/* Adds a triangle by interpolating over the given edges (which are expected to
* contain an intersection).
* The edges are specified by their vertices (u is the first edge, v the second,
* etc.)
*/
void interpolate_edges(triangle *triangles, unsigned char isovalue, cell c,
int u0, int u1,
int v0, int v1,
int w0, int w1)
{
vec3 p1, p2, p3;
p1 = interpolate_points(isovalue, c.p[u0], c.p[u1], c.value[u0], c.value[u1]);
p2 = interpolate_points(isovalue, c.p[v0], c.p[v1], c.value[v0], c.value[v1]);
p3 = interpolate_points(isovalue, c.p[w0], c.p[w1], c.value[w0], c.value[w1]);
triangles->p[0] = p1;
triangles->p[1] = p2;
triangles->p[2] = p3;
// the surface-normal is the cross-product between 2 of the edges making up
// the face
vec3 normal = v3_crossprod(v3_subtract(p1, p2),
v3_subtract(p3, p1));
normal = v3_normalize(normal);
normal = v3_multiply(normal, -1);
triangles->n[0] = normal;
triangles->n[1] = normal;
triangles->n[2] = normal;
}
static void
draw_bvh_inner_nodes(int level, bvh_node* node)
{
vec3 center, size;
if (node->is_leaf)
return;
if (level == draw_bvh_mode)
{
center = v3_multiply(v3_add(node->bbox.min, node->bbox.max), 0.5);
size = v3_subtract(node->bbox.max, node->bbox.min);
glColor3f(1, 0, 0);
glPushMatrix();
glTranslatef(center.x, center.y, center.z);
glScalef(size.x, size.y, size.z);
glutWireCube(1.0);
glPopMatrix();
}
else
{
draw_bvh_inner_nodes(level+1, node->u.inner.left_child);
draw_bvh_inner_nodes(level+1, node->u.inner.right_child);
}
}
void *compute_next_dynamics(void *arg)
{
struct Work_Unit *chunk = (struct Work_Unit *)arg;
// For each object...
for( int object_i = chunk->start_index; object_i < chunk->stop_index; ++object_i ) {
Vector3 total_force = { 0.0, 0.0, 0.0 };
// Consider interactions with all other objects...
for( int object_j = 0; object_j < OBJECT_COUNT; ++object_j ) {
if( object_i == object_j ) continue;
Vector3 displacement = v3_subtract(
current_dynamics[object_j].position, current_dynamics[object_i].position );
double distance_squared = magnitude_squared( displacement );
double distance = sqrt( distance_squared );
double force_magnitude =
( G * object_array[object_i].mass * object_array[object_j].mass ) / distance_squared;
Vector3 force = v3_multiply( (force_magnitude / distance ), displacement );
total_force = v3_add( total_force, force );
}
// Total force on object_i is now known. Compute acceleration, velocity and position.
Vector3 acceleration = v3_divide( total_force, object_array[object_i].mass );
Vector3 delta_v = v3_multiply( TIME_STEP, acceleration );
Vector3 delta_position = v3_multiply( TIME_STEP, current_dynamics[object_i].velocity );
next_dynamics[object_i].velocity =
v3_add( current_dynamics[object_i].velocity, delta_v );
next_dynamics[object_i].position =
v3_add( current_dynamics[object_i].position, delta_position );
}
return NULL;
}
// Check if the given sphere is intersected by the given ray.
// See Shirley et.al., section 10.3.1
// Returns 1 if there is an intersection (and sets the appropriate
// fields of ip), or 0 otherwise.
static int
ray_intersects_sphere(intersection_point* ip, sphere sph,
vec3 ray_origin, vec3 ray_direction)
{
float A, B, C, D;
vec3 diff;
float t_hit;
A = v3_dotprod(ray_direction, ray_direction);
diff = v3_subtract(ray_origin, sph.center);
B = 2.0 * v3_dotprod(diff, ray_direction);
C = v3_dotprod(diff, diff) - sph.radius * sph.radius;
D = B*B - 4*A*C;
if (D < 0.0)
return 0;
D = sqrt(D);
// We're only interested in the first hit, i.e. the one with
// the smallest t_hit, so we check -B-D first, followed by -B+D
t_hit = (-B - D)/(2*A);
if (t_hit < 0.0)
{
t_hit = (-B + D)/(2*A);
if (t_hit < 0.0)
return 0;
}
ip->t = t_hit;
ip->p = v3_add(ray_origin, v3_multiply(ray_direction, t_hit));
ip->n = v3_normalize(v3_subtract(ip->p, sph.center));
ip->i = v3_normalize(v3_negate(ray_direction));
ip->material = sph.material;
return 1;
}
// Recursively subdivide triangles into two groups, by determining
// a split plane and sorting the triangles into "left-of" and "right-of".
