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b=780059 accept fbconfigs with alpha bits for opaque Pixmaps if visual matches r=mattwoodrow

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--HG--
extra : rebase_source : 50072bf87e489781af734d3863fa1d134f7c9136
This commit is contained in:
Karl Tomlinson 2012-08-20 16:21:07 +12:00
parent 927f25cc6b
commit 3a8ca1fb6c
1 changed files with 61 additions and 15 deletions
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76
gfx/gl/GLContextProviderGLX.cpp
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@ -291,6 +291,7 @@ GLXLibrary::CreatePixmap(gfxASurface* aSurface)
attribs,
&numConfigs));
// Find an fbconfig that matches the pixel format used on the Pixmap.
int matchIndex = -1;
const XRenderDirectFormat& direct = format->direct;
unsigned long redMask =
@ -299,34 +300,79 @@ GLXLibrary::CreatePixmap(gfxASurface* aSurface)
static_cast<unsigned long>(direct.greenMask) << direct.green;
unsigned long blueMask =
static_cast<unsigned long>(direct.blueMask) << direct.blue;
// XVisualInfo doesn't have information on the alpha channel, so just
// check the number of bits.
int alphaSize;
PR_FLOOR_LOG2(alphaSize, direct.alphaMask + 1);
NS_ASSERTION((1 << alphaSize) - 1 == direct.alphaMask,
"Unexpected render format with non-adjacent alpha bits");
ScopedXFree<XVisualInfo> vinfo;
// This is true if the Pixmap has bits for alpha or unused bits.
bool haveNonColorBits =
~(redMask | greenMask | blueMask) != -1UL << format->depth;
for (int i = 0; i < numConfigs; i++) {
int size;
if (sGLXLibrary.xGetFBConfigAttrib(display, cfgs[i],
GLX_ALPHA_SIZE, &size) != Success ||
size != alphaSize) {
int id = None;
sGLXLibrary.xGetFBConfigAttrib(display, cfgs[i], GLX_VISUAL_ID, &id);
Visual *visual;
int depth;
FindVisualAndDepth(display, id, &visual, &depth);
if (!visual ||
visual->c_class != TrueColor ||
visual->red_mask != redMask ||
visual->green_mask != greenMask ||
visual->blue_mask != blueMask ) {
continue;
}
// The visual depth won't necessarily match the render format depth as
// it may not include the alpha channel.
vinfo = sGLXLibrary.xGetVisualFromFBConfig(display, cfgs[i]);
if (!vinfo ||
vinfo->c_class != TrueColor ||
vinfo->red_mask != redMask ||
vinfo->green_mask != greenMask ||
vinfo->blue_mask != blueMask ) {
// Historically Xlib Visuals did not try to represent an alpha channel
// and there was no means to use an alpha channel on a Pixmap. The
// Xlib Visual from the fbconfig was not intended to have any
// information about alpha bits.
//
// Since then, RENDER has added formats for 32 bit depth Pixmaps.
// Some of these formats have bits for alpha and some have unused
// bits.
//
// Then the Composite extension added a 32 bit depth Visual intended
// for Windows with an alpha channel, so bits not in the visual color
// masks were expected to be treated as alpha bits.
//
// Usually GLX counts only color bits in the Visual depth, but the
// depth of Composite's ARGB Visual includes alpha bits. However,
// bits not in the color masks are not necessarily alpha bits because
// sometimes (NVIDIA) 32 bit Visuals are added for fbconfigs with 32
// bit BUFFER_SIZE but zero alpha bits and 24 color bits (NVIDIA
// again).
//
// This checks that the depth matches in one of the two ways.
if (depth != format->depth && depth != format->depth - alphaSize) {
continue;
}
// If all bits of the Pixmap are color bits and the Pixmap depth
// matches the depth of the fbconfig visual, then we can assume that
// the driver will do whatever is necessary to ensure that any
// GLXPixmap alpha bits are treated as set. We can skip the
// ALPHA_SIZE check in this situation. We need to skip this check for
// situations (ATI) where there are no fbconfigs without alpha bits.
//
// glXChooseFBConfig should prefer configs with smaller
// GLX_BUFFER_SIZE, so we should still get zero alpha bits if
// available, except perhaps with NVIDIA drivers where buffer size is
// not the specified sum of the component sizes.
if (haveNonColorBits) {
// There are bits in the Pixmap format that haven't been matched
// against the fbconfig visual. These bits could either represent
// alpha or be unused, so just check that the number of alpha bits
// matches.
int size = 0;
sGLXLibrary.xGetFBConfigAttrib(display, cfgs[i],
GLX_ALPHA_SIZE, &size);
if (size != alphaSize) {
continue;
}
}
matchIndex = i;
break;
}
if (matchIndex == -1) {
NS_WARNING("[GLX] Couldn't find a FBConfig matching Pixmap format");