src/dawn/native/ExternalTexture.cpp - dawn - Git at Google

 // Copyright 2021 The Dawn & Tint Authors
 //
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are met:
 //
 // 1. Redistributions of source code must retain the above copyright notice, this
 //    list of conditions and the following disclaimer.
 //
 // 2. Redistributions in binary form must reproduce the above copyright notice,
 //    this list of conditions and the following disclaimer in the documentation
 //    and/or other materials provided with the distribution.
 //
 // 3. Neither the name of the copyright holder nor the names of its
 //    contributors may be used to endorse or promote products derived from
 //    this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 // DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 // FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 // DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 // SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 // CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 // OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 #include "dawn/native/ExternalTexture.h"

 #include <algorithm>
 #include <utility>

 #include "dawn/native/Buffer.h"
 #include "dawn/native/Device.h"
 #include "dawn/native/ObjectType_autogen.h"
 #include "dawn/native/Queue.h"
 #include "dawn/native/Texture.h"

 #include "dawn/native/dawn_platform.h"

 namespace dawn::native {

 MaybeError ValidateExternalTexturePlane(const TextureViewBase* textureView) {
     DAWN_INVALID_IF(
         (textureView->GetTexture()->GetUsage() & wgpu::TextureUsage::TextureBinding) == 0,
         "The external texture plane (%s) usage (%s) doesn't include the required usage (%s)",
         textureView, textureView->GetTexture()->GetUsage(), wgpu::TextureUsage::TextureBinding);

     DAWN_INVALID_IF(textureView->GetDimension() != wgpu::TextureViewDimension::e2D,
                     "The external texture plane (%s) dimension (%s) is not 2D.", textureView,
                     textureView->GetDimension());

     DAWN_INVALID_IF(textureView->GetLevelCount() > 1,
                     "The external texture plane (%s) mip level count (%u) is not 1.", textureView,
                     textureView->GetLevelCount());

     DAWN_INVALID_IF(textureView->GetTexture()->GetSampleCount() != 1,
                     "The external texture plane (%s) sample count (%u) is not one.", textureView,
                     textureView->GetTexture()->GetSampleCount());

     return {};
 }

 MaybeError ValidateExternalTextureDescriptor(const DeviceBase* device,
                                              const ExternalTextureDescriptor* descriptor) {
     DAWN_ASSERT(descriptor);
     DAWN_ASSERT(descriptor->plane0);

     DAWN_TRY(device->ValidateObject(descriptor->plane0));

     DAWN_INVALID_IF(!descriptor->gamutConversionMatrix,
                     "The gamut conversion matrix must be non-null.");

     DAWN_INVALID_IF(!descriptor->srcTransferFunctionParameters,
                     "The source transfer function parameters must be non-null.");

     DAWN_INVALID_IF(!descriptor->dstTransferFunctionParameters,
                     "The destination transfer function parameters must be non-null.");

     DAWN_TRY(ValidateExternalTexturePlane(descriptor->plane0));

     auto CheckPlaneFormat = [](const DeviceBase* device, const Format& format,
                                uint32_t requiredComponentCount) -> MaybeError {
         DAWN_INVALID_IF(format.aspects != Aspect::Color, "The format (%s) is not a color format.",
                         format.format);
         DAWN_INVALID_IF(!IsSubset(SampleTypeBit::Float,
                                   format.GetAspectInfo(Aspect::Color).supportedSampleTypes),
                         "The format (%s) is not filterable float.", format.format);
         DAWN_INVALID_IF(format.componentCount != requiredComponentCount,
                         "The format (%s) component count (%u) is not %u.", format.format,
                         requiredComponentCount, format.componentCount);
         return {};
     };

     if (descriptor->plane1) {
         DAWN_INVALID_IF(
             !descriptor->yuvToRgbConversionMatrix,
             "When more than one plane is set, the YUV-to-RGB conversion matrix must be non-null.");

         DAWN_TRY(device->ValidateObject(descriptor->plane1));
         DAWN_TRY(ValidateExternalTexturePlane(descriptor->plane1));

         // Y + UV case.
         DAWN_TRY_CONTEXT(CheckPlaneFormat(device, descriptor->plane0->GetFormat(), 1),
                          "validating the format of plane 0 (%s)", descriptor->plane0);
         DAWN_TRY_CONTEXT(CheckPlaneFormat(device, descriptor->plane1->GetFormat(), 2),
                          "validating the format of plane 1 (%s)", descriptor->plane1);
     } else {
         // RGBA case.
         DAWN_TRY_CONTEXT(CheckPlaneFormat(device, descriptor->plane0->GetFormat(), 4),
                          "validating the format of plane 0 (%s)", descriptor->plane0);
     }

