When performing offscreen rendering on windows, attempt to use a pbuffer context.

include/utils/SkWGL.h

 
 /*
  * 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 "SkRefCnt.h"
 
@@ skipping 38 matching lines @@
 #define SK_WGL_CONTEXT_FLAGS                        0x2094
 #define SK_WGL_CONTEXT_PROFILE_MASK                 0x9126
 #define SK_WGL_CONTEXT_DEBUG_BIT                    0x0001
 #define SK_WGL_CONTEXT_FORWARD_COMPATIBLE_BIT       0x0002
 #define SK_WGL_CONTEXT_CORE_PROFILE_BIT             0x00000001
 #define SK_WGL_CONTEXT_COMPATIBILITY_PROFILE_BIT    0x00000002
 #define SK_WGL_CONTEXT_ES2_PROFILE_BIT              0x00000004
 #define SK_ERROR_INVALID_VERSION                    0x2095
 #define SK_ERROR_INVALID_PROFILE                    0x2096
 
+DECLARE_HANDLE(HPBUFFER);
+
 class SkWGLExtensions {
 public:
     SkWGLExtensions();
     /**
      * Determines if an extensions is available for a given DC.
      * WGL_extensions_string is considered a prerequisite for all other
      * extensions. It is necessary to check this before calling other class
      * functions.
      */
     bool hasExtension(HDC dc, const char* ext) const;
 
     const char* getExtensionsString(HDC hdc) const;
     BOOL choosePixelFormat(HDC hdc, const int*, const FLOAT*, UINT, int*, UINT*) const;
     BOOL getPixelFormatAttribiv(HDC, int, int, UINT, const int*, int*) const;
     BOOL getPixelFormatAttribfv(HDC hdc, int, int, UINT, const int*, FLOAT*) const;
     HGLRC createContextAttribs(HDC, HGLRC, const int *) const;
 
+    BOOL swapInterval(int interval) const;
+
+    HPBUFFER createPbuffer(HDC, int , int, int, const int*) const;
+    HDC getPbufferDC(HPBUFFER) const;
+    int releasePbufferDC(HPBUFFER, HDC) const;
+    BOOL destroyPbuffer(HPBUFFER) const;
+
     /**
      * WGL doesn't have precise rules for the ordering of formats returned
      * by wglChoosePixelFormat. This function helps choose among the set of
      * formats returned by wglChoosePixelFormat. The rules in decreasing
      * priority are:
      *     * Choose formats with the smallest sample count that is >=
      *       desiredSampleCount (or the largest sample count if all formats have
      *       fewer samples than desiredSampleCount.)
      *     * Choose formats with the fewest color samples when coverage sampling
      *       is available.
      *     * If the above rules leave multiple formats, choose the one that
      *       appears first in the formats array parameter.
      */
     int selectFormat(const int formats[],
                      int formatCount,
                      HDC dc,
-                     int desiredSampleCount);
+                     int desiredSampleCount) const;
 private:
-    typedef const char* (WINAPI *GetExtensionsStringProc)(HDC hdc);
-    typedef BOOL (WINAPI *ChoosePixelFormatProc)(HDC hdc, const int *, const FLOAT *, UINT, int *, UINT *);
+    typedef const char* (WINAPI *GetExtensionsStringProc)(HDC);
+    typedef BOOL (WINAPI *ChoosePixelFormatProc)(HDC, const int *, const FLOAT *, UINT, int *, UINT *);
     typedef BOOL (WINAPI *GetPixelFormatAttribivProc)(HDC, int, int, UINT, const int*, int*);
-    typedef BOOL (WINAPI *GetPixelFormatAttribfvProc)(HDC hdc, int, int, UINT, const int*, FLOAT*);
-    typedef HGLRC (WINAPI *CreateContextAttribsProc)(HDC hDC, HGLRC, const int *);
+    typedef BOOL (WINAPI *GetPixelFormatAttribfvProc)(HDC, int, int, UINT, const int*, FLOAT*);
+    typedef HGLRC (WINAPI *CreateContextAttribsProc)(HDC, HGLRC, const int *);
+    typedef BOOL (WINAPI* SwapIntervalProc)(int);
+    typedef HPBUFFER (WINAPI* CreatePbufferProc)(HDC, int , int, int, const int*);
+    typedef HDC (WINAPI* GetPbufferDCProc)(HPBUFFER);
+    typedef int (WINAPI* ReleasePbufferDCProc)(HPBUFFER, HDC);
+    typedef BOOL (WINAPI* DestroyPbufferProc)(HPBUFFER);
 
     GetExtensionsStringProc fGetExtensionsString;
     ChoosePixelFormatProc fChoosePixelFormat;
     GetPixelFormatAttribfvProc fGetPixelFormatAttribfv;
     GetPixelFormatAttribivProc fGetPixelFormatAttribiv;
     CreateContextAttribsProc fCreateContextAttribs;
+    SwapIntervalProc fSwapInterval;
+    CreatePbufferProc fCreatePbuffer;
+    GetPbufferDCProc fGetPbufferDC;
+    ReleasePbufferDCProc fReleasePbufferDC;
+    DestroyPbufferProc fDestroyPbuffer;
 };
 
 enum SkWGLContextRequest {
     /** Requests to create core profile context if possible, otherwise
         compatibility profile. */
     kGLPreferCoreProfile_SkWGLContextRequest,
     /** Requests to create compatibility profile context if possible, otherwise
         core profile. */
     kGLPreferCompatibilityProfile_SkWGLContextRequest,
     /** Requests to create GL ES profile context. */
     kGLES_SkWGLContextRequest
 };
 /**
  * Helper to create an OpenGL context for a DC using WGL. Configs with a sample count >= to
  * msaaSampleCount are preferred but if none is available then a context with a lower sample count
  * (including non-MSAA) will be created. If preferCoreProfile is true but a core profile cannot be
  * created then a compatible profile context will be created.
  */
 HGLRC SkCreateWGLContext(HDC dc, int msaaSampleCount, SkWGLContextRequest context);
 
+/**
+ * Helper class for creating a pbuffer context and deleting all the handles when finished. This
+ * requires that a device context has been created. However, the pbuffer gets its own device
+ * context. The original device context can be released once the pbuffer context is created.
+ */
+class SkWGLPbufferContext : public SkRefCnt {
+public:
+    static SkWGLPbufferContext* Create(HDC parentDC, int msaaSampleCount,
+                                       SkWGLContextRequest contextType);
+
+    virtual ~SkWGLPbufferContext();
+
+    HDC getDC() const { return fDC; }
+    HGLRC getGLRC() const { return fGLRC; }
+
+private:
+    SkWGLPbufferContext(HPBUFFER pbuffer, HDC dc, HGLRC glrc);
+
+    HPBUFFER        fPbuffer;
+    HDC             fDC;
+    HGLRC           fGLRC;
+    SkWGLExtensions fExtensions;
+};
+
 #endif