145 lines
4.2 KiB
GLSL
145 lines
4.2 KiB
GLSL
// noise3.jpg
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// Created by inigo quilez - iq/2013
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// License Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.
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// Volumetric clouds. It performs level of detail (LOD) for faster rendering
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float noise( in vec3 x )
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{
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vec3 p = floor(x);
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vec3 f = fract(x);
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f = f*f*(3.0-2.0*f);
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#if 1
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vec2 uv = (p.xy+vec2(37.0,17.0)*p.z) + f.xy;
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vec2 rg = textureLod( iChannel0, (uv+ 0.5)/256.0, 0. ).yx;
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#else
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ivec3 q = ivec3(p);
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ivec2 uv = q.xy + ivec2(37,17)*q.z;
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vec2 rg = mix( mix( texelFetch( iChannel0, (uv )&255, 0 ),
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texelFetch( iChannel0, (uv+ivec2(1,0))&255, 0 ), f.x ),
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mix( texelFetch( iChannel0, (uv+ivec2(0,1))&255, 0 ),
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texelFetch( iChannel0, (uv+ivec2(1,1))&255, 0 ), f.x ), f.y ).yx;
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#endif
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return -1.0+2.0*mix( rg.x, rg.y, f.z );
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}
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float map5( in vec3 p )
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{
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vec3 q = p - vec3(0.0,0.1,1.0)*iGlobalTime;
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float f;
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f = 0.50000*noise( q ); q = q*2.02;
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f += 0.25000*noise( q ); q = q*2.03;
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f += 0.12500*noise( q ); q = q*2.01;
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f += 0.06250*noise( q ); q = q*2.02;
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f += 0.03125*noise( q );
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return clamp( 1.5 - p.y - 2.0 + 1.75*f, 0.0, 1.0 );
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}
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float map4( in vec3 p )
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{
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vec3 q = p - vec3(0.0,0.1,1.0)*iGlobalTime;
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float f;
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f = 0.50000*noise( q ); q = q*2.02;
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f += 0.25000*noise( q ); q = q*2.03;
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f += 0.12500*noise( q ); q = q*2.01;
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f += 0.06250*noise( q );
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return clamp( 1.5 - p.y - 2.0 + 1.75*f, 0.0, 1.0 );
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}
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float map3( in vec3 p )
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{
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vec3 q = p - vec3(0.0,0.1,1.0)*iGlobalTime;
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float f;
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f = 0.50000*noise( q ); q = q*2.02;
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f += 0.25000*noise( q ); q = q*2.03;
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f += 0.12500*noise( q );
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return clamp( 1.5 - p.y - 2.0 + 1.75*f, 0.0, 1.0 );
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}
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float map2( in vec3 p )
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{
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vec3 q = p - vec3(0.0,0.1,1.0)*iGlobalTime;
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float f;
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f = 0.50000*noise( q ); q = q*2.02;
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f += 0.25000*noise( q );;
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return clamp( 1.5 - p.y - 2.0 + 1.75*f, 0.0, 1.0 );
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}
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vec3 sundir = normalize( vec3(-1.0,0.0,-1.0) );
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vec4 integrate( in vec4 sum, in float dif, in float den, in vec3 bgcol, in float t )
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{
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// lighting
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vec3 lin = vec3(0.65,0.7,0.75)*1.4 + vec3(1.0, 0.6, 0.3)*dif;
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vec4 col = vec4( mix( vec3(1.0,0.95,0.8), vec3(0.25,0.3,0.35), den ), den );
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col.xyz *= lin;
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col.xyz = mix( col.xyz, bgcol, 1.0-exp(-0.003*t*t) );
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// front to back blending
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col.a *= 0.4;
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col.rgb *= col.a;
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return sum + col*(1.0-sum.a);
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}
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#define MARCH(STEPS,MAPLOD) for(int i=0; i<STEPS; i++) { vec3 pos = ro + t*rd; if( pos.y<-3.0 || pos.y>2.0 || sum.a > 0.99 ) break; float den = MAPLOD( pos ); if( den>0.01 ) { float dif = clamp((den - MAPLOD(pos+0.3*sundir))/0.6, 0.0, 1.0 ); sum = integrate( sum, dif, den, bgcol, t ); } t += max(0.05,0.02*t); }
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vec4 raymarch( in vec3 ro, in vec3 rd, in vec3 bgcol, in ivec2 px )
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{
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vec4 sum = vec4(0.0);
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float t = 0.05*texelFetch( iChannel0, px&255, 0 ).x;
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MARCH(30,map5);
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MARCH(30,map4);
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MARCH(30,map3);
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MARCH(30,map2);
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return clamp( sum, 0.0, 1.0 );
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}
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mat3 setCamera( in vec3 ro, in vec3 ta, float cr )
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{
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vec3 cw = normalize(ta-ro);
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vec3 cp = vec3(sin(cr), cos(cr),0.0);
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vec3 cu = normalize( cross(cw,cp) );
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vec3 cv = normalize( cross(cu,cw) );
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return mat3( cu, cv, cw );
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}
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vec4 render( in vec3 ro, in vec3 rd, in ivec2 px )
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{
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// background sky
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float sun = clamp( dot(sundir,rd), 0.0, 1.0 );
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vec3 col = vec3(0.6,0.71,0.75) - rd.y*0.2*vec3(1.0,0.5,1.0) + 0.15*0.5;
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col += 0.2*vec3(1.0,.6,0.1)*pow( sun, 8.0 );
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// clouds
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vec4 res = raymarch( ro, rd, col, px );
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col = col*(1.0-res.w) + res.xyz;
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// sun glare
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col += 0.2*vec3(1.0,0.4,0.2)*pow( sun, 3.0 );
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return vec4( col, 1.0 );
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}
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void mainImage( out vec4 fragColor, in vec2 fragCoord )
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{
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vec2 p = (-iResolution.xy + 2.0*fragCoord.xy)/ iResolution.y;
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vec2 m = iMouse.xy/iResolution.xy;
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// camera
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vec3 ro = 4.0*normalize(vec3(sin(3.0*m.x), 0.4*m.y, cos(3.0*m.x)));
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vec3 ta = vec3(0.0, -1.0, 0.0);
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mat3 ca = setCamera( ro, ta, 0.0 );
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// ray
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vec3 rd = ca * normalize( vec3(p.xy,1.5));
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fragColor = render( ro, rd, ivec2(fragCoord-0.5) );
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}
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void mainVR( out vec4 fragColor, in vec2 fragCoord, in vec3 fragRayOri, in vec3 fragRayDir )
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{
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fragColor = render( fragRayOri, fragRayDir, ivec2(fragCoord-0.5) );
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} |