nuclear@21: uniform vec2 viewport;
nuclear@21: 
nuclear@21: void main()
nuclear@21: {
nuclear@21: 	const float psize = 1.0;
nuclear@21: 
nuclear@21: 	vec4 ppos = gl_ModelViewProjectionMatrix * gl_Vertex;
nuclear@21: 	gl_Position = ppos;
nuclear@21: 
nuclear@21: 	float vs_z = (gl_ModelViewMatrix * gl_Vertex).z;
nuclear@21: 	vec4 p0 = gl_ProjectionMatrix * vec4(0.0, 0.0, vs_z, 1.0);
nuclear@21: 	vec4 p1 = gl_ProjectionMatrix * vec4(psize, 0.0, vs_z, 1.0);
nuclear@21: 
nuclear@21: 	p0.xyz /= p0.w;
nuclear@21: 	p1.xyz /= p1.w;
nuclear@21: 
nuclear@21: 	p0.xy = (p0.xy * vec2(0.5, 0.5) + vec2(0.5, 0.5)) * viewport;
nuclear@21: 	p1.xy = (p1.xy * vec2(0.5, 0.5) + vec2(0.5, 0.5)) * viewport;
nuclear@21: 
nuclear@21: 	float sz = length(p1.xy - p0.xy);
nuclear@21: 	gl_PointSize = sz;
nuclear@21: }