/* [lightsdf] samples occlusion diagonally (root of unity?) ,to estimate non-point-light-emnmitters (like a pseudo-DFT?) This fails for large curvature and convex emmitters , but gives you some cheap decent RADiosity almost for free , but still looks decent. (roudned corners of convex square emmitter) , but it LOD-scales VERY nicely, can be VERY fast and look convincing (see in lowres) Bayer matrix is used in favor of better (and more dynamic) performance; my scaling of bayerMatrix*X/iResolution seems off (semi intentionally) making the bayer matix exponentially lower res than screenspace resolution. this way it keeps (inverse-)cubic performance on low res , while getting exponentially better quality on higher res. - this is mostly a lowres-preview opengl-crashing evasion. - but also demoes how you could to a buas -, by [DistanceToScreenCenter*DistanceToMouseCursor] of [ /XdXBzH ] this shader does not rotate bayer matrixces, like [ /ltKcDt ] does. - mostly because i tend to not trust complex transforms on bayer-hyperplane moire. - but also because this shader samples rotated anyways. this shader does not use any frame buffers , which should easily get performance/quality a lot higher , but also makes the shader a lot less compatible to bifferless canvases. */ //crepuscularity with bayer (with RADiosity) //self (bayer,instead of hash) : https://www.shadertoy.com/view/Xtcfzj //crepuscularity without bayer (with RADiosity) //parent (hash instead of bayer) : https://www.shadertoy.com/view/lldcDf //crepuscularity with 3dto2d differenceGrad : https://www.shadertoy.com/view/4lXBW2 //crepuscularity without bayer (no RADiosity? hard to tell.) //dr2-noise with a bias for3d derivatives : https://www.shadertoy.com/view/llXfRs //in comparison to slow 3d (crashes opengl) : https://www.shadertoy.com/view/lltfRB // //crepuscularity with (no RADiosity) //crepuscularity with highres Bayer : https://www.shadertoy.com/view/4dyXWy //crepuscularity with highres Bayer2 : https://www.shadertoy.com/view/ltsyWl //crepuscularity with only 3 hyperplaneTaps : https://www.shadertoy.com/view/ltKcDt //compare that to [bayer-toggled bokeh (no radiosity, no crepuscularity): //then you can define "quality" depentant on "eye focus" //- "eye focus" is something like DistanceToScreenCenter*DistanceToMouseCursor //- scale that gradient by a bayer matrix and use that as if(){} quality-bias //- ,that toggles/mixes 4 Crepuscularity/Radiosity/bokeh-compositions, as in //- https://www.shadertoy.com/view/XdXBzH //this works best for "bokeh" as it implies correlated things;focus/peripheralVision //,but it should work just as well to set bayer-quality for crepuscularity/radiosity //2d zoom #define ViewZoom 10. //divide by/aa for hairline drawing and sharp smoothstep() #define Aa (min(iResolution.x,iResolution.y)/ViewZoom) #define fra(u)(u-.5*iResolution.xy)*ViewZoom/iResolution.y//usually first function of mainImage(),not typecast. #define pi acos(-1.)//trig definition for 3.14...can be better for smarter compilers. #define vec1 float #define sat(x)clamp(x,0.,1.) #define dd(a)dot(a,a) #define u5(a)((a)*.5+.5) #define u2(a)((a)*2.