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| // ========== distance ==========
float sdSphere(in vec3 pos, float rad)
{
return length(pos)-rad;
}
float sdPlane(in vec3 pos, float height)
{
return pos.y-height;
}
// ========== get min distance ==========
vec2 map(in vec3 pos)
{
// 1.0:ground 2.0:sphere
vec2 dID1 = vec2(sdSphere(pos-vec3(0.0,0.5,0.0), 0.3),2.0);
vec2 dID2 = vec2(sdPlane(pos,-0.46),1.0);
return (dID1.x<dID2.x)?dID1:dID2;
}
// ========== get min t ==========
vec2 castRay(in vec3 ro, vec3 rd)
{
float t = 0.0;
float id = -1.0;
for(int i=0;i<100;i++)
{
vec3 pos = ro+t*rd;
vec2 dID = map(pos);
float d = dID.x;
id = dID.y;
if (d<0.001)
{
break;
}
t += d;
if(t>20.0)
{
break;
id = -1.0;
}
}
return vec2(t,id);
}
vec3 calNormal(in vec3 pos)
{
vec2 e = vec2(0.0001,0.0);
return normalize( vec3( map(pos+e.xyy).x-map(pos-e.xyy).x,
map(pos+e.yxy).x-map(pos-e.yxy).x,
map(pos+e.yyx).x-map(pos-e.yyx).x));
}
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
vec2 p = (2.0*fragCoord-iResolution.xy)/iResolution.y;
vec3 col = vec3(0.76); //sky color
float an = iMouse.x/iResolution.x*10.0;
vec3 ta = vec3(0.0,0.65,0.0);
vec3 ro = ta + vec3(2.0*sin(an),0.0,2.0*cos(an));
vec3 ww = normalize(ta-ro);
vec3 uu = normalize(cross(ww,vec3(0.0,1.0,0.0)));
vec3 vv = normalize(cross(uu,ww));
vec3 rd = normalize(vec3(p.x*uu+p.y*vv+1.5*ww));
vec2 tID = castRay(ro,rd);
float t = tID.x;
if(t<20.0)
{
// 1.0:ground 2.0:sphere
vec3 mate = vec3(0.87,0.84,0.86);
if (tID.y<1.5)//ground
{
mate = vec3(0.59,0.61,0.58);
}
else //sphere
{
mate = vec3(0.495,0.475,0.54);
}
vec3 pos = ro+t*rd;
vec3 nor = calNormal(pos);
vec3 sun_dir = normalize( vec3(0.8,0.6,0.2) );
float sun_dif = clamp(dot(nor,sun_dir),0.0,1.0);
float sun_sha = clamp(castRay(pos+0.001*nor,sun_dir).x,0.0,1.0);
float sky_dif = clamp( 0.5+0.5*dot(nor,vec3(0.0,1.0,0.0) ),0.0,1.0);
float bou_dif = clamp( 0.5+0.5*dot(nor,vec3(0.0,-1.0,0.0) ),0.0,1.0);
col = mate*0.5*vec3(0.8,0.55,0.2)*sun_dif*sun_sha;
col += mate*vec3(0.86,0.94,0.95)*sky_dif;
col += mate*0.3*vec3(0.7,0.3,0.2)*bou_dif;
}
fragColor = vec4(col,1.0);
}
|
