1 files changed, 150 insertions, 0 deletions
diff --git a/dom/canvas/WebGL2ContextBuffers.cpp b/dom/canvas/WebGL2ContextBuffers.cpp
new file mode 100644
index 0000000000..ebbda995ee
--- /dev/null
+++ b/dom/canvas/WebGL2ContextBuffers.cpp
@@ -0,0 +1,150 @@
+/* -*- 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 "WebGL2Context.h"
+
+#include "ClientWebGLContext.h"
+#include "GLContext.h"
+#include "WebGLBuffer.h"
+#include "WebGLTransformFeedback.h"
+
+namespace mozilla {
+
+// -------------------------------------------------------------------------
+// Buffer objects
+
+void WebGL2Context::CopyBufferSubData(GLenum readTarget, GLenum writeTarget,
+                                      uint64_t readOffset, uint64_t writeOffset,
+                                      uint64_t size) const {
+  const FuncScope funcScope(*this, "copyBufferSubData");
+  if (IsContextLost()) return;
+
+  const auto& readBuffer = ValidateBufferSelection(readTarget);
+  if (!readBuffer) return;
+
+  const auto& writeBuffer = ValidateBufferSelection(writeTarget);
+  if (!writeBuffer) return;
+
+  if (!CheckedInt<GLintptr>(readOffset).isValid() ||
+      !CheckedInt<GLintptr>(writeOffset).isValid() ||
+      !CheckedInt<GLsizeiptr>(size).isValid())
+    return ErrorOutOfMemory("offset or size too large for platform.");
+
+  const auto fnValidateOffsetSize = [&](const char* info, WebGLintptr offset,
+                                        const WebGLBuffer* buffer) {
+    const auto neededBytes = CheckedInt<uint64_t>(offset) + size;
+    if (!neededBytes.isValid() || neededBytes.value() > buffer->ByteLength()) {
+      ErrorInvalidValue("Invalid %s range.", info);
+      return false;
+    }
+    return true;
+  };
+
+  if (!fnValidateOffsetSize("read", readOffset, readBuffer) ||
+      !fnValidateOffsetSize("write", writeOffset, writeBuffer)) {
+    return;
+  }
+
+  if (readBuffer == writeBuffer) {
+    const bool separate =
+        (readOffset + size <= writeOffset || writeOffset + size <= readOffset);
+    if (!separate) {
+      ErrorInvalidValue(
+          "Ranges [readOffset, readOffset + size) and"
+          " [writeOffset, writeOffset + size) overlap.");
+      return;
+    }
+  }
+
+  const auto& readType = readBuffer->Content();
+  const auto& writeType = writeBuffer->Content();
+  MOZ_ASSERT(readType != WebGLBuffer::Kind::Undefined);
+  MOZ_ASSERT(writeType != WebGLBuffer::Kind::Undefined);
+  if (writeType != readType) {
+    ErrorInvalidOperation(
+        "Can't copy %s data to %s data.",
+        (readType == WebGLBuffer::Kind::OtherData) ? "other" : "element",
+        (writeType == WebGLBuffer::Kind::OtherData) ? "other" : "element");
+    return;
+  }
+
+  const ScopedLazyBind readBind(gl, readTarget, readBuffer);
+  const ScopedLazyBind writeBind(gl, writeTarget, writeBuffer);
+  gl->fCopyBufferSubData(readTarget, writeTarget, readOffset, writeOffset,
+                         size);
+
+  writeBuffer->ResetLastUpdateFenceId();
+}
+
+bool WebGL2Context::GetBufferSubData(GLenum target, uint64_t srcByteOffset,
+                                     const Range<uint8_t>& dest) const {
+  const FuncScope funcScope(*this, "getBufferSubData");
+  if (IsContextLost()) return false;
+
+  const auto& buffer = ValidateBufferSelection(target);
+  if (!buffer) return false;
+
+  const auto byteLen = dest.length();
+  if (!buffer->ValidateRange(srcByteOffset, byteLen)) return false;
+
+  ////
+
+  if (!CheckedInt<GLintptr>(srcByteOffset).isValid() ||
+      !CheckedInt<GLsizeiptr>(byteLen).isValid()) {
+    ErrorOutOfMemory("offset or size too large for platform.");
+    return false;
+  }
+  const GLsizeiptr glByteLen(byteLen);
+
+  ////
+
+  switch (buffer->mUsage) {
+    case LOCAL_GL_STATIC_READ:
+    case LOCAL_GL_STREAM_READ:
+    case LOCAL_GL_DYNAMIC_READ:
+      if (mCompletedFenceId < buffer->mLastUpdateFenceId) {
+        GenerateWarning(
+            "Reading from a buffer without checking for previous"
+            " command completion likely causes pipeline stalls."
+            " Please use FenceSync.");
+      }
+      break;
+    default:
+      GenerateWarning(
+          "Reading from a buffer with usage other than *_READ"
+          " causes pipeline stalls. Copy through a STREAM_READ buffer.");
+      break;
+  }
+
+  ////
+
+  const ScopedLazyBind readBind(gl, target, buffer);
+
+  if (byteLen) {
+    const bool isTF = (target == LOCAL_GL_TRANSFORM_FEEDBACK_BUFFER);
+    GLenum mapTarget = target;
+    if (isTF) {
+      gl->fBindTransformFeedback(LOCAL_GL_TRANSFORM_FEEDBACK, mEmptyTFO);
+      gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, buffer->mGLName);
+      mapTarget = LOCAL_GL_ARRAY_BUFFER;
+    }
+
+    const auto mappedBytes = gl->fMapBufferRange(
+        mapTarget, srcByteOffset, glByteLen, LOCAL_GL_MAP_READ_BIT);
+    memcpy(dest.begin().get(), mappedBytes, dest.length());
+    gl->fUnmapBuffer(mapTarget);
+
+    if (isTF) {
+      const GLuint vbo = (mBoundArrayBuffer ? mBoundArrayBuffer->mGLName : 0);
+      gl->fBindBuffer(LOCAL_GL_ARRAY_BUFFER, vbo);
+      const GLuint tfo =
+          (mBoundTransformFeedback ? mBoundTransformFeedback->mGLName : 0);
+      gl->fBindTransformFeedback(LOCAL_GL_TRANSFORM_FEEDBACK, tfo);
+    }
+  }
+  return true;
+}
+
+}  // namespace mozilla