nuclear@12: /* vim: set ft=opencl:ts=4:sw=4 */
nuclear@12: 
nuclear@2: struct RendInfo {
nuclear@22: 	float4 ambient;
nuclear@2: 	int xsz, ysz;
nuclear@9: 	int num_faces, num_lights;
nuclear@2: 	int max_iter;
nuclear@2: };
nuclear@2: 
nuclear@9: struct Vertex {
nuclear@2: 	float4 pos;
nuclear@9: 	float4 normal;
nuclear@12: 	float4 tex;
nuclear@12: 	float4 padding;
nuclear@9: };
nuclear@9: 
nuclear@9: struct Face {
nuclear@9: 	struct Vertex v[3];
nuclear@9: 	float4 normal;
nuclear@9: 	int matid;
nuclear@12: 	int padding[3];
nuclear@9: };
nuclear@9: 
nuclear@9: struct Material {
nuclear@5: 	float4 kd, ks;
nuclear@9: 	float kr, kt;
nuclear@9: 	float spow;
nuclear@12: 	float padding;
nuclear@2: };
nuclear@2: 
nuclear@3: struct Light {
nuclear@3: 	float4 pos, color;
nuclear@3: };
nuclear@3: 
nuclear@2: struct Ray {
nuclear@2: 	float4 origin, dir;
nuclear@2: };
nuclear@2: 
nuclear@2: struct SurfPoint {
nuclear@2: 	float t;
nuclear@12: 	float4 pos, norm, dbg;
nuclear@9: 	global const struct Face *obj;
nuclear@19: 	struct Material mat;
nuclear@2: };
nuclear@2: 
nuclear@16: struct Scene {
nuclear@16: 	float4 ambient;
nuclear@16: 	global const struct Face *faces;
nuclear@16: 	int num_faces;
nuclear@16: 	global const struct Light *lights;
nuclear@16: 	int num_lights;
nuclear@16: 	global const struct Material *matlib;
nuclear@16: };
nuclear@2: 
nuclear@16: #define MIN_ENERGY	0.001
nuclear@21: #define EPSILON		1e-5
nuclear@16: 
nuclear@16: float4 shade(struct Ray ray, struct Scene *scn, const struct SurfPoint *sp);
nuclear@16: bool find_intersection(struct Ray ray, const struct Scene *scn, struct SurfPoint *sp);
nuclear@9: bool intersect(struct Ray ray, global const struct Face *face, struct SurfPoint *sp);
nuclear@16: 
nuclear@8: float4 reflect(float4 v, float4 n);
nuclear@8: float4 transform(float4 v, global const float *xform);
nuclear@16: void transform_ray(struct Ray *ray, global const float *xform, global const float *invtrans);
nuclear@12: float4 calc_bary(float4 pt, global const struct Face *face, float4 norm);
nuclear@19: float mean(float4 v);
nuclear@4: 
nuclear@4: kernel void render(global float4 *fb,
nuclear@4: 		global const struct RendInfo *rinf,
nuclear@9: 		global const struct Face *faces,
nuclear@9: 		global const struct Material *matlib,
nuclear@4: 		global const struct Light *lights,
nuclear@7: 		global const struct Ray *primrays,
nuclear@12: 		global const float *xform,
nuclear@20: 		global const float *invtrans)
nuclear@2: {
nuclear@2: 	int idx = get_global_id(0);
nuclear@2: 
nuclear@16: 	struct Scene scn;
nuclear@16: 	scn.ambient = rinf->ambient;
nuclear@16: 	scn.faces = faces;
nuclear@16: 	scn.num_faces = rinf->num_faces;
nuclear@16: 	scn.lights = lights;
nuclear@16: 	scn.num_lights = rinf->num_lights;
nuclear@16: 	scn.matlib = matlib;
nuclear@8: 
nuclear@16: 	struct Ray ray = primrays[idx];
nuclear@16: 	transform_ray(&ray, xform, invtrans);
nuclear@4: 
nuclear@19: 	float4 pixel = (float4)(0, 0, 0, 0);
nuclear@22: 	float4 energy = (float4)(1.0, 1.0, 1.0, 0.0);
