[PATCH] Native opengl32 seems to consider values set to 0 in the pixel format descriptor as DONTCARE. The attached test case proofs the behavior and this fixes a natsy bug in Serious Sam TSE.
Roderick Colenbrander
thunderbird2k at gmx.net
Mon Mar 31 17:18:14 CDT 2008
---
dlls/opengl32/tests/opengl.c | 75 +++++++++++++++++++
dlls/winex11.drv/opengl.c | 165 +++++++++++++++++++++++-------------------
2 files changed, 164 insertions(+), 76 deletions(-)
diff --git a/dlls/opengl32/tests/opengl.c b/dlls/opengl32/tests/opengl.c
index 0200dfd..4da7fd7 100644
--- a/dlls/opengl32/tests/opengl.c
+++ b/dlls/opengl32/tests/opengl.c
@@ -176,6 +176,80 @@ static void test_pbuffers(HDC hdc)
else skip("Pbuffer test for offscreen pixelformat skipped as no offscreen-only format with pbuffer capabilities has been found\n");
}
+static void test_choosepixelformat(HDC hdc)
+{
+ int iPixelFormat;
+ int nFormats;
+ BOOL found=FALSE;
+ PIXELFORMATDESCRIPTOR pfd = {
+ sizeof(PIXELFORMATDESCRIPTOR),
+ 1, /* version */
+ PFD_DRAW_TO_WINDOW |
+ PFD_SUPPORT_OPENGL |
+ PFD_DOUBLEBUFFER,
+ PFD_TYPE_RGBA,
+ 32, /* 32-bit color depth */
+ 0, 0, 0, 0, 0, 0, /* color bits */
+ 0, /* alpha buffer */
+ 0, /* shift bit */
+ 0, /* accumulation buffer */
+ 0, 0, 0, 0, /* accum bits */
+ 0, /* z-buffer */
+ 0, /* stencil buffer */
+ 0, /* auxiliary buffer */
+ PFD_MAIN_PLANE, /* main layer */
+ 0, /* reserved */
+ 0, 0, 0 /* layer masks */
+ };
+
+ /* Below we test the behavior of ChoosePixelFormat. As documented on MSDN this
+ * function doesn't give any guarantees about its outcome. Programs should not
+ * rely on weird behavior of the function but unfortunately a few programs like
+ * e.g. Serious Sam TSE rely on it.
+ *
+ * MSDN documents of a few flags like double buffering / stereo that they can be set to DONTCARE.
+ * It appears that a 0 value on other options like alpha, red, .. means DONTCARE. The hypothesis
+ * is that ChoosePixelFormat returns the first available format which matches the criteria.
+ *
+ * This test tries to proof the DONTCARE behavior by passing an almost 'empty' pfd to
+ * ChoosePixelFormat. The pfd only has some really needed flags (RGBA, window, double buffer) set.
+ * Further a 32 bit color buffer has been requested. The idea is that when a format with e.g. depth or stencil bits
+ * is returned, while there are also 'better' candidates in the list wihtout them (but located AFTER the returned one)
+ * that an option set to zero means DONTCARE. We try to proof this by checking the aux/depth/stencil bits.
+ * Proofing this behavior for the color bits isn't possible as all formats have red/green/blue/(alpha), so we assume
+ * that if it holds for aux/depth/stencil it also holds for the others.
+ *
+ * The test below passes at least on various ATI cards (rv250, r300) and Nvidia cards.