     DAWN_INVALID_IF(descriptor->visibleSize.width == 0 || descriptor->visibleSize.height == 0,
                     "VisibleSize %s have 0 on width or height.", &descriptor->visibleSize);

     const Extent3D textureSize = descriptor->plane0->GetSingleSubresourceVirtualSize();
     DAWN_INVALID_IF(descriptor->visibleSize.width > textureSize.width ||
                         descriptor->visibleSize.height > textureSize.height,
                     "VisibleSize %s is exceed the texture size, defined by Plane0 size (%u, %u).",
                     &descriptor->visibleSize, textureSize.width, textureSize.height);
     DAWN_INVALID_IF(
         descriptor->visibleOrigin.x > textureSize.width - descriptor->visibleSize.width ||
             descriptor->visibleOrigin.y > textureSize.height - descriptor->visibleSize.height,
         "VisibleRect[Origin: %s, Size: %s] is exceed the texture size, defined by "
         "Plane0 size (%u, %u).",
         &descriptor->visibleOrigin, &descriptor->visibleSize, textureSize.width,
         textureSize.height);

     return {};
 }

 // static
 ResultOrError<Ref<ExternalTextureBase>> ExternalTextureBase::Create(
     DeviceBase* device,
     const ExternalTextureDescriptor* descriptor) {
     Ref<ExternalTextureBase> externalTexture =
         AcquireRef(new ExternalTextureBase(device, descriptor));
     DAWN_TRY(externalTexture->Initialize(device, descriptor));
     return std::move(externalTexture);
 }

 ExternalTextureBase::ExternalTextureBase(DeviceBase* device,
                                          const ExternalTextureDescriptor* descriptor)
     : ApiObjectBase(device, descriptor->label),
       mVisibleOrigin(descriptor->visibleOrigin),
       mVisibleSize(descriptor->visibleSize),
       mState(ExternalTextureState::Active) {
     GetObjectTrackingList()->Track(this);
 }

 // Error external texture cannot be used in bind group.
 ExternalTextureBase::ExternalTextureBase(DeviceBase* device,
                                          ObjectBase::ErrorTag tag,
                                          const char* label)
     : ApiObjectBase(device, tag, label), mState(ExternalTextureState::Destroyed) {}

 ExternalTextureBase::~ExternalTextureBase() = default;

 MaybeError ExternalTextureBase::Initialize(DeviceBase* device,
                                            const ExternalTextureDescriptor* descriptor) {
     // Store any passed in TextureViews associated with individual planes.
     mTextureViews[0] = descriptor->plane0;

     if (descriptor->plane1) {
         mTextureViews[1] = descriptor->plane1;
     } else {
         DAWN_TRY_ASSIGN(mTextureViews[1],
                         device->GetOrCreatePlaceholderTextureViewForExternalTexture());
     }

     // We must create a buffer to store parameters needed by a shader that operates on this
     // external texture.
     BufferDescriptor bufferDesc;
     bufferDesc.size = sizeof(ExternalTextureParams);
     bufferDesc.usage = wgpu::BufferUsage::Uniform | wgpu::BufferUsage::CopyDst;
     bufferDesc.label = "Dawn_External_Texture_Params_Buffer";

     DAWN_TRY_ASSIGN(mParamsBuffer, device->CreateBuffer(&bufferDesc));

     ExternalTextureParams params;
     params.numPlanes = descriptor->plane1 == nullptr ? 1 : 2;

     params.doYuvToRgbConversionOnly = descriptor->doYuvToRgbConversionOnly ? 1 : 0;

     // YUV-to-RGB conversion is performed by multiplying the source YUV values with a 4x3 matrix
     // passed from Chromium. The matrix was originally sourced from /skia/src/core/SkYUVMath.cpp.
     // This matrix is only used in multiplanar scenarios.
     if (params.numPlanes == 2) {
         DAWN_ASSERT(descriptor->yuvToRgbConversionMatrix);
         const float* yMat = descriptor->yuvToRgbConversionMatrix;
         std::copy(yMat, yMat + 12, params.yuvToRgbConversionMatrix.begin());
     }

     // Gamut correction is performed by multiplying a 3x3 matrix passed from Chromium. The
     // matrix was computed by multiplying the appropriate source and destination gamut
     // matrices sourced from ui/gfx/color_space.cc.
     const float* gMat = descriptor->gamutConversionMatrix;
     params.gamutConversionMatrix = {gMat[0], gMat[1], gMat[2], 0.0f,  //
                                     gMat[3], gMat[4], gMat[5], 0.0f,  //
                                     gMat[6], gMat[7], gMat[8], 0.0f};

     // Gamma decode/encode is performed by the logic:
     //    if (abs(v) < params.D) {
     //        return sign(v) * (params.C * abs(v) + params.F);
     //    }
     //    return pow(A * x + B, G) + E
     //
     // Constants are passed from Chromium and originally sourced from ui/gfx/color_space.cc
     const float* srcFn = descriptor->srcTransferFunctionParameters;
     std::copy(srcFn, srcFn + 7, params.gammaDecodingParams.begin());

     const float* dstFn = descriptor->dstTransferFunctionParameters;
     std::copy(dstFn, dstFn + 7, params.gammaEncodingParams.begin());

     // Unlike WGSL, which stores matrices in column vectors, the following arithmetic uses row
     // vectors, so elements are stored in the following order:
     //
     // ┌         ┐
     // │ 0, 1, 2 │
     // │ 3, 4, 5 │
     // └         ┘
     //
     // The matrix is transposed at the end.
     //
     // Note that we are working in homogeneous coordinates so there is an implied third row
     // containing [0, 0, 1].
     using mat2x3 = std::array<float, 6>;
     // Likewise the vectors have an implicit last element that's 1.
     using vec2 = std::array<float, 2>;

