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Fixed bug #77

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If the ARB pixel format selection fails, use a version of ChoosePixelFormat() that doesn't return a less capable format than was requested.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%402422
This commit is contained in:
Sam Lantinga 2007-07-05 06:14:26 +00:00
parent 31871b763d
commit b3a581c625
1 changed files with 102 additions and 1 deletions
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103
src/video/win32/SDL_win32opengl.c
View file

@ -155,6 +155,107 @@ WIN_GL_SetupPixelFormat(_THIS, PIXELFORMATDESCRIPTOR * pfd)
pfd->cStencilBits = _this->gl_config.stencil_size;
}
/* Choose the closest pixel format that meets or exceeds the target.
FIXME: Should we weight any particular attribute over any other?
*/
static int
WIN_GL_ChoosePixelFormat(HDC hdc, PIXELFORMATDESCRIPTOR * target)
{
PIXELFORMATDESCRIPTOR pfd;
int count, index, best = 0;
unsigned int dist, best_dist = ~0U;
count = DescribePixelFormat(hdc, 1, sizeof(pfd), NULL);
for (index = 1; index <= count; index++) {
if (!DescribePixelFormat(hdc, index, sizeof(pfd), &pfd)) {
continue;
}
if ((pfd.dwFlags & target->dwFlags) != target->dwFlags) {
continue;
}
if (pfd.iLayerType != target->iLayerType) {
continue;
}
if (pfd.iPixelType != target->iPixelType) {
continue;
}
dist = 0;
if (pfd.cColorBits < target->cColorBits) {
continue;
} else {
dist += (pfd.cColorBits - target->cColorBits);
}
if (pfd.cRedBits < target->cRedBits) {
continue;
} else {
dist += (pfd.cRedBits - target->cRedBits);
}
if (pfd.cGreenBits < target->cGreenBits) {
continue;
} else {
dist += (pfd.cGreenBits - target->cGreenBits);
}
if (pfd.cBlueBits < target->cBlueBits) {
continue;
} else {
dist += (pfd.cBlueBits - target->cBlueBits);
}
if (pfd.cAlphaBits < target->cAlphaBits) {
continue;
} else {
dist += (pfd.cAlphaBits - target->cAlphaBits);
}
if (pfd.cAccumBits < target->cAccumBits) {
continue;
} else {
dist += (pfd.cAccumBits - target->cAccumBits);
}
if (pfd.cAccumRedBits < target->cAccumRedBits) {
continue;
} else {
dist += (pfd.cAccumRedBits - target->cAccumRedBits);
}
if (pfd.cAccumGreenBits < target->cAccumGreenBits) {
continue;
} else {
dist += (pfd.cAccumGreenBits - target->cAccumGreenBits);
}
if (pfd.cAccumBlueBits < target->cAccumBlueBits) {
continue;
} else {
dist += (pfd.cAccumBlueBits - target->cAccumBlueBits);
}
if (pfd.cAccumAlphaBits < target->cAccumAlphaBits) {
continue;
} else {
dist += (pfd.cAccumAlphaBits - target->cAccumAlphaBits);
}
if (pfd.cDepthBits < target->cDepthBits) {
continue;
} else {
dist += (pfd.cDepthBits - target->cDepthBits);
}
if (pfd.cStencilBits < target->cStencilBits) {
continue;
} else {
dist += (pfd.cStencilBits - target->cStencilBits);
}
if (dist < best_dist) {
best = index;
best_dist = dist;
}
}
return best;
}
static SDL_bool
HasExtension(const char *extension, const char *extensions)
{
@ -398,7 +499,7 @@ WIN_GL_SetupWindow(_THIS, SDL_Window * window)
|| !_this->gl_data->wglChoosePixelFormatARB(hdc, iAttribs, fAttribs,
1, &pixel_format,
&matching) || !matching) {
pixel_format = ChoosePixelFormat(hdc, &pfd);
pixel_format = WIN_GL_ChoosePixelFormat(hdc, &pfd);
}
if (!pixel_format) {
SDL_SetError("No matching GL pixel format available");