nuclear@19: 	int iter = 0;
nuclear@19: 
nuclear@19: 	while(iter++ < rinf->max_iter && mean(energy) > MIN_ENERGY) {
nuclear@19: 		struct SurfPoint sp;
nuclear@19: 		if(find_intersection(ray, &scn, &sp)) {
nuclear@19: 			pixel += shade(ray, &scn, &sp) * energy;
nuclear@19: 
nuclear@19: 			float4 refl_col = sp.mat.ks * sp.mat.kr;
nuclear@19: 
nuclear@19: 			ray.origin = sp.pos;
nuclear@19: 			ray.dir = reflect(-ray.dir, sp.norm);
nuclear@19: 
nuclear@19: 			energy *= sp.mat.ks * sp.mat.kr;
nuclear@19: 		} else {
nuclear@19: 			iter = INT_MAX - 1;	// to break out of the loop
nuclear@19: 		}
nuclear@17: 	}
nuclear@19: 
nuclear@19: 	fb[idx] = pixel;
nuclear@4: }
nuclear@4: 
nuclear@16: float4 shade(struct Ray ray, struct Scene *scn, const struct SurfPoint *sp)
nuclear@16: {
nuclear@16: 	float4 norm = sp->norm;
nuclear@12: 	bool entering = true;
nuclear@12: 
nuclear@12: 	if(dot(ray.dir, norm) >= 0.0) {
nuclear@12: 		norm = -norm;
nuclear@12: 		entering = false;
nuclear@12: 	}
nuclear@12: 
nuclear@19: 	float4 dcol = scn->ambient * sp->mat.kd;
nuclear@8: 	float4 scol = (float4)(0, 0, 0, 0);
nuclear@5: 
nuclear@16: 	for(int i=0; i<scn->num_lights; i++) {
nuclear@16: 		float4 ldir = scn->lights[i].pos - sp->pos;
nuclear@5: 
nuclear@16: 		struct Ray shadowray;
nuclear@16: 		shadowray.origin = sp->pos;
nuclear@16: 		shadowray.dir = ldir;
nuclear@5: 
nuclear@16: 		if(!find_intersection(shadowray, scn, 0)) {
nuclear@16: 			ldir = normalize(ldir);
nuclear@16: 			float4 vdir = -normalize(ray.dir);
nuclear@16: 			float4 vref = reflect(vdir, norm);
nuclear@16: 
nuclear@16: 			float diff = fmax(dot(ldir, norm), 0.0f);
nuclear@22: 			dcol += sp->mat.kd * scn->lights[i].color * diff;
nuclear@16: 
nuclear@20: 			float spec = powr(fmax(dot(ldir, vref), 0.0f), sp->mat.spow);
nuclear@22: 			scol += sp->mat.ks * scn->lights[i].color * spec;
nuclear@16: 		}
nuclear@16: 	}
nuclear@16: 
nuclear@8: 	return dcol + scol;
nuclear@2: }
nuclear@2: 
nuclear@16: 
nuclear@16: bool find_intersection(struct Ray ray, const struct Scene *scn, struct SurfPoint *spres)
nuclear@12: {
nuclear@16: 	struct SurfPoint sp, sp0;
nuclear@16: 	sp0.t = 1.0;
nuclear@16: 	sp0.obj = 0;
nuclear@16: 
nuclear@16: 	for(int i=0; i<scn->num_faces; i++) {
nuclear@16: 		if(intersect(ray, scn->faces + i, &sp) && sp.t < sp0.t) {
nuclear@16: 			sp0 = sp;
nuclear@16: 		}
nuclear@16: 	}
nuclear@16: 
nuclear@16: 	if(!sp0.obj) {
nuclear@16: 		return false;
nuclear@16: 	}
nuclear@16: 
nuclear@16: 	if(spres) {
nuclear@16: 		*spres = sp0;
nuclear@19: 		spres->mat = scn->matlib[sp0.obj->matid];
nuclear@16: 	}
nuclear@16: 	return true;
nuclear@12: }
nuclear@12: 
nuclear@16: bool intersect(struct Ray ray, global const struct Face *face, struct SurfPoint *sp)
nuclear@2: {
nuclear@12: 	float4 origin = ray.origin;
nuclear@12: 	float4 dir = ray.dir;
nuclear@12: 	float4 norm = face->normal;
nuclear@12: 
nuclear@16: 	float ndotdir = dot(dir, norm);
nuclear@12: 
nuclear@9: 	if(fabs(ndotdir) <= EPSILON) {
nuclear@9: 		return false;
