michael@0: /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "WebGLContext.h"
michael@0: 
michael@0: #include "GLContext.h"
michael@0: #include "mozilla/CheckedInt.h"
michael@0: #include "WebGLBuffer.h"
michael@0: #include "WebGLContextUtils.h"
michael@0: #include "WebGLFramebuffer.h"
michael@0: #include "WebGLProgram.h"
michael@0: #include "WebGLRenderbuffer.h"
michael@0: #include "WebGLShader.h"
michael@0: #include "WebGLTexture.h"
michael@0: #include "WebGLUniformInfo.h"
michael@0: #include "WebGLVertexArray.h"
michael@0: #include "WebGLVertexAttribData.h"
michael@0: 
michael@0: using namespace mozilla;
michael@0: using namespace mozilla::dom;
michael@0: using namespace mozilla::gl;
michael@0: 
michael@0: // For a Tegra workaround.
michael@0: static const int MAX_DRAW_CALLS_SINCE_FLUSH = 100;
michael@0: 
michael@0: bool
michael@0: WebGLContext::DrawInstanced_check(const char* info)
michael@0: {
michael@0:     // This restriction was removed in GLES3, so WebGL2 shouldn't have it.
michael@0:     if (!IsWebGL2() &&
michael@0:         IsExtensionEnabled(WebGLExtensionID::ANGLE_instanced_arrays) &&
michael@0:         !mBufferFetchingHasPerVertex)
michael@0:     {
michael@0:         /* http://www.khronos.org/registry/gles/extensions/ANGLE/ANGLE_instanced_arrays.txt
michael@0:          *  If all of the enabled vertex attribute arrays that are bound to active
michael@0:          *  generic attributes in the program have a non-zero divisor, the draw
michael@0:          *  call should return INVALID_OPERATION.
michael@0:          *
michael@0:          * NB: This also appears to apply to NV_instanced_arrays, though the
michael@0:          * INVALID_OPERATION emission is not explicitly stated.
michael@0:          * ARB_instanced_arrays does not have this restriction.
michael@0:          */
michael@0:         ErrorInvalidOperation("%s: at least one vertex attribute divisor should be 0", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: bool WebGLContext::DrawArrays_check(GLint first, GLsizei count, GLsizei primcount, const char* info)
michael@0: {
michael@0:     if (first < 0 || count < 0) {
michael@0:         ErrorInvalidValue("%s: negative first or count", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (primcount < 0) {
michael@0:         ErrorInvalidValue("%s: negative primcount", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (!ValidateStencilParamsForDrawCall()) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // If count is 0, there's nothing to do.
michael@0:     if (count == 0 || primcount == 0) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // Any checks below this depend on a program being available.
michael@0:     if (!mCurrentProgram) {
michael@0:         ErrorInvalidOperation("%s: null CURRENT_PROGRAM", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (!ValidateBufferFetching(info)) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     CheckedInt<GLsizei> checked_firstPlusCount = CheckedInt<GLsizei>(first) + count;
michael@0: 
michael@0:     if (!checked_firstPlusCount.isValid()) {
michael@0:         ErrorInvalidOperation("%s: overflow in first+count", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (uint32_t(checked_firstPlusCount.value()) > mMaxFetchedVertices) {
michael@0:         ErrorInvalidOperation("%s: bound vertex attribute buffers do not have sufficient size for given first and count", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (uint32_t(primcount) > mMaxFetchedInstances) {
michael@0:         ErrorInvalidOperation("%s: bound instance attribute buffers do not have sufficient size for given primcount", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     MakeContextCurrent();
michael@0: 
michael@0:     if (mBoundFramebuffer) {
michael@0:         if (!mBoundFramebuffer->CheckAndInitializeAttachments()) {
michael@0:             ErrorInvalidFramebufferOperation("%s: incomplete framebuffer", info);
