AJ Kelly
68 lines
2.4 KiB
GLSL
68 lines
2.4 KiB
GLSL
uniform sampler2D Texture1;
|
|
uniform sampler2D Texture2;
|
|
|
|
vec4 ApplyOverlay( vec4 over, vec4 under, float fill )
|
|
{
|
|
// we want to compare against black for the alpha pass, I think...
|
|
vec3 NeutralColor = vec3(0.5,0.5,0.5);
|
|
over.rgb = mix( NeutralColor, over.rgb, fill );
|
|
|
|
vec4 ret;
|
|
ret.rgb = under.rgb * over.rgb * 2.0;
|
|
|
|
ret.rgb = min(ret.rgb, 1.0);
|
|
ret.rgb *= over.a * under.a;
|
|
|
|
ret.a = over.a * under.a;
|
|
return ret;
|
|
}
|
|
|
|
void main(void)
|
|
{
|
|
// creates two vec4s that represent the two textures.
|
|
vec4 under = texture2DProj( Texture1, gl_TexCoord[0] );
|
|
vec4 over = texture2DProj( Texture2, gl_TexCoord[0] );
|
|
|
|
// the return value is also a vec4.
|
|
vec4 ret = ApplyOverlay( over, under, gl_Color.a );
|
|
|
|
// glenn does some math here that I don't understand just yet.
|
|
ret.rgb += (1.0 - over.a) * under.rgb * under.a;
|
|
ret.a += (1.0 - over.a) * under.a;
|
|
|
|
over.a *= gl_Color.a;
|
|
ret.rgb += (1.0 - under.a) * over.rgb * over.a;
|
|
ret.a += (1.0 - under.a) * over.a;
|
|
|
|
// this is unpremultiply though:
|
|
ret.rgb /= ret.a;
|
|
|
|
gl_FragColor = ret;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* Copyright (c) 2009 AJ Kelly
|
|
* All rights reserved.
|
|
*
|
|
* 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, and/or sell copies of the Software, and to permit persons to
|
|
* whom the Software is furnished to do so, provided that the above
|
|
* copyright notice(s) and this permission notice appear in all copies of
|
|
* the Software and that both the above copyright notice(s) and this
|
|
* permission notice appear in supporting documentation.
|
|
*
|
|
* 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 OF
|
|
* THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
|
|
* INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
|
|
* OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
|
|
* OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
|
|
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
|
|
* PERFORMANCE OF THIS SOFTWARE.
|
|
*/
|