+ */
+
+ iPixelFormat = ChoosePixelFormat(hdc, &pfd);
+ if(iPixelFormat) {
+ PIXELFORMATDESCRIPTOR pfd_tmp;
+ BOOL res;
+ int i;
+
+ memset(&pfd, 0, sizeof(PIXELFORMATDESCRIPTOR));
+ res = DescribePixelFormat(hdc, iPixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &pfd);
+
+ nFormats = DescribePixelFormat(hdc, 0, 0, NULL);
+ /* Start testing from iPixelFormat, second formats start counting from index=1, so use '<=' */
+ for(i=iPixelFormat; i<=nFormats; i++) {
+ memset(&pfd_tmp, 0, sizeof(PIXELFORMATDESCRIPTOR));
+ res = DescribePixelFormat(hdc, i, sizeof(PIXELFORMATDESCRIPTOR), &pfd_tmp);
+ if(!res)
+ continue;
+
+ /* Check if there is a format which better matches the requirements */
+ if((pfd_tmp.cAuxBuffers < pfd.cAuxBuffers) || (pfd_tmp.cDepthBits < pfd.cDepthBits) || (pfd_tmp.cStencilBits < pfd.cStencilBits))
+ found = TRUE;
+ }
+
+ /* When found=TRUE we were able to confirm our hypothesis */
+ ok(found == TRUE, "Unable to confirm DONTCARE behavior of unset pixelformatdescriptor flags\n");
+ }
+
+}
+
static void test_setpixelformat(HDC winhdc)
{
int res = 0;
@@ -398,6 +472,7 @@ START_TEST(opengl)
ok(res, "wglMakeCurrent failed!\n");
init_functions();
+ test_choosepixelformat(hdc);
test_setpixelformat(hdc);
test_colorbits(hdc);
test_gdi_dbuf(hdc);
diff --git a/dlls/winex11.drv/opengl.c b/dlls/winex11.drv/opengl.c
index b6b3fc7..5a0469c 100644
--- a/dlls/winex11.drv/opengl.c
+++ b/dlls/winex11.drv/opengl.c
@@ -1145,96 +1145,109 @@ int X11DRV_ChoosePixelFormat(X11DRV_PDEVICE *physDev,
/* Below we will do a number of checks to select the 'best' pixelformat.
* We assume the precedence cColorBits > cAlphaBits > cDepthBits > cStencilBits -> cAuxBuffers.
* The code works by trying to match the most important options as close as possible.
- * When a reasonable format is found, we will try to match more options. */
+ * When a reasonable format is found, we will try to match more options.
+ * It appears (see the opengl32 test) that Windows opengl drivers ignore options
+ * like cColorBits, cAlphaBits and friends if they are set to 0, so they are considered
+ * as DONTCARE. At least Serious Sam TSE relies on this behavior. */
/* Color bits */
- if( ((ppfd->cColorBits > bestColor) && (color > bestColor)) ||
- ((color >= ppfd->cColorBits) && (color < bestColor)) )
- {
- bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
- bestStereo = dwFlags & PFD_STEREO;
- bestAlpha = alpha;
- bestColor = color;
- bestDepth = depth;
- bestStencil = stencil;
- bestAux = aux;
- bestFormat = i;
- continue;
- } else if(bestColor != color) { /* Do further checks if the format is compatible */
- TRACE("color mismatch for iPixelFormat=%d\n", i+1);
- continue;
+ if(ppfd->cColorBits) {
+ if( ((ppfd->cColorBits > bestColor) && (color > bestColor)) ||
+ ((color >= ppfd->cColorBits) && (color < bestColor)) )
+ {
+ bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
+ bestStereo = dwFlags & PFD_STEREO;
+ bestAlpha = alpha;
+ bestColor = color;
+ bestDepth = depth;
+ bestStencil = stencil;
+ bestAux = aux;
+ bestFormat = i;
+ continue;
+ } else if(bestColor != color) { /* Do further checks if the format is compatible */
+ TRACE("color mismatch for iPixelFormat=%d\n", i+1);
+ continue;
+ }
}
/* Alpha bits */
- if( ((ppfd->cAlphaBits > bestAlpha) && (alpha > bestAlpha)) ||
- ((alpha >= ppfd->cAlphaBits) && (alpha < bestAlpha)) )
- {
- bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
- bestStereo = dwFlags & PFD_STEREO;
- bestAlpha = alpha;
- bestColor = color;
- bestDepth = depth;
- bestStencil = stencil;
- bestAux = aux;
- bestFormat = i;