michael@0:             return false;
michael@0:         }
michael@0:     } else {
michael@0:         ClearBackbufferIfNeeded();
michael@0:     }
michael@0: 
michael@0:     if (!DoFakeVertexAttrib0(checked_firstPlusCount.value())) {
michael@0:         return false;
michael@0:     }
michael@0:     BindFakeBlackTextures();
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::DrawArrays(GLenum mode, GLint first, GLsizei count)
michael@0: {
michael@0:     if (IsContextLost())
michael@0:         return;
michael@0: 
michael@0:     if (!ValidateDrawModeEnum(mode, "drawArrays: mode"))
michael@0:         return;
michael@0: 
michael@0:     if (!DrawArrays_check(first, count, 1, "drawArrays"))
michael@0:         return;
michael@0: 
michael@0:     SetupContextLossTimer();
michael@0:     gl->fDrawArrays(mode, first, count);
michael@0: 
michael@0:     Draw_cleanup();
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::DrawArraysInstanced(GLenum mode, GLint first, GLsizei count, GLsizei primcount)
michael@0: {
michael@0:     if (IsContextLost())
michael@0:         return;
michael@0: 
michael@0:     if (!ValidateDrawModeEnum(mode, "drawArraysInstanced: mode"))
michael@0:         return;
michael@0: 
michael@0:     if (!DrawArrays_check(first, count, primcount, "drawArraysInstanced"))
michael@0:         return;
michael@0: 
michael@0:     if (!DrawInstanced_check("drawArraysInstanced"))
michael@0:         return;
michael@0: 
michael@0:     SetupContextLossTimer();
michael@0:     gl->fDrawArraysInstanced(mode, first, count, primcount);
michael@0: 
michael@0:     Draw_cleanup();
michael@0: }
michael@0: 
michael@0: bool
michael@0: WebGLContext::DrawElements_check(GLsizei count, GLenum type,
michael@0:                                  WebGLintptr byteOffset, GLsizei primcount,
michael@0:                                  const char* info, GLuint* out_upperBound)
michael@0: {
michael@0:     if (count < 0 || byteOffset < 0) {
michael@0:         ErrorInvalidValue("%s: negative count or offset", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (primcount < 0) {
michael@0:         ErrorInvalidValue("%s: negative primcount", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (!ValidateStencilParamsForDrawCall()) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // If count is 0, there's nothing to do.
michael@0:     if (count == 0 || primcount == 0) {
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     CheckedUint32 checked_byteCount;
michael@0: 
michael@0:     GLsizei first = 0;
michael@0: 
michael@0:     if (type == LOCAL_GL_UNSIGNED_SHORT) {
michael@0:         checked_byteCount = 2 * CheckedUint32(count);
michael@0:         if (byteOffset % 2 != 0) {
michael@0:             ErrorInvalidOperation("%s: invalid byteOffset for UNSIGNED_SHORT (must be a multiple of 2)", info);
michael@0:             return false;
michael@0:         }
michael@0:         first = byteOffset / 2;
michael@0:     }
michael@0:     else if (type == LOCAL_GL_UNSIGNED_BYTE) {
michael@0:         checked_byteCount = count;
michael@0:         first = byteOffset;
michael@0:     }
michael@0:     else if (type == LOCAL_GL_UNSIGNED_INT && IsExtensionEnabled(WebGLExtensionID::OES_element_index_uint)) {
michael@0:         checked_byteCount = 4 * CheckedUint32(count);
michael@0:         if (byteOffset % 4 != 0) {
michael@0:             ErrorInvalidOperation("%s: invalid byteOffset for UNSIGNED_INT (must be a multiple of 4)", info);
michael@0:             return false;
michael@0:         }
michael@0:         first = byteOffset / 4;
michael@0:     }
michael@0:     else {
michael@0:         ErrorInvalidEnum("%s: type must be UNSIGNED_SHORT or UNSIGNED_BYTE", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (!checked_byteCount.isValid()) {
michael@0:         ErrorInvalidValue("%s: overflow in byteCount", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     // Any checks below this depend on a program being available.