     // Multiplies the two mat2x3 matrices, by treating the RHS matrix as a mat3x3 where the last row
     // is [0, 0, 1].
     auto Mul = [](const mat2x3& lhs, const mat2x3& rhs) -> mat2x3 {
         auto& a = lhs[0];
         auto& b = lhs[1];
         auto& c = lhs[2];
         auto& d = lhs[3];
         auto& e = lhs[4];
         auto& f = lhs[5];
         auto& g = rhs[0];
         auto& h = rhs[1];
         auto& i = rhs[2];
         auto& j = rhs[3];
         auto& k = rhs[4];
         auto& l = rhs[5];
         // ┌         ┐   ┌         ┐
         // │ a, b, c │   │ g, h, i │
         // │ d, e, f │ x │ j, k, l │
         // └         ┘   │ 0, 0, 1 │
         //               └         ┘
         return mat2x3{
             a * g + b * j,      //
             a * h + b * k,      //
             a * i + b * l + c,  //
             d * g + e * j,      //
             d * h + e * k,      //
             d * i + e * l + f,  //
         };
     };
     auto Scale = [](float x, float y) -> mat2x3 { return {x, 0, 0, 0, y, 0}; };
     auto ScaleVec = [&](vec2 v) -> mat2x3 { return Scale(v[0], v[1]); };
     auto Translate = [](float x, float y) -> mat2x3 { return mat2x3{1, 0, x, 0, 1, y}; };
     auto TranslateVec = [&](vec2 v) -> mat2x3 { return Translate(v[0], v[1]); };
     auto TransposeForWGSL = [](const mat2x3& m) -> std::array<float, 6> {
         return {m[0], m[3], m[1], m[4], m[2], m[5]};
     };

     // Vector operations
     auto Add = [](const vec2& a, const vec2& b) -> vec2 { return {a[0] + b[0], a[1] + b[1]}; };
     auto Sub = [](const vec2& a, const vec2& b) -> vec2 { return {a[0] - b[0], a[1] - b[1]}; };
     auto Div = [](const vec2& a, const vec2& b) -> vec2 { return {a[0] / b[0], a[1] / b[1]}; };

     // Extract all the relevant sizes as float to avoid extra casts in later computations.
     Extent3D plane0Extent = descriptor->plane0->GetSingleSubresourceVirtualSize();
     Extent3D plane1Extent = {1, 1, 1};
     if (params.numPlanes == 2) {
         plane1Extent = descriptor->plane1->GetSingleSubresourceVirtualSize();
     }
     vec2 plane0Size = {static_cast<float>(plane0Extent.width),
                        static_cast<float>(plane0Extent.height)};
     vec2 plane1Size = {static_cast<float>(plane1Extent.width),
                        static_cast<float>(plane1Extent.height)};
     vec2 visibleOrigin = {static_cast<float>(mVisibleOrigin.x),
                           static_cast<float>(mVisibleOrigin.y)};
     vec2 visibleSize = {static_cast<float>(mVisibleSize.width),
                         static_cast<float>(mVisibleSize.height)};

     // Offset the coordinates so the center texel is at the origin, so we can apply rotations and
     // y-flips. After translation, coordinates range from [-0.5 .. +0.5] in both U and V.
     mat2x3 sampleTransform = Translate(-0.5, -0.5);

     // The video frame metadata both rotation and mirroring information. The rotation happens before
     // the mirroring when processing the video frame, so do the inverse order when converting UV
     // coordinates.
     if (descriptor->mirrored) {
         sampleTransform = Mul(Scale(-1, 1), sampleTransform);
     }

     // Apply rotations as needed this may rotate the shader-visible size of the texture for
     // textureLoad operations.
     std::array<uint32_t, 2> loadBounds = {mVisibleSize.width - 1, mVisibleSize.height - 1};
     switch (descriptor->rotation) {
         case wgpu::ExternalTextureRotation::Rotate0Degrees:
             break;
         case wgpu::ExternalTextureRotation::Rotate90Degrees:
             std::swap(loadBounds[0], loadBounds[1]);
             sampleTransform = Mul(mat2x3{0, +1, 0,   // x' = y
                                          -1, 0, 0},  // y' = -x
                                   sampleTransform);
             break;
         case wgpu::ExternalTextureRotation::Rotate180Degrees:
             sampleTransform = Mul(mat2x3{-1, 0, 0,   // x' = -x
                                          0, -1, 0},  // y' = -y
                                   sampleTransform);
             break;
         case wgpu::ExternalTextureRotation::Rotate270Degrees:
             std::swap(loadBounds[0], loadBounds[1]);
             sampleTransform = Mul(mat2x3{0, -1, 0,   // x' = -y
                                          +1, 0, 0},  // y' = x
                                   sampleTransform);
             break;
     }

     // Offset the coordinates so the bottom-left texel is at origin.
     // After translation, coordinates range from [0 .. 1] in both U and V.
     sampleTransform = Mul(Translate(0.5, 0.5), sampleTransform);

