Make the Sk GL context class an abstract base class

Make the Sk GL context class, SkGLNativeContext, an abstract base class. Before,
it depended on ifdefs to implement the platform dependent polymorphism.  Move
the logic to subclasses of the various platform implementations.

This a step to enable Skia embedders to compile dm and bench_pictures. The
concrete goal is to support running these test apps with Chromium command buffer.

With this change, Chromium can implement its own version of SkGLNativeContext
that uses command buffer, and host the implementation in its own repository.

Implements the above by renaming the SkGLContextHelper to SkGLContext and
removing the unneeded SkGLNativeContext. Also removes
SkGLNativeContext::AutoRestoreContext functionality, it appeared to be unused:
no use in Skia code, and no tests.

BUG=skia:2992

Committed: https://skia.googlesource.com/skia/+/a90ed4e83897b45d6331ee4c54e1edd4054de9a8

Review URL: https://codereview.chromium.org/630843002

1 files changed, 187 insertions, 0 deletions

diff --git a/src/gpu/gl/win/SkCreatePlatformGLContext_win.cpp b/src/gpu/gl/win/SkCreatePlatformGLContext_win.cpp
new file mode 100644
index 0000000000..d362556a4e
--- /dev/null
+++ b/src/gpu/gl/win/SkCreatePlatformGLContext_win.cpp
@@ -0,0 +1,187 @@
+
+/*
+ * 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 "gl/SkGLContext.h"
+
+#include <windows.h>
+#include <GL/GL.h>
+#include "SkWGL.h"
+
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+
+namespace {
+
+class WinGLContext : public SkGLContext {
+public:
+    WinGLContext();
+
+    virtual ~WinGLContext();
+
+    virtual void makeCurrent() const SK_OVERRIDE;
+    virtual void swapBuffers() const SK_OVERRIDE;
+protected:
+    virtual const GrGLInterface* createGLContext(GrGLStandard forcedGpuAPI) SK_OVERRIDE;
+    virtual void destroyGLContext() SK_OVERRIDE;
+
+private:
+    HWND fWindow;
+    HDC fDeviceContext;
+    HGLRC fGlRenderContext;
+    static ATOM gWC;
+    SkWGLPbufferContext* fPbufferContext;
+};
+
+ATOM WinGLContext::gWC = 0;
+
+WinGLContext::WinGLContext()
+    : fWindow(NULL)
+    , fDeviceContext(NULL)
+    , fGlRenderContext(0)
+    , fPbufferContext(NULL) {
+}
+
+WinGLContext::~WinGLContext() {
+    this->destroyGLContext();
+}
+
+void WinGLContext::destroyGLContext() {
+    SkSafeSetNull(fPbufferContext);
+    if (fGlRenderContext) {
+        wglDeleteContext(fGlRenderContext);
+        fGlRenderContext = 0;
+    }
+    if (fWindow && fDeviceContext) {
+        ReleaseDC(fWindow, fDeviceContext);
+        fDeviceContext = 0;
+    }
+    if (fWindow) {
+        DestroyWindow(fWindow);
+        fWindow = 0;
+    }
+}
+
+const GrGLInterface* WinGLContext::createGLContext(GrGLStandard forcedGpuAPI) {
+    HINSTANCE hInstance = (HINSTANCE)GetModuleHandle(NULL);
+
+    if (!gWC) {
+        WNDCLASS wc;
+        wc.cbClsExtra = 0;
+        wc.cbWndExtra = 0;
+        wc.hbrBackground = NULL;
+        wc.hCursor = LoadCursor(NULL, IDC_ARROW);
+        wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
+        wc.hInstance = hInstance;
+        wc.lpfnWndProc = (WNDPROC) DefWindowProc;
+        wc.lpszClassName = TEXT("Griffin");
+        wc.lpszMenuName = NULL;
+        wc.style = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
+
+        gWC = RegisterClass(&wc);
+        if (!gWC) {
+            SkDebugf("Could not register window class.\n");
+            return NULL;
+        }
+    }
+
+    if (!(fWindow = CreateWindow(TEXT("Griffin"),
+                                 TEXT("The Invisible Man"),
+                                 WS_OVERLAPPEDWINDOW,
+                                 0, 0, 1, 1,
+                                 NULL, NULL,
+                                 hInstance, NULL))) {
+        SkDebugf("Could not create window.\n");
+        return NULL;
+    }
+
+    if (!(fDeviceContext = GetDC(fWindow))) {
+        SkDebugf("Could not get device context.\n");
+        this->destroyGLContext();
+        return NULL;
+    }
+    // Requesting a Core profile would bar us from using NVPR. So we request
+    // compatibility profile or GL ES.
+    SkWGLContextRequest contextType =
+        kGLES_GrGLStandard == forcedGpuAPI ?
+        kGLES_SkWGLContextRequest : kGLPreferCompatibilityProfile_SkWGLContextRequest;
+
+    fPbufferContext = SkWGLPbufferContext::Create(fDeviceContext, 0, contextType);
+
+    HDC dc;
+    HGLRC glrc;
+
+    if (NULL == fPbufferContext) {
+        if (!(fGlRenderContext = SkCreateWGLContext(fDeviceContext, 0, contextType))) {
+            SkDebugf("Could not create rendering context.\n");
+            this->destroyGLContext();
+            return NULL;
+        }
+        dc = fDeviceContext;
+        glrc = fGlRenderContext;
+    } else {
+        ReleaseDC(fWindow, fDeviceContext);
+        fDeviceContext = 0;
+        DestroyWindow(fWindow);
+        fWindow = 0;
+
+        dc = fPbufferContext->getDC();
+        glrc = fPbufferContext->getGLRC();
+    }
+
+    if (!(wglMakeCurrent(dc, glrc))) {
+        SkDebugf("Could not set the context.\n");
+        this->destroyGLContext();
+        return NULL;
+    }
+
+    const GrGLInterface* interface = GrGLCreateNativeInterface();
+    if (NULL == interface) {
+        SkDebugf("Could not create GL interface.\n");
+        this->destroyGLContext();
+        return NULL;
+    }
+
+    return interface;
+}
+
+void WinGLContext::makeCurrent() const {
+    HDC dc;
+    HGLRC glrc;
+
+    if (NULL == fPbufferContext) {
+        dc = fDeviceContext;
+        glrc = fGlRenderContext;
+    } else {
+        dc = fPbufferContext->getDC();
+        glrc = fPbufferContext->getGLRC();
+    }
+
+    if (!wglMakeCurrent(dc, glrc)) {
+        SkDebugf("Could not create rendering context.\n");
+    }
+}
+
+void WinGLContext::swapBuffers() const {
+    HDC dc;
+
+    if (NULL == fPbufferContext) {
+        dc = fDeviceContext;
+    } else {
+        dc = fPbufferContext->getDC();
+    }
+    if (!SwapBuffers(dc)) {
+        SkDebugf("Could not complete SwapBuffers.\n");
+    }
+}
+
+} // anonymous namespace
+
+SkGLContext* SkCreatePlatformGLContext() {
+    return SkNEW(WinGLContext);
+}
+