michael@0:     if (!mCurrentProgram) {
michael@0:         ErrorInvalidOperation("%s: null CURRENT_PROGRAM", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (!mBoundVertexArray->mBoundElementArrayBuffer) {
michael@0:         ErrorInvalidOperation("%s: must have element array buffer binding", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     WebGLBuffer& elemArrayBuffer = *mBoundVertexArray->mBoundElementArrayBuffer;
michael@0: 
michael@0:     if (!elemArrayBuffer.ByteLength()) {
michael@0:         ErrorInvalidOperation("%s: bound element array buffer doesn't have any data", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     CheckedInt<GLsizei> checked_neededByteCount = checked_byteCount.toChecked<GLsizei>() + byteOffset;
michael@0: 
michael@0:     if (!checked_neededByteCount.isValid()) {
michael@0:         ErrorInvalidOperation("%s: overflow in byteOffset+byteCount", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (uint32_t(checked_neededByteCount.value()) > elemArrayBuffer.ByteLength()) {
michael@0:         ErrorInvalidOperation("%s: bound element array buffer is too small for given count and offset", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (!ValidateBufferFetching(info))
michael@0:         return false;
michael@0: 
michael@0:     if (!mMaxFetchedVertices ||
michael@0:         !elemArrayBuffer.Validate(type, mMaxFetchedVertices - 1, first, count, out_upperBound))
michael@0:     {
michael@0:         ErrorInvalidOperation(
michael@0:                               "%s: bound vertex attribute buffers do not have sufficient "
michael@0:                               "size for given indices from the bound element array", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     if (uint32_t(primcount) > mMaxFetchedInstances) {
michael@0:         ErrorInvalidOperation("%s: bound instance attribute buffers do not have sufficient size for given primcount", info);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     MakeContextCurrent();
michael@0: 
michael@0:     if (mBoundFramebuffer) {
michael@0:         if (!mBoundFramebuffer->CheckAndInitializeAttachments()) {
michael@0:             ErrorInvalidFramebufferOperation("%s: incomplete framebuffer", info);
michael@0:             return false;
michael@0:         }
michael@0:     } else {
michael@0:         ClearBackbufferIfNeeded();
michael@0:     }
michael@0: 
michael@0:     if (!DoFakeVertexAttrib0(mMaxFetchedVertices)) {
michael@0:         return false;
michael@0:     }
michael@0:     BindFakeBlackTextures();
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::DrawElements(GLenum mode, GLsizei count, GLenum type,
michael@0:                            WebGLintptr byteOffset)
michael@0: {
michael@0:     if (IsContextLost())
michael@0:         return;
michael@0: 
michael@0:     if (!ValidateDrawModeEnum(mode, "drawElements: mode"))
michael@0:         return;
michael@0: 
michael@0:     GLuint upperBound = UINT_MAX;
michael@0:     if (!DrawElements_check(count, type, byteOffset, 1, "drawElements",
michael@0:                             &upperBound))
michael@0:     {
michael@0:         return;
michael@0:     }
michael@0: 
michael@0:     SetupContextLossTimer();
michael@0: 
michael@0:     if (gl->IsSupported(gl::GLFeature::draw_range_elements)) {
michael@0:         gl->fDrawRangeElements(mode, 0, upperBound,
michael@0:                                count, type, reinterpret_cast<GLvoid*>(byteOffset));
michael@0:     } else {
michael@0:         gl->fDrawElements(mode, count, type, reinterpret_cast<GLvoid*>(byteOffset));
michael@0:     }
michael@0: 
michael@0:     Draw_cleanup();
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::DrawElementsInstanced(GLenum mode, GLsizei count, GLenum type,
michael@0:                                     WebGLintptr byteOffset, GLsizei primcount)
michael@0: {
michael@0:     if (IsContextLost())
michael@0:         return;
michael@0: 
michael@0:     if (!ValidateDrawModeEnum(mode, "drawElementsInstanced: mode"))
michael@0:         return;
michael@0: 
michael@0:     if (!DrawElements_check(count, type, byteOffset, primcount, "drawElementsInstanced"))
michael@0:         return;
michael@0: 
michael@0:     if (!DrawInstanced_check("drawElementsInstanced"))
michael@0:         return;
michael@0: 
michael@0:     SetupContextLossTimer();
michael@0:     gl->fDrawElementsInstanced(mode, count, type, reinterpret_cast<GLvoid*>(byteOffset), primcount);
michael@0: 
michael@0:     Draw_cleanup();
michael@0: }
michael@0: 
michael@0: void WebGLContext::Draw_cleanup()
michael@0: {
michael@0:     UndoFakeVertexAttrib0();
michael@0:     UnbindFakeBlackTextures();
michael@0: 
michael@0:     if (!mBoundFramebuffer) {
michael@0:         Invalidate();
michael@0:         mShouldPresent = true;
michael@0:         MOZ_ASSERT(!mBackbufferNeedsClear);
michael@0:     }
michael@0: 
michael@0:     if (gl->WorkAroundDriverBugs()) {
michael@0:         if (gl->Renderer() == gl::GLRenderer::Tegra) {
michael@0:             mDrawCallsSinceLastFlush++;
michael@0: 
michael@0:             if (mDrawCallsSinceLastFlush >= MAX_DRAW_CALLS_SINCE_FLUSH) {
michael@0:                 gl->fFlush();
michael@0:                 mDrawCallsSinceLastFlush = 0;
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // Let's check the viewport
michael@0:     const WebGLRectangleObject* rect = CurValidFBRectObject();
michael@0:     if (rect) {
michael@0:         if (mViewportWidth > rect->Width() ||
michael@0:             mViewportHeight > rect->Height())
michael@0:         {
michael@0:             if (!mAlreadyWarnedAboutViewportLargerThanDest) {
michael@0:                 GenerateWarning("Drawing to a destination rect smaller than the viewport rect. "
michael@0:                                 "(This warning will only be given once)");
michael@0:                 mAlreadyWarnedAboutViewportLargerThanDest = true;
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * Verify that state is consistent for drawing, and compute max number of elements (maxAllowedCount)
michael@0:  * that will be legal to be read from bound VBOs.
