111 lines
2.1 KiB
C
111 lines
2.1 KiB
C
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#include "vec3.h"
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#include "ray.h"
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#include <draw.h>
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#include <event.h>
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void
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eresized(int new)
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{
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if(new&& getwindow(display, Refnone) < 0)
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sysfatal("can't reattach to window");
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}
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double
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hit_sphere(vec3 centr, double rad, ray r)
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{
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vec3 oc = vecsub(r.origin, centr);
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double a = length_sq(r.direction);
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double h_b = dot(oc, r.direction);
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double c = length_sq(oc) - rad*rad;
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double dis = h_b*h_b - a*c;
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if (dis < 0) {
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return -1.0;
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} else {
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return (-h_b - sqrt(dis) ) / a;
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}
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}
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vec3
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ray_color(ray r)
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{
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double t = hit_sphere(point3(0,0,-1), 0.5, r);
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if (t > 0.0) {
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vec3 N = unit_vector(vecsub(at(r, t), point3(0,0,-1)));
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N.e[0] += 1;
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N.e[1] += 1;
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N.e[2] += 1;
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vec3 col = vecscale(0.5, N);
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return col;
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}
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vec3 u_dir = unit_vector(r.direction);
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t = 0.5 * (u_dir.e[1] + 1.0);
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vec3 o = vecadd(vecscale((1.0-t), color(1.0, 1.0, 1.0)), vecscale(t, color(0.5, 0.7, 1.0)));
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return o;
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}
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void
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main(int argc, char* argv[])
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{
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USED(argc, argv);
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Mouse m;
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Image *color;
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Point min, max;
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int i, j;
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unsigned int ir, ig, ib, rgb;
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double u, v;
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// Camera
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vec3 llc = {-2.0, -1.0, -1.0};
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vec3 hor = {4.0, 0.0, 0.0};
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vec3 ver = {0.0, 2.0, 0.0};
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vec3 ori = {0.0, 0.0, 0.0};
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vec3 dir = {0.0, 0.0, 0.0};
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ray r;
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r.origin = ori;
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r.direction = dir;
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initdraw(0, 0, "Plan9 Raytracer");
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eresized(0);
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einit(Emouse);
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min = screen->r.min;
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max = screen->r.max;
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for(j = max.y; j >= min.y; --j)
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{
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for(i = min.x; i < max.x; ++i)
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{
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u = (double)(i - min.x)/(double)(max.x - min.x);
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v = (double)(j - min.y)/(double)(max.y - min.y);
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r.origin = ori;
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r.direction = vecsub(vecadd(vecadd(llc, vecscale(u,hor)), vecscale(v,ver)), ori);
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vec3 rc = ray_color(r);
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ir = (unsigned char)255.99*rc.e[0];
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ig = (unsigned char)255.99*rc.e[1];
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ib = (unsigned char)255.99*rc.e[2];
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rgb = ((ir & 0xFF) << 24) + ((ig & 0xFF) << 16) + ((ib & 0xFF) << 8) + (255 & 0xFF);
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color = allocimage(display, Rect(0,0,1,1), RGBA32, 1, rgb);
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draw(screen, Rect(i, j, i+1, j+1), color, nil, ZP);
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freeimage(color);
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}
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}
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flushimage(display, Refnone);
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/* Main loop */
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for(;;) {
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m = emouse();
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if(m.buttons & 4)
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break;
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}
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}
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