static bvh_node*
bvh_build_recursive(int depth, boundingbox bbox, triangle* triangles, int num_triangles)
{
vec3 bbox_size, bbox_center;
int i, j, t;
int sorted_dimensions[3];
int split_axis;
float split_value;
int num_triangles_left, num_triangles_right;
boundingbox left_bbox, right_bbox;
bvh_node *left_child, *right_child;
if (depth == max_depth || num_triangles <= acceptable_leaf_size)
{
// Create a leaf node
#ifdef VERBOSE
if (num_triangles > acceptable_leaf_size)
printf("[%d] Maximum depth reached, forced to create a leaf of %d triangles\n", depth, num_triangles);
else
printf("[%d] Creating a leaf node of %d triangles\n", depth, num_triangles);
#endif
return create_leaf_node(bbox, triangles, num_triangles);
}
//
// Split the triangles into two groups, using a split plane based
// on largest bbox side
//
bbox_size = v3_subtract(bbox.max, bbox.min);
bbox_center = v3_multiply(v3_add(bbox.min, bbox.max), 0.5);
// Sort bbox sides by size in descending order
sorted_dimensions[0] = 0;
sorted_dimensions[1] = 1;
sorted_dimensions[2] = 2;
// Good old bubble sort :)
for (i = 0; i < 2; i++)
{
for (j = i+1; j < 3; j++)
{
if (v3_component(bbox_size, sorted_dimensions[i])
<
v3_component(bbox_size, sorted_dimensions[j]))
{
t = sorted_dimensions[i];
sorted_dimensions[i] = sorted_dimensions[j];
sorted_dimensions[j] = t;
}
}
}
// Iterate over the three split dimensions in descending order of
// bbox size on that dimension. When the triangles are unsplitable
// (or not very favorably) continue to the next dimension. Create a
// leaf with all triangles in case none of dimensions is a good
// split candidate.
for (i = 0; i < 3; i++)
{
// Partition the triangles on the chosen split axis, with the
// split plane at the center of the bbox
split_axis = sorted_dimensions[i];
split_value = v3_component(bbox_center, split_axis);
#ifdef VERBOSE
printf("[%d] Splitting on axis %d, value %.3f\n", depth, split_axis, split_value);
#endif
partition_on_split_value(&num_triangles_left, &num_triangles_right,
triangles, num_triangles, split_axis, split_value);
#ifdef VERBOSE
printf("[%d] %d left, %d right\n", depth, num_triangles_left, num_triangles_right);
#endif
if (num_triangles_left == 0 || num_triangles_right == 0)
continue;
// Determine bboxes for the two new groups of triangles
left_bbox = bound_triangles(triangles, num_triangles_left);
if (v3_component(v3_subtract(left_bbox.max, left_bbox.min), split_axis)
>
0.9 * v3_component(bbox_size, split_axis))
{
//printf("[%d] skipping dimension (left)\n", split_axis);
continue;
}
#ifdef VERBOSE
printf("[%d] left bbox: %.3f, %.3f, %.3f .. %.3f, %.3f, %.3f\n",
depth, left_bbox.min.x, left_bbox.min.y, left_bbox.min.z,
left_bbox.max.x, left_bbox.max.y, left_bbox.max.z);
#endif
right_bbox = bound_triangles(triangles+num_triangles_left, num_triangles_right);
if (v3_component(v3_subtract(right_bbox.max, right_bbox.min), split_axis)
>
0.9 * v3_component(bbox_size, split_axis))
{
//printf("[%d] skipping dimension (right)\n", split_axis);
continue;
}
#ifdef VERBOSE
printf("[%d] right bbox: %.3f, %.3f, %.3f .. %.3f, %.3f, %.3f\n",
depth, right_bbox.min.x, right_bbox.min.y, right_bbox.min.z,
right_bbox.max.x, right_bbox.max.y, right_bbox.max.z);
#endif
// Recurse using the two new groups
left_child = bvh_build_recursive(depth+1, left_bbox, triangles, num_triangles_left);
right_child = bvh_build_recursive(depth+1, right_bbox, triangles+num_triangles_left, num_triangles_right);
// Create an inner code with two children
return create_inner_node(left_child, right_child);
}
// Split dimensions exhausted, forced to create a leaf