     // Finally, scale and translate based on the visible rect. This applies cropping.
     vec2 rectScale = Div(visibleSize, plane0Size);
     vec2 rectOffset = Div(visibleOrigin, plane0Size);
     sampleTransform = Mul(TranslateVec(rectOffset), Mul(ScaleVec(rectScale), sampleTransform));

     params.sampleTransform = TransposeForWGSL(sampleTransform);

     // Compute the load transformation matrix by using toTexels * sampleTransform * toNormalized
     // Note that coords starts from 0 so the max value is size - 1.
     {
         mat2x3 toTexels = ScaleVec(Sub(plane0Size, {1.0f, 1.0f}));
         mat2x3 toNormalized = Scale(1.0f / loadBounds[0], 1.0f / loadBounds[1]);
         mat2x3 loadTransform = Mul(toTexels, Mul(sampleTransform, toNormalized));

         params.loadTransform = TransposeForWGSL(loadTransform);
     }

     // Compute the clamping for each plane individually: to avoid bleeding of OOB texels due to
     // interpolation we need to offset by a half texel in, which depends on the size of the plane.
     {
         vec2 plane0HalfTexel = Div({0.5f, 0.5f}, plane0Size);
         vec2 plane1HalfTexel = Div({0.5f, 0.5f}, plane1Size);

         params.samplePlane0RectMin = Add(rectOffset, plane0HalfTexel);
         params.samplePlane1RectMin = Add(rectOffset, plane1HalfTexel);
         params.samplePlane0RectMax = Sub(Add(rectOffset, rectScale), plane0HalfTexel);
         params.samplePlane1RectMax = Sub(Add(rectOffset, rectScale), plane1HalfTexel);
     }

     params.plane1CoordFactor = Div(plane1Size, plane0Size);
     params.visibleSize = loadBounds;

     DAWN_TRY(device->GetQueue()->WriteBuffer(mParamsBuffer.Get(), 0, &params,
                                              sizeof(ExternalTextureParams)));

     return {};
 }

 const std::array<Ref<TextureViewBase>, kMaxPlanesPerFormat>& ExternalTextureBase::GetTextureViews()
     const {
     return mTextureViews;
 }

 MaybeError ExternalTextureBase::ValidateCanUseInSubmitNow() const {
     DAWN_ASSERT(!IsError());
     DAWN_INVALID_IF(mState != ExternalTextureState::Active,
                     "External texture %s used in a submit is not active.", this);

     for (uint32_t i = 0; i < kMaxPlanesPerFormat; ++i) {
         if (mTextureViews[i] != nullptr) {
             DAWN_TRY_CONTEXT(mTextureViews[i]->GetTexture()->ValidateCanUseInSubmitNow(),
                              "Validate plane %u of %s can be used in a submit.", i, this);
         }
     }
     return {};
 }

 MaybeError ExternalTextureBase::ValidateRefresh() {
     DAWN_TRY(GetDevice()->ValidateObject(this));
     DAWN_INVALID_IF(mState == ExternalTextureState::Destroyed, "%s is destroyed.", this);
     return {};
 }

 MaybeError ExternalTextureBase::ValidateExpire() {
     DAWN_TRY(GetDevice()->ValidateObject(this));
     DAWN_INVALID_IF(mState != ExternalTextureState::Active, "%s is not active.", this);
     return {};
 }

 void ExternalTextureBase::APIRefresh() {
     if (GetDevice()->ConsumedError(ValidateRefresh(), "calling %s.Refresh()", this)) {
         return;
     }
     mState = ExternalTextureState::Active;
 }

 void ExternalTextureBase::APIExpire() {
     if (GetDevice()->ConsumedError(ValidateExpire(), "calling %s.Expire()", this)) {
         return;
     }
     mState = ExternalTextureState::Expired;
 }

 void ExternalTextureBase::APIDestroy() {
     Destroy();
 }

 void ExternalTextureBase::DestroyImpl() {
     // TODO(crbug.com/dawn/831): DestroyImpl is called from two places.
     // - It may be called if the texture is explicitly destroyed with APIDestroy.
     //   This case is NOT thread-safe and needs proper synchronization with other
     //   simultaneous uses of the texture.
     // - It may be called when the last ref to the texture is dropped and the texture
     //   is implicitly destroyed. This case is thread-safe because there are no
     //   other threads using the texture since there are no other live refs.
     mState = ExternalTextureState::Destroyed;
 }

 // static
 Ref<ExternalTextureBase> ExternalTextureBase::MakeError(DeviceBase* device, const char* label) {
     return AcquireRef(new ExternalTextureBase(device, ObjectBase::kError, label));
 }

 BufferBase* ExternalTextureBase::GetParamsBuffer() const {
     return mParamsBuffer.Get();
 }

 ObjectType ExternalTextureBase::GetType() const {
     return ObjectType::ExternalTexture;
 }

 const Extent2D& ExternalTextureBase::GetVisibleSize() const {
     DAWN_ASSERT(!IsError());
     return mVisibleSize;
 }

 const Origin2D& ExternalTextureBase::GetVisibleOrigin() const {
     DAWN_ASSERT(!IsError());
     return mVisibleOrigin;
 }

