Refactor to not render to rgba32float

Compat will not have rgba32float as a render target support
except as an optional feature so refactor to not use it.

src/webgpu/shader/execution/expression/call/builtin/texture_utils.ts

@@ -4470,7 +4470,7 @@ function createTextureCallsRunner<T extends Dimensionality>(
   const samplerType = isCompare ? 'sampler_comparison' : 'sampler';
 
   const renderTarget = t.createTextureTracked({
-    format: resultFormat,
+    format: 'rgba32uint',
     size: [calls.length, 1],
     usage: GPUTextureUsage.COPY_SRC | GPUTextureUsage.RENDER_ATTACHMENT,
   });
@@ -4510,23 +4510,33 @@ function createTextureCallsRunner<T extends Dimensionality>(
               getResult(instance_index, ${derivativeType}(0)));
 }
 
-@fragment fn fsVertex(v: VOut) -> @location(0) ${returnType} {
-  return v.result;
+@fragment fn fsVertex(v: VOut) -> @location(0) vec4u {
+  return bitcast<vec4u>(v.result);
 }
 `
       : stage === 'fragment'
       ? `
 // --------------------------- fragment stage shaders --------------------------------
+fn convertToVec4u(v: ${returnType}) -> vec4u {
+  return ${
+    returnType === 'rgba32uint'
+      ? 'v'
+      : returnType === 'rgba32int'
+      ? 'bitcast<vec4u>(v)'
+      : 'bitcast<vec4u>(v)'
+  };
+}
+
 @vertex fn vsFragment(
     @builtin(vertex_index) vertex_index : u32,
     @builtin(instance_index) instance_index : u32) -> VOut {
   let positions = array(vec2f(-1, 3), vec2f(3, -1), vec2f(-1, -1));
   return VOut(vec4f(positions[vertex_index], 0, 1), instance_index, ${returnType}(0));
 }
 
-@fragment fn fsFragment(v: VOut) -> @location(0) ${returnType} {
+@fragment fn fsFragment(v: VOut) -> @location(0) vec4u {
   ${derivativeBaseWGSL}
-  return getResult(v.ndx, derivativeBase);
+  return bitcast<vec4u>(getResult(v.ndx, derivativeBase));
 }
 `
       : `
@@ -4696,7 +4706,7 @@ ${stageWGSL}
           vertex: { module },
           fragment: {
             module,
-            targets: [{ format: renderTarget.format }],
+            targets: [{ format: 'rgba32uint' }],
           },
         });
         break;