#ifdef VERBOSE
printf("Split dimensions exhausted, creating a leaf of %d triangles\n", num_triangles);
#endif
return create_leaf_node(bbox, triangles, num_triangles);
}
void
ray_trace(void)
{
vec3 forward_vector, right_vector, up_vector;
int i, j;
float image_plane_width, image_plane_height;
vec3 color;
char buf[128];
struct timeval t0, t1;
float time_taken;
fprintf(stderr, "Ray tracing ...");
gettimeofday(&t0, NULL);
num_rays_shot = num_shadow_rays_shot = num_triangles_tested = num_bboxes_tested = 0;
// Compute camera coordinate system from camera position
// and look-at point
up_vector = v3_create(0, 0, 1);
forward_vector = v3_normalize(v3_subtract(scene_camera_lookat, scene_camera_position));
right_vector = v3_normalize(v3_crossprod(forward_vector, up_vector));
up_vector = v3_crossprod(right_vector, forward_vector);
// Compute size of image plane from the chosen field-of-view
// and image aspect ratio. This is the size of the plane at distance
// of one unit from the camera position.
image_plane_height = 2.0 * tan(0.5*VFOV/180*M_PI);
image_plane_width = image_plane_height * (1.0 * framebuffer_width / framebuffer_height);
vec3 d, e, u, v, w, ud, vd;
float l, r, b, t, nx, ny;
// direction d, origin e
// ONB u, v, w
// image plane edges l, r, b, t
// window size nx, ny
e = scene_camera_position;
u = right_vector, v = up_vector, w = v3_negate(forward_vector);
l = -0.5 * image_plane_width, r = 0.5 * image_plane_width;
b = 0.5 * image_plane_height, t = -0.5 * image_plane_height;
nx = framebuffer_width, ny = framebuffer_height;
// Loop over all pixels in the framebuffer
for (j = 0; j < ny; j++) {
for (i = 0; i < nx; i++) {
ud = v3_multiply(u, (l + (r - l) * ((i + 0.5) / nx)));
vd = v3_multiply(v, (b + (t - b) * ((j + 0.5) / ny)));
d = v3_add(v3_add(ud, vd), v3_negate(w));
color = ray_color(0, e, d);
put_pixel(i, j, color.x, color.y, color.z);
}
sprintf(buf, "Ray-tracing ::: %.0f%% done", 100.0*j/framebuffer_height);
glutSetWindowTitle(buf);
}
// Done!
gettimeofday(&t1, NULL);
glutSetWindowTitle("Ray-tracing ::: done");
// Output some statistics
time_taken = 1.0 * (t1.tv_sec - t0.tv_sec) + (t1.tv_usec - t0.tv_usec) / 1000000.0;
fprintf(stderr, " done in %.1f seconds\n", time_taken);
fprintf(stderr, "... %lld total rays shot, of which %d camera rays and "
"%lld shadow rays\n", num_rays_shot,
do_antialiasing ? 4*framebuffer_width*framebuffer_height :
framebuffer_width*framebuffer_height,
num_shadow_rays_shot);
fprintf(stderr, "... %lld triangles intersection tested "
"(avg %.1f tri/ray)\n",
num_triangles_tested, 1.0*num_triangles_tested/num_rays_shot);
fprintf(stderr, "... %lld bboxes intersection tested (avg %.1f bbox/ray)\n",
num_bboxes_tested, 1.0*num_bboxes_tested/num_rays_shot);
}
void
ray_trace(void)
{
vec3 forward_vector, right_vector, up_vector;
int i, j;
float image_plane_width, image_plane_height;
vec3 color;
char buf[128];
struct timeval t0, t1;
float time_taken;
fprintf(stderr, "Ray tracing ...");
gettimeofday(&t0, NULL);
num_rays_shot = num_shadow_rays_shot = num_triangles_tested = num_bboxes_tested = 0;
// Compute camera coordinate system from camera position
// and look-at point
up_vector = v3_create(0, 0, 1);
forward_vector = v3_normalize(v3_subtract(scene_camera_lookat, scene_camera_position));
right_vector = v3_normalize(v3_crossprod(forward_vector, up_vector));
up_vector = v3_crossprod(right_vector, forward_vector);
// Compute size of image plane from the chosen field-of-view
// and image aspect ratio. This is the size of the plane at distance
// of one unit from the camera position.