michael@0:  */
michael@0: 
michael@0: bool
michael@0: WebGLContext::ValidateBufferFetching(const char *info)
michael@0: {
michael@0: #ifdef DEBUG
michael@0:     GLint currentProgram = 0;
michael@0:     MakeContextCurrent();
michael@0:     gl->fGetIntegerv(LOCAL_GL_CURRENT_PROGRAM, &currentProgram);
michael@0:     MOZ_ASSERT(GLuint(currentProgram) == mCurrentProgram->GLName(),
michael@0:                "WebGL: current program doesn't agree with GL state");
michael@0: #endif
michael@0: 
michael@0:     if (mBufferFetchingIsVerified) {
michael@0:         return true;
michael@0:     }
michael@0: 
michael@0:     bool hasPerVertex = false;
michael@0:     uint32_t maxVertices = UINT32_MAX;
michael@0:     uint32_t maxInstances = UINT32_MAX;
michael@0:     uint32_t attribs = mBoundVertexArray->mAttribs.Length();
michael@0: 
michael@0:     for (uint32_t i = 0; i < attribs; ++i) {
michael@0:         const WebGLVertexAttribData& vd = mBoundVertexArray->mAttribs[i];
michael@0: 
michael@0:         // If the attrib array isn't enabled, there's nothing to check;
michael@0:         // it's a static value.
michael@0:         if (!vd.enabled)
michael@0:             continue;
michael@0: 
michael@0:         if (vd.buf == nullptr) {
michael@0:             ErrorInvalidOperation("%s: no VBO bound to enabled vertex attrib index %d!", info, i);
michael@0:             return false;
michael@0:         }
michael@0: 
michael@0:         // If the attrib is not in use, then we don't have to validate
michael@0:         // it, just need to make sure that the binding is non-null.
michael@0:         if (!mCurrentProgram->IsAttribInUse(i))
michael@0:             continue;
michael@0: 
michael@0:         // the base offset
michael@0:         CheckedUint32 checked_byteLength = CheckedUint32(vd.buf->ByteLength()) - vd.byteOffset;
michael@0:         CheckedUint32 checked_sizeOfLastElement = CheckedUint32(vd.componentSize()) * vd.size;
michael@0: 
michael@0:         if (!checked_byteLength.isValid() ||
michael@0:             !checked_sizeOfLastElement.isValid())
michael@0:         {
michael@0:             ErrorInvalidOperation("%s: integer overflow occured while checking vertex attrib %d", info, i);
michael@0:             return false;
michael@0:         }
michael@0: 
michael@0:         if (checked_byteLength.value() < checked_sizeOfLastElement.value()) {
michael@0:             maxVertices = 0;
michael@0:             maxInstances = 0;
michael@0:             break;
michael@0:         }
michael@0: 
michael@0:         CheckedUint32 checked_maxAllowedCount = ((checked_byteLength - checked_sizeOfLastElement) / vd.actualStride()) + 1;
michael@0: 
michael@0:         if (!checked_maxAllowedCount.isValid()) {
michael@0:             ErrorInvalidOperation("%s: integer overflow occured while checking vertex attrib %d", info, i);
michael@0:             return false;
michael@0:         }
michael@0: 
michael@0:         if (vd.divisor == 0) {
michael@0:             maxVertices = std::min(maxVertices, checked_maxAllowedCount.value());
michael@0:             hasPerVertex = true;
michael@0:         } else {
michael@0:             maxInstances = std::min(maxInstances, checked_maxAllowedCount.value() / vd.divisor);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     mBufferFetchingIsVerified = true;
michael@0:     mBufferFetchingHasPerVertex = hasPerVertex;
michael@0:     mMaxFetchedVertices = maxVertices;
michael@0:     mMaxFetchedInstances = maxInstances;
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: WebGLVertexAttrib0Status
