qzdoom/wadsrc/static/shaders/glsl/main.vp

out vec4 pixelpos;
out vec2 glowdist;

void main()
{
	vec4 worldcoord = ModelMatrix * gl_Vertex;
	vec4 eyeCoordPos = ViewMatrix * worldcoord;

	gl_FrontColor = gl_Color;
	
	pixelpos.xyz = worldcoord.xyz;
	pixelpos.w = -eyeCoordPos.z/eyeCoordPos.w;

	glowdist.x = -((uGlowTopPlane.w + uGlowTopPlane.x * worldcoord.x + uGlowTopPlane.y * worldcoord.z) * uGlowTopPlane.z) - worldcoord.y;
	glowdist.y = worldcoord.y + ((uGlowBottomPlane.w + uGlowBottomPlane.x * worldcoord.x + uGlowBottomPlane.y * worldcoord.z) * uGlowBottomPlane.z);
	
	#ifdef SPHEREMAP
		vec3 u = normalize(eyeCoordPos.xyz);
		vec3 n = normalize(gl_NormalMatrix * gl_Normal);
		vec3 r = reflect(u, n);
		float m = 2.0 * sqrt( r.x*r.x + r.y*r.y + (r.z+1.0)*(r.z+1.0) );
		vec2 sst = vec2(r.x/m + 0.5,  r.y/m + 0.5);
		gl_TexCoord[0].xy = sst;
	#else
		gl_TexCoord[0] = TextureMatrix * gl_MultiTexCoord0;
	#endif
	
	gl_Position = ProjectionMatrix * eyeCoordPos;
}