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@28: 	int kd_depth;
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@43: 	//global const struct KDNode *kdtree;
nuclear@28: };
nuclear@28: 
nuclear@28: struct AABBox {
nuclear@28: 	float4 min, max;
nuclear@28: };
nuclear@28: 
nuclear@43: #define MAX_NODE_FACES	32
nuclear@28: struct KDNode {
nuclear@29: 	struct AABBox aabb;
nuclear@43: 	int face_idx[MAX_NODE_FACES];
nuclear@28: 	int num_faces;
nuclear@35: 	int left, right;
nuclear@35: 	int padding;
nuclear@16: };
nuclear@2: 
nuclear@43: #define RAY_MAG		500.0
nuclear@16: #define MIN_ENERGY	0.001
nuclear@21: #define EPSILON		1e-5
nuclear@16: 
nuclear@43: float4 shade(struct Ray ray, struct Scene *scn, const struct SurfPoint *sp, read_only image2d_t kdimg);
nuclear@43: bool find_intersection(struct Ray ray, const struct Scene *scn, struct SurfPoint *sp, read_only image2d_t kdimg);
nuclear@9: bool intersect(struct Ray ray, global const struct Face *face, struct SurfPoint *sp);
nuclear@28: bool intersect_aabb(struct Ray ray, struct AABBox aabb);
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@43: void read_kdnode(int idx, struct KDNode *node, read_only image2d_t kdimg);
nuclear@43: 
nuclear@39: 
nuclear@39: kernel void render(write_only image2d_t 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@28: 		global const float *invtrans,
nuclear@43: 		//global const struct KDNode *kdtree
nuclear@43: 		read_only image2d_t kdtree_img)
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@43: 	//scn.kdtree_img = kdtree_img;
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@43: 		if(find_intersection(ray, &scn, &sp, kdtree_img)) {
nuclear@43: 			pixel += shade(ray, &scn, &sp, kdtree_img) * 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@35: 			energy *= refl_col;
nuclear@19: 		} else {
nuclear@43: 			energy = (float4)(0.0, 0.0, 0.0, 0.0);
nuclear@19: 		}
nuclear@17: 	}
nuclear@19: 
nuclear@39: 	int2 coord;
nuclear@43: 	coord.x = idx % rinf->xsz;
nuclear@43: 	coord.y = idx / rinf->xsz;
nuclear@39: 
nuclear@39: 	write_imagef(fb, coord, pixel);
nuclear@4: }
nuclear@4: 
nuclear@43: float4 shade(struct Ray ray, struct Scene *scn, const struct SurfPoint *sp, read_only image2d_t kdimg)
nuclear@16: {
nuclear@16: 	float4 norm = sp->norm;
nuclear@43: 	//bool entering = true;
nuclear@12: 
nuclear@12: 	if(dot(ray.dir, norm) >= 0.0) {
nuclear@12: 		norm = -norm;
nuclear@43: 		//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@43: 		if(!find_intersection(shadowray, scn, 0, kdimg)) {
nuclear@16: 			ldir = normalize(ldir);
nuclear@43: 			float4 vdir = -ray.dir;
nuclear@43: 			vdir.x = native_divide(vdir.x, RAY_MAG);
nuclear@43: 			vdir.y = native_divide(vdir.y, RAY_MAG);
nuclear@43: 			vdir.z = native_divide(vdir.z, RAY_MAG);
nuclear@16: 			float4 vref = reflect(vdir, norm);
nuclear@16: 
nuclear@16: 			float diff = fmax(dot(ldir, norm), 0.0f);
nuclear@43: 			dcol += sp->mat.kd /* scn->lights[i].color*/ * diff;
nuclear@16: 
nuclear@43: 			float spec = native_powr(fmax(dot(ldir, vref), 0.0f), sp->mat.spow);
nuclear@43: 			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@30: #define STACK_SIZE	64
nuclear@43: bool find_intersection(struct Ray ray, const struct Scene *scn, struct SurfPoint *spres, read_only image2d_t kdimg)
nuclear@28: {
nuclear@29: 	struct SurfPoint sp0;
nuclear@29: 	sp0.t = 1.0;
nuclear@29: 	sp0.obj = 0;
nuclear@29: 
nuclear@29: 	int idxstack[STACK_SIZE];
nuclear@31: 	int top = 0;			// points after the topmost element of the stack
nuclear@35: 	idxstack[top++] = 0;	// root at tree[0]
nuclear@29: 
nuclear@31: 	while(top > 0) {
nuclear@31: 		int idx = idxstack[--top];	// remove this index from the stack and process it
nuclear@30: 
nuclear@43: 		struct KDNode node;
nuclear@43: 		read_kdnode(idx, &node, kdimg);
nuclear@29: 
nuclear@43: 		if(intersect_aabb(ray, node.aabb)) {
nuclear@43: 			if(node.left == -1) {
nuclear@31: 				// leaf node... check each face in turn and update the nearest intersection as needed
nuclear@43: 				for(int i=0; i<node.num_faces; i++) {