michael@0: WebGLContext::WhatDoesVertexAttrib0Need()
michael@0: {
michael@0:     MOZ_ASSERT(mCurrentProgram);
michael@0: 
michael@0:     // work around Mac OSX crash, see bug 631420
michael@0: #ifdef XP_MACOSX
michael@0:     if (gl->WorkAroundDriverBugs() &&
michael@0:         mBoundVertexArray->IsAttribArrayEnabled(0) &&
michael@0:         !mCurrentProgram->IsAttribInUse(0))
michael@0:     {
michael@0:         return WebGLVertexAttrib0Status::EmulatedUninitializedArray;
michael@0:     }
michael@0: #endif
michael@0: 
michael@0:     if (MOZ_LIKELY(gl->IsGLES() ||
michael@0:                    mBoundVertexArray->IsAttribArrayEnabled(0)))
michael@0:     {
michael@0:         return WebGLVertexAttrib0Status::Default;
michael@0:     }
michael@0: 
michael@0:     return mCurrentProgram->IsAttribInUse(0)
michael@0:            ? WebGLVertexAttrib0Status::EmulatedInitializedArray
michael@0:            : WebGLVertexAttrib0Status::EmulatedUninitializedArray;
michael@0: }
michael@0: 
michael@0: bool
michael@0: WebGLContext::DoFakeVertexAttrib0(GLuint vertexCount)
michael@0: {
michael@0:     WebGLVertexAttrib0Status whatDoesAttrib0Need = WhatDoesVertexAttrib0Need();
michael@0: 
michael@0:     if (MOZ_LIKELY(whatDoesAttrib0Need == WebGLVertexAttrib0Status::Default))
michael@0:         return true;
michael@0: 
michael@0:     if (!mAlreadyWarnedAboutFakeVertexAttrib0) {
michael@0:         GenerateWarning("Drawing without vertex attrib 0 array enabled forces the browser "
michael@0:                         "to do expensive emulation work when running on desktop OpenGL "
michael@0:                         "platforms, for example on Mac. It is preferable to always draw "
michael@0:                         "with vertex attrib 0 array enabled, by using bindAttribLocation "
michael@0:                         "to bind some always-used attribute to location 0.");
michael@0:         mAlreadyWarnedAboutFakeVertexAttrib0 = true;
michael@0:     }
michael@0: 
michael@0:     CheckedUint32 checked_dataSize = CheckedUint32(vertexCount) * 4 * sizeof(GLfloat);
michael@0: 
michael@0:     if (!checked_dataSize.isValid()) {
michael@0:         ErrorOutOfMemory("Integer overflow trying to construct a fake vertex attrib 0 array for a draw-operation "
michael@0:                          "with %d vertices. Try reducing the number of vertices.", vertexCount);
michael@0:         return false;
michael@0:     }
michael@0: 
michael@0:     GLuint dataSize = checked_dataSize.value();
michael@0: 
michael@0:     if (!mFakeVertexAttrib0BufferObject) {
michael@0:         gl->fGenBuffers(1, &mFakeVertexAttrib0BufferObject);
michael@0:     }
michael@0: 
michael@0:     // if the VBO status is already exactly what we need, or if the only difference is that it's initialized and
michael@0:     // we don't need it to be, then consider it OK
michael@0:     bool vertexAttrib0BufferStatusOK =
michael@0:         mFakeVertexAttrib0BufferStatus == whatDoesAttrib0Need ||
michael@0:         (mFakeVertexAttrib0BufferStatus == WebGLVertexAttrib0Status::EmulatedInitializedArray &&
michael@0:          whatDoesAttrib0Need == WebGLVertexAttrib0Status::EmulatedUninitializedArray);
michael@0: 
michael@0:     if (!vertexAttrib0BufferStatusOK ||
michael@0:         mFakeVertexAttrib0BufferObjectSize < dataSize ||
michael@0:         mFakeVertexAttrib0BufferObjectVector[0] != mVertexAttrib0Vector[0] ||
michael@0:         mFakeVertexAttrib0BufferObjectVector[1] != mVertexAttrib0Vector[1] ||
michael@0:         mFakeVertexAttrib0BufferObjectVector[2] != mVertexAttrib0Vector[2] ||
