Implements missing _captureBackBuffer method for GL gfx layer.

GL layer was missing _captureBackBuffer() implementation which caused screenShot() function to fail. Also caused ScreenShot::capture() to be called every frame afterward which caused significant performance issues.

Engine/source/gfx/gl/gfxGLDevice.cpp

@@ -25,7 +25,7 @@
 #include "platform/platformGL.h"
 
 #include "gfx/gfxCubemap.h"
-#include "gfx/screenshot.h"
+#include "gfx/gl/screenshotGL.h"
 #include "gfx/gfxDrawUtil.h"
 
 #include "gfx/gl/gfxGLEnumTranslate.h"
@@ -230,7 +230,7 @@ GFXGLDevice::GFXGLDevice(U32 adapterIndex) :
    mDeviceSwizzle24 = &Swizzles::rgb;
 
    mTextureManager = new GFXGLTextureManager();
-   gScreenShot = new ScreenShot();
+   gScreenShot = new ScreenShotGL();
 
    for(U32 i = 0; i < TEXTURE_STAGE_COUNT; i++)
       mActiveTextureType[i] = GL_ZERO;

Engine/source/gfx/gl/screenshotGL.cpp

@@ -0,0 +1,47 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2016 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#include "platform/platform.h"
+#include "gfx/gl/screenshotGL.h"
+#include "gfx/gl/gfxGLDevice.h"
+#include "gfx/bitmap/gBitmap.h"
+
+//Note if MSAA is ever enabled this will need fixing
+GBitmap* ScreenShotGL::_captureBackBuffer()
+{
+   glPixelStorei(GL_PACK_ALIGNMENT, 1);
+   glReadBuffer(GL_BACK);
+
+   Point2I size = GFX->getViewport().extent;
+   U8* pixels = new U8[size.x * size.y * 4];
+   glReadPixels(0, 0, size.x, size.y, GL_RGB, GL_UNSIGNED_BYTE, pixels);
+
+   GBitmap* bitmap = new GBitmap(size.x, size.y);
+
+   for (U32 y = 0; y < (U32)size.y; y++)
+      dMemcpy(bitmap->getAddress(0, y), pixels + y * size.x * 3, U32(size.x * 3));
+
+   delete[] pixels;
+
+   return bitmap;
+}
+

Engine/source/gfx/gl/screenshotGL.h

@@ -0,0 +1,39 @@
+//-----------------------------------------------------------------------------
+// Copyright (c) 2016 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+#ifndef _SCREENSHOTGL_H_
+#define _SCREENSHOTGL_H_
+
+#include "gfx/screenshot.h"
+
+//**************************************************************************
+// OpenGL implementation of screenshot
+//**************************************************************************
+class ScreenShotGL : public ScreenShot
+{
+protected:
+
+   GBitmap* _captureBackBuffer();
+
+};
+
+
+#endif  // _SCREENSHOTGL_H_