 }  // namespace dawn::native
	// Copyright 2021 The Dawn & Tint Authors
	//
	// Redistribution and use in source and binary forms, with or without
	// modification, are permitted provided that the following conditions are met:
	//
	// 1. Redistributions of source code must retain the above copyright notice, this
	// list of conditions and the following disclaimer.
	//
	// 2. Redistributions in binary form must reproduce the above copyright notice,
	// this list of conditions and the following disclaimer in the documentation
	// and/or other materials provided with the distribution.
	//
	// 3. Neither the name of the copyright holder nor the names of its
	// contributors may be used to endorse or promote products derived from
	// this software without specific prior written permission.
	//
	// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
	// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
	// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
	// FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	// DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
	// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
	// CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
	// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

	#include "dawn/native/ExternalTexture.h"

	#include <algorithm>
	#include <utility>

	#include "dawn/native/Buffer.h"
	#include "dawn/native/Device.h"
	#include "dawn/native/ObjectType_autogen.h"
	#include "dawn/native/Queue.h"
	#include "dawn/native/Texture.h"

	#include "dawn/native/dawn_platform.h"

	namespace dawn::native {

	MaybeError ValidateExternalTexturePlane(const TextureViewBase* textureView) {
	DAWN_INVALID_IF(
	(textureView->GetTexture()->GetUsage() & wgpu::TextureUsage::TextureBinding) == 0,
	"The external texture plane (%s) usage (%s) doesn't include the required usage (%s)",
	textureView, textureView->GetTexture()->GetUsage(), wgpu::TextureUsage::TextureBinding);

	DAWN_INVALID_IF(textureView->GetDimension() != wgpu::TextureViewDimension::e2D,
	"The external texture plane (%s) dimension (%s) is not 2D.", textureView,
	textureView->GetDimension());

	DAWN_INVALID_IF(textureView->GetLevelCount() > 1,
	"The external texture plane (%s) mip level count (%u) is not 1.", textureView,
	textureView->GetLevelCount());

	DAWN_INVALID_IF(textureView->GetTexture()->GetSampleCount() != 1,
	"The external texture plane (%s) sample count (%u) is not one.", textureView,
	textureView->GetTexture()->GetSampleCount());

	return {};
	}

	MaybeError ValidateExternalTextureDescriptor(const DeviceBase* device,
	const ExternalTextureDescriptor* descriptor) {
	DAWN_ASSERT(descriptor);
	DAWN_ASSERT(descriptor->plane0);

	DAWN_TRY(device->ValidateObject(descriptor->plane0));

	DAWN_INVALID_IF(!descriptor->gamutConversionMatrix,
	"The gamut conversion matrix must be non-null.");

	DAWN_INVALID_IF(!descriptor->srcTransferFunctionParameters,
	"The source transfer function parameters must be non-null.");

	DAWN_INVALID_IF(!descriptor->dstTransferFunctionParameters,
	"The destination transfer function parameters must be non-null.");

	DAWN_TRY(ValidateExternalTexturePlane(descriptor->plane0));

	auto CheckPlaneFormat = [](const DeviceBase* device, const Format& format,
	uint32_t requiredComponentCount) -> MaybeError {
	DAWN_INVALID_IF(format.aspects != Aspect::Color, "The format (%s) is not a color format.",
	format.format);
	DAWN_INVALID_IF(!IsSubset(SampleTypeBit::Float,
	format.GetAspectInfo(Aspect::Color).supportedSampleTypes),
	"The format (%s) is not filterable float.", format.format);
	DAWN_INVALID_IF(format.componentCount != requiredComponentCount,
	"The format (%s) component count (%u) is not %u.", format.format,
	requiredComponentCount, format.componentCount);
	return {};
	};

	if (descriptor->plane1) {
	DAWN_INVALID_IF(
	!descriptor->yuvToRgbConversionMatrix,
	"When more than one plane is set, the YUV-to-RGB conversion matrix must be non-null.");

	DAWN_TRY(device->ValidateObject(descriptor->plane1));
	DAWN_TRY(ValidateExternalTexturePlane(descriptor->plane1));

	// Y + UV case.
	DAWN_TRY_CONTEXT(CheckPlaneFormat(device, descriptor->plane0->GetFormat(), 1),
	"validating the format of plane 0 (%s)", descriptor->plane0);
	DAWN_TRY_CONTEXT(CheckPlaneFormat(device, descriptor->plane1->GetFormat(), 2),
	"validating the format of plane 1 (%s)", descriptor->plane1);
	} else {
	// RGBA case.
	DAWN_TRY_CONTEXT(CheckPlaneFormat(device, descriptor->plane0->GetFormat(), 4),
	"validating the format of plane 0 (%s)", descriptor->plane0);
	}