michael@0:         mFakeVertexAttrib0BufferObjectVector[3] != mVertexAttrib0Vector[3])
michael@0:     {
michael@0:         mFakeVertexAttrib0BufferStatus = whatDoesAttrib0Need;
michael@0:         mFakeVertexAttrib0BufferObjectSize = dataSize;
michael@0:         mFakeVertexAttrib0BufferObjectVector[0] = mVertexAttrib0Vector[0];
michael@0:         mFakeVertexAttrib0BufferObjectVector[1] = mVertexAttrib0Vector[1];
michael@0:         mFakeVertexAttrib0BufferObjectVector[2] = mVertexAttrib0Vector[2];
michael@0:         mFakeVertexAttrib0BufferObjectVector[3] = mVertexAttrib0Vector[3];
michael@0: 
michael@0:         gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, mFakeVertexAttrib0BufferObject);
michael@0: 
michael@0:         GetAndFlushUnderlyingGLErrors();
michael@0: 
michael@0:         if (mFakeVertexAttrib0BufferStatus == WebGLVertexAttrib0Status::EmulatedInitializedArray) {
michael@0:             nsAutoArrayPtr<GLfloat> array(new GLfloat[4 * vertexCount]);
michael@0:             for(size_t i = 0; i < vertexCount; ++i) {
michael@0:                 array[4 * i + 0] = mVertexAttrib0Vector[0];
michael@0:                 array[4 * i + 1] = mVertexAttrib0Vector[1];
michael@0:                 array[4 * i + 2] = mVertexAttrib0Vector[2];
michael@0:                 array[4 * i + 3] = mVertexAttrib0Vector[3];
michael@0:             }
michael@0:             gl->fBufferData(LOCAL_GL_ARRAY_BUFFER, dataSize, array, LOCAL_GL_DYNAMIC_DRAW);
michael@0:         } else {
michael@0:             gl->fBufferData(LOCAL_GL_ARRAY_BUFFER, dataSize, nullptr, LOCAL_GL_DYNAMIC_DRAW);
michael@0:         }
michael@0:         GLenum error = GetAndFlushUnderlyingGLErrors();
michael@0: 
michael@0:         gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, mBoundArrayBuffer ? mBoundArrayBuffer->GLName() : 0);
michael@0: 
michael@0:         // note that we do this error checking and early return AFTER having restored the buffer binding above
michael@0:         if (error) {
michael@0:             ErrorOutOfMemory("Ran out of memory trying to construct a fake vertex attrib 0 array for a draw-operation "
michael@0:                              "with %d vertices. Try reducing the number of vertices.", vertexCount);
michael@0:             return false;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, mFakeVertexAttrib0BufferObject);
michael@0:     gl->fVertexAttribPointer(0, 4, LOCAL_GL_FLOAT, LOCAL_GL_FALSE, 0, 0);
michael@0: 
michael@0:     return true;
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::UndoFakeVertexAttrib0()
michael@0: {
michael@0:     WebGLVertexAttrib0Status whatDoesAttrib0Need = WhatDoesVertexAttrib0Need();
michael@0: 
michael@0:     if (MOZ_LIKELY(whatDoesAttrib0Need == WebGLVertexAttrib0Status::Default))
michael@0:         return;
michael@0: 
michael@0:     if (mBoundVertexArray->HasAttrib(0) && mBoundVertexArray->mAttribs[0].buf) {
michael@0:         const WebGLVertexAttribData& attrib0 = mBoundVertexArray->mAttribs[0];
michael@0:         gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, attrib0.buf->GLName());
michael@0:         gl->fVertexAttribPointer(0,
michael@0:                                  attrib0.size,
michael@0:                                  attrib0.type,
michael@0:                                  attrib0.normalized,
michael@0:                                  attrib0.stride,
michael@0:                                  reinterpret_cast<const GLvoid *>(attrib0.byteOffset));
michael@0:     } else {
michael@0:         gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, 0);
michael@0:     }
michael@0: 
