Add OpenGL context to Viewer.

tools/viewer/sk_app/GLWindowContext.cpp

Index: tools/viewer/sk_app/GLWindowContext.cpp
diff --git a/tools/viewer/sk_app/GLWindowContext.cpp b/tools/viewer/sk_app/GLWindowContext.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..a491321a2ac97f980c08680ef791badb6fba0091
--- /dev/null
+++ b/tools/viewer/sk_app/GLWindowContext.cpp
@@ -0,0 +1,112 @@
+
+/*
+ * 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 "GrContext.h"
+#include "SkSurface.h"
+#include "GLWindowContext.h"
+
+#include "gl/GrGLDefines.h"
+
+#include "gl/GrGLUtil.h"
+#include "GrRenderTarget.h"
+#include "GrContext.h"
+
+#include "SkCanvas.h"
+#include "SkImage_Base.h"
+
+namespace sk_app {
+
+GLWindowContext::GLWindowContext(void* platformData, const DisplayParams& params) 
+    : WindowContext()
+    , fBackendContext(nullptr)
+    , fRenderTarget(nullptr)
+    , fSurface(nullptr) {
+}
+
+void GLWindowContext::initializeContext(void* platformData, const DisplayParams& params) {
+
+    this->onInitializeContext(platformData, params);
+
+    fDisplayParams = params;
+
+    SkAutoTUnref<const GrGLInterface> glInterface;
+    glInterface.reset(GrGLCreateNativeInterface());
+    fBackendContext.reset(GrGLInterfaceRemoveNVPR(glInterface.get()));
+
+    SkASSERT(nullptr == fContext);
+    fContext = GrContext::Create(kOpenGL_GrBackend, (GrBackendContext)fBackendContext.get());
+
+    // We may not have real sRGB support (ANGLE, in particular), so check for
+    // that, and fall back to L32:
+    //
+    // ... and, if we're using a 10-bit/channel FB0, it doesn't do sRGB conversion on write,
+    // so pretend that it's non-sRGB 8888:
+    fPixelConfig = fContext->caps()->srgbSupport() &&
+                   SkColorAndProfileAreGammaCorrect(fDisplayParams.fColorType,
+                                                    fDisplayParams.fProfileType) &&
+                   (fColorBits != 30) ? kSkiaGamma8888_GrPixelConfig : kSkia8888_GrPixelConfig;
+}
+
+void GLWindowContext::destroyContext() {
+    fSurface.reset(nullptr);
+    fRenderTarget.reset(nullptr);
+
+    if (fContext) {
+        // in case we have outstanding refs to this guy (lua?)
+        fContext->abandonContext();
+        fContext->unref();
+        fContext = nullptr;
+    }
+    
+    fBackendContext.reset(nullptr);
+
+    this->onDestroyContext();
+}
+
+sk_sp<SkSurface> GLWindowContext::getBackbufferSurface() {
+    if (nullptr == fSurface) {
+        fActualColorBits = SkTMax(fColorBits, 24);
+
+        if (fContext) {
+            GrBackendRenderTargetDesc desc;
+            desc.fWidth = this->fWidth;
+            desc.fHeight = this->fHeight;
+            desc.fConfig = fPixelConfig;
+            desc.fOrigin = kBottomLeft_GrSurfaceOrigin;
+            desc.fSampleCnt = fSampleCount;
+            desc.fStencilBits = fStencilBits;
+            GrGLint buffer;
+            GR_GL_CALL(fBackendContext, GetIntegerv(GR_GL_FRAMEBUFFER_BINDING, &buffer));
+            desc.fRenderTargetHandle = buffer;
+            fRenderTarget.reset(fContext->textureProvider()->wrapBackendRenderTarget(desc));
+
+            fSurface = this->createRenderSurface(fRenderTarget, fActualColorBits);
+        }
+    }
+
+    return fSurface;
+}
+
+void GLWindowContext::swapBuffers() {
+    this->presentRenderSurface(fSurface, fRenderTarget, fActualColorBits);
+    this->onSwapBuffers();
+}
+
+void GLWindowContext::resize(uint32_t w, uint32_t h) {
+    this->destroyContext();
+
+    this->initializeContext(nullptr, fDisplayParams);
+}
+
+void GLWindowContext::setDisplayParams(const DisplayParams& params) {
+    this->destroyContext();
+
+    this->initializeContext(nullptr, params);
+}
+
+}   //namespace sk_app