Use common display initialization logic for Unix

src/gpu/gl/glx/GrNativeDisplay_glx.cpp

+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ *
+ */
+
+#include "GrNativeDisplay_glx.h"
+
+#include "SkTypes.h"
+
+namespace GrNativeDisplay {
+

[robertphillips, 2015/10/16 14:54:40]

const int* visualAttribs ?

+bool Initialize(int* visualAttribs, Display* display, GLXFBConfig* bestConfig) {
+    SkASSERT(visualAttribs && display && bestConfig);

[robertphillips, 2015/10/16 14:54:40]

glxMajor, glxMinor ?

Do we even need the glx ?

+    int glx_major, glx_minor;
+
+    // FBConfigs were added in GLX version 1.3.
+    if (!glXQueryVersion(display, &glx_major, &glx_minor) ||
+        ((glx_major == 1) && (glx_minor < 3)) || (glx_major < 1)) {
+        SkDebugf("GLX version 1.3 or higher required.\n");
+        return false;
+    }
+
+    //SkDebugf("Getting matching framebuffer configs.\n");
+    int fbcount;
+    GLXFBConfig *fbc = glXChooseFBConfig(display, DefaultScreen(display),
+                                         visualAttribs, &fbcount);
+    if (!fbc) {
+        SkDebugf("Failed to retrieve a framebuffer config.\n");
+        return false;
+    }
+    //SkDebugf("Found %d matching FB configs.\n", fbcount);
+
+    // Pick the FB config/visual with the most samples per pixel
+    //SkDebugf("Getting XVisualInfos.\n");

[robertphillips, 2015/10/16 14:54:40]

bestFBC, maxNumSamples ?

+    int best_fbc = -1, best_num_samp = -1;
+
+    int i;
+    for (i = 0; i < fbcount; ++i) {
+        XVisualInfo *vi = glXGetVisualFromFBConfig(display, fbc[i]);
+        if (vi) {

[robertphillips, 2015/10/16 14:54:40]

sampleBuffers ?

+            int samp_buf, samples;
+            glXGetFBConfigAttrib(display, fbc[i], GLX_SAMPLE_BUFFERS, &samp_buf);
+            glXGetFBConfigAttrib(display, fbc[i], GLX_SAMPLES, &samples);
+
+            //SkDebugf("  Matching fbconfig %d, visual ID 0x%2x: SAMPLE_BUFFERS = %d,"
+            //       " SAMPLES = %d\n",
+            //        i, (unsigned int)vi->visualid, samp_buf, samples);
+

[robertphillips, 2015/10/16 14:54:40]

add {} to this ?

+            if (best_fbc < 0 || (samp_buf && samples > best_num_samp))
+                best_fbc = i, best_num_samp = samples;
+        }
+        XFree(vi);
+    }
+
+    *bestConfig = fbc[best_fbc];
+
+    // Be sure to free the FBConfig list allocated by glXChooseFBConfig()
+    XFree(fbc);
+    return true;
+}
+
+};