michael@0:     gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, mBoundArrayBuffer ? mBoundArrayBuffer->GLName() : 0);
michael@0: }
michael@0: 
michael@0: WebGLContextFakeBlackStatus
michael@0: WebGLContext::ResolvedFakeBlackStatus()
michael@0: {
michael@0:     // handle this case first, it's the generic case
michael@0:     if (MOZ_LIKELY(mFakeBlackStatus == WebGLContextFakeBlackStatus::NotNeeded))
michael@0:         return mFakeBlackStatus;
michael@0: 
michael@0:     if (mFakeBlackStatus == WebGLContextFakeBlackStatus::Needed)
michael@0:         return mFakeBlackStatus;
michael@0: 
michael@0:     for (int32_t i = 0; i < mGLMaxTextureUnits; ++i) {
michael@0:         if ((mBound2DTextures[i] && mBound2DTextures[i]->ResolvedFakeBlackStatus() != WebGLTextureFakeBlackStatus::NotNeeded) ||
michael@0:             (mBoundCubeMapTextures[i] && mBoundCubeMapTextures[i]->ResolvedFakeBlackStatus() != WebGLTextureFakeBlackStatus::NotNeeded))
michael@0:         {
michael@0:             mFakeBlackStatus = WebGLContextFakeBlackStatus::Needed;
michael@0:             return mFakeBlackStatus;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     // we have exhausted all cases where we do need fakeblack, so if the status is still unknown,
michael@0:     // that means that we do NOT need it.
michael@0:     mFakeBlackStatus = WebGLContextFakeBlackStatus::NotNeeded;
michael@0:     return mFakeBlackStatus;
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::BindFakeBlackTexturesHelper(
michael@0:     GLenum target,
michael@0:     const nsTArray<WebGLRefPtr<WebGLTexture> > & boundTexturesArray,
michael@0:     ScopedDeletePtr<FakeBlackTexture> & opaqueTextureScopedPtr,
michael@0:     ScopedDeletePtr<FakeBlackTexture> & transparentTextureScopedPtr)
michael@0: {
michael@0:     for (int32_t i = 0; i < mGLMaxTextureUnits; ++i) {
michael@0:         if (!boundTexturesArray[i]) {
michael@0:             continue;
michael@0:         }
michael@0: 
michael@0:         WebGLTextureFakeBlackStatus s = boundTexturesArray[i]->ResolvedFakeBlackStatus();
michael@0:         MOZ_ASSERT(s != WebGLTextureFakeBlackStatus::Unknown);
michael@0: 
michael@0:         if (MOZ_LIKELY(s == WebGLTextureFakeBlackStatus::NotNeeded)) {
michael@0:             continue;
michael@0:         }
michael@0: 
michael@0:         bool alpha = s == WebGLTextureFakeBlackStatus::UninitializedImageData &&
michael@0:                      FormatHasAlpha(boundTexturesArray[i]->ImageInfoBase().WebGLFormat());
michael@0:         ScopedDeletePtr<FakeBlackTexture>&
michael@0:             blackTexturePtr = alpha
michael@0:                               ? transparentTextureScopedPtr
michael@0:                               : opaqueTextureScopedPtr;
michael@0: 
michael@0:         if (!blackTexturePtr) {
michael@0:             GLenum format = alpha ? LOCAL_GL_RGBA : LOCAL_GL_RGB;
michael@0:             blackTexturePtr
michael@0:                 = new FakeBlackTexture(gl, target, format);
michael@0:         }
michael@0: 
michael@0:         gl->fActiveTexture(LOCAL_GL_TEXTURE0 + i);
michael@0:         gl->fBindTexture(target,
michael@0:                          blackTexturePtr->GLName());
michael@0:     }
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::BindFakeBlackTextures()
michael@0: {
michael@0:     // this is the generic case: try to return early
michael@0:     if (MOZ_LIKELY(ResolvedFakeBlackStatus() == WebGLContextFakeBlackStatus::NotNeeded))
michael@0:         return;
michael@0: 
michael@0:     BindFakeBlackTexturesHelper(LOCAL_GL_TEXTURE_2D,
