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

#ifndef NO_FOG
	varying vec4 pixelpos;
	attribute vec4 fogparams;
	varying vec4 fogparm;
#endif
#ifndef NO_GLOW
	varying vec2 glowdist;
	uniform vec4 glowbottomplane, glowtopplane;
#endif

#ifdef SOFTLIGHT
	attribute float lightlevel_in;
	varying float lightlevel;
#endif

void main()
{
	#ifdef SOFTLIGHT
		lightlevel = lightlevel_in;
	#endif

	#ifndef NO_SM4
		// Yes, I know... But using a texture matrix here saves me from the hassle of tracking its state across shaders. ;)
		vec4 worldcoord = gl_TextureMatrix[7] * gl_Vertex;
	#else
		vec4 worldcoord = gl_Vertex;
	#endif
	vec4 eyeCoordPos = gl_ModelViewMatrix * worldcoord;

	gl_FrontColor = gl_Color;

	#ifndef NO_FOG
		pixelpos.xyz = worldcoord.xyz;
		pixelpos.w = -eyeCoordPos.z/eyeCoordPos.w;
		fogparm = fogparams;
	#endif
	
	#ifndef NO_GLOW
		glowdist.x = -((glowtopplane.w + glowtopplane.x * worldcoord.x + glowtopplane.y * worldcoord.z) * glowtopplane.z) - worldcoord.y;
		glowdist.y = worldcoord.y + ((glowbottomplane.w + glowbottomplane.x * worldcoord.x + glowbottomplane.y * worldcoord.z) * glowbottomplane.z);
	#endif
	
	#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);
	#endif
	
	
	#ifndef SPHEREMAP_0
		gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
	#else
		gl_TexCoord[0].xy = sst;
	#endif
	
	#ifndef NO_SM4
		gl_Position = gl_ModelViewProjectionMatrix * worldcoord;
	#else
		gl_Position = ftransform();
	#endif
    #ifdef __GLSL_CG_DATA_TYPES
		gl_ClipVertex = eyeCoordPos;
	#endif
}