nuclear@31: 					struct SurfPoint spt;
nuclear@43: 					int fidx = node.face_idx[i];
nuclear@29: 
nuclear@31: 					if(intersect(ray, scn->faces + fidx, &spt) && spt.t < sp0.t) {
nuclear@31: 						sp0 = spt;
nuclear@29: 					}
nuclear@29: 				}
nuclear@31: 			} else {
nuclear@31: 				// internal node... recurse to the children
nuclear@43: 				idxstack[top++] = node.left;
nuclear@43: 				idxstack[top++] = node.right;
nuclear@29: 			}
nuclear@29: 		}
nuclear@29: 	}
nuclear@29: 
nuclear@29: 	if(!sp0.obj) {
nuclear@29: 		return false;
nuclear@29: 	}
nuclear@29: 
nuclear@29: 	if(spres) {
nuclear@29: 		*spres = sp0;
nuclear@29: 		spres->mat = scn->matlib[sp0.obj->matid];
nuclear@29: 	}
nuclear@29: 	return true;
nuclear@28: }
nuclear@16: 
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@43: 	float t = native_divide(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@28: bool intersect_aabb(struct Ray ray, struct AABBox aabb)
nuclear@28: {
nuclear@28: 	if(ray.origin.x >= aabb.min.x && ray.origin.y >= aabb.min.y && ray.origin.z >= aabb.min.z &&
nuclear@28: 			ray.origin.x < aabb.max.x && ray.origin.y < aabb.max.y && ray.origin.z < aabb.max.z) {
nuclear@28: 		return true;
nuclear@28: 	}
nuclear@28: 
nuclear@29: 	float4 bbox[2] = {
nuclear@29: 		aabb.min.x, aabb.min.y, aabb.min.z, 0,
nuclear@29: 		aabb.max.x, aabb.max.y, aabb.max.z, 0
nuclear@29: 	};
nuclear@28: 
nuclear@28: 	int xsign = (int)(ray.dir.x < 0.0);
nuclear@43: 	float invdirx = native_recip(ray.dir.x);
nuclear@28: 	float tmin = (bbox[xsign].x - ray.origin.x) * invdirx;
nuclear@28: 	float tmax = (bbox[1 - xsign].x - ray.origin.x) * invdirx;
nuclear@28: 
nuclear@28: 	int ysign = (int)(ray.dir.y < 0.0);
nuclear@43: 	float invdiry = native_recip(ray.dir.y);
nuclear@28: 	float tymin = (bbox[ysign].y - ray.origin.y) * invdiry;
nuclear@28: 	float tymax = (bbox[1 - ysign].y - ray.origin.y) * invdiry;
nuclear@28: 
nuclear@28: 	if(tmin > tymax || tymin > tmax) {
nuclear@28: 		return false;
nuclear@28: 	}
nuclear@28: 
nuclear@28: 	if(tymin > tmin) tmin = tymin;
nuclear@28: 	if(tymax < tmax) tmax = tymax;
nuclear@28: 
nuclear@28: 	int zsign = (int)(ray.dir.z < 0.0);
nuclear@43: 	float invdirz = native_recip(ray.dir.z);
nuclear@28: 	float tzmin = (bbox[zsign].z - ray.origin.z) * invdirz;
nuclear@28: 	float tzmax = (bbox[1 - zsign].z - ray.origin.z) * invdirz;
nuclear@28: 
nuclear@28: 	if(tmin > tzmax || tzmin > tmax) {
nuclear@28: 		return false;
nuclear@28: 	}
nuclear@28: 
nuclear@29: 	return tmin < 1.0 && tmax > 0.0;
nuclear@28: }
nuclear@28: 
nuclear@8: float4 reflect(float4 v, float4 n)
nuclear@5: {
nuclear@23: 	return 2.0f * dot(v, n) * n - v;
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@43: 	bc.x = native_divide(a0, area);
nuclear@43: 	bc.y = native_divide(a1, area);
nuclear@43: 	bc.z = native_divide(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: }
nuclear@43: 
nuclear@43: 
nuclear@43: const sampler_t kdsampler = CLK_NORMALIZED_COORDS_FALSE | CLK_ADDRESS_NONE | CLK_FILTER_NEAREST;
nuclear@43: 
nuclear@43: // read a KD-tree node from a texture scanline
nuclear@43: void read_kdnode(int idx, struct KDNode *node, read_only image2d_t kdimg)
nuclear@43: {
nuclear@43: 	int2 tc;
nuclear@43: 	tc.x = 0;
nuclear@43: 	tc.y = idx;
nuclear@43: 
nuclear@43: 	node->aabb.min = read_imagef(kdimg, kdsampler, tc); tc.x++;
nuclear@43: 	node->aabb.max = read_imagef(kdimg, kdsampler, tc);
nuclear@43: 
nuclear@43: 	tc.x = 2 + MAX_NODE_FACES / 4;
nuclear@43: 	float4 pix = read_imagef(kdimg, kdsampler, tc);
nuclear@43: 	node->num_faces = (int)pix.x;
nuclear@43: 	node->left = (int)pix.y;
nuclear@43: 	node->right = (int)pix.z;
nuclear@43: 
nuclear@43: 	tc.x = 2;
nuclear@43: 	for(int i=0; i<node->num_faces; i+=4) {
nuclear@43: 		float4 pix = read_imagef(kdimg, kdsampler, tc); tc.x++;
nuclear@43: 		node->face_idx[i] = (int)pix.x;
nuclear@43: 		node->face_idx[i + 1] = (int)pix.y;
nuclear@43: 		node->face_idx[i + 2] = (int)pix.z;
nuclear@43: 		node->face_idx[i + 3] = (int)pix.w;
nuclear@43: 	}
nuclear@43: }