michael@0:                                 mBound2DTextures,
michael@0:                                 mBlackOpaqueTexture2D,
michael@0:                                 mBlackTransparentTexture2D);
michael@0:     BindFakeBlackTexturesHelper(LOCAL_GL_TEXTURE_CUBE_MAP,
michael@0:                                 mBoundCubeMapTextures,
michael@0:                                 mBlackOpaqueTextureCubeMap,
michael@0:                                 mBlackTransparentTextureCubeMap);
michael@0: }
michael@0: 
michael@0: void
michael@0: WebGLContext::UnbindFakeBlackTextures()
michael@0: {
michael@0:     // this is the generic case: try to return early
michael@0:     if (MOZ_LIKELY(ResolvedFakeBlackStatus() == WebGLContextFakeBlackStatus::NotNeeded))
michael@0:         return;
michael@0: 
michael@0:     for (int32_t i = 0; i < mGLMaxTextureUnits; ++i) {
michael@0:         if (mBound2DTextures[i] && mBound2DTextures[i]->ResolvedFakeBlackStatus() != WebGLTextureFakeBlackStatus::NotNeeded) {
michael@0:             gl->fActiveTexture(LOCAL_GL_TEXTURE0 + i);
michael@0:             gl->fBindTexture(LOCAL_GL_TEXTURE_2D, mBound2DTextures[i]->GLName());
michael@0:         }
michael@0:         if (mBoundCubeMapTextures[i] && mBoundCubeMapTextures[i]->ResolvedFakeBlackStatus() != WebGLTextureFakeBlackStatus::NotNeeded) {
michael@0:             gl->fActiveTexture(LOCAL_GL_TEXTURE0 + i);
michael@0:             gl->fBindTexture(LOCAL_GL_TEXTURE_CUBE_MAP, mBoundCubeMapTextures[i]->GLName());
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     gl->fActiveTexture(LOCAL_GL_TEXTURE0 + mActiveTexture);
michael@0: }
michael@0: 
michael@0: WebGLContext::FakeBlackTexture::FakeBlackTexture(GLContext *gl, GLenum target, GLenum format)
michael@0:     : mGL(gl)
michael@0:     , mGLName(0)
michael@0: {
michael@0:   MOZ_ASSERT(target == LOCAL_GL_TEXTURE_2D || target == LOCAL_GL_TEXTURE_CUBE_MAP);
michael@0:   MOZ_ASSERT(format == LOCAL_GL_RGB || format == LOCAL_GL_RGBA);
michael@0: 
michael@0:   mGL->MakeCurrent();
michael@0:   GLuint formerBinding = 0;
michael@0:   gl->GetUIntegerv(target == LOCAL_GL_TEXTURE_2D
michael@0:                    ? LOCAL_GL_TEXTURE_BINDING_2D
michael@0:                    : LOCAL_GL_TEXTURE_BINDING_CUBE_MAP,
michael@0:                    &formerBinding);
michael@0:   gl->fGenTextures(1, &mGLName);
michael@0:   gl->fBindTexture(target, mGLName);
michael@0: 
michael@0:   // we allocate our zeros on the heap, and we overallocate (16 bytes instead of 4)
michael@0:   // to minimize the risk of running into a driver bug in texImage2D, as it is
michael@0:   // a bit unusual maybe to create 1x1 textures, and the stack may not have the alignment
michael@0:   // that texImage2D expects.
michael@0:   void* zeros = calloc(1, 16);
michael@0:   if (target == LOCAL_GL_TEXTURE_2D) {
michael@0:       gl->fTexImage2D(target, 0, format, 1, 1,
michael@0:                       0, format, LOCAL_GL_UNSIGNED_BYTE, zeros);
michael@0:   } else {
michael@0:       for (GLuint i = 0; i < 6; ++i) {
michael@0:           gl->fTexImage2D(LOCAL_GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, format, 1, 1,
michael@0:                           0, format, LOCAL_GL_UNSIGNED_BYTE, zeros);
michael@0:       }
michael@0:   }
michael@0:   free(zeros);
michael@0: 
michael@0:   gl->fBindTexture(target, formerBinding);
michael@0: }
michael@0: 
michael@0: WebGLContext::FakeBlackTexture::~FakeBlackTexture()
michael@0: {
michael@0:   if (mGL) {
michael@0:       mGL->MakeCurrent();
michael@0:       mGL->fDeleteTextures(1, &mGLName);
michael@0:   }
michael@0: }