Get Mac viewer working with SDL

tools/viewer/sk_app/mac/GLWindowContext_mac.cpp

Index: tools/viewer/sk_app/mac/GLWindowContext_mac.cpp
diff --git a/tools/viewer/sk_app/mac/GLWindowContext_mac.cpp b/tools/viewer/sk_app/mac/GLWindowContext_mac.cpp
index c2de0df621b61da53d958e1efebb5d1cda5a1317..bc86df30d0396bfb5fc104063787ce6251688fda 100644
--- a/tools/viewer/sk_app/mac/GLWindowContext_mac.cpp
+++ b/tools/viewer/sk_app/mac/GLWindowContext_mac.cpp
@@ -9,7 +9,9 @@
 #include "../GLWindowContext.h"
 #include "WindowContextFactory_mac.h"
 
-//#include <GL/gl.h>
+#include "SDL.h"
+
+#include <OpenGL/gl.h>
 
 using sk_app::DisplayParams;
 using sk_app::window_context_factory::MacWindowInfo;
@@ -29,25 +31,16 @@ public:
     void onDestroyContext() override;
     
 private:
-  
-#if 0
-    // TODO: add Mac-specific GL display objects
-    Display*     fDisplay;
-    XWindow      fWindow;
-    XVisualInfo* fVisualInfo;
-    GLXContext   fGLContext;
-#endif
+    SDL_Window*   fWindow;
+    SDL_GLContext fGLContext;
+    
+    typedef GLWindowContext INHERITED;
 };
 
 GLWindowContext_mac::GLWindowContext_mac(const MacWindowInfo& info, const DisplayParams& params)
-    : GLWindowContext(params)
-#if 0
-    // TODO: init Mac-specific OpenGL objects
-    , fDisplay(nullptr)
-    , fWindow(0)
-    , fGLContext(0)
-#endif
-    {
+    : INHERITED(params)
+    , fWindow(info.fWindow)
+    , fGLContext(nullptr) {
 
     // any config code here (particularly for msaa)?
 
@@ -59,68 +52,57 @@ GLWindowContext_mac::~GLWindowContext_mac() {
 }
 
 void GLWindowContext_mac::onInitializeContext() {
-#if 0
-    // TODO: Init for Mac
-    SkASSERT(fDisplay);
+    SkASSERT(fWindow);
 
-    fGLContext = glXCreateContext(fDisplay, fVisualInfo, nullptr, GL_TRUE);
+    fGLContext = SDL_GL_CreateContext(fWindow);
     if (!fGLContext) {
+        SkDebugf("%s\n", SDL_GetError());
         return;
     }
 
-    if (glXMakeCurrent(fDisplay, fWindow, fGLContext)) {
+    if (0 == SDL_GL_MakeCurrent(fWindow, fGLContext)) {
         glClearStencil(0);
         glClearColor(0, 0, 0, 0);
         glStencilMask(0xffffffff);
         glClear(GL_STENCIL_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
 
         int redBits, greenBits, blueBits;
-        glXGetConfig(fDisplay, fVisualInfo, GLX_RED_SIZE, &redBits);
-        glXGetConfig(fDisplay, fVisualInfo, GLX_GREEN_SIZE, &greenBits);
-        glXGetConfig(fDisplay, fVisualInfo, GLX_BLUE_SIZE, &blueBits);
+        SDL_GL_GetAttribute(SDL_GL_RED_SIZE, &redBits);
+        SDL_GL_GetAttribute(SDL_GL_GREEN_SIZE, &greenBits);
+        SDL_GL_GetAttribute(SDL_GL_BLUE_SIZE, &blueBits);
         fColorBits = redBits + greenBits + blueBits;
-        glXGetConfig(fDisplay, fVisualInfo, GLX_STENCIL_SIZE, &fStencilBits);
-        glXGetConfig(fDisplay, fVisualInfo, GLX_SAMPLES_ARB, &fSampleCount);
-
-        XWindow root;
-        int x, y;
-        unsigned int border_width, depth;
-        XGetGeometry(fDisplay, fWindow, &root, &x, &y,
-                     (unsigned int*)&fWidth, (unsigned int*)&fHeight, &border_width, &depth); 
+
+        SDL_GL_GetAttribute(SDL_GL_STENCIL_SIZE, &fStencilBits);
+        SDL_GL_GetAttribute(SDL_GL_MULTISAMPLESAMPLES, &fSampleCount);
+
+        SDL_GetWindowSize(fWindow, &fWidth, &fHeight);
         glViewport(0, 0, fWidth, fHeight);
+    } else {
+        SkDebugf("MakeCurrent failed: %s\n", SDL_GetError());
     }
-#endif
 }
 
 void GLWindowContext_mac::onDestroyContext() {
-#if 0
-    // TODO: teardown for Mac
-    if (!fDisplay || !fGLContext) {
+    if (!fWindow || !fGLContext) {
         return;
     }
-    glXMakeCurrent(fDisplay, None, nullptr);
-    glXDestroyContext(fDisplay, fGLContext);
+    SDL_GL_DeleteContext(fGLContext);
     fGLContext = nullptr;
-#endif
 }
 
 
 void GLWindowContext_mac::onSwapBuffers() {
-#if 0
-    // TODO: swap for Mac
-    if (fDisplay && fGLContext) {
-        glXSwapBuffers(fDisplay, fWindow);
+    if (fWindow && fGLContext) {
+        SDL_GL_SwapWindow(fWindow);
     }
-#endif
 }
 
 }  // anonymous namespace
 
-
 namespace sk_app {
 namespace window_context_factory {
 
-WindowContext* MakeGLForMac(const MacWindowInfo& info, const DisplayParams& params) {
+WindowContext* NewGLForMac(const MacWindowInfo& info, const DisplayParams& params) {
     WindowContext* ctx = new GLWindowContext_mac(info, params);
     if (!ctx->isValid()) {
         delete ctx;