-1.) #define ss(a,u)smoothstep(a,-a,u) vec1 suv(vec4 a){return dot(vec4(1),a);}vec1 suv(vec3 a){return dot(vec3(1),a);}vec1 suv(vec2 a){return a.x+a.y;}//sum of vector #define minx(a,b)mix(b,a,step(a.x,b.x)) #define manx(a,b)mix(a,-b,step(a.x,-b.x)) #define maxx(a,b)-minx(-a,-b) vec1 miv(vec2 a){return min(a.y,a.x);}vec1 miv(vec3 a){return min(a.z,miv(a.xy));}vec1 miv(vec4 a){return min(miv(a.zw),miv(a.xy));} #define mav(a)-miv(-a) #define cs(a) vec2(cos(a),sin(a)) //fract(dot(1031))hash summer 2018 seems ot be generally superior to fract(sin())hashes vec3 g3(vec1 a){return vec3(a);} vec3 g3(vec2 a){return a.xyx;} vec3 g3(vec3 a){return a;} vec4 g4(vec1 a){return vec4(a);} vec4 g4(vec2 a){return a.xyxy;} vec4 g4(vec3 a){return a.xyzy;} vec4 g4(vec4 a){return a;} //hashes by David Hoskins,Creative Commons Attribution-ShareAlike 4.0 International Public License //parent https://www.shadertoy.com/view/4djSRW #define hs vec4(.1031,.1030,.0973,.1099) //#define HASHSCALE3 vec3(443.897,441.423,437.195,444.129)//For smaller input rangers like audio tick or 0-1 UVs use these... #define hout1(a)fract((a.x+a.y)*a.z) #define hout2(a)fract((a.xx+a.yz)*a.zy) #define hout3(a)fract((a.xxy+a.yzz)*a.zyx) #define hout4(a)fract((a.xxyz+a.yzzw)*a.zywx) #define h3mid(a)((a)+dot(a,a.yzx+19.19)) #define h4mid(a)((a)+dot(a,a.wzxy+19.19)) //hashes are named by output type,NEVER by input type //hash1 mirrors at y=x and has strong banding on diagonals. //only hash4 takes in vec4.all hash functions take vey1,v3c2,vec3 in (a vec4 generalizations is a mild overkill for most vec2,vec3 contexts) #define hash1(a)hout1(h3mid(fract(hs.x*g3(a)))) #define hash2(a)hout2(h3mid(fract(hs.xyz*g3(a)))) #define hash3(a)hout3(h3mid(fract(hs.xyz*g3(a)))) #define hash4(a)hout4(h4mid(hs*g4(a))) //not sure if its this shaders fault,likely a fract()error,but the avobe hsh gives bad lines. //float hash1(float n){ return fract(sin(n)*1e4);} #define ab012(a,b)(a+b*vec3(0,1,2))//desaturation.rgb kernel;b scales offset //rainbow*()ro from purple to purple for range[0..1],this makes ab012()desaturate into semi-gaussian scattering. vec3 rainbow(float a,float b){return u5(cos(2.*pi*ab012(a,b)));}//sine rainbow with offsets,desaturates colors for small b vec3 rainbow2(float a,float b){return abs(u2(fract(ab012(a,b))));}//triangle rainbow with offsets,desaturates colors for small b vec3 rainbow(float a){return rainbow(a,1./3.);} vec3 rainbow2(float a){return rainbow2(a,1./3.);} #define SAMPLES 64. #define iterBayerMat 1 #define bayer2x2(a)(4-(a).x-((a).y<<1))%4 float boxSDF(vec2 p,vec2 s ){vec2 r=abs(p)-s ;return min(max(r.x,r.y),0.)+length(max(r,vec2(0)));} vec3 colormap(float x ){//float s=sin(x*6.28) ;return vec3(1,vec2(-1,1)*sign(x))*.25+.25;} void AddObj(inout float dist,inout vec3 color,float d,vec3 c ){if(dist>d){dist=d;color=c;}} vec4 scene(vec2 u,vec2 m ){float dist=1e9; ;vec3 color=vec3(0) ;AddObj(dist,color,boxSDF(u-vec2(-3,1),vec2(1,1)),vec3(.6,.8,1.)) ;AddObj(dist,color,length(u-vec2(3,1))- 1.,vec3(1,.9,.8)) ;AddObj(dist,color,length(u-vec2(.3*sin(iTime),-2))- 0.5,vec3(0,.1,0)) ;AddObj(dist,color,boxSDF(u-m,vec2(1.5,0.1)),vec3(.3,.1,.1)) ;return vec4(color,dist);} vec3 trace(vec2 p,vec2 dir,vec2 m ){for (int a=128;a>0;a-- ){vec4 s=scene(p,m) ;if(s.w<1e-1)return s.xyz ;if(s.w>10.)return vec3(0) ;p+=dir*s.w; }return vec3(0);} //return bayer matrix(bitwise operands for speed over compatibility) float GetBayerFromCoordLevel(vec2 pixelpos//https://www.shadertoy.com/view/XtV3RG ){ivec2 p=ivec2(pixelpos);int a=0 ;for(int i=0;i>(iterBayerMat-1-i)&1)<<(2*i) ;}return float(a)/float(2<<(iterBayerMat*2-1));} //float hash1(vec2 _st){return fract(sin(dot(_st.xy,vec2(12.9898,78.233)))*43758.5453123);} void mainImage(out vec4 fragColor,vec2 u ){u=fra(u)//(u-(iResolution.xy*.5))/iResolution.y*ViewZoom ;vec2 m=vec2(0) ;if(iMouse.z<=0.)m.xy=vec2(.5)+vec2(cos(iTime),sin(iTime*1.61))*.3*ViewZoom ;else m=fra(iMouse.xy) ;vec3 c=vec3(0) ;float phi=sqrt(5.)*.5-.5 ;for(float i=0.;i