	DAWN_INVALID_IF(descriptor->visibleSize.width == 0 \|\| descriptor->visibleSize.height == 0,
	"VisibleSize %s have 0 on width or height.", &descriptor->visibleSize);

	const Extent3D textureSize = descriptor->plane0->GetSingleSubresourceVirtualSize();
	DAWN_INVALID_IF(descriptor->visibleSize.width > textureSize.width \|\|
	descriptor->visibleSize.height > textureSize.height,
	"VisibleSize %s is exceed the texture size, defined by Plane0 size (%u, %u).",
	&descriptor->visibleSize, textureSize.width, textureSize.height);
	DAWN_INVALID_IF(
	descriptor->visibleOrigin.x > textureSize.width - descriptor->visibleSize.width \|\|
	descriptor->visibleOrigin.y > textureSize.height - descriptor->visibleSize.height,
	"VisibleRect[Origin: %s, Size: %s] is exceed the texture size, defined by "
	"Plane0 size (%u, %u).",
	&descriptor->visibleOrigin, &descriptor->visibleSize, textureSize.width,
	textureSize.height);

	return {};
	}

	// static
	ResultOrError<Ref<ExternalTextureBase>> ExternalTextureBase::Create(
	DeviceBase* device,
	const ExternalTextureDescriptor* descriptor) {
	Ref<ExternalTextureBase> externalTexture =
	AcquireRef(new ExternalTextureBase(device, descriptor));
	DAWN_TRY(externalTexture->Initialize(device, descriptor));
	return std::move(externalTexture);
	}

	ExternalTextureBase::ExternalTextureBase(DeviceBase* device,
	const ExternalTextureDescriptor* descriptor)
	: ApiObjectBase(device, descriptor->label),
	mVisibleOrigin(descriptor->visibleOrigin),
	mVisibleSize(descriptor->visibleSize),
	mState(ExternalTextureState::Active) {
	GetObjectTrackingList()->Track(this);
	}

	// Error external texture cannot be used in bind group.
	ExternalTextureBase::ExternalTextureBase(DeviceBase* device,
	ObjectBase::ErrorTag tag,
	const char* label)
	: ApiObjectBase(device, tag, label), mState(ExternalTextureState::Destroyed) {}

	ExternalTextureBase::~ExternalTextureBase() = default;

	MaybeError ExternalTextureBase::Initialize(DeviceBase* device,
	const ExternalTextureDescriptor* descriptor) {
	// Store any passed in TextureViews associated with individual planes.
	mTextureViews[0] = descriptor->plane0;

	if (descriptor->plane1) {
	mTextureViews[1] = descriptor->plane1;
	} else {
	DAWN_TRY_ASSIGN(mTextureViews[1],
	device->GetOrCreatePlaceholderTextureViewForExternalTexture());
	}

	// We must create a buffer to store parameters needed by a shader that operates on this
	// external texture.
	BufferDescriptor bufferDesc;
	bufferDesc.size = sizeof(ExternalTextureParams);
	bufferDesc.usage = wgpu::BufferUsage::Uniform \| wgpu::BufferUsage::CopyDst;
	bufferDesc.label = "Dawn_External_Texture_Params_Buffer";

	DAWN_TRY_ASSIGN(mParamsBuffer, device->CreateBuffer(&bufferDesc));

	ExternalTextureParams params;
	params.numPlanes = descriptor->plane1 == nullptr ? 1 : 2;

	params.doYuvToRgbConversionOnly = descriptor->doYuvToRgbConversionOnly ? 1 : 0;

	// YUV-to-RGB conversion is performed by multiplying the source YUV values with a 4x3 matrix
	// passed from Chromium. The matrix was originally sourced from /skia/src/core/SkYUVMath.cpp.
	// This matrix is only used in multiplanar scenarios.
	if (params.numPlanes == 2) {
	DAWN_ASSERT(descriptor->yuvToRgbConversionMatrix);
	const float* yMat = descriptor->yuvToRgbConversionMatrix;
	std::copy(yMat, yMat + 12, params.yuvToRgbConversionMatrix.begin());
	}

	// Gamut correction is performed by multiplying a 3x3 matrix passed from Chromium. The
	// matrix was computed by multiplying the appropriate source and destination gamut
	// matrices sourced from ui/gfx/color_space.cc.
	const float* gMat = descriptor->gamutConversionMatrix;
	params.gamutConversionMatrix = {gMat[0], gMat[1], gMat[2], 0.0f, //
	gMat[3], gMat[4], gMat[5], 0.0f, //
	gMat[6], gMat[7], gMat[8], 0.0f};

	// Gamma decode/encode is performed by the logic:
	// if (abs(v) < params.D) {
	// return sign(v) * (params.C * abs(v) + params.F);
	// }
	// return pow(A * x + B, G) + E
	//
	// Constants are passed from Chromium and originally sourced from ui/gfx/color_space.cc
	const float* srcFn = descriptor->srcTransferFunctionParameters;
	std::copy(srcFn, srcFn + 7, params.gammaDecodingParams.begin());

	const float* dstFn = descriptor->dstTransferFunctionParameters;
	std::copy(dstFn, dstFn + 7, params.gammaEncodingParams.begin());

	// Unlike WGSL, which stores matrices in column vectors, the following arithmetic uses row
	// vectors, so elements are stored in the following order:
	//
	// ┌ ┐
	// │ 0, 1, 2 │
	// │ 3, 4, 5 │
	// └ ┘
	//
	// The matrix is transposed at the end.
	//
	// Note that we are working in homogeneous coordinates so there is an implied third row
	// containing [0, 0, 1].
	using mat2x3 = std::array<float, 6>;
	// Likewise the vectors have an implicit last element that's 1.
	using vec2 = std::array<float, 2>;

