On 09/26/2017 05:35 PM, Thomas Hellstrom wrote:
Don't create GLX visuals that would be viewed as identical as an already
existing GLX visual by glXChooseVisual. Multiple fbconfigs may point to
the same GLX visual.
Signed-off-by: Thomas Hellstrom <[email protected]>
---
glx/glxscreens.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 66 insertions(+), 1 deletion(-)
diff --git a/glx/glxscreens.c b/glx/glxscreens.c
index 99bf6dd..f07850d 100644
--- a/glx/glxscreens.c
+++ b/glx/glxscreens.c
@@ -158,6 +158,55 @@ static const char GLServerExtensions[] =
"GL_SGIX_shadow_ambient "
"GL_SUN_slice_accum ";
+/**
+ * Are visuals equal in terms of glXChooseVisual?
+ *
+ * Some fields of the __GLXconfig structure are, according to the
+ * GLX spec not part of the visual structure meaning that their
+ * corresponding attribute can not be used in glXChooseVisual, nor
+ * using glXGetConfig. Eliminating those fields, check whether
+ * two __GLXconfigs would be considered equal.
+ */
+static Bool
+glxVisualsEqual(const __GLXconfig *c1, const __GLXconfig *c2) {
+ /* GLX 1.4 spec */
+ return c1->rgbBits == c2->rgbBits &&
+ c1->indexBits == c2->indexBits &&
+ c1->level == c2->level &&
+ (c1->renderType & GLX_RGBA_BIT) ==
+ (c2->renderType & GLX_RGBA_BIT) &&
+ c1->doubleBufferMode == c2->doubleBufferMode &&
+ c1->stereoMode == c2->stereoMode &&
+ c1->numAuxBuffers == c2->numAuxBuffers &&
+ c1->redBits == c2->redBits &&
+ c1->greenBits == c2->greenBits &&
+ c1->blueBits == c2->blueBits &&
+ c1->alphaBits == c2->alphaBits &&
+ c1->depthBits == c2->depthBits &&
+ c1->stencilBits == c2->stencilBits &&
+ c1->accumRedBits == c2->accumRedBits &&
+ c1->accumGreenBits == c2->accumGreenBits &&
+ c1->accumBlueBits == c2->accumBlueBits &&
+ c1->accumAlphaBits == c2->accumAlphaBits &&
+ c1->sampleBuffers == c2->sampleBuffers &&
+ c1->samples == c2->samples &&
+ c1->visualType == c2->visualType &&
+ /* EXT_visual_rating, but NOT GLX 1.4 */
+ c1->visualRating == c2->visualRating &&
+ /* EXT_visual_info, but NOT GLX 1.4 */
+ c1->transparentPixel == c2->transparentPixel &&
+ c1->transparentRed == c2->transparentRed &&
+ c1->transparentGreen == c2->transparentGreen &&
+ c1->transparentBlue == c2->transparentBlue &&
+ c1->transparentAlpha == c2->transparentAlpha &&
+ c1->transparentIndex == c2->transparentIndex &&
+ /* SGIX_visual_select_group */
+ c1->visualSelectGroup == c2->visualSelectGroup &&
+ /* ARB_framebuffer_sRGB */
+ c1->sRGBCapable == c2->sRGBCapable;
Actually, if reducing visuals like this appears to be a good thing, we
should probably also check the value of
the "duplicatedForComp" field.
/Thomas
+}
+
+
static Bool
glxCloseScreen(ScreenPtr pScreen)
{
@@ -358,9 +407,10 @@ __glXScreenInit(__GLXscreen * pGlxScreen, ScreenPtr
pScreen)
* an existing, appropriate visual.
*/
for (config = pGlxScreen->fbconfigs; config != NULL; config =
config->next) {
- int depth;
+ int depth, vis;
VisualPtr visual;
+ const __GLXconfig *config2;
if (config->visualID != 0)
continue;
@@ -393,6 +443,21 @@ __glXScreenInit(__GLXscreen * pGlxScreen, ScreenPtr
pScreen)
continue;
}
+ /* We don't need to create a new visual if we already have an
+ * identical visual. Instead we will have multiple fbconfigs
+ * pointing to the same GLX visual.
+ */
+ for (vis = 0; vis < pGlxScreen->numVisuals; ++vis) {
+ config2 = pGlxScreen->visuals[vis];
+ if (glxVisualsEqual(config, config2)) {
+ config->visualID = config2->visualID;
+ break;
+ }
+ }
+
+ if (config->visualID != 0)
+ continue;
+
/* Create a new X visual for our FBconfig. */
visual = AddScreenVisuals(pScreen, 1, depth);
if (visual == NULL)
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