Make SkOSWindow return the sample count and stencil bit count for its GL context.

src/views/unix/SkOSWindow_Unix.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include <X11/Xlib.h>
 #include <X11/Xatom.h>
 #include <X11/XKBlib.h>
@@ skipping 19 matching lines @@
 
 // Determine which events to listen for.
 const long EVENT_MASK = StructureNotifyMask|ButtonPressMask|ButtonReleaseMask
         |ExposureMask|PointerMotionMask|KeyPressMask|KeyReleaseMask;
 
 SkOSWindow::SkOSWindow(void* unused)
     : fVi(NULL)
     , fMSAASampleCount(0) {
     fUnixWindow.fDisplay = NULL;
     fUnixWindow.fGLContext = NULL;
-    this->initWindow(0);
+    this->initWindow(0, NULL);
     this->resize(WIDTH, HEIGHT);
 }
 
 SkOSWindow::~SkOSWindow() {
     this->closeWindow();
 }
 
 void SkOSWindow::closeWindow() {
     if (NULL != fUnixWindow.fDisplay) {
         this->detach();
         SkASSERT(NULL != fUnixWindow.fGc);
         XFreeGC(fUnixWindow.fDisplay, fUnixWindow.fGc);
         fUnixWindow.fGc = NULL;
         XDestroyWindow(fUnixWindow.fDisplay, fUnixWindow.fWin);
         fVi = NULL;
         XCloseDisplay(fUnixWindow.fDisplay);
         fUnixWindow.fDisplay = NULL;
         fMSAASampleCount = 0;
     }
 }
 
-void SkOSWindow::initWindow(int requestedMSAASampleCount) {
+void SkOSWindow::initWindow(int requestedMSAASampleCount, AttachmentInfo* info) {
     if (fMSAASampleCount != requestedMSAASampleCount) {
         this->closeWindow();
     }
     // presence of fDisplay means we already have a window
     if (NULL != fUnixWindow.fDisplay) {
+        if (NULL != info) {
+            if (NULL != fVi) {
+                glXGetConfig(fUnixWindow.fDisplay, fVi, GLX_SAMPLES_ARB, &info->fSampleCount);
+                glXGetConfig(fUnixWindow.fDisplay, fVi, GLX_STENCIL_SIZE, &info->fStencilBits);
+            } else {
+                info->fSampleCount = 0;
+                info->fStencilBits = 0;
+            }
+        }
         return;
     }
     fUnixWindow.fDisplay = XOpenDisplay(NULL);
     Display* dsp = fUnixWindow.fDisplay;
     if (NULL == dsp) {
         SkDebugf("Could not open an X Display");
         return;
     }
     // Attempt to create a window that supports GL
     GLint att[] = {
@@ skipping 16 matching lines @@
         msaaAtt[kAttCount + 3] = None;
         fVi = glXChooseVisual(dsp, DefaultScreen(dsp), msaaAtt);
         fMSAASampleCount = requestedMSAASampleCount;
     }
     if (NULL == fVi) {
         fVi = glXChooseVisual(dsp, DefaultScreen(dsp), att);
         fMSAASampleCount = 0;
     }
 
     if (fVi) {
+        if (NULL != info) {
+            glXGetConfig(dsp, fVi, GLX_SAMPLES_ARB, &info->fSampleCount);
+            glXGetConfig(dsp, fVi, GLX_STENCIL_SIZE, &info->fStencilBits);
+        }
         Colormap colorMap = XCreateColormap(dsp,
                                             RootWindow(dsp, fVi->screen),
                                             fVi->visual,
                                              AllocNone);
         XSetWindowAttributes swa;
         swa.colormap = colorMap;
         swa.event_mask = EVENT_MASK;
         fUnixWindow.fWin = XCreateWindow(dsp,
                                          RootWindow(dsp, fVi->screen),
                                          0, 0, // x, y
                                          WIDTH, HEIGHT,
                                          0, // border width
                                          fVi->depth,
                                          InputOutput,
                                          fVi->visual,
                                          CWEventMask | CWColormap,
                                          &swa);
     } else {
+        if (NULL != info) {
+            info->fSampleCount = 0;
+            info->fStencilBits = 0;
+        }
         // Create a simple window instead.  We will not be able to show GL
         fUnixWindow.fWin = XCreateSimpleWindow(dsp,
                                                DefaultRootWindow(dsp),
                                                0, 0,  // x, y
                                                WIDTH, HEIGHT,
                                                0,     // border width
                                                0,     // border value
                                                0);    // background value
     }
     this->mapWindowAndWait();
@@ skipping 111 matching lines @@
     XSelectInput(dsp, win, eventMask);
 
     // Wait until screen is ready.
     XEvent evt;
     do {
         XNextEvent(dsp, &evt);
     } while(evt.type != MapNotify);
 
 }
 
-bool SkOSWindow::attach(SkBackEndTypes /* attachType */, int msaaSampleCount) {
-    this->initWindow(msaaSampleCount);
+bool SkOSWindow::attach(SkBackEndTypes, int msaaSampleCount, AttachmentInfo* info) {
+    this->initWindow(msaaSampleCount, info);
+
     if (NULL == fUnixWindow.fDisplay) {
         return false;
     }
     if (NULL == fUnixWindow.fGLContext) {
         SkASSERT(NULL != fVi);
 
         fUnixWindow.fGLContext = glXCreateContext(fUnixWindow.fDisplay,
                                                   fVi,
                                                   NULL,
                                                   GL_TRUE);
@@ skipping 98 matching lines @@
     return false;
 }
 
 bool SkOSWindow::onHandleKey(SkKey key) {
     return false;
 }
 
 bool SkOSWindow::onHandleKeyUp(SkKey key) {
     return false;
 }