fix alpha blending issues

src/framework/graphics/framebuffer.cpp

@@ -157,6 +157,7 @@ void FrameBuffer::internalRelease()
         // restore screen original content
         g_painter->setCompositionMode(Painter::CompositionMode_Replace);
         g_painter->drawTexturedRect(screenRect, m_screenBackup, screenRect);
+        g_painter->resetCompositionMode();
     }
 }
 

src/framework/graphics/graphics.cpp

@@ -330,3 +330,14 @@ bool Graphics::canUseClampToEdge()
     return m_useClampToEdge;
 #endif
 }
+
+bool Graphics::canUseBlendFuncSeparate()
+{
+#ifdef OPENGL_ES
+    return true;
+#else
+    if(!GLEW_VERSION_1_4)
+        return false;
+    return true;
+#endif
+}

src/framework/graphics/graphics.h

@@ -63,6 +63,7 @@ public:
     bool canUseMipmaps();
     bool canUseHardwareMipmaps();
     bool canUseClampToEdge();
+    bool canUseBlendFuncSeparate();
 
 private:
     Size m_viewportSize;

src/framework/graphics/painter.cpp

@@ -132,7 +132,11 @@ void Painter::updateGlCompositionMode()
 {
     switch(m_compositionMode) {
         case CompositionMode_Normal:
-            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+            if(g_graphics.canUseBlendFuncSeparate())
+                glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE);
+            else {
+                glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+            }
             break;
         case CompositionMode_Multiply:
             glBlendFunc(GL_DST_COLOR, GL_ONE_MINUS_SRC_ALPHA);

src/framework/platform/win32window.cpp

@@ -304,7 +304,7 @@ void WIN32Window::internalChooseGLVisual()
                                          PFD_TYPE_RGBA,
                                          32,                         // Select Our Color Depth
                                          0, 0, 0, 0, 0, 0,           // Color Bits Ignored
-                                         1,                          // Alpha Buffer Bits
+                                         8,                          // Alpha Buffer Bits
                                          0,                          // Shift Bit Ignored
                                          0,                          // No Accumulation Buffer
                                          0, 0, 0, 0,                 // Accumulation Bits Ignored