X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=dosdemo;a=blobdiff_plain;f=src%2Fscr%2Frt.c;fp=src%2Fscr%2Frt.c;h=13f2dbe4560a38d2037d625c2b8ef5178e364711;hp=0000000000000000000000000000000000000000;hb=dfc6ebacd7bcc1e6b9e7168c3e4824d241d2d5c8;hpb=0aeee13aa695ec617ec22253824f17209660bd39

diff --git a/src/scr/rt.c b/src/scr/rt.c
new file mode 100644
index 0000000..13f2dbe
--- /dev/null
+++ b/src/scr/rt.c
@@ -0,0 +1,261 @@
+#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(&lt->p, x, y, z);
+	lt->color = cur_col;
+
+	darr_push(scn->lt, &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;
+}