diff options
Diffstat (limited to 'ray.c')
| -rw-r--r-- | ray.c | 79 |
1 files changed, 73 insertions, 6 deletions
@@ -5,6 +5,8 @@ #include "ray.h" +#define PI 3.14159265359 + // https://en.wikipedia.org/wiki/Line%E2%80%93sphere_intersection // http://viclw17.github.io/2018/07/16/raytracing-ray-sphere-intersection/ // https://www.scratchapixel.com/lessons/3d-basic-rendering/minimal-ray-tracer-rendering-simple-shapes/ray-sphere-intersection @@ -104,7 +106,7 @@ object_t *ray_cast(space_t *s, ray_t *r, COORD_T *dist_ret, bool chk, COORD_T ch COORD_T d = ray_intersect(o, r, false); if (d > ZERO_APROX) { - if (chk && chk_dist > d) { + if (chk && ( chk_dist > d || chk_dist == 0)) { if (dist_ret) { *dist_ret = d; } @@ -129,7 +131,7 @@ object_t *ray_cast(space_t *s, ray_t *r, COORD_T *dist_ret, bool chk, COORD_T ch return smallest; } -static void ray_calc_light(space_t *s, color_t *dest, object_t *o, vector_t *N, vector_t *eye, vector_t *point) +static void direct_light(space_t *s, color_t *dest, object_t *o, vector_t *N, vector_t *eye, vector_t *point) { ray_t r; r.start = point; @@ -187,10 +189,70 @@ static void ray_calc_light(space_t *s, color_t *dest, object_t *o, vector_t *N, } } -// Calculates the environmental light. Pretty slow -// https://www.scratchapixel.com/lessons/3d-basic-rendering/global-illumination-path-tracing -static void light_environment(space_t *s, color_t *dest, object_t *o, vector_t *N, vector_t *eye, vector_t *point) +// Calculates the global illumination. Pretty slow +// https://www.scratchapixel.com/lessons/3d-basic-rendering/global-illumination-path-tracing/global-illumination-path-tracing-practical-implementation +static void env_light(space_t *s, color_t *dest, object_t *o, vector_t *N, vector_t *eye, vector_t *point) { + // Create new coordinate system where N is up. To do this we need two more vectors for the other axises. + // Create the 2. by setting x or y to 0 + vector_t Nt; + if (N->x > N->y) { + vector_set(&Nt, N->z, 0, -N->x); + } else { + vector_set(&Nt, 0, -N->z, N->y); + } + // Normalice + vector_scale_inv(&Nt, &Nt, vector_len(&Nt)); + + // Create the 3. axis by taking the cross of the other + vector_t Nb; + vector_cross(&Nb, N, &Nt); + + // Prepare ray + ray_t r; + r.start = point; + + // Tmp color for accumilating colors + color_t acc; + color_set(&acc, 0, 0, 0); + + for (unsigned i = 0; i < s->env_samples; i++) { + // Do the monte carlo random distribution thing from the article + COORD_T r1 = (COORD_T) rand() / RAND_MAX; + COORD_T r2 = (COORD_T) rand() / RAND_MAX; + + COORD_T sinTheta = sqrt(1 - r1 * r1); + COORD_T phi = 2 * PI * r2; + + // Calculate the random direction vector + vector_t randdir; + vector_set(&randdir, sinTheta * cos(phi), r1, sinTheta * sin(phi)); + + // Convert to world cordinates using the calculated N vectors. + vector_set(&randdir, randdir.x * Nb.x + randdir.y * N->x + randdir.z * Nt.x, + randdir.x * Nb.y + randdir.y * N->y + randdir.z * Nt.y, + randdir.x * Nb.z + randdir.y * N->z + randdir.z * Nt.z); + + // Check the direction for obstacles + r.direction = &randdir; + object_t *obs = ray_cast(s, &r, NULL, true, 0); + if (obs) { + // If we hit something don't add the light + continue; + } + + // Add the light together after scaling it + color_t tmp; + color_scale(&tmp, &s->env_color, r1); + + acc.r += tmp.r; acc.g += tmp.g; acc.b += tmp.b; + } + + // Devide by number of samples and pdf + color_scale(&acc, &acc, ((COORD_T) 1/ s->env_samples) * (2 * PI)); + + // Add to dest + color_add(dest, dest, &acc); } @@ -219,7 +281,12 @@ int ray_trace_recur(space_t *s, color_t *dest, ray_t *ray, unsigned hop, COORD_T // Check if we should calculate light if (o->m->defuse + o->m->specular > ZERO_APROX) { // Add all light hitting o at r.start to c - ray_calc_light(s, &c, o, &N, ray->start, r.start); + direct_light(s, &c, o, &N, ray->start, r.start); + } + + // Calculate environmental light + if (s->env_samples) { + env_light(s, &c, o, &N, ray->start, r.start); } // Calculate reflection vector |