dom/canvas/WebGLTransformFeedback.cpp

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "WebGLTransformFeedback.h"
   7
   8 #include "GLContext.h"
   9 #include "mozilla/dom/WebGL2RenderingContextBinding.h"
  10 #include "mozilla/IntegerRange.h"
  11 #include "WebGL2Context.h"
  12 #include "WebGLBuffer.h"
  13 #include "WebGLProgram.h"
  14
  15 namespace mozilla {
  16
  17 WebGLTransformFeedback::WebGLTransformFeedback(WebGLContext* webgl, GLuint tf)
  18     : WebGLContextBoundObject(webgl),
  19       mGLName(tf),
  20       mIndexedBindings(webgl->Limits().maxTransformFeedbackSeparateAttribs),
  21       mIsPaused(false),
  22       mIsActive(false) {}
  23
  24 WebGLTransformFeedback::~WebGLTransformFeedback() {
  25   if (!mContext) return;
  26   if (mGLName) {
  27     mContext->gl->fDeleteTransformFeedbacks(1, &mGLName);
  28   }
  29 }
  30
  31 ////////////////////////////////////////
  32
  33 void WebGLTransformFeedback::BeginTransformFeedback(GLenum primMode) {
  34   if (mIsActive) return mContext->ErrorInvalidOperation("Already active.");
  35
  36   switch (primMode) {
  37     case LOCAL_GL_POINTS:
  38     case LOCAL_GL_LINES:
  39     case LOCAL_GL_TRIANGLES:
  40       break;
  41     default:
  42       mContext->ErrorInvalidEnum(
  43           "`primitiveMode` must be one of POINTS, LINES, or"
  44           " TRIANGLES.");
  45       return;
  46   }
  47
  48   const auto& prog = mContext->mCurrentProgram;
  49   if (!prog || !prog->IsLinked() ||
  50       prog->LinkInfo()->componentsPerTFVert.empty()) {
  51     mContext->ErrorInvalidOperation(
  52         "Current program not valid for transform"
  53         " feedback.");
  54     return;
  55   }
  56
  57   const auto& linkInfo = prog->LinkInfo();
  58   const auto& componentsPerTFVert = linkInfo->componentsPerTFVert;
  59
  60   size_t minVertCapacity = SIZE_MAX;
  61   for (size_t i = 0; i < componentsPerTFVert.size(); i++) {
  62     const auto& indexedBinding = mIndexedBindings[i];
  63     const auto& componentsPerVert = componentsPerTFVert[i];
  64
  65     const auto& buffer = indexedBinding.mBufferBinding;
  66     if (!buffer) {
  67       mContext->ErrorInvalidOperation(
  68           "No buffer attached to required transform"
  69           " feedback index %u.",
  70           (uint32_t)i);
  71       return;
  72     }
  73
  74     for (const auto iBound : IntegerRange(mIndexedBindings.size())) {
  75       const auto& bound = mIndexedBindings[iBound].mBufferBinding.get();
  76       if (iBound != i && buffer == bound) {
  77         mContext->GenErrorIllegalUse(
  78             LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<uint32_t>(i),
  79             LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<uint32_t>(iBound));
  80         return;
  81       }
  82     }
  83
  84     const size_t vertCapacity = buffer->ByteLength() / 4 / componentsPerVert;
  85     minVertCapacity = std::min(minVertCapacity, vertCapacity);
  86   }
  87
  88   ////
  89
  90   const auto& gl = mContext->gl;
  91   gl->fBeginTransformFeedback(primMode);
  92
  93   ////
  94
  95   mIsActive = true;
  96   MOZ_ASSERT(!mIsPaused);
  97
  98   mActive_Program = prog;
  99   mActive_PrimMode = primMode;
 100   mActive_VertPosition = 0;
 101   mActive_VertCapacity = minVertCapacity;
 102
 103   ////
 104
 105   mActive_Program->mNumActiveTFOs++;
 106 }
 107
 108 void WebGLTransformFeedback::EndTransformFeedback() {
 109   if (!mIsActive) return mContext->ErrorInvalidOperation("Not active.");
 110
 111   ////
 112
 113   const auto& gl = mContext->gl;
 114   gl->fEndTransformFeedback();
 115
 116   if (gl->WorkAroundDriverBugs()) {
 117 #ifdef XP_MACOSX
 118     // Multi-threaded GL on mac will generate INVALID_OP in some cases for at
 119     // least BindBufferBase after an EndTransformFeedback if there is not a
 120     // flush between the two. Single-threaded GL does not have this issue. This
 121     // is likely due to not synchronizing client/server state, and erroring in
 122     // BindBufferBase because the client thinks we're still in transform
 123     // feedback.
 124     gl->fFlush();
 125 #endif
 126   }
 127
 128   ////
 129
 130   mIsActive = false;
 131   mIsPaused = false;
 132
 133   ////
 134
 135   mActive_Program->mNumActiveTFOs--;
 136 }
 137
 138 void WebGLTransformFeedback::PauseTransformFeedback() {
 139   if (!mIsActive || mIsPaused) {
 140     mContext->ErrorInvalidOperation("Not active or is paused.");
 141     return;
 142   }
 143
 144   ////
 145
 146   const auto& gl = mContext->gl;
 147   gl->fPauseTransformFeedback();
 148
 149   ////
 150
 151   mIsPaused = true;
 152 }
 153
 154 void WebGLTransformFeedback::ResumeTransformFeedback() {
 155   if (!mIsPaused) return mContext->ErrorInvalidOperation("Not paused.");
 156
 157   if (mContext->mCurrentProgram != mActive_Program) {
 158     mContext->ErrorInvalidOperation("Active program differs from original.");
 159     return;
 160   }
 161
 162   ////
 163
 164   const auto& gl = mContext->gl;
 165   gl->fResumeTransformFeedback();
 166
 167   ////
 168
 169   MOZ_ASSERT(mIsActive);
 170   mIsPaused = false;
 171 }
 172
 173 }  // namespace mozilla