image_plane_height = 2.0 * tan(0.5*VFOV/180*M_PI);
image_plane_width = image_plane_height * (1.0 * framebuffer_width / framebuffer_height);
// vector points to the middle of the monitor
vec3 plane_center = v3_add(scene_camera_position, forward_vector);
// vector points to the left side of the monitor
vec3 le_unnormalized = v3_multiply(right_vector, -(image_plane_width / 2.0));
// vector points to the up side of the monitor
vec3 up_unnormalized = v3_multiply(up_vector, image_plane_height / 2.0);
// vector points to the coordinates 0,0 (left up) of the monitor
vec3 left_up = v3_add(plane_center, v3_add(le_unnormalized, up_unnormalized));
// vector points to right, and has length equal to width of a pixel
vec3 pixel2pixel_x = v3_multiply(right_vector, (image_plane_width / framebuffer_width));
// vector points to down, and has length equal to height of a pixel
vec3 pixel2pixel_y = v3_multiply(up_vector, -(image_plane_height / framebuffer_height));
// ANTI-ALIASING LOOP
if (do_antialiasing) {
// loop over all pixels in the framebuffer
for (j = 0; j < framebuffer_height; j++) {
for (i = 0; i < framebuffer_width; i++) {
// for each pixel, shoot four rays
vec3 ray_direction_00 = v3_add(v3_add(left_up, v3_multiply(pixel2pixel_y, j + 0.25)), v3_multiply(pixel2pixel_x, i + 0.25));
vec3 ray_direction_01 = v3_add(v3_add(left_up, v3_multiply(pixel2pixel_y, j + 0.75)), v3_multiply(pixel2pixel_x, i + 0.25));
vec3 ray_direction_10 = v3_add(v3_add(left_up, v3_multiply(pixel2pixel_y, j + 0.25)), v3_multiply(pixel2pixel_x, i + 0.75));
vec3 ray_direction_11 = v3_add(v3_add(left_up, v3_multiply(pixel2pixel_y, j + 0.75)), v3_multiply(pixel2pixel_x, i + 0.75));
// for each ray fired, get the difference
ray_direction_00 = v3_subtract(ray_direction_00, scene_camera_position);
ray_direction_01 = v3_subtract(ray_direction_01, scene_camera_position);
ray_direction_10 = v3_subtract(ray_direction_10, scene_camera_position);
ray_direction_11 = v3_subtract(ray_direction_11, scene_camera_position);
// add the colors of the four rays, then divide by four
color = ray_color(0, scene_camera_position, ray_direction_00);
color = v3_add(color, ray_color(0, scene_camera_position, ray_direction_01));
color = v3_add(color, ray_color(0, scene_camera_position, ray_direction_10));
color = v3_add(color, ray_color(0, scene_camera_position, ray_direction_11));
color = v3_multiply(color, 0.25);
// output pixel color
put_pixel(i, j, color.x, color.y, color.z);
}
sprintf(buf, "Ray-tracing (AA enabled) ::: %.0f%% done", 100.0*j/framebuffer_height);
glutSetWindowTitle(buf);
}
}
// NON-ANTI-ALIASING LOOP
else {
// loop over all pixels in the framebuffer
for (j = 0; j < framebuffer_height; j++) {
for (i = 0; i < framebuffer_width; i++) {
// select the currently relevant pixel
vec3 ray_direction = v3_add(v3_add(left_up, v3_multiply(pixel2pixel_y, j + 0.5)), v3_multiply(pixel2pixel_x, i + 0.5));
// get diference between the two points
ray_direction = v3_subtract(ray_direction, scene_camera_position);
// set color
color = ray_color(0, scene_camera_position, ray_direction);
// output pixel color
put_pixel(i, j, color.x, color.y, color.z);
}
sprintf(buf, "Ray-tracing ::: %.0f%% done", 100.0*j/framebuffer_height);
glutSetWindowTitle(buf);
}
}
// set a detailed title, useful for testing
if (use_bvh && do_antialiasing)
glutSetWindowTitle("Ray-tracing is done. AA=yes, BVH=yes");
else if (use_bvh && !do_antialiasing)
glutSetWindowTitle("Ray-tracing is done. AA=no, BVH=yes");
else if (!use_bvh && do_antialiasing)
glutSetWindowTitle("Ray-tracing is done. AA=yes, BVH=no");
else
glutSetWindowTitle("Ray-tracing is done. AA=no, BVH=no");
// Done!
