quakeforge/libs/video/renderer/glsl/quakeski.frag

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uniform sampler2D palette;
uniform sampler2D solid;
uniform sampler2D trans;
uniform float realtime;
uniform vec4 fog;
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varying vec3 direction;
const float SCALE = 189.0 / 64.0;
float
sqr (float x)
{
return x * x;
}
vec4
fogBlend (vec4 color)
{
float f;
vec4 fog_color = vec4 (fog.rgb, 1.0);
f = exp (-sqr (fog.a / gl_FragCoord.w));
return mix (fog_color, color, f);
}
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void
main (void)
{
float len;
float pix;
vec2 flow = vec2 (1.0, 1.0);
vec2 st;
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vec3 dir = direction;
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dir.z *= 3.0;
len = dot (dir, dir);
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len = SCALE * inversesqrt (len);
st = direction.xy * len + flow * realtime / 8.0;
pix = texture2D (trans, st).r;
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if (pix == 0.0) {
st = direction.xy * len + flow * realtime / 16.0;
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pix = texture2D (solid, st).r;
}
gl_FragColor = fogBlend (texture2D (palette, vec2 (pix, 0.0)));
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}