105 lines
2.7 KiB
Forth
105 lines
2.7 KiB
Forth
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//noise3.jpg
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//Magnetismic by nimitz (twitter: @stormoid)
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//Getting 60fps here at high quality
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#define HIGH_QUALITY
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#ifdef HIGH_QUALITY
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#define STEPS 100
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#define ALPHA_WEIGHT 0.025
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#define BASE_STEP 0.05
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#else
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#define STEPS 50
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#define ALPHA_WEIGHT 0.05
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#define BASE_STEP 0.1
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#endif
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#define time iGlobalTime
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vec2 mo;
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vec2 rot(in vec2 p, in float a){float c = cos(a), s = sin(a);return p*mat2(c,s,-s,c);}
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float hash21(in vec2 n){ return fract(sin(dot(n, vec2(12.9898, 4.1414))) * 43758.5453); }
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float noise(in vec3 p) //iq's ubiquitous 3d noise
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{
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vec3 ip = floor(p), f = fract(p);
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#ifdef HIGH_QUALITY
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f = f*f*f*(f*(f*6. - 15.) + 10.); //Quintic smoothing
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#else
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f = f*f*(3.0-2.0*f); //Cubic smoothing
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#endif
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vec2 uv = (ip.xy+vec2(37.0,17.0)*ip.z) + f.xy;
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vec2 rg = textureLod( iChannel0, (uv+ 0.5)/256.0, 0.0 ).yx;
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return mix(rg.x, rg.y, f.z);
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}
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float fbm(in vec3 p, in float sr)
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{
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p *= 3.5;
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float rz = 0., z = 1.;
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for(int i=0;i<4;i++)
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{
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float n = noise(p-time*.6);
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rz += (sin(n*4.4)-.45)*z;
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z *= .47;
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p *= 3.5;
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}
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return rz;
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}
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vec4 map(in vec3 p)
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{
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float dtp = dot(p,p);
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p = .5*p/(dtp + .2);
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p.xz = rot(p.xz, p.y*2.5);
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p.xy = rot(p.xz, p.y*2.);
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float dtp2 = dot(p, p);
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p = (mo.y + .6)*3.*p/(dtp2 - 5.);
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float r = clamp(fbm(p, dtp*0.1)*1.5-dtp*(.35-sin(time*0.3)*0.15), 0. ,1.);
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vec4 col = vec4(.5,1.7,.5,.96)*r;
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float grd = clamp((dtp+.7)*0.4,0.,1.);
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col.b += grd*.6;
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col.r -= grd*.5;
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vec3 lv = mix(p,vec3(0.3),2.);
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grd = clamp((col.w - fbm(p+lv*.05,1.))*2., 0.01, 1.5 );
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col.rgb *= vec3(.5, 0.4, .6)*grd + vec3(4.,0.,.4);
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col.a *= clamp(dtp*2.-1.,0.,1.)*0.07+0.93;
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return col;
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}
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vec4 vmarch(in vec3 ro, in vec3 rd)
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{
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vec4 rz = vec4(0);
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float t = 2.5;
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t += 0.03*hash21(gl_FragCoord.xy);
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for(int i=0; i<STEPS; i++)
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{
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if(rz.a > 0.99 || t > 6.)break;
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vec3 pos = ro + t*rd;
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vec4 col = map(pos);
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float den = col.a;
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col.a *= ALPHA_WEIGHT;
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col.rgb *= col.a*1.7;
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rz += col*(1. - rz.a);
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t += BASE_STEP - den*(BASE_STEP-BASE_STEP*0.015);
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}
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return rz;
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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 = fragCoord.xy/iResolution.xy*2. - 1.;
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p.x *= iResolution.x/iResolution.y*0.95;
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mo = 2.0*iMouse.xy/iResolution.xy;
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mo = (mo==vec2(.0))?mo=vec2(0.5,1.):mo;
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vec3 ro = 4.*normalize(vec3(cos(2.75-2.0*(mo.x+time*0.05)), sin(time*0.22)*0.2, sin(2.75-2.0*(mo.x+time*0.05))));
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vec3 eye = normalize(vec3(0) - ro);
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vec3 rgt = normalize(cross(vec3(0,1,0), eye));
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vec3 up = cross(eye,rgt);
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vec3 rd = normalize(p.x*rgt + p.y*up + (3.3-sin(time*0.3)*.7)*eye);
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vec4 col = vmarch(ro, rd);
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fragColor = vec4(col.rgb, 1.0);
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}
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