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| -rw-r--r-- | bcardrt.c | 113 | ||||
| -rw-r--r-- | mkfile | 8 |
2 files changed, 121 insertions, 0 deletions
diff --git a/bcardrt.c b/bcardrt.c new file mode 100644 index 0000000..57bd833 --- /dev/null +++ b/bcardrt.c @@ -0,0 +1,113 @@ +#include <u.h> +#include <libc.h> + +typedef struct { double x, y, z; } vec; + +vec v(double x, double y, double z) { return (vec){x,y,z}; } +vec vadd(vec a, vec b) { return v(a.x+b.x,a.y+b.y,a.z+b.z); } +vec vmul(vec u, double s) { return v(u.x*s,u.y*s,u.z*s); } +double vdot(vec a, vec b) { return a.x*b.x+a.y*b.y+a.z*b.z; } +vec vcross(vec a, vec b) { return v(a.y*b.z-a.z*b.y,a.z*b.x-a.x*b.z,a.x*b.y-a.y*b.x); } +vec vnorm(vec u) { return vmul(u,1/sqrt(vdot(u,u))); } + +/* aek */ +//int G[] = {247570, 280596, 280600, 249748, 18578, 18577, 231184, 16, 16}; +/* rgl */ +int G[] = {263948, 264338, 262288, 266128, 395408, 346256, 296720, 16, 16}; + +double R(void) { return (double)rand() / 0x7ffffffd; } + +int +TraceRay(vec src, vec dst, double *t, vec *normal) +{ + int m, k, j; + double p; + + *t = 1e9; + m = 0; + p = -src.z / dst.z; + if(p > 0.01){ + *t = p; + *normal = v(0,0,1); + m = 1; + } + + for (k = 19; k--;) + for (j = 9; j--;) + if ((G[j] & 1<<k) != 0) { + vec p; + double b, c, q; + + p = vadd(src, v(-k,0,-j - 4)); + b = vdot(p, dst); + c = vdot(p, p) - 1; + q = b*b - c; + + if(q > 0){ + double s; + + s = -b - sqrt(q); + if(s > 0.01 && s < *t){ + *t = s; + *normal = vnorm(vadd(p, vmul(dst, *t))); + m = 2; + } + } + } + return m; +} + +vec +Sample(vec src, vec dst) +{ + vec normal, intersection, light_dir, half_vec; + double t, lamb_f, color; + int match; + + match = TraceRay(src, dst, &t, &normal); + if(!match) + return vmul(v(0.7,0.6,1), pow(1 - dst.z, 4)); + + intersection = vadd(src, vmul(dst, t)); + light_dir = vnorm(vadd(v(9 + R(),9 + R(),16), vmul(intersection, -1))); + half_vec = vadd(dst, vmul(normal, vdot(normal, dst) * -2)); + + lamb_f = vdot(light_dir, normal); + + if(lamb_f < 0 || TraceRay(intersection, light_dir, &t, &normal)) + lamb_f = 0; + + color = pow(vdot(light_dir, half_vec) * (lamb_f > 0), 99); + + if((match & 1) != 0){ + intersection = vmul(intersection, 0.2); + return ((int)(ceil(intersection.x) + ceil(intersection.y)) & 1) != 0? v(3,1,1): vmul(v(3,3,3), (lamb_f * 0.2 + 0.1)); + } + + return vadd(v(color,color,color), vmul(Sample(intersection, half_vec), 0.5)); +} + +void +main() +{ + vec cam_forward, cam_up, cam_right, c, color, delta; + int x, y, r; + + print("P6 512 512 255 "); + + cam_forward = vnorm(v(-6,-16,0)); + cam_up = vmul(vnorm(vcross(v(0,0,1), cam_forward)), 0.002); + cam_right = vmul(vnorm(vcross(cam_forward, cam_up)), 0.002); + c = vadd(vmul(vadd(cam_up, cam_right), -256), cam_forward); + + for(y = 512; y--;) + for(x = 512; x--;){ + color = v(13,13,13); + for(r = 64; r--;){ + delta = vadd(vmul(vmul(cam_up, R() - 0.5), 99), vmul(vmul(cam_right, R() - 0.5), 99)); + color = vadd(vmul(Sample(vadd(v(17,16,8), delta), vnorm(vmul(vadd(vmul(delta, -1), vadd(vadd(vmul(cam_up, R()+x), vmul(cam_right, R()+y)), c)), 16))), 3.5), color); + } + print("%c%c%c", (int)color.x, (int)color.y, (int)color.z); + } + exits(nil); +} @@ -0,0 +1,8 @@ +</$objtype/mkfile + +BIN=/$objtype/bin +TARG=bcardrt +OFILES=\ + bcardrt.$O\ + +</sys/src/cmd/mkone |