nuclear@9: 	}
nuclear@2: 
nuclear@9: 	float4 pt = face->v[0].pos;
nuclear@12: 	float4 vec = pt - origin;
nuclear@2: 
nuclear@16: 	float ndotvec = dot(norm, vec);
nuclear@9: 	float t = ndotvec / ndotdir;
nuclear@2: 
nuclear@2: 	if(t < EPSILON || t > 1.0) {
nuclear@2: 		return false;
nuclear@2: 	}
nuclear@12: 	pt = origin + dir * t;
nuclear@9: 
nuclear@12: 
nuclear@12: 	float4 bc = calc_bary(pt, face, norm);
nuclear@9: 	float bc_sum = bc.x + bc.y + bc.z;
nuclear@9: 
nuclear@20: 	if(bc_sum < 1.0 - EPSILON || bc_sum > 1.0 + EPSILON) {
nuclear@9: 		return false;
nuclear@12: 		bc *= 1.2;
nuclear@9: 	}
nuclear@2: 
nuclear@2: 	sp->t = t;
nuclear@9: 	sp->pos = pt;
nuclear@21: 	sp->norm = normalize(face->v[0].normal * bc.x + face->v[1].normal * bc.y + face->v[2].normal * bc.z);
nuclear@9: 	sp->obj = face;
nuclear@12: 	sp->dbg = bc;
nuclear@2: 	return true;
nuclear@2: }
nuclear@5: 
nuclear@8: float4 reflect(float4 v, float4 n)
nuclear@5: {
nuclear@12: 	float4 res = 2.0f * dot(v, n) * n - v;
nuclear@12: 	return res;
nuclear@5: }
nuclear@8: 
nuclear@8: float4 transform(float4 v, global const float *xform)
nuclear@8: {
nuclear@8: 	float4 res;
nuclear@8: 	res.x = v.x * xform[0] + v.y * xform[4] + v.z * xform[8] + xform[12];
nuclear@8: 	res.y = v.x * xform[1] + v.y * xform[5] + v.z * xform[9] + xform[13];
nuclear@8: 	res.z = v.x * xform[2] + v.y * xform[6] + v.z * xform[10] + xform[14];
nuclear@12: 	res.w = 0.0;
nuclear@8: 	return res;
nuclear@8: }
nuclear@8: 
nuclear@16: void transform_ray(struct Ray *ray, global const float *xform, global const float *invtrans)
nuclear@8: {
nuclear@16: 	ray->origin = transform(ray->origin, xform);
nuclear@16: 	ray->dir = transform(ray->dir, invtrans);
nuclear@8: }
nuclear@9: 
nuclear@12: float4 calc_bary(float4 pt, global const struct Face *face, float4 norm)
nuclear@9: {
nuclear@12: 	float4 bc = (float4)(0, 0, 0, 0);
nuclear@9: 
nuclear@12: 	// calculate area of the whole triangle
nuclear@12: 	float4 v1 = face->v[1].pos - face->v[0].pos;
nuclear@12: 	float4 v2 = face->v[2].pos - face->v[0].pos;
nuclear@12: 	float4 xv1v2 = cross(v1, v2);
nuclear@12: 
nuclear@16: 	float area = fabs(dot(xv1v2, norm)) * 0.5;
nuclear@9: 	if(area < EPSILON) {
nuclear@9: 		return bc;
nuclear@9: 	}
nuclear@9: 
nuclear@9: 	float4 pv0 = face->v[0].pos - pt;
nuclear@9: 	float4 pv1 = face->v[1].pos - pt;
nuclear@9: 	float4 pv2 = face->v[2].pos - pt;
nuclear@9: 
nuclear@12: 	// calculate the area of each sub-triangle
nuclear@12: 	float4 x12 = cross(pv1, pv2);
nuclear@12: 	float4 x20 = cross(pv2, pv0);
nuclear@12: 	float4 x01 = cross(pv0, pv1);
nuclear@12: 
nuclear@16: 	float a0 = fabs(dot(x12, norm)) * 0.5;
nuclear@16: 	float a1 = fabs(dot(x20, norm)) * 0.5;
nuclear@16: 	float a2 = fabs(dot(x01, norm)) * 0.5;
nuclear@9: 
nuclear@9: 	bc.x = a0 / area;
nuclear@9: 	bc.y = a1 / area;
nuclear@9: 	bc.z = a2 / area;
nuclear@9: 	return bc;
nuclear@9: }
nuclear@19: 
nuclear@19: float mean(float4 v)
nuclear@19: {
nuclear@19: 	return native_divide(v.x + v.y + v.z, 3.0);
nuclear@19: }