static void
trace_pixel(ri_vector_t *radiance, int x, int y)
{
unsigned char type;
double bsdf[3];
ri_ray_t ray;
ri_intersection_state_t state;
pathnode_t node;
ri_vector_t Le;
/* first check a ray hits scene object through pixel (x, y) */
ri_vector_copy(&ray.org, cam_pos);
sample_pixel(&ray.dir, x, y);
ray.thread_num = 0;
if (!ri_raytrace(ri_render_get(), &ray, &state)) {
/* hits background */
ri_texture_ibl_fetch(radiance, light->texture, ray.dir);
return;
}
node.depth = 2;
node.G[0] = 1.0; node.G[1] = 1.0; node.G[2] = 1.0;
ri_mem_copy(&node.state, &state, sizeof(ri_intersection_state_t));
ri_vector_copy(&node.indir, ray.dir);
// assume that the camera is not located in the transparent object
node.interior = 0;
trace_path(&node);
/* connect the path to the IBL light source */
type = sample_reflection_type(node.state.geom->material);
//if (node.interior) printf("???\n");
sample_outdir(&ray.dir, &type,
node.interior,
node.state.geom->material,
node.indir, node.state.Ng);
brdf(bsdf,
type, &node.state,
node.indir, ray.dir, node.state.Ng);
node.G[0] *= bsdf[0];
node.G[1] *= bsdf[1];
node.G[2] *= bsdf[2];
ri_vector_copy(&ray.org, node.state.P);
light_sample(&Le, ray.org, ray.dir);
radiance->f[0] = Le.f[0] * node.G[0];
radiance->f[1] = Le.f[1] * node.G[1];
radiance->f[2] = Le.f[2] * node.G[2];
}
/**
* Samples a snapshot from the camera to retrieve the line following error
*
* @param white_count The number of white pixels detected, updated by reference.
* @return The line-following error in the image
*/
inline int sample_image(LineInfo &line)
{
line = {false, false, false, false, 0, 0};
int error = 0;
take_picture();
// Get pixels from across the entire image, not just one line
for (int x = 0; x < IMAGE_SIZE_X; x += SAMPLE_STEPS) {
for (int y = 0; y < IMAGE_SIZE_Y; y += SAMPLE_STEPS)
{
error += sample_pixel(line, x, y);
}
}
return error;
}
