Mercurial > sdl-ios-xcode
diff src/video/win32/SDL_win32opengl.c @ 2150:abbe2c1dcf0a
Fixed bug #77
If the ARB pixel format selection fails, use a version of ChoosePixelFormat() that doesn't return a less capable format than was requested.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Thu, 05 Jul 2007 06:14:26 +0000 |
parents | 420716272158 |
children | 114a541cfae2 |
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--- a/src/video/win32/SDL_win32opengl.c Thu Jul 05 05:57:31 2007 +0000 +++ b/src/video/win32/SDL_win32opengl.c Thu Jul 05 06:14:26 2007 +0000 @@ -155,6 +155,107 @@ 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 @@ || !_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");