angle::Result ComputeStartVertex(ContextImpl *contextImpl,
const gl::IndexRange &indexRange,
GLint baseVertex,
GLint *firstVertexOut)
{
// The entire index range should be within the limits of a 32-bit uint because the largest
// GL index type is GL_UNSIGNED_INT.
ASSERT(indexRange.start <= std::numeric_limits<uint32_t>::max() &&
indexRange.end <= std::numeric_limits<uint32_t>::max());
// The base vertex is only used in DrawElementsIndirect. Given the assertion above and the
// type of mBaseVertex (GLint), adding them both as 64-bit ints is safe.
int64_t startVertexInt64 =
static_cast<int64_t>(baseVertex) + static_cast<int64_t>(indexRange.start);
// OpenGL ES 3.2 spec section 10.5: "Behavior of DrawElementsOneInstance is undefined if the
// vertex ID is negative for any element"
ANGLE_CHECK_GL_MATH(contextImpl, startVertexInt64 >= 0);
// OpenGL ES 3.2 spec section 10.5: "If the vertex ID is larger than the maximum value
// representable by type, it should behave as if the calculation were upconverted to 32-bit
// unsigned integers(with wrapping on overflow conditions)." ANGLE does not fully handle
// these rules, an overflow error is returned if the start vertex cannot be stored in a
// 32-bit signed integer.
ANGLE_CHECK_GL_MATH(contextImpl, startVertexInt64 <= std::numeric_limits<GLint>::max());
*firstVertexOut = static_cast<GLint>(startVertexInt64);
return angle::Result::Continue;
}
angle::Result FramebufferD3D::readPixels(const gl::Context *context,
const gl::Rectangle &area,
GLenum format,
GLenum type,
void *pixels)
{
// Clip read area to framebuffer.
const gl::Extents fbSize = getState().getReadAttachment()->getSize();
const gl::Rectangle fbRect(0, 0, fbSize.width, fbSize.height);
gl::Rectangle clippedArea;
if (!ClipRectangle(area, fbRect, &clippedArea))
{
// nothing to read
return angle::Result::Continue;
}
const gl::PixelPackState &packState = context->getState().getPackState();
const gl::InternalFormat &sizedFormatInfo = gl::GetInternalFormatInfo(format, type);
ContextD3D *contextD3D = GetImplAs<ContextD3D>(context);
GLuint outputPitch = 0;
ANGLE_CHECK_GL_MATH(contextD3D,
sizedFormatInfo.computeRowPitch(type, area.width, packState.alignment,
packState.rowLength, &outputPitch));
GLuint outputSkipBytes = 0;
ANGLE_CHECK_GL_MATH(contextD3D, sizedFormatInfo.computeSkipBytes(
type, outputPitch, 0, packState, false, &outputSkipBytes));
outputSkipBytes += (clippedArea.x - area.x) * sizedFormatInfo.pixelBytes +
(clippedArea.y - area.y) * outputPitch;
return readPixelsImpl(context, clippedArea, format, type, outputPitch, packState,
static_cast<uint8_t *>(pixels) + outputSkipBytes);
}
