undefined) {
               FES.userError('type error', `You've returned an incomplete struct from ${hookType.name}.\n` +
                 `Expected: { ${expectedReturnType.properties.map(p => p.name).join(', ')} }\n` +
-                `Received: { ${Object.keys(userReturned).join(', ')} }\n` +
+                `Received: { ${Object.keys(effectiveReturn).join(', ')} }\n` +
                 `All of the properties are required!`);
             }
             const expectedTypeInfo = expectedProp.dataType;
@@ -448,7 +463,7 @@
           throw new Error(`Missing dataType for return type ${expectedReturnType.typeName}`);
         }
         const expectedTypeInfo = expectedReturnType.dataType;
-        rootNodeID = enforceReturnTypeMatch(strandsContext, expectedTypeInfo, userReturned, hookType.name);
+        rootNodeID = enforceReturnTypeMatch(strandsContext, expectedTypeInfo, effectiveReturn, hookType.name);
       }
       const fullHookName = `${hookType.returnType.typeName} ${hookType.name}`;
       const hookInfo = availableHooks[fullHookName];

test/unit/visual/cases/webgl.js

@@ -928,6 +928,111 @@ visualSuite('WebGL', function() {
       p5.circle(p5.noise(0), p5.noise(0), 20);
       screenshot();
     });
+
+    visualSuite('auto-return for shader hooks', () => {
+      visualTest('auto-returns input struct when return is omitted', (p5, screenshot) => {
+        p5.createCanvas(50, 50, p5.WEBGL);
+        const shader = p5.baseMaterialShader().modify(() => {
+          p5.getWorldInputs((inputs) => {
+            inputs.position.x += 10;
+            // No explicit return - should auto-return inputs
+          });
+        }, { p5 });
+        p5.background(255);
+        p5.noStroke();
+        p5.shader(shader);
+        p5.sphere(20);
+        screenshot();
+      });
+
+      visualTest('explicit return still works', (p5, screenshot) => {
+        p5.createCanvas(50, 50, p5.WEBGL);
+        const shader = p5.baseMaterialShader().modify(() => {
+          p5.getWorldInputs((inputs) => {
+            inputs.position.x += 10;
+            return inputs; // Explicit return should still work
+          });
+        }, { p5 });
+        p5.background(255);
+        p5.noStroke();
+        p5.shader(shader);
+        p5.sphere(20);
+        screenshot();
+      });
+
+      visualTest('auto-return works with getObjectInputs', (p5, screenshot) => {
+        p5.createCanvas(50, 50, p5.WEBGL);
+        const shader = p5.baseMaterialShader().modify(() => {
+          p5.getObjectInputs((inputs) => {
+            inputs.position.x += 0.25;
+            // No explicit return
+          });
+        }, { p5 });
+        p5.background(255);
+        p5.lights();
+        p5.fill('red');
+        p5.noStroke();
+        p5.rotateY(p5.PI / 2);
+        p5.camera(-800, 0, 0, 0, 0, 0);
+        p5.shader(shader);
+        p5.sphere(20);
+        screenshot();
+      });
+
+      visualTest('auto-return works with getCameraInputs', (p5, screenshot) => {
+        p5.createCanvas(50, 50, p5.WEBGL);
+        const shader = p5.baseMaterialShader().modify(() => {
+          p5.getCameraInputs((inputs) => {
+            inputs.position.x += 10;
+            // No explicit return
+          });
+        }, { p5 });
+        p5.background(255);
+        p5.lights();
+        p5.fill('red');
+        p5.noStroke();
+        p5.rotateY(p5.PI / 2);
+        p5.camera(-800, 0, 0, 0, 0, 0);
+        p5.shader(shader);
+        p5.sphere(20);
+        screenshot();
+      });
+
+      visualTest('auto-return preserves multiple property modifications', (p5, screenshot) => {
+        p5.createCanvas(50, 50, p5.WEBGL);
+        const shader = p5.baseMaterialShader().modify(() => {
+          p5.getWorldInputs((inputs) => {
+            inputs.position.x += 5;
+            inputs.position.y += 5;
+            inputs.normal.x += 0.5;
+            inputs.normal = p5.normalize(inputs.normal);
+            // No explicit return - all modifications should be preserved
+          });
+        }, { p5 });
+        p5.background(255);
+        p5.lights();
+        p5.fill('red');
+        p5.noStroke();
+        p5.shader(shader);
+        p5.sphere(20);
+        screenshot();
+      });
+
+      visualTest('auto-return works with getPixelInputs', (p5, screenshot) => {
+        p5.createCanvas(50, 50, p5.WEBGL);
+        const shader = p5.baseMaterialShader().modify(() => {
+          p5.getPixelInputs((inputs) => {
+            inputs.color = p5.vec4(1.0, 0.0, 0.0, 1.0); // Red
+            // No explicit return
+          });
+        }, { p5 });
+        p5.background(255);
+        p5.noStroke();
+        p5.shader(shader);
+        p5.circle(0, 0, 40);
+        screenshot();
+      });
+    });
   });
 
   visualSuite('background()', function () {

test/unit/visual/screenshots/WebGL/p5.strands/auto-return for shader hooks/auto-return preserves multiple property modifications/metadata.json

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

test/unit/visual/screenshots/WebGL/p5.strands/auto-return for shader hooks/auto-return works with getCameraInputs/metadata.json

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

test/unit/visual/screenshots/WebGL/p5.strands/auto-return for shader hooks/auto-return works with getObjectInputs/metadata.json

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

test/unit/visual/screenshots/WebGL/p5.strands/auto-return for shader hooks/auto-return works with getPixelInputs/metadata.json

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

test/unit/visual/screenshots/WebGL/p5.strands/auto-return for shader hooks/auto-returns input struct when return is omitted/metadata.json

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

test/unit/visual/screenshots/WebGL/p5.strands/auto-return for shader hooks/explicit return still works/metadata.json

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