kwin/effects/data/explosion.frag

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uniform sampler2D winTexture;
uniform sampler2D startOffsetTexture;
uniform sampler2D endOffsetTexture;
uniform float factor;
uniform float scale;
const float regionTexSize = 512.0;
vec2 getOffset(sampler2D texture, vec2 pos)
{
return (texture2D(texture, pos / regionTexSize).xy - 0.5) / (5.0 / 256.0);
}
void main()
{
// Original (unscaled) position in pixels
vec2 origpos = gl_TexCoord[0].xy;
// Position in pixels on the scaled window
vec2 pos = origpos * scale;
// Start/end position of current region
vec2 rstart = origpos + getOffset(startOffsetTexture, origpos);
vec2 rend = origpos + getOffset(endOffsetTexture, origpos);
float alpha = texture2D(startOffsetTexture, origpos / regionTexSize).b;
// Distance from the start of the region
vec2 dist = pos - rstart*scale;
if(any(greaterThan(dist, rend-rstart)))
discard;//alpha = 0.0;
vec4 transformedtexcoord = vec4(rstart + dist, vec2(1.0)) * gl_TextureMatrix[0];
vec3 tex = texture2D(winTexture, transformedtexcoord.xy).rgb;
#if 0
// ATM we ignore custom opacity values because Fade effect fades out the
// window which results in the explosion being way too quick. Once there's
// a way to suppress Fade effect when ExplosionEffect is active, we can
// use the custom opacity again
gl_FragColor = vec4(tex, (1.0 - factor*factor) * alpha * opacity);
#else
gl_FragColor = vec4(tex, (1.0 - factor*factor) * alpha);
#endif
}