| |
| |
| #include <algorithm> |
| #include <cmath> |
| #include <vector> |
| #include <cstdint> |
|
|
| extern "C" void rasterize(int n, const double* xyz, const float* normals, |
| const float* colours, int width, int height, |
| const double* light, const double* view, |
| uint8_t* image) { |
| std::vector<double> depth(static_cast<size_t>(width)*height, -1e40); |
| for(int y=0;y<height;++y) for(int x=0;x<width;++x) { |
| const float k=float(y)/height; |
| const size_t j=(static_cast<size_t>(y)*width+x)*3; |
| image[j]=uint8_t(246-10*k);image[j+1]=uint8_t(248-9*k);image[j+2]=uint8_t(251-8*k); |
| } |
| double halfv[3];double hl=0; |
| for(int c=0;c<3;++c){halfv[c]=light[c]+view[c];hl+=halfv[c]*halfv[c];} |
| for(int c=0;c<3;++c)halfv[c]/=std::sqrt(hl); |
| for(int t=0;t<n;++t) { |
| const double* a=xyz+t*9;const float* nn=normals+t*9;const float* col=colours+t*3; |
| double x0=a[0],y0=a[1],x1=a[3],y1=a[4],x2=a[6],y2=a[7]; |
| double den=(y1-y2)*(x0-x2)+(x2-x1)*(y0-y2); |
| if(std::abs(den)<1e-12)continue; |
| int left=std::max(0,int(std::floor(std::min({x0,x1,x2})))); |
| int right=std::min(width-1,int(std::ceil(std::max({x0,x1,x2})))); |
| int top=std::max(0,int(std::floor(std::min({y0,y1,y2})))); |
| int bottom=std::min(height-1,int(std::ceil(std::max({y0,y1,y2})))); |
| for(int y=top;y<=bottom;++y)for(int x=left;x<=right;++x){ |
| double px=x+.5,py=y+.5; |
| double b0=((y1-y2)*(px-x2)+(x2-x1)*(py-y2))/den; |
| double b1=((y2-y0)*(px-x2)+(x0-x2)*(py-y2))/den; |
| double b2=1-b0-b1; |
| if(b0 < -1e-8 || b1 < -1e-8 || b2 < -1e-8)continue; |
| double z=b0*a[2]+b1*a[5]+b2*a[8];size_t idx=static_cast<size_t>(y)*width+x; |
| if(z<=depth[idx]+1e-9)continue; |
| depth[idx]=z; |
| double nx=b0*nn[0]+b1*nn[3]+b2*nn[6]; |
| double ny=b0*nn[1]+b1*nn[4]+b2*nn[7]; |
| double nz=b0*nn[2]+b1*nn[5]+b2*nn[8]; |
| double norm=std::sqrt(nx*nx+ny*ny+nz*nz); |
| if(norm<1e-10)norm=1; |
| nx/=norm;ny/=norm;nz/=norm; |
| double lam=std::max(0.,nx*light[0]+ny*light[1]+nz*light[2]); |
| double facing=std::max(0.,nx*view[0]+ny*view[1]+nz*view[2]); |
| double spec=std::pow(std::max(0.,nx*halfv[0]+ny*halfv[1]+nz*halfv[2]),44.); |
| double bright=.47+.47*lam+.06*facing; |
| double metal=std::max({col[0],col[1],col[2]}); |
| for(int c=0;c<3;++c){ |
| double value=col[c]*bright+spec*(metal>.5?.18:.055); |
| image[idx*3+c]=uint8_t(255*std::clamp(value,0.,1.)); |
| } |
| } |
| } |
| } |
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