Test indexing of a matrix using non-const index

Signed-off-by: sagudev <[email protected]>

src/webgpu/shader/execution/expression/access/matrix/index.spec.ts

@@ -11,7 +11,9 @@ import {
   abstractFloat,
   f32,
   vec,
+  Value,
 } from '../../../../../util/conversion.js';
+import { align } from '../../../../../util/math.js';
 import { Case } from '../../case.js';
 import { allInputSources, basicExpressionBuilder, run } from '../../expression.js';
 
@@ -198,3 +200,73 @@ g.test('abstract_float_element')
       cases
     );
   });
+
+g.test('non_const_index')
+  .specURL('https://www.w3.org/TR/WGSL/#matrix-access-expr')
+  .desc(`Test indexing of a matrix using non-const index`)
+  .params(u => u.combine('columns', [2, 3, 4] as const).combine('rows', [2, 3, 4] as const))
+  .fn(t => {
+    let cols = t.params.columns;
+    let rows = t.params.rows;
+    const values = Array.from(Array(cols * rows).keys());
+    const wgsl = `
+@group(0) @binding(0) var<storage, read_write> output : array<f32, ${cols * rows}>;
+
+@compute @workgroup_size(${cols}, ${rows})
+fn main(@builtin(local_invocation_id) invocation_id : vec3<u32>) {
+  let m = mat${cols}x${rows}f(${values.join(', ')});
+  output[invocation_id.x*${rows} + invocation_id.y] = m[invocation_id.x][invocation_id.y];
+}
+`;
+
+    const pipeline = t.device.createComputePipeline({
+      layout: 'auto',
+      compute: {
+        module: t.device.createShaderModule({ code: wgsl }),
+        entryPoint: 'main',
+      },
+    });
+
+    const bufferSize = (arr: Value[]) => {
+      let offset = 0;
+      let alignment = 0;
+      for (const value of arr) {
+        alignment = Math.max(alignment, value.type.alignment);
+        offset = align(offset, value.type.alignment) + value.type.size;
+      }
+      return align(offset, alignment);
+    };
+
+    const toArray = (arr: Value[]) => {
+      const array = new Uint8Array(bufferSize(arr));
+      let offset = 0;
+      for (const value of arr) {
+        offset = align(offset, value.type.alignment);
+        value.copyTo(array, offset);
+        offset += value.type.size;
+      }
+      return array;
+    };
+
+    const expected = values.map(i => Type['f32'].create(i));
+
+    const outputBuffer = t.createBufferTracked({
+      size: bufferSize(expected),
+      usage: GPUBufferUsage.STORAGE | GPUBufferUsage.COPY_SRC,
+    });
+
+    const bindGroup = t.device.createBindGroup({
+      layout: pipeline.getBindGroupLayout(0),
+      entries: [{ binding: 0, resource: { buffer: outputBuffer } }],
+    });
+
+    const encoder = t.device.createCommandEncoder();
+    const pass = encoder.beginComputePass();
+    pass.setPipeline(pipeline);
+    pass.setBindGroup(0, bindGroup);
+    pass.dispatchWorkgroups(1);
+    pass.end();
+    t.queue.submit([encoder.finish()]);
+
+    t.expectGPUBufferValuesEqual(outputBuffer, toArray(expected));
+  });