	// Multiplies the two mat2x3 matrices, by treating the RHS matrix as a mat3x3 where the last row
	// is [0, 0, 1].
	auto Mul = [](const mat2x3& lhs, const mat2x3& rhs) -> mat2x3 {
	auto& a = lhs[0];
	auto& b = lhs[1];
	auto& c = lhs[2];
	auto& d = lhs[3];
	auto& e = lhs[4];
	auto& f = lhs[5];
	auto& g = rhs[0];
	auto& h = rhs[1];
	auto& i = rhs[2];
	auto& j = rhs[3];
	auto& k = rhs[4];
	auto& l = rhs[5];
	// ┌ ┐ ┌ ┐
	// │ a, b, c │ │ g, h, i │
	// │ d, e, f │ x │ j, k, l │
	// └ ┘ │ 0, 0, 1 │
	// └ ┘
	return mat2x3{
	a * g + b * j, //
	a * h + b * k, //
	a * i + b * l + c, //
	d * g + e * j, //
	d * h + e * k, //
	d * i + e * l + f, //
	};
	};
	auto Scale = [](float x, float y) -> mat2x3 { return {x, 0, 0, 0, y, 0}; };
	auto ScaleVec = [&](vec2 v) -> mat2x3 { return Scale(v[0], v[1]); };
	auto Translate = [](float x, float y) -> mat2x3 { return mat2x3{1, 0, x, 0, 1, y}; };
	auto TranslateVec = [&](vec2 v) -> mat2x3 { return Translate(v[0], v[1]); };
	auto TransposeForWGSL = [](const mat2x3& m) -> std::array<float, 6> {
	return {m[0], m[3], m[1], m[4], m[2], m[5]};
	};

	// Vector operations
	auto Add = [](const vec2& a, const vec2& b) -> vec2 { return {a[0] + b[0], a[1] + b[1]}; };
	auto Sub = [](const vec2& a, const vec2& b) -> vec2 { return {a[0] - b[0], a[1] - b[1]}; };
	auto Div = [](const vec2& a, const vec2& b) -> vec2 { return {a[0] / b[0], a[1] / b[1]}; };

	// Extract all the relevant sizes as float to avoid extra casts in later computations.
	Extent3D plane0Extent = descriptor->plane0->GetSingleSubresourceVirtualSize();
	Extent3D plane1Extent = {1, 1, 1};
	if (params.numPlanes == 2) {
	plane1Extent = descriptor->plane1->GetSingleSubresourceVirtualSize();
	}
	vec2 plane0Size = {static_cast<float>(plane0Extent.width),
	static_cast<float>(plane0Extent.height)};
	vec2 plane1Size = {static_cast<float>(plane1Extent.width),
	static_cast<float>(plane1Extent.height)};
	vec2 visibleOrigin = {static_cast<float>(mVisibleOrigin.x),
	static_cast<float>(mVisibleOrigin.y)};
	vec2 visibleSize = {static_cast<float>(mVisibleSize.width),
	static_cast<float>(mVisibleSize.height)};

	// Offset the coordinates so the center texel is at the origin, so we can apply rotations and
	// y-flips. After translation, coordinates range from [-0.5 .. +0.5] in both U and V.
	mat2x3 sampleTransform = Translate(-0.5, -0.5);

	// The video frame metadata both rotation and mirroring information. The rotation happens before
	// the mirroring when processing the video frame, so do the inverse order when converting UV
	// coordinates.
	if (descriptor->mirrored) {
	sampleTransform = Mul(Scale(-1, 1), sampleTransform);
	}

	// Apply rotations as needed this may rotate the shader-visible size of the texture for
	// textureLoad operations.
	std::array<uint32_t, 2> loadBounds = {mVisibleSize.width - 1, mVisibleSize.height - 1};
	switch (descriptor->rotation) {
	case wgpu::ExternalTextureRotation::Rotate0Degrees:
	break;
	case wgpu::ExternalTextureRotation::Rotate90Degrees:
	std::swap(loadBounds[0], loadBounds[1]);
	sampleTransform = Mul(mat2x3{0, +1, 0, // x' = y
	-1, 0, 0}, // y' = -x
	sampleTransform);
	break;
	case wgpu::ExternalTextureRotation::Rotate180Degrees:
	sampleTransform = Mul(mat2x3{-1, 0, 0, // x' = -x
	0, -1, 0}, // y' = -y
	sampleTransform);
	break;
	case wgpu::ExternalTextureRotation::Rotate270Degrees:
	std::swap(loadBounds[0], loadBounds[1]);
	sampleTransform = Mul(mat2x3{0, -1, 0, // x' = -y
	+1, 0, 0}, // y' = x
	sampleTransform);
	break;
	}

	// Offset the coordinates so the bottom-left texel is at origin.
	// After translation, coordinates range from [0 .. 1] in both U and V.
	sampleTransform = Mul(Translate(0.5, 0.5), sampleTransform);

