1 files changed, 173 insertions, 0 deletions
diff --git a/dom/canvas/WebGLTransformFeedback.cpp b/dom/canvas/WebGLTransformFeedback.cpp
new file mode 100644
index 0000000000..ffcf7b6479
--- /dev/null
+++ b/dom/canvas/WebGLTransformFeedback.cpp
@@ -0,0 +1,173 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "WebGLTransformFeedback.h"
+
+#include "GLContext.h"
+#include "mozilla/dom/WebGL2RenderingContextBinding.h"
+#include "mozilla/IntegerRange.h"
+#include "WebGL2Context.h"
+#include "WebGLBuffer.h"
+#include "WebGLProgram.h"
+
+namespace mozilla {
+
+WebGLTransformFeedback::WebGLTransformFeedback(WebGLContext* webgl, GLuint tf)
+    : WebGLContextBoundObject(webgl),
+      mGLName(tf),
+      mIndexedBindings(webgl::kMaxTransformFeedbackSeparateAttribs),
+      mIsPaused(false),
+      mIsActive(false) {}
+
+WebGLTransformFeedback::~WebGLTransformFeedback() {
+  if (!mContext) return;
+  if (mGLName) {
+    mContext->gl->fDeleteTransformFeedbacks(1, &mGLName);
+  }
+}
+
+////////////////////////////////////////
+
+void WebGLTransformFeedback::BeginTransformFeedback(GLenum primMode) {
+  if (mIsActive) return mContext->ErrorInvalidOperation("Already active.");
+
+  switch (primMode) {
+    case LOCAL_GL_POINTS:
+    case LOCAL_GL_LINES:
+    case LOCAL_GL_TRIANGLES:
+      break;
+    default:
+      mContext->ErrorInvalidEnum(
+          "`primitiveMode` must be one of POINTS, LINES, or"
+          " TRIANGLES.");
+      return;
+  }
+
+  const auto& prog = mContext->mCurrentProgram;
+  if (!prog || !prog->IsLinked() ||
+      prog->LinkInfo()->componentsPerTFVert.empty()) {
+    mContext->ErrorInvalidOperation(
+        "Current program not valid for transform"
+        " feedback.");
+    return;
+  }
+
+  const auto& linkInfo = prog->LinkInfo();
+  const auto& componentsPerTFVert = linkInfo->componentsPerTFVert;
+
+  size_t minVertCapacity = SIZE_MAX;
+  for (size_t i = 0; i < componentsPerTFVert.size(); i++) {
+    const auto& indexedBinding = mIndexedBindings[i];
+    const auto& componentsPerVert = componentsPerTFVert[i];
+
+    const auto& buffer = indexedBinding.mBufferBinding;
+    if (!buffer) {
+      mContext->ErrorInvalidOperation(
+          "No buffer attached to required transform"
+          " feedback index %u.",
+          (uint32_t)i);
+      return;
+    }
+
+    for (const auto iBound : IntegerRange(mIndexedBindings.size())) {
+      const auto& bound = mIndexedBindings[iBound].mBufferBinding.get();
+      if (iBound != i && buffer == bound) {
+        mContext->GenErrorIllegalUse(
+            LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<uint32_t>(i),
+            LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER, static_cast<uint32_t>(iBound));
+        return;
+      }
+    }
+
+    const size_t vertCapacity = buffer->ByteLength() / 4 / componentsPerVert;
+    minVertCapacity = std::min(minVertCapacity, vertCapacity);
+  }
+
+  ////
+
+  const auto& gl = mContext->gl;
+  gl->fBeginTransformFeedback(primMode);
+
+  ////
+
+  mIsActive = true;
+  MOZ_ASSERT(!mIsPaused);
+
+  mActive_Program = prog;
+  mActive_PrimMode = primMode;
+  mActive_VertPosition = 0;
+  mActive_VertCapacity = minVertCapacity;
+
+  ////
+
+  mActive_Program->mNumActiveTFOs++;
+}
+
+void WebGLTransformFeedback::EndTransformFeedback() {
+  if (!mIsActive) return mContext->ErrorInvalidOperation("Not active.");
+
+  ////
+
+  const auto& gl = mContext->gl;
+  gl->fEndTransformFeedback();
+
+  if (gl->WorkAroundDriverBugs()) {
+#ifdef XP_MACOSX
+    // Multi-threaded GL on mac will generate INVALID_OP in some cases for at
+    // least BindBufferBase after an EndTransformFeedback if there is not a
+    // flush between the two. Single-threaded GL does not have this issue. This
+    // is likely due to not synchronizing client/server state, and erroring in
+    // BindBufferBase because the client thinks we're still in transform
+    // feedback.
+    gl->fFlush();
+#endif
+  }
+
+  ////
+
+  mIsActive = false;
+  mIsPaused = false;
+
+  ////
+
+  mActive_Program->mNumActiveTFOs--;
+}
+
+void WebGLTransformFeedback::PauseTransformFeedback() {
+  if (!mIsActive || mIsPaused) {
+    mContext->ErrorInvalidOperation("Not active or is paused.");
+    return;
+  }
+
+  ////
+
+  const auto& gl = mContext->gl;
+  gl->fPauseTransformFeedback();
+
+  ////
+
+  mIsPaused = true;
+}
+
+void WebGLTransformFeedback::ResumeTransformFeedback() {
+  if (!mIsPaused) return mContext->ErrorInvalidOperation("Not paused.");
+
+  if (mContext->mCurrentProgram != mActive_Program) {
+    mContext->ErrorInvalidOperation("Active program differs from original.");
+    return;
+  }
+
+  ////
+
+  const auto& gl = mContext->gl;
+  gl->fResumeTransformFeedback();
+
+  ////
+
+  MOZ_ASSERT(mIsActive);
+  mIsPaused = false;
+}
+
+}  // namespace mozilla