Avoid using constant color when blending #7520
Conversation
If it's just ONE/ZERO or etc., we can keep those constants. May be faster, and apparently less buggy in some drivers.
| @@ -384,11 +388,14 @@ void TransformDrawEngine::ApplyBlendState() { | |||
| default: | |||
| break; | |||
| } | |||
| needsConstantAlpha = constantAlpha < 1.0f; | |||
There was a problem hiding this comment.
Well, currently it's not smart enough to optimize out 0, but yeah, that should be doable...
-[Unknown]
There was a problem hiding this comment.
Okay, b5126f7 avoids GL_CONSTANT_ALPHA where safe too. Probably ZERO is pretty common.
-[Unknown]
|
(see #7510, just for the record) |
|
Cool. I tried all the games I have with problematic alpha/stencil and nothing seems to break, really tempted to merge before 1.0.1 .. hm |
| glBlendFuncA = GL_CONSTANT_COLOR; | ||
| } else if (glBlendFuncA != GL_INVALID_ENUM && glBlendFuncB == GL_INVALID_ENUM) { | ||
| // Can use blendcolor trivially. | ||
| const float blendColor[4] = {fixB.x, fixB.y, fixB.z, constantAlpha}; | ||
| glstate.blendColor.set(blendColor); | ||
| setBlendColorv(fixB); | ||
| glBlendFuncB = GL_CONSTANT_COLOR; | ||
| } else if (glBlendFuncA == GL_INVALID_ENUM && glBlendFuncB == GL_INVALID_ENUM) { | ||
| if (blendColorSimilar(fixA, Vec3f::AssignToAll(constantAlpha) - fixB)) { |
There was a problem hiding this comment.
I'm not sure about this line. Why is it constantAlpha - fixB? Should it just be 1.0f, or is there some special handling of alpha for GL_ONE_MINUS_CONSTANT_COLOR? I think it was just a mistake I made search/replacing. Normally we will premultiply in the shader anyway.
-[Unknown]
There was a problem hiding this comment.
I think it's intended for the case where the blend factors are say 0x111111 and 0xEEEEEE, in which case we can set one as constant color, and the other as GL_ONE_MINUS_CONSTANT_COLOR, to simulate that we have two constant colors even though we don't.
Uh, and yes, it should be 1.0f - ...
There was a problem hiding this comment.
Right, just wasn't sure why I had constantAlpha there instead of 1.0f for the check to see if we can use that.
-[Unknown]
I'm pretty sure this was not intentional.
|
Yeah, that should be right. |
Avoid using constant color when blending
If it's just ONE/ZERO or etc., we can keep those constants (without setting one explicitly.) May be faster, and apparently less buggy in some drivers.
-[Unknown]