gettimeofday(&t1, NULL);
// Output some statistics
time_taken = 1.0 * (t1.tv_sec - t0.tv_sec) + (t1.tv_usec - t0.tv_usec) / 1000000.0;
fprintf(stderr, " done in %.1f seconds\n", time_taken);
fprintf(stderr, "... %d total rays shot, of which %d camera rays and %d shadow rays\n",
num_rays_shot,
do_antialiasing ? 4*framebuffer_width*framebuffer_height : framebuffer_width*framebuffer_height,
num_shadow_rays_shot);
fprintf(stderr, "... %d triangles intersection tested (avg %.1f tri/ray)\n",
num_triangles_tested, 1.0*num_triangles_tested/num_rays_shot);
fprintf(stderr, "... %d bboxes intersection tested (avg %.1f bbox/ray)\n",
num_bboxes_tested, 1.0*num_bboxes_tested/num_rays_shot);
}
void
ray_trace(void)
{
vec3 forward_vector, right_vector, up_vector;
int i, j;
float image_plane_width, image_plane_height;
vec3 color;
char buf[128];
struct timeval t0, t1;
float time_taken;
fprintf(stderr, "Ray tracing ...");
gettimeofday(&t0, NULL);
num_rays_shot = num_shadow_rays_shot = num_triangles_tested = num_bboxes_tested = 0;
// Compute camera coordinate system from camera position
// and look-at point
up_vector = v3_create(0, 0, 1);
forward_vector = v3_normalize(v3_subtract(scene_camera_lookat, scene_camera_position));
right_vector = v3_normalize(v3_crossprod(forward_vector, up_vector));
up_vector = v3_crossprod(right_vector, forward_vector);
// Compute size of image plane from the chosen field-of-view
// and image aspect ratio. This is the size of the plane at distance
// of one unit from the camera position.
image_plane_height = 2.0 * tan(0.5*VFOV/180*M_PI);
image_plane_width = image_plane_height * (1.0 * framebuffer_width / framebuffer_height);
printf("imageplane: (%f, %f)\n", image_plane_width, image_plane_height);
// the borders of the image plane in camera coordinates
float left = -(image_plane_width / 2),
right = image_plane_width / 2,
bottom = (image_plane_height / 2),
top = -image_plane_height / 2;
// rays are expressed as a location vector and direction vector
vec3 ray_origin = scene_camera_position;
float u, v, w;
// Loop over all pixels in the framebuffer
for (j = 0; j < framebuffer_height; j++)
{
for (i = 0; i < framebuffer_width; i++)
{
vec3 directions[4];
int directions_i = 0;
float offsets[2];
int offsets_n;
// if anti-aliasing is activated, shoot 4 rays through each pixel
// slightly offset from the center
if (do_antialiasing) {
offsets_n = 2;
offsets[0] = 0.25;
offsets[1] = 0.75;
}
// without anti-aliasing, just send a single ray through the
// pixel-center
else {
offsets_n = 1;
offsets[0] = 0.5;
}
// calculate the [u, v, w] components of the pixel's location
// relative to the camera
for (int u_offset = 0; u_offset < offsets_n; ++u_offset) {
for (int v_offset = 0; v_offset < offsets_n; ++v_offset) {
w = 1;
u = left + (right - left) * (i + offsets[u_offset]) / framebuffer_width;
v = bottom + (top - bottom) * (j + offsets[v_offset]) / framebuffer_height;
// the direction of the ray is a a linear combination of the camera
// basisvectors
directions[directions_i] = v3_add3(v3_multiply(forward_vector, w),
v3_multiply(right_vector, u),
v3_multiply(up_vector, v));
directions_i += 1;
}
}
// Output average pixel color
color = v3_create(0.0, 0.0, 0.0);
int num_directions = do_antialiasing ? 2 * offsets_n : 1;
for (int dir = 0; dir < num_directions; ++dir) {
color = v3_add(color, ray_color(0, ray_origin, directions[dir]) );
}
color = v3_multiply(color, 1.0 / num_directions);
put_pixel(i, j, color.x, color.y, color.z);
}
sprintf(buf, "Ray-tracing ::: %.0f%% done", 100.0*j/framebuffer_height);
glutSetWindowTitle(buf);
}
// Done!
