b=570660; add ability to resize pbuffer GL contexts; r=joe

content/canvas/src/WebGLContext.cpp

@@ -152,6 +152,22 @@ WebGLContext::SetDimensions(PRInt32 width, PRInt32 height)
     if (mWidth == width && mHeight == height)
         return NS_OK;
 
+    if (gl) {
+        // hey we already have something
+        if (gl->Resize(gfxIntSize(width, height))) {
+
+            mWidth = width;
+            mHeight = height;
+
+            gl->fViewport(0, 0, mWidth, mHeight);
+            gl->fClearColor(0, 0, 0, 0);
+            gl->fClear(LOCAL_GL_COLOR_BUFFER_BIT | LOCAL_GL_DEPTH_BUFFER_BIT | LOCAL_GL_STENCIL_BUFFER_BIT);
+
+            // great success!
+            return NS_OK;
+        }
+    }
+
     LogMessage("Canvas 3D: creating PBuffer...");
 
     GLContextProvider::ContextFormat format(GLContextProvider::ContextFormat::BasicRGBA32);

gfx/thebes/public/GLContext.h

@@ -1,3 +1,4 @@
+/* -*- Mode: c++; c-basic-offset: 4; indent-tabs-mode: nil; tab-width: 40; -*- */
 /* ***** BEGIN LICENSE BLOCK *****
  * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  *
@@ -45,7 +46,7 @@
 #endif
 
 #include "GLDefs.h"
-#include "gfxTypes.h"
+#include "gfxRect.h"
 #include "nsISupportsImpl.h"
 #include "prlink.h"
 
@@ -84,19 +85,19 @@ class LibrarySymbolLoader
     } SymLoadStruct;
 
     PRBool LoadSymbols(SymLoadStruct *firstStruct,
-		       PRBool tryplatform = PR_FALSE,
-		       const char *prefix = nsnull);
+                       PRBool tryplatform = PR_FALSE,
+                       const char *prefix = nsnull);
 
     /*
      * Static version of the functions in this class
      */
     static PRFuncPtr LookupSymbol(PRLibrary *lib,
-				  const char *symname,
-				  PlatformLookupFunction lookupFunction = nsnull);
+                                  const char *symname,
+                                  PlatformLookupFunction lookupFunction = nsnull);
     static PRBool LoadSymbols(PRLibrary *lib,
-			      SymLoadStruct *firstStruct,
-			      PlatformLookupFunction lookupFunction = nsnull,
-			      const char *prefix = nsnull);
+                              SymLoadStruct *firstStruct,
+                              PlatformLookupFunction lookupFunction = nsnull,
+                              const char *prefix = nsnull);
 protected:
     LibrarySymbolLoader() {
         mLibrary = nsnull;
@@ -125,13 +126,13 @@ class GLContext
     virtual PRBool SetupLookupFunction() = 0;
 
     void *GetUserData(void *aKey) {
-	void *result = nsnull;
-	mUserData.Get(aKey, &result);
-	return result;
+        void *result = nsnull;
+        mUserData.Get(aKey, &result);
+        return result;
     }
 
     void SetUserData(void *aKey, void *aValue) {
-	mUserData.Put(aKey, aValue);
+        mUserData.Put(aKey, aValue);
     }
 
     enum NativeDataType {
@@ -143,6 +144,16 @@ class GLContext
     };
 
     virtual void *GetNativeData(NativeDataType aType) { return NULL; }
+
+    /* If this is a PBuffer context, resize the pbufer to the given dimensions,
+     * keping the same format and attributes.  If the resize succeeds, return
+     * PR_TRUE.  Otherwise, or if this is not a pbuffer, return PR_FALSE.
+     *
+     * On a successful resize, the previous contents of the pbuffer are cleared,
+     * and the new contents are undefined.
+     */
+    virtual PRBool Resize(const gfxIntSize& aNewSize) { return PR_FALSE; }
+
 protected:
 
     PRBool mInitialized;

gfx/thebes/src/GLContextProviderWGL.cpp

@@ -181,11 +181,12 @@ class GLContextWGL : public GLContext
 {
 public:
     GLContextWGL(HDC aDC, HGLRC aContext)
-        : mContext(aContext), mDC(aDC), mPBuffer(nsnull)
+        : mContext(aContext), mDC(aDC), mPBuffer(nsnull), mPixelFormat(-1)
     { }
 
-    GLContextWGL(HANDLE aPBuffer) {
+    GLContextWGL(HANDLE aPBuffer, int aPixelFormat) {
         mPBuffer = aPBuffer;
+        mPixelFormat = aPixelFormat;
         mDC = sWGLLibrary.fGetPbufferDC(mPBuffer);
         mContext = sWGLLibrary.fCreateContext(mDC);
     }
@@ -241,10 +242,52 @@ class GLContextWGL : public GLContext
         }
     }
 
+    PRBool Resize(const gfxIntSize& aNewSize) {
+        if (!mPBuffer)
+            return PR_FALSE;
+
+        nsTArray<int> pbattribs;
+        pbattribs.AppendElement(LOCAL_WGL_TEXTURE_FORMAT_ARB);
+        // XXX fixme after bug 571092 lands and we have the format available
+        if (true /*aFormat.alpha > 0*/) {
+            pbattribs.AppendElement(LOCAL_WGL_TEXTURE_RGBA_ARB);
+        } else {
+            pbattribs.AppendElement(LOCAL_WGL_TEXTURE_RGB_ARB);
+        }
+        pbattribs.AppendElement(LOCAL_WGL_TEXTURE_TARGET_ARB);
+        pbattribs.AppendElement(LOCAL_WGL_TEXTURE_2D_ARB);
+
+        pbattribs.AppendElement(0);
+
+        HANDLE newbuf = sWGLLibrary.fCreatePbuffer(gDummyWindowDC, mPixelFormat,
+                                                   aNewSize.width, aNewSize.height,
+                                                   pbattribs.Elements());
+        if (!newbuf)
+            return PR_FALSE;
+
+        bool isCurrent = false;
+        if (sWGLLibrary.fGetCurrentContext() == mContext) {
+            sWGLLibrary.fMakeCurrent(NULL, NULL);
+            isCurrent = true;
+        }
+
+        // hey, it worked!
+        sWGLLibrary.fDestroyPbuffer(mPBuffer);
+
+        mPBuffer = newbuf;
+        mDC = sWGLLibrary.fGetPbufferDC(mPBuffer);
+
+        if (isCurrent)
+            MakeCurrent();
+
+        return PR_TRUE;
+    }
+
 private:
     HGLRC mContext;
     HDC mDC;
     HANDLE mPBuffer;
+    int mPixelFormat;
 };
 
 already_AddRefed<GLContext>
@@ -362,7 +405,7 @@ GLContextProvider::CreatePBuffer(const gfxIntSize& aSize, const ContextFormat& a
         return nsnull;
     }
 
-    nsRefPtr<GLContextWGL> glContext = new GLContextWGL(pbuffer);
+    nsRefPtr<GLContextWGL> glContext = new GLContextWGL(pbuffer, chosenFormat);
     glContext->Init();
 
     return glContext.forget().get();