- continue;
- } else if(bestAlpha != alpha) {
- TRACE("alpha mismatch for iPixelFormat=%d\n", i+1);
- continue;
+ if(ppfd->cAlphaBits) {
+ if( ((ppfd->cAlphaBits > bestAlpha) && (alpha > bestAlpha)) ||
+ ((alpha >= ppfd->cAlphaBits) && (alpha < bestAlpha)) )
+ {
+ bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
+ bestStereo = dwFlags & PFD_STEREO;
+ bestAlpha = alpha;
+ bestColor = color;
+ bestDepth = depth;
+ bestStencil = stencil;
+ bestAux = aux;
+ bestFormat = i;
+ continue;
+ } else if(bestAlpha != alpha) {
+ TRACE("alpha mismatch for iPixelFormat=%d\n", i+1);
+ continue;
+ }
}
/* Depth bits */
- if( ((ppfd->cDepthBits > bestDepth) && (depth > bestDepth)) ||
- ((depth >= ppfd->cDepthBits) && (depth < bestDepth)) )
- {
- bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
- bestStereo = dwFlags & PFD_STEREO;
- bestAlpha = alpha;
- bestColor = color;
- bestDepth = depth;
- bestStencil = stencil;
- bestAux = aux;
- bestFormat = i;
- continue;
- } else if(bestDepth != depth) {
- TRACE("depth mismatch for iPixelFormat=%d\n", i+1);
- continue;
+ if(ppfd->cDepthBits) {
+ if( ((ppfd->cDepthBits > bestDepth) && (depth > bestDepth)) ||
+ ((depth >= ppfd->cDepthBits) && (depth < bestDepth)) )
+ {
+ bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
+ bestStereo = dwFlags & PFD_STEREO;
+ bestAlpha = alpha;
+ bestColor = color;
+ bestDepth = depth;
+ bestStencil = stencil;
+ bestAux = aux;
+ bestFormat = i;
+ continue;
+ } else if(bestDepth != depth) {
+ TRACE("depth mismatch for iPixelFormat=%d\n", i+1);
+ continue;
+ }
}
/* Stencil bits */
- if( ((ppfd->cStencilBits > bestStencil) && (stencil > bestStencil)) ||
- ((stencil >= ppfd->cStencilBits) && (stencil < bestStencil)) )
- {
- bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
- bestStereo = dwFlags & PFD_STEREO;
- bestAlpha = alpha;
- bestColor = color;
- bestDepth = depth;
- bestStencil = stencil;
- bestAux = aux;
- bestFormat = i;
- continue;
- } else if(bestStencil != stencil) {
- TRACE("stencil mismatch for iPixelFormat=%d\n", i+1);
- continue;
+ if(ppfd->cStencilBits) {
+ if( ((ppfd->cStencilBits > bestStencil) && (stencil > bestStencil)) ||
+ ((stencil >= ppfd->cStencilBits) && (stencil < bestStencil)) )
+ {
+ bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
+ bestStereo = dwFlags & PFD_STEREO;
+ bestAlpha = alpha;
+ bestColor = color;
+ bestDepth = depth;
+ bestStencil = stencil;
+ bestAux = aux;
+ bestFormat = i;
+ continue;
+ } else if(bestStencil != stencil) {
+ TRACE("stencil mismatch for iPixelFormat=%d\n", i+1);
+ continue;
+ }
}
/* Aux buffers */
- if( ((ppfd->cAuxBuffers > bestAux) && (aux > bestAux)) ||
- ((aux >= ppfd->cAuxBuffers) && (aux < bestAux)) )
- {
- bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
- bestStereo = dwFlags & PFD_STEREO;
- bestAlpha = alpha;
- bestColor = color;
- bestDepth = depth;
- bestStencil = stencil;
- bestAux = aux;
- bestFormat = i;
- continue;
- } else if(bestAux != aux) {
- TRACE("aux mismatch for iPixelFormat=%d\n", i+1);
- continue;
+ if(ppfd->cAuxBuffers) {
+ if( ((ppfd->cAuxBuffers > bestAux) && (aux > bestAux)) ||
+ ((aux >= ppfd->cAuxBuffers) && (aux < bestAux)) )
+ {
+ bestDBuffer = dwFlags & PFD_DOUBLEBUFFER;
+ bestStereo = dwFlags & PFD_STEREO;
+ bestAlpha = alpha;
+ bestColor = color;
+ bestDepth = depth;
+ bestStencil = stencil;
+ bestAux = aux;
+ bestFormat = i;
+ continue;
+ } else if(bestAux != aux) {
+ TRACE("aux mismatch for iPixelFormat=%d\n", i+1);
+ continue;
+ }
}
}
--
1.5.3.4
--========GMX122311206994897638898--
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