gettimeofday(&t1, NULL);
glutSetWindowTitle("Ray-tracing ::: done");
// Output some statistics
time_taken = 1.0 * (t1.tv_sec - t0.tv_sec) + (t1.tv_usec - t0.tv_usec) / 1000000.0;
fprintf(stderr, " done in %.1f seconds\n", time_taken);
fprintf(stderr, "... %d total rays shot, of which %d camera rays and %d shadow rays\n",
num_rays_shot,
do_antialiasing ? 4*framebuffer_width*framebuffer_height : framebuffer_width*framebuffer_height,
num_shadow_rays_shot);
fprintf(stderr, "... %d triangles intersection tested (avg %.1f tri/ray)\n",
num_triangles_tested, 1.0*num_triangles_tested/num_rays_shot);
fprintf(stderr, "... %d bboxes intersection tested (avg %.1f bbox/ray)\n",
num_bboxes_tested, 1.0*num_bboxes_tested/num_rays_shot);
}
static int
ray_intersects_triangle(intersection_point* ip, triangle tri,
vec3 ray_origin, vec3 ray_direction)
{
vec3 edge1, edge2;
vec3 tvec, pvec, qvec;
double det, inv_det;
double t, u, v; // u, v are barycentric coordinates
// t is ray parameter
num_triangles_tested++;
edge1 = v3_subtract(scene_vertices[tri.v[1]], scene_vertices[tri.v[0]]);
edge2 = v3_subtract(scene_vertices[tri.v[2]], scene_vertices[tri.v[0]]);
pvec = v3_crossprod(ray_direction, edge2);
det = v3_dotprod(edge1, pvec);
if (det < 1.0e-6)
return 0;
tvec = v3_subtract(ray_origin, scene_vertices[tri.v[0]]);
u = v3_dotprod(tvec, pvec);
if (u < 0.0 || u > det)
return 0;
qvec = v3_crossprod(tvec, edge1);
v = v3_dotprod(ray_direction, qvec);
if (v < 0.0 || u+v > det)
return 0;
t = v3_dotprod(edge2, qvec);
if (t < 0.0)
return 0;
inv_det = 1.0 / det;
t *= inv_det;
u *= inv_det;
v *= inv_det;
// We have a triangle intersection!
// Return the relevant intersection values.
// Compute the actual intersection point
ip->t = t;
ip->p = v3_add(ray_origin, v3_multiply(ray_direction, t));
// Compute an interpolated normal for this intersection point, i.e.
// we use the barycentric coordinates as weights for the vertex normals
ip->n = v3_normalize(v3_add(
v3_add(
v3_multiply(tri.vn[0], 1.0-u-v),
v3_multiply(tri.vn[1], u)
),
v3_multiply(tri.vn[2], v)));
ip->i = v3_normalize(v3_negate(ray_direction));
ip->material = tri.material;
return 1;
}
void
ray_trace(void)
{
vec3 forward_vector, right_vector, up_vector;
int i, j;
float image_plane_width, image_plane_height;
vec3 color;
char buf[128];
struct timeval t0, t1;
float time_taken;
fprintf(stderr, "Ray tracing ...");
gettimeofday(&t0, NULL);
num_rays_shot = num_shadow_rays_shot = num_triangles_tested = num_bboxes_tested = 0;
// Compute camera coordinate system from camera position
// and look-at point
up_vector = v3_create(0, 0, 1);
forward_vector = v3_normalize(v3_subtract(scene_camera_lookat, scene_camera_position));
right_vector = v3_normalize(v3_crossprod(forward_vector, up_vector));
up_vector = v3_crossprod(right_vector, forward_vector);
// Compute size of image plane from the chosen field-of-view
// and image aspect ratio. This is the size of the plane at distance
// of one unit from the camera position.
