Missing field maxColorAttachmentBytesPerSample in requiredLimits for wgpuAdapterRequestDevice

[pkomon-tgm]

When requesting a webGPU device, a device descriptor is passed. The device descriptor may specify certain limits, the device must be capable of supporting ("required limits"). Currently, the limit maxColorAttachmentBytesPerSample is always ignored.

The C function for requesting a webGPU device is wgpuAdapterRequestDevice and its binding is in library_webgpu.js:

emscripten/src/library_webgpu.js

Line 2550 in 11bd2d9

wgpuAdapterRequestDevice: (adapterId, descriptor, callback, userdata) => {

The descriptor passed is a C struct, which is used to fill a javascript object requiredLimits. The fields are explicitly copied using setLimitU32IfDefined/setLimitU64IfDefined, but the field maxColorAttachmentBytesPerSample is missing. This means, specifying this limits as part of the required limits for the device won't have any effect and the device will always support the default value for maxColorAttachmentBytesPerSample.

emscripten/src/library_webgpu.js

Lines 2562 to 2613 in 11bd2d9

	var requiredLimitsPtr = {{{ makeGetValue('descriptor', C_STRUCTS.WGPUDeviceDescriptor.requiredLimits, '*') }}};
	if (requiredLimitsPtr) {
	{{{ gpu.makeCheckDescriptor('requiredLimitsPtr') }}}
	var limitsPtr = requiredLimitsPtr + {{{ C_STRUCTS.WGPURequiredLimits.limits }}};
	var requiredLimits = {};
	function setLimitU32IfDefined(name, limitOffset) {
	var ptr = limitsPtr + limitOffset;
	var value = {{{ gpu.makeGetU32('ptr', 0) }}};
	if (value != {{{ gpu.LIMIT_U32_UNDEFINED }}}) {
	requiredLimits[name] = value;
	}
	}
	function setLimitU64IfDefined(name, limitOffset) {
	var ptr = limitsPtr + limitOffset;
	// Handle WGPU_LIMIT_U64_UNDEFINED.
	var limitPart1 = {{{ gpu.makeGetU32('ptr', 0) }}};
	var limitPart2 = {{{ gpu.makeGetU32('ptr', 4) }}};
	if (limitPart1 != 0xFFFFFFFF || limitPart2 != 0xFFFFFFFF) {
	requiredLimits[name] = {{{ gpu.makeGetU64('ptr', 0) }}}
	}
	}
	setLimitU32IfDefined("maxTextureDimension1D", {{{ C_STRUCTS.WGPULimits.maxTextureDimension1D }}});
	setLimitU32IfDefined("maxTextureDimension2D", {{{ C_STRUCTS.WGPULimits.maxTextureDimension2D }}});
	setLimitU32IfDefined("maxTextureDimension3D", {{{ C_STRUCTS.WGPULimits.maxTextureDimension3D }}});
	setLimitU32IfDefined("maxTextureArrayLayers", {{{ C_STRUCTS.WGPULimits.maxTextureArrayLayers }}});
	setLimitU32IfDefined("maxBindGroups", {{{ C_STRUCTS.WGPULimits.maxBindGroups }}});
	setLimitU32IfDefined('maxBindGroupsPlusVertexBuffers', {{{ C_STRUCTS.WGPULimits.maxBindGroupsPlusVertexBuffers }}});
	setLimitU32IfDefined("maxDynamicUniformBuffersPerPipelineLayout", {{{ C_STRUCTS.WGPULimits.maxDynamicUniformBuffersPerPipelineLayout }}});
	setLimitU32IfDefined("maxDynamicStorageBuffersPerPipelineLayout", {{{ C_STRUCTS.WGPULimits.maxDynamicStorageBuffersPerPipelineLayout }}});
	setLimitU32IfDefined("maxSampledTexturesPerShaderStage", {{{ C_STRUCTS.WGPULimits.maxSampledTexturesPerShaderStage }}});
	setLimitU32IfDefined("maxSamplersPerShaderStage", {{{ C_STRUCTS.WGPULimits.maxSamplersPerShaderStage }}});
	setLimitU32IfDefined("maxStorageBuffersPerShaderStage", {{{ C_STRUCTS.WGPULimits.maxStorageBuffersPerShaderStage }}});
	setLimitU32IfDefined("maxStorageTexturesPerShaderStage", {{{ C_STRUCTS.WGPULimits.maxStorageTexturesPerShaderStage }}});
	setLimitU32IfDefined("maxUniformBuffersPerShaderStage", {{{ C_STRUCTS.WGPULimits.maxUniformBuffersPerShaderStage }}});
	setLimitU32IfDefined("minUniformBufferOffsetAlignment", {{{ C_STRUCTS.WGPULimits.minUniformBufferOffsetAlignment }}});
	setLimitU32IfDefined("minStorageBufferOffsetAlignment", {{{ C_STRUCTS.WGPULimits.minStorageBufferOffsetAlignment }}});
	setLimitU64IfDefined("maxUniformBufferBindingSize", {{{ C_STRUCTS.WGPULimits.maxUniformBufferBindingSize }}});
	setLimitU64IfDefined("maxStorageBufferBindingSize", {{{ C_STRUCTS.WGPULimits.maxStorageBufferBindingSize }}});
	setLimitU32IfDefined("maxVertexBuffers", {{{ C_STRUCTS.WGPULimits.maxVertexBuffers }}});
	setLimitU32IfDefined("maxVertexAttributes", {{{ C_STRUCTS.WGPULimits.maxVertexAttributes }}});
	setLimitU32IfDefined("maxVertexBufferArrayStride", {{{ C_STRUCTS.WGPULimits.maxVertexBufferArrayStride }}});
	setLimitU32IfDefined("maxInterStageShaderComponents", {{{ C_STRUCTS.WGPULimits.maxInterStageShaderComponents }}});
	setLimitU32IfDefined("maxInterStageShaderVariables", {{{ C_STRUCTS.WGPULimits.maxInterStageShaderVariables }}});
	setLimitU32IfDefined("maxColorAttachments", {{{ C_STRUCTS.WGPULimits.maxColorAttachments }}});
	setLimitU32IfDefined("maxComputeWorkgroupStorageSize", {{{ C_STRUCTS.WGPULimits.maxComputeWorkgroupStorageSize }}});
	setLimitU32IfDefined("maxComputeInvocationsPerWorkgroup", {{{ C_STRUCTS.WGPULimits.maxComputeInvocationsPerWorkgroup }}});
	setLimitU32IfDefined("maxComputeWorkgroupSizeX", {{{ C_STRUCTS.WGPULimits.maxComputeWorkgroupSizeX }}});
	setLimitU32IfDefined("maxComputeWorkgroupSizeY", {{{ C_STRUCTS.WGPULimits.maxComputeWorkgroupSizeY }}});
	setLimitU32IfDefined("maxComputeWorkgroupSizeZ", {{{ C_STRUCTS.WGPULimits.maxComputeWorkgroupSizeZ }}});
	setLimitU32IfDefined("maxComputeWorkgroupsPerDimension", {{{ C_STRUCTS.WGPULimits.maxComputeWorkgroupsPerDimension }}});
	desc["requiredLimits"] = requiredLimits;