-/* gph-cmath - C graphics math library
- * Copyright (C) 2018 John Tsiombikas <nuclear@member.fsf.org>
- *
- * This program is free software. Feel free to use, modify, and/or redistribute
- * it under the terms of the MIT/X11 license. See LICENSE for details.
- * If you intend to redistribute parts of the code without the LICENSE file
- * replace this paragraph with the full contents of the LICENSE file.
- */
-#include <stdlib.h>
-
-static inline float cgm_deg_to_rad(float deg)
-{
- return M_PI * deg / 180.0f;
-}
-
-static inline float cgm_rad_to_deg(float rad)
-{
- return 180.0f * rad / M_PI;
-}
-
-static inline float cgm_smoothstep(float a, float b, float x)
-{
- if(x < a) return 0.0f;
- if(x >= b) return 1.0f;
-
- x = (x - a) / (b - a);
- return x * x * (3.0f - 2.0f * x);
-}
-
-static inline float cgm_lerp(float a, float b, float t)
-{
- return a + (b - a) * t;
-}
-
-static inline float cgm_bezier(float a, float b, float c, float d, float t)
-{
- float omt, omt3, t3, f;
- t3 = t * t * t;
- omt = 1.0f - t;
- omt3 = omt * omt * omt;
- f = 3.0f * t * omt;
-
- return (a * omt3) + (b * f * omt) + (c * f * t) + (d * t3);
-}
-
-static inline void cgm_discrand(cgm_vec3 *pt, float rad)
-{
- float theta = 2.0f * M_PI * (float)rand() / RAND_MAX;
- float r = sqrt((float)rand() / RAND_MAX) * rad;
- pt->x = cos(theta) * r;
- pt->y = sin(theta) * r;
- pt->z = 0.0f;
-}
-
-static inline void cgm_sphrand(cgm_vec3 *pt, float rad)
-{
- float u, v, theta, phi;
-
- u = (float)rand() / RAND_MAX;
- v = (float)rand() / RAND_MAX;
-
- theta = 2.0f * M_PI * u;
- phi = acos(2.0f * v - 1.0f);
-
- pt->x = cos(theta) * sin(phi) * rad;
- pt->y = sin(theta) * sin(phi) * rad;
- pt->z = cos(phi) * rad;
-}
-
-static inline void cgm_unproject(cgm_vec3 *res, const cgm_vec3 *norm_scrpos,
- const float *inv_viewproj)
-{
- cgm_vec4 pos;
-
- pos.x = 2.0f * norm_scrpos->x - 1.0f;
- pos.y = 2.0f * norm_scrpos->y - 1.0f;
- pos.z = 2.0f * norm_scrpos->z - 1.0f;
- pos.w = 1.0f;
-
- cgm_wmul_m4v4(&pos, inv_viewproj);
-
- res->x = pos.x / pos.w;
- res->y = pos.y / pos.w;
- res->z = pos.z / pos.w;
-}
-
-static inline void cgm_glu_unproject(float winx, float winy, float winz,
- const float *view, const float *proj, const int *vp,
- float *objx, float *objy, float *objz)
-{
- cgm_vec3 npos, res;
- float inv_pv[16];
-
- cgm_mcopy(inv_pv, proj);
- cgm_mmul(inv_pv, view);
-
- npos.x = (winx - vp[0]) / vp[2];
- npos.y = (winy - vp[1]) / vp[4];
- npos.z = winz;
-
- cgm_unproject(&res, &npos, inv_pv);
-
- *objx = res.x;
- *objy = res.y;
- *objz = res.z;
-}
-
-static inline void cgm_pick_ray(cgm_ray *ray, float nx, float ny,
- const float *viewmat, const float *projmat)
-{
- cgm_vec3 npos, farpt;
- float inv_pv[16];
-
- cgm_mcopy(inv_pv, projmat);
- cgm_mmul(inv_pv, viewmat);
-
- cgm_vcons(&npos, nx, ny, 0.0f);
- cgm_unproject(&ray->origin, &npos, inv_pv);
- npos.z = 1.0f;
- cgm_unproject(&farpt, &npos, inv_pv);
-
- ray->dir.x = farpt.x - ray->origin.x;
- ray->dir.y = farpt.y - ray->origin.y;
- ray->dir.z = farpt.z - ray->origin.z;
-}
-
-static inline void cgm_raypos(cgm_vec3 *p, const cgm_ray *ray, float t)
-{
- p->x = ray->origin.x + ray->dir.x * t;
- p->y = ray->origin.y + ray->dir.y * t;
- p->z = ray->origin.z + ray->dir.z * t;
-}
-
-static inline void cgm_bary(cgm_vec3 *bary, const cgm_vec3 *a,
- const cgm_vec3 *b, const cgm_vec3 *c, const cgm_vec3 *pt)
-{
- float d00, d01, d11, d20, d21, denom;
- cgm_vec3 v0 = *b, v1 = *c, v2 = *pt;
-
- cgm_vsub(&v0, a);
- cgm_vsub(&v1, a);
- cgm_vsub(&v2, a);
-
- d00 = cgm_vdot(&v0, &v0);
- d01 = cgm_vdot(&v0, &v1);
- d11 = cgm_vdot(&v1, &v1);
- d20 = cgm_vdot(&v2, &v0);
- d21 = cgm_vdot(&v2, &v1);
- denom = d00 * d11 - d01 * d01;
-
- bary->y = (d11 * d20 - d01 * d21) / denom;
- bary->z = (d00 * d21 - d01 * d20) / denom;
- bary->x = 1.0f - bary->y - bary->z;
-}