This update fixes the problem with GLX failing to find a valid configuration on Linux laptops (Issue 513).

The base issue here was that the default GLX implementation on some Linux laptops lies about its version numbering. Code in SkNativeGLContext_unix.cpp was checking the version number to avoid using FBConfigs in versions prior to 1.3 and thus incorrectly stopped processing.

To resolve this a separate configuration path has been added that uses the pre-1.3 method (i.e., XGetVisualInfo and glXGetConfig). The run-time version check has also been removed and a #define has been added to toggle between the two implementations. This allows the FBConfig method to be used with the wayward GLX implementation while the legacy method can be used with older implementations.

Please see http://codereview.appspot.com/5823049/ for more information.

git-svn-id: http://skia.googlecode.com/svn/trunk@3384 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 45 insertions, 16 deletions

diff --git a/src/gpu/unix/SkNativeGLContext_unix.cpp b/src/gpu/unix/SkNativeGLContext_unix.cpp
index f4199eb0e7..f9c582cd09 100644
--- a/src/gpu/unix/SkNativeGLContext_unix.cpp
+++ b/src/gpu/unix/SkNativeGLContext_unix.cpp
@@ -9,6 +9,8 @@
 
 #include <GL/glu.h>
 
+#define GLX_1_3 1
+
 SkNativeGLContext::AutoContextRestore::AutoContextRestore() {
     fOldGLXContext = glXGetCurrentContext();
     fOldDisplay = glXGetCurrentDisplay();
@@ -80,17 +82,7 @@ const GrGLInterface* SkNativeGLContext::createGLContext() {
         None
     };
 
-    int glx_major, glx_minor;
-
-    // FBConfigs were added in GLX version 1.3.
-    if (!glXQueryVersion(fDisplay, &glx_major, &glx_minor) ||
-            ( (glx_major == 1) && (glx_minor < 3) ) || (glx_major < 1))
-    {
-        SkDebugf("Invalid GLX version.");
-        this->destroyGLContext();
-        return NULL;
-    }
-
+#ifdef GLX_1_3
     //SkDebugf("Getting matching framebuffer configs.\n");
     int fbcount;
     GLXFBConfig *fbc = glXChooseFBConfig(fDisplay, DefaultScreen(fDisplay),
@@ -104,7 +96,7 @@ const GrGLInterface* SkNativeGLContext::createGLContext() {
 
     // Pick the FB config/visual with the most samples per pixel
     //SkDebugf("Getting XVisualInfos.\n");
-    int best_fbc = -1, worst_fbc = -1, best_num_samp = -1, worst_num_samp = 999;
+    int best_fbc = -1, best_num_samp = -1;
 
     int i;
     for (i = 0; i < fbcount; ++i) {
@@ -120,9 +112,7 @@ const GrGLInterface* SkNativeGLContext::createGLContext() {
 
             if (best_fbc < 0 || (samp_buf && samples > best_num_samp))
                 best_fbc = i, best_num_samp = samples;
-            if (worst_fbc < 0 || !samp_buf || samples < worst_num_samp)
-                worst_fbc = i, worst_num_samp = samples;
-        }
+        } 
         XFree(vi);
     }
 
@@ -134,6 +124,36 @@ const GrGLInterface* SkNativeGLContext::createGLContext() {
     // Get a visual
     XVisualInfo *vi = glXGetVisualFromFBConfig(fDisplay, bestFbc);
     //SkDebugf("Chosen visual ID = 0x%x\n", (unsigned int)vi->visualid);
+#else
+    int numVisuals;
+    XVisualInfo visTemplate, *visReturn;
+
+    visReturn = XGetVisualInfo(fDisplay, VisualNoMask, &visTemplate, &numVisuals);
+    if (NULL == visReturn)
+    {
+        SkDebugf("Failed to get visual information.\n");
+        this->destroyGLContext();
+        return NULL;
+    }
+
+    int best = -1, best_num_samp = -1;
+
+    for (int i = 0; i < numVisuals; ++i)
+    {
+        int samp_buf, samples;
+
+        glXGetConfig(fDisplay, &visReturn[i], GLX_SAMPLE_BUFFERS, &samp_buf);
+        glXGetConfig(fDisplay, &visReturn[i], GLX_SAMPLES, &samples);
+
+        if (best < 0 || (samp_buf && samples > best_num_samp))
+            best = i, best_num_samp = samples;
+    }
+
+    XVisualInfo temp = visReturn[best];
+    XVisualInfo *vi = &temp;
+
+    XFree(visReturn);
+#endif
 
     fPixmap = XCreatePixmap(fDisplay, RootWindow(fDisplay, vi->screen), 10, 10, vi->depth);
 
@@ -145,8 +165,10 @@ const GrGLInterface* SkNativeGLContext::createGLContext() {
 
     fGlxPixmap = glXCreateGLXPixmap(fDisplay, vi, fPixmap);
 
+#ifdef GLX_1_3
     // Done with the visual info data
     XFree(vi);
+#endif
 
     // Create the context
 
@@ -173,9 +195,15 @@ const GrGLInterface* SkNativeGLContext::createGLContext() {
     {
         //SkDebugf("GLX_ARB_create_context not found."
         //       " Using old-style GLX context.\n");
+#ifdef GLX_1_3
         fContext = glXCreateNewContext(fDisplay, bestFbc, GLX_RGBA_TYPE, 0, True);
+#else
+        fContext = glXCreateContext(fDisplay, vi, 0, True);
+#endif
 
-    } else {
+    } 
+#ifdef GLX_1_3
+    else {
         //SkDebugf("Creating context.\n");
 
         PFNGLXCREATECONTEXTATTRIBSARBPROC glXCreateContextAttribsARB = 
@@ -215,6 +243,7 @@ const GrGLInterface* SkNativeGLContext::createGLContext() {
             );
         }
     }
+#endif
 
     // Sync to ensure any errors generated are processed.
     XSync(fDisplay, False);