image_plane_height = 2.0 * tan(0.5*VFOV/180*M_PI);
image_plane_width = image_plane_height * (1.0 * framebuffer_width / framebuffer_height);
float bottom, left, Us, Vs;
left = -image_plane_width * 0.5;
bottom = image_plane_height * 0.5;
fprintf(stderr, "%d %d\r\n", framebuffer_height, framebuffer_width);
// Loop over all pixels in the framebuffer
for (j = 0; j < framebuffer_height; j++)
{
for (i = 0; i < framebuffer_width; i++)
{
if(!do_antialiasing){
/* With the formula "b + (t−b) * ((j+ 0.5) / ny)" the vector is calculated.
* (t-b) equals the negative image_plane_height
*/
Us = bottom + (-image_plane_height*(j+0.5)/framebuffer_height);
/* using the formula: "l + (r−l) * ((i+ 0.5) / nx)" to calculate the vector
* (r-l) equals the image_plane_width.
*/
Vs = left + (image_plane_width*(i+0.5)/framebuffer_width);
/*
/* Calculate the vector through the pixel (for "Ray through pixel")
* Using the formula "Us * U + Vs * v + n * w"
*/
vec3 UV = v3_add(v3_multiply(up_vector, Us), v3_multiply(right_vector, Vs));
vec3 ray = v3_add(forward_vector, UV);
/* Fills the color */
color = ray_color(0, scene_camera_position, ray);
} else {
float Us1 = bottom + (-image_plane_height*(j+0.25)/framebuffer_height);
float Us2 = bottom + (-image_plane_height*(j+0.75)/framebuffer_height);
float Vs1 = left + (image_plane_width*(i+0.25)/framebuffer_width);
float Vs2 = left + (image_plane_width*(i+0.75)/framebuffer_width);
vec3 UV1 = v3_add(v3_multiply(up_vector, Us1), v3_multiply(right_vector, Vs1));
vec3 UV2 = v3_add(v3_multiply(up_vector, Us2), v3_multiply(right_vector, Vs1));
vec3 UV3 = v3_add(v3_multiply(up_vector, Us1), v3_multiply(right_vector, Vs2));
vec3 UV4 = v3_add(v3_multiply(up_vector, Us2), v3_multiply(right_vector, Vs2));
vec3 color1 = ray_color(0, scene_camera_position, v3_add(forward_vector, UV1));
vec3 color2 = ray_color(0, scene_camera_position, v3_add(forward_vector, UV2));
vec3 color3 = ray_color(0, scene_camera_position, v3_add(forward_vector, UV3));
vec3 color4 = ray_color(0, scene_camera_position, v3_add(forward_vector, UV4));
color = v3_multiply( v3_add(v3_add(color1, color2), v3_add(color3, color4)), 0.25 );
}
/* Output pixel color */
put_pixel(i, j, color.x, color.y, color.z);
}
sprintf(buf, "Ray-tracing ::: %.0f%% done", 100.0*j/framebuffer_height);
glutSetWindowTitle(buf);
}
// Done!
gettimeofday(&t1, NULL);
glutSetWindowTitle("Ray-tracing ::: done");
// Output some statistics
time_taken = 1.0 * (t1.tv_sec - t0.tv_sec) + (t1.tv_usec - t0.tv_usec) / 1000000.0;
fprintf(stderr, " done in %.1f seconds\n", time_taken);
fprintf(stderr, "... %lld total rays shot, of which %d camera rays and "
"%lld shadow rays\n", num_rays_shot,
do_antialiasing ? 4*framebuffer_width*framebuffer_height :
framebuffer_width*framebuffer_height,
num_shadow_rays_shot);
fprintf(stderr, "... %lld triangles intersection tested "
"(avg %.1f tri/ray)\n",
num_triangles_tested, 1.0*num_triangles_tested/num_rays_shot);
fprintf(stderr, "... %lld bboxes intersection tested (avg %.1f bbox/ray)\n",
num_bboxes_tested, 1.0*num_bboxes_tested/num_rays_shot);
}
