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Bug 912196 - Deal with reading RGBA from RGBX. - r=kamidphish

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This commit is contained in:
Jeff Gilbert 2014-10-08 16:34:14 -07:00
parent 3f421c31e9
commit c082718b63
1 changed files with 67 additions and 51 deletions
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118
dom/canvas/WebGLContextGL.cpp
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@ -2104,6 +2104,58 @@ WebGLContext::PixelStorei(GLenum pname, GLint param)
}
}
// `width` in pixels.
// `stride` in bytes.
static bool
SetFullAlpha(void* data, GLenum format, GLenum type, size_t width,
size_t height, size_t stride)
{
if (format == LOCAL_GL_ALPHA && type == LOCAL_GL_UNSIGNED_BYTE) {
// Just memset the rows.
for (size_t j = 0; j < height; ++j) {
uint8_t* row = static_cast<uint8_t*>(data) + j*stride;
memset(row, 0xff, width);
row += stride;
}
return true;
}
if (format == LOCAL_GL_RGBA && type == LOCAL_GL_UNSIGNED_BYTE) {
for (size_t j = 0; j < height; ++j) {
uint8_t* row = static_cast<uint8_t*>(data) + j*stride;
uint8_t* pAlpha = row + 3;
uint8_t* pAlphaEnd = pAlpha + 4*width;
while (pAlpha != pAlphaEnd) {
*pAlpha = 0xff;
pAlpha += 4;
}
}
return true;
}
if (format == LOCAL_GL_RGBA && type == LOCAL_GL_FLOAT) {
for (size_t j = 0; j < height; ++j) {
uint8_t* rowBytes = static_cast<uint8_t*>(data) + j*stride;
float* row = reinterpret_cast<float*>(rowBytes);
float* pAlpha = row + 3;
float* pAlphaEnd = pAlpha + 4*width;
while (pAlpha != pAlphaEnd) {
*pAlpha = 1.0f;
pAlpha += 4;
}
}
return true;
}
MOZ_ASSERT(false, "Unhandled case, how'd we get here?");
return false;
}
void
WebGLContext::ReadPixels(GLint x, GLint y, GLsizei width,
GLsizei height, GLenum format,
@ -2347,61 +2399,25 @@ WebGLContext::ReadPixels(GLint x, GLint y, GLsizei width,
// if we're reading alpha, we may need to do fixup. Note that we don't allow
// GL_ALPHA to readpixels currently, but we had the code written for it already.
if (format == LOCAL_GL_ALPHA ||
format == LOCAL_GL_RGBA)
{
bool needAlphaFixup;
if (mBoundFramebuffer) {
needAlphaFixup = !mBoundFramebuffer->ColorAttachment(0).HasAlpha();
} else {
needAlphaFixup = gl->GetPixelFormat().alpha == 0;
}
if (needAlphaFixup) {
if (format == LOCAL_GL_ALPHA && type == LOCAL_GL_UNSIGNED_BYTE) {
// this is easy; it's an 0xff memset per row
uint8_t *row = static_cast<uint8_t*>(data);
for (GLint j = 0; j < height; ++j) {
memset(row, 0xff, checked_plainRowSize.value());
row += checked_alignedRowSize.value();
}
} else if (format == LOCAL_GL_RGBA && type == LOCAL_GL_UNSIGNED_BYTE) {
// this is harder, we need to just set the alpha byte here
uint8_t *row = static_cast<uint8_t*>(data);
for (GLint j = 0; j < height; ++j) {
uint8_t *rowp = row;
#if MOZ_LITTLE_ENDIAN
// offset to get the alpha byte; we're always going to
// move by 4 bytes
rowp += 3;
#endif
uint8_t *endrowp = rowp + 4 * width;
while (rowp != endrowp) {
*rowp = 0xff;
rowp += 4;
}
const bool formatHasAlpha = format == LOCAL_GL_ALPHA ||
format == LOCAL_GL_RGBA;
if (!formatHasAlpha)
return;
row += checked_alignedRowSize.value();
}
} else if (format == LOCAL_GL_RGBA && type == LOCAL_GL_FLOAT) {
float* row = static_cast<float*>(data);
bool needAlphaFilled;
if (mBoundFramebuffer) {
needAlphaFilled = !mBoundFramebuffer->ColorAttachment(0).HasAlpha();
} else {
needAlphaFilled = !mOptions.alpha;
}
for (GLint j = 0; j < height; ++j) {
float* pAlpha = row + 3;
float* pAlphaEnd = pAlpha + 4*width;
if (!needAlphaFilled)
return;
while (pAlpha != pAlphaEnd) {
*pAlpha = 1.0f;
pAlpha += 4;
}
row += checked_alignedRowSize.value();
}
} else {
NS_WARNING("Unhandled case, how'd we get here?");
return rv.Throw(NS_ERROR_FAILURE);
}
}
size_t stride = checked_alignedRowSize.value(); // In bytes!
if (!SetFullAlpha(data, format, type, width, height, stride)) {
return rv.Throw(NS_ERROR_FAILURE);
}
}