--- /dev/null
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <float.h>
+#include "rt.h"
+#include "util.h"
+#include "darray.h"
+
+static cgm_vec3 cur_col, cur_spec;
+static float cur_shin;
+static struct image *cur_tex;
+
+void rt_init(struct rtscene *scn)
+{
+ scn->obj = darr_alloc(0, sizeof *scn->obj);
+ scn->num_obj = 0;
+ scn->lt = darr_alloc(0, sizeof *scn->lt);
+ scn->num_lt = 0;
+
+ cgm_vcons(&cur_col, 1, 1, 1);
+ cgm_vcons(&cur_spec, 0, 0, 0);
+ cur_shin = 1;
+ cur_tex = 0;
+}
+
+void rt_destroy(struct rtscene *scn)
+{
+ darr_free(scn->obj);
+ darr_free(scn->lt);
+ memset(scn, 0, sizeof *scn);
+}
+
+
+void rt_color(float r, float g, float b)
+{
+ cgm_vcons(&cur_col, r, g, b);
+}
+
+void rt_specular(float r, float g, float b)
+{
+ cgm_vcons(&cur_spec, r, g, b);
+}
+
+void rt_shininess(float s)
+{
+ cur_shin = s;
+}
+
+static union rtobject *add_object(struct rtscene *scn, enum rt_obj_type type)
+{
+ union rtobject *obj;
+
+ obj = calloc_nf(1, sizeof *obj);
+ obj->type = type;
+
+ obj->x.mtl.kd = cur_col;
+ obj->x.mtl.ks = cur_spec;
+ obj->x.mtl.shin = cur_shin;
+ obj->x.mtl.tex = cur_tex;
+
+ darr_push(scn->obj, &obj);
+ scn->num_obj = darr_size(scn->obj);
+ return obj;
+}
+
+union rtobject *rt_add_sphere(struct rtscene *scn, float x, float y, float z, float r)
+{
+ union rtobject *obj = add_object(scn, RT_SPH);
+ cgm_vcons(&obj->s.p, x, y, z);
+ obj->s.r = r;
+ return obj;
+}
+
+union rtobject *rt_add_plane(struct rtscene *scn, float nx, float ny, float nz, float d)
+{
+ union rtobject *obj = add_object(scn, RT_PLANE);
+ cgm_vcons(&obj->p.n, nx, ny, nz);
+ obj->p.d = d;
+ return obj;
+}
+
+struct rtlight *rt_add_light(struct rtscene *scn, float x, float y, float z)
+{
+ struct rtlight *lt = calloc_nf(1, sizeof *lt);
+
+ cgm_vcons(<->p, x, y, z);
+ lt->color = cur_col;
+
+ darr_push(scn->lt, <);
+ scn->num_lt = darr_size(scn->lt);
+ return lt;
+}
+
+
+/* color is initialized to black */
+static void shade(struct rayhit *hit, struct rtscene *scn, int lvl, cgm_vec3 *color)
+{
+ int i;
+ float ndotl, vdotr, spec;
+ cgm_ray sray;
+ cgm_vec3 col, rdir;
+ struct rtlight *lt;
+ struct rtmaterial *mtl = &hit->obj->x.mtl;
+
+ sray.origin = hit->p;
+ cgm_vnormalize(&hit->n);
+ cgm_vnormalize(&hit->ray->dir);
+
+ for(i=0; i<scn->num_lt; i++) {
+ lt = scn->lt[i];
+ sray.dir = lt->p;
+ cgm_vsub(&sray.dir, &sray.origin);
+
+ if(ray_scene(&sray, scn, 1.0f, 0)) continue;
+
+ cgm_vnormalize(&sray.dir);
+ ndotl = cgm_vdot(&sray.dir, &hit->n);
+ if(ndotl < 0.0f) ndotl = 0.0f;
+
+ rdir = hit->ray->dir;
+ cgm_vreflect(&rdir, &hit->n);
+ vdotr = cgm_vdot(&sray.dir, &rdir);
+ if(vdotr < 0.0f) vdotr = 0.0f;
+ spec = pow(vdotr, mtl->shin);
+
+ color->x += (mtl->kd.x * ndotl + mtl->ks.x * spec) * lt->color.x;
+ color->y += (mtl->kd.y * ndotl + mtl->ks.y * spec) * lt->color.y;
