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

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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
1 changed files with 14 additions and 4 deletions
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18
src/SFML/Graphics/Drawable.cpp
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@ -379,12 +379,22 @@ void Drawable::Draw(RenderTarget& Target) const
{ {
GLCheck(glEnable(GL_BLEND)); 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) switch (myBlendMode)
{ {
case Blend::Alpha : GLCheck(glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)); break; case Blend::Alpha :
case Blend::Add : GLCheck(glBlendFunc(GL_SRC_ALPHA, GL_ONE)); break; GLCheck(glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ONE_MINUS_SRC_ALPHA));
case Blend::Multiply : GLCheck(glBlendFunc(GL_DST_COLOR, GL_ZERO)); break; break;
default : 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;
} }
} }