engine/engine/shaders/glsl/postproc_laea.glsl

46 lines
874 B
GLSL

!!cvarf ffov
!!samps screen:samplerCube=0
//my attempt at lambert azimuthal equal-area view rendering, because you'll remember that name easily.
#ifdef VERTEX_SHADER
attribute vec2 v_texcoord;
varying vec2 texcoord;
uniform float cvar_ffov;
void main()
{
texcoord = v_texcoord.xy;
//make sure the ffov cvar actually does something meaningful
texcoord *= cvar_ffov / 90.0;
gl_Position = ftetransform();
}
#endif
#ifdef FRAGMENT_SHADER
varying vec2 texcoord;
void main()
{
vec3 tc;
vec2 d;
vec2 ang;
d = texcoord;
//compute the 2d->3d projection
float sq = d.x*d.x+d.y*d.y;
if (sq > 4.0)
gl_FragColor = vec4(0,0,0,1);
else
{
tc.x = sqrt(1.0-(sq/4.0))*d.x;
tc.y = sqrt(1.0-(sq/4.0))*d.y;
tc.z = -1.0 + (sq/2.0);
tc.y *= -1.0;
tc.z *= -1.0;
gl_FragColor = textureCube(s_screen, tc);
}
}
#endif