Fixed blending functions so that alpha is properly forwarded when rendered to a RenderImage

git-svn-id: https://sfml.svn.sourceforge.net/svnroot/sfml/branches/sfml2@1137 4e206d99-4929-0410-ac5d-dfc041789085
This commit is contained in:
laurentgom 2009-06-13 19:09:02 +00:00
parent 0704e242c0
commit 92e79b8123

View File

@ -379,12 +379,22 @@ void Drawable::Draw(RenderTarget& Target) const
{
GLCheck(glEnable(GL_BLEND));
// We have to use glBlendFuncSeparate so that the resulting alpha is
// not alpha², which is incorrect and would cause problems when rendering
// alpha pixels to a RenderImage that would be in turn rendered to another render target
switch (myBlendMode)
{
case Blend::Alpha : GLCheck(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)); break;
case Blend::Add : GLCheck(glBlendFunc(GL_SRC_ALPHA, GL_ONE)); break;
case Blend::Multiply : GLCheck(glBlendFunc(GL_DST_COLOR, GL_ZERO)); break;
default : break;
case Blend::Alpha :
GLCheck(glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA));
break;
case Blend::Add :
GLCheck(glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE, GL_ONE, GL_ONE_MINUS_SRC_ALPHA));
break;
case Blend::Multiply :
GLCheck(glBlendFuncSeparate(GL_DST_COLOR, GL_ZERO, GL_ONE, GL_ONE_MINUS_SRC_ALPHA));
break;
default :
break;
}
}