sky shader

sky.frag

vec3 lightPos_ = vec3(
	-cos(iGlobalTime*0.1)*-8.5, 
	3.5+sin(iGlobalTime*0.05)*3.0, 
	-(sin(iGlobalTime*0.1)*4.0-5.4)
);
vec3 bgLight = normalize(lightPos_);
vec3 lightPos = bgLight * 9999.0;
vec3 sun = vec3(5.0, 3.5, 2.0)*4.0;

vec3 shadeBg(vec3 dir, vec3 nml)
{
	vec3 bgCol = vec3(0.2, 0.15, 0.1);
	float bgDiff = dot(nml, vec3(0.0, 1.0, 0.0));
	float sunPow = dot(nml, bgLight);
	bgCol += bgDiff*vec3(0.25, 0.5, 0.5);
	bgCol += sun*(0.1*pow( max(sunPow, 0.0), 2.0) + pow( max(sunPow, 0.0), abs(bgLight.y)*256.0));
	bgCol += bgCol*(2.0*pow( max(-sunPow, 0.0), 2.0)+ pow( max(sunPow, 0.0), abs(bgLight.y)*128.0));
	return max(vec3(0.0), bgCol);
}