+ color->z += (mtl->kd.z * ndotl + mtl->ks.z * spec) * lt->color.z;
+ }
+}
+
+int ray_trace(cgm_ray *ray, struct rtscene *scn, int lvl, cgm_vec3 *color)
+{
+ struct rayhit hit;
+
+ color->x = color->y = color->z = 0.0f;
+ if(!ray_scene(ray, scn, FLT_MAX, &hit)) {
+ return 0;
+ }
+ hit.ray = ray;
+ shade(&hit, scn, lvl, color);
+ return 1;
+}
+
+
+int ray_scene(cgm_ray *ray, struct rtscene *scn, float maxt, struct rayhit *hit)
+{
+ int i;
+
+ if(hit) {
+ struct rayhit hit0 = {FLT_MAX};
+
+ /* find nearest hit */
+ for(i=0; i<scn->num_obj; i++) {
+ if(ray_object(ray, scn->obj[i], maxt, hit) && hit->t < hit0.t) {
+ hit0 = *hit;
+ }
+ }
+
+ if(hit0.obj) {
+ *hit = hit0;
+ return 1;
+ }
+ } else {
+ /* find any hit */
+ for(i=0; i<scn->num_obj; i++) {
+ if(ray_object(ray, scn->obj[i], maxt, 0)) {
+ return 1;
+ }
+ }
+ }
+
+ return 0;
+}
+
+int ray_object(cgm_ray *ray, union rtobject *obj, float maxt, struct rayhit *hit)
+{
+ switch(obj->type) {
+ case RT_SPH:
+ return ray_sphere(ray, &obj->s, maxt, hit);
+ case RT_PLANE:
+ return ray_plane(ray, &obj->p, maxt, hit);
+ default:
+ break;
+ }
+ return 0;
+}
+
+#define SQ(x) ((x) * (x))
+int ray_sphere(cgm_ray *ray, struct rtsphere *sph, float maxt, struct rayhit *hit)
+{
+ float a, a2, b, c, d, sqrt_d, t1, t2;
+
+ a = SQ(ray->dir.x) + SQ(ray->dir.y) + SQ(ray->dir.z);
+ b = 2.0f * ray->dir.x * (ray->origin.x - sph->p.x) +
+ 2.0f * ray->dir.y * (ray->origin.y - sph->p.y) +
+ 2.0f * ray->dir.z * (ray->origin.z - sph->p.z);
+ c = SQ(sph->p.x) + SQ(sph->p.y) + SQ(sph->p.z) +
+ SQ(ray->origin.x) + SQ(ray->origin.y) + SQ(ray->origin.z) +
+ 2.0f * (-sph->p.x * ray->origin.x - sph->p.y * ray->origin.y - sph->p.z * ray->origin.z) -
+ SQ(sph->r);
+
+ if((d = SQ(b) - 4.0f * a * c) < 0.0f) return 0;
+
+ sqrt_d = sqrt(d);
+ a2 = 2.0f * a;
+ t1 = (-b + sqrt_d) / a2;
+ t2 = (-b - sqrt_d) / a2;
+
+ if((t1 < 1e-5f && t2 < 1e-5f) || (t1 > maxt && t2 > maxt)) {
+ return 0;
+ }
+
+ if(hit) {
+ float t;
+ if(t1 < 1e-5f) {
+ t = t2;
+ } else if(t2 < 1e-5f) {
+ t = t1;
+ } else {
+ t = t1 < t2 ? t1 : t2;
+ }
+
+ hit->t = t;
+ cgm_raypos(&hit->p, ray, t);
+
+ hit->n.x = hit->p.x - sph->p.x;
+ hit->n.y = hit->p.y - sph->p.y;
+ hit->n.z = hit->p.z - sph->p.z;
+
+ hit->obj = (union rtobject*)sph;
+ }
+ return 1;
+}
+
+int ray_plane(cgm_ray *ray, struct rtplane *plane, float maxt, struct rayhit *hit)
+{
+ cgm_vec3 vo;
+ float t, ndotdir;
+
+ ndotdir = cgm_vdot(&plane->n, &ray->dir);
+ if(fabs(ndotdir) < 1e-5) {
+ return 0;
+ }
+
+ vo.x = plane->n.x * plane->d - ray->origin.x;
+ vo.y = plane->n.y * plane->d - ray->origin.y;
+ vo.z = plane->n.z * plane->d - ray->origin.z;
+ t = cgm_vdot(&plane->n, &vo) / ndotdir;
+
+ if(t < 1e-5 || t > maxt) return 0;
+
+ if(hit) {
+ hit->t = t;
+ cgm_raypos(&hit->p, ray, t);
+ hit->n = plane->n;
+
+ hit->obj = (union rtobject*)plane;
+ }
+ return 1;
+}
projects / dosdemo / blobdiff