	// Finally, scale and translate based on the visible rect. This applies cropping.
	vec2 rectScale = Div(visibleSize, plane0Size);
	vec2 rectOffset = Div(visibleOrigin, plane0Size);
	sampleTransform = Mul(TranslateVec(rectOffset), Mul(ScaleVec(rectScale), sampleTransform));

	params.sampleTransform = TransposeForWGSL(sampleTransform);

	// Compute the load transformation matrix by using toTexels * sampleTransform * toNormalized
	// Note that coords starts from 0 so the max value is size - 1.
	{
	mat2x3 toTexels = ScaleVec(Sub(plane0Size, {1.0f, 1.0f}));
	mat2x3 toNormalized = Scale(1.0f / loadBounds[0], 1.0f / loadBounds[1]);
	mat2x3 loadTransform = Mul(toTexels, Mul(sampleTransform, toNormalized));

	params.loadTransform = TransposeForWGSL(loadTransform);
	}

	// Compute the clamping for each plane individually: to avoid bleeding of OOB texels due to
	// interpolation we need to offset by a half texel in, which depends on the size of the plane.
	{
	vec2 plane0HalfTexel = Div({0.5f, 0.5f}, plane0Size);
	vec2 plane1HalfTexel = Div({0.5f, 0.5f}, plane1Size);

	params.samplePlane0RectMin = Add(rectOffset, plane0HalfTexel);
	params.samplePlane1RectMin = Add(rectOffset, plane1HalfTexel);
	params.samplePlane0RectMax = Sub(Add(rectOffset, rectScale), plane0HalfTexel);
	params.samplePlane1RectMax = Sub(Add(rectOffset, rectScale), plane1HalfTexel);
	}

	params.plane1CoordFactor = Div(plane1Size, plane0Size);
	params.visibleSize = loadBounds;

	DAWN_TRY(device->GetQueue()->WriteBuffer(mParamsBuffer.Get(), 0, &params,
	sizeof(ExternalTextureParams)));

	return {};
	}

	const std::array<Ref<TextureViewBase>, kMaxPlanesPerFormat>& ExternalTextureBase::GetTextureViews()
	const {
	return mTextureViews;
	}

	MaybeError ExternalTextureBase::ValidateCanUseInSubmitNow() const {
	DAWN_ASSERT(!IsError());
	DAWN_INVALID_IF(mState != ExternalTextureState::Active,
	"External texture %s used in a submit is not active.", this);

	for (uint32_t i = 0; i < kMaxPlanesPerFormat; ++i) {
	if (mTextureViews[i] != nullptr) {
	DAWN_TRY_CONTEXT(mTextureViews[i]->GetTexture()->ValidateCanUseInSubmitNow(),
	"Validate plane %u of %s can be used in a submit.", i, this);
	}
	}
	return {};
	}

	MaybeError ExternalTextureBase::ValidateRefresh() {
	DAWN_TRY(GetDevice()->ValidateObject(this));
	DAWN_INVALID_IF(mState == ExternalTextureState::Destroyed, "%s is destroyed.", this);
	return {};
	}

	MaybeError ExternalTextureBase::ValidateExpire() {
	DAWN_TRY(GetDevice()->ValidateObject(this));
	DAWN_INVALID_IF(mState != ExternalTextureState::Active, "%s is not active.", this);
	return {};
	}

	void ExternalTextureBase::APIRefresh() {
	if (GetDevice()->ConsumedError(ValidateRefresh(), "calling %s.Refresh()", this)) {
	return;
	}
	mState = ExternalTextureState::Active;
	}

	void ExternalTextureBase::APIExpire() {
	if (GetDevice()->ConsumedError(ValidateExpire(), "calling %s.Expire()", this)) {
	return;
	}
	mState = ExternalTextureState::Expired;
	}

	void ExternalTextureBase::APIDestroy() {
	Destroy();
	}

	void ExternalTextureBase::DestroyImpl() {
	// TODO(crbug.com/dawn/831): DestroyImpl is called from two places.
	// - It may be called if the texture is explicitly destroyed with APIDestroy.
	// This case is NOT thread-safe and needs proper synchronization with other
	// simultaneous uses of the texture.
	// - It may be called when the last ref to the texture is dropped and the texture
	// is implicitly destroyed. This case is thread-safe because there are no
	// other threads using the texture since there are no other live refs.
	mState = ExternalTextureState::Destroyed;
	}

	// static
	Ref<ExternalTextureBase> ExternalTextureBase::MakeError(DeviceBase* device, const char* label) {
	return AcquireRef(new ExternalTextureBase(device, ObjectBase::kError, label));
	}

	BufferBase* ExternalTextureBase::GetParamsBuffer() const {
	return mParamsBuffer.Get();
	}

	ObjectType ExternalTextureBase::GetType() const {
	return ObjectType::ExternalTexture;
	}

	const Extent2D& ExternalTextureBase::GetVisibleSize() const {
	DAWN_ASSERT(!IsError());
	return mVisibleSize;
	}

	const Origin2D& ExternalTextureBase::GetVisibleOrigin() const {
	DAWN_ASSERT(!IsError());
	return mVisibleOrigin;
	}

	} // namespace dawn::native