camera.h

   1 #pragma once
   2 #if 0
   3
   4 typedef struct camera camera;
   5 struct camera{
   6    /* Input */
   7    v3f angles;
   8    v3f pos;
   9    float fov, nearz, farz;
  10
  11    /* Output */
  12    m4x3f transform,
  13          transform_inverse;
  14
  15    struct camera_mtx{
  16       m4x4f p,
  17             v,
  18             pv;
  19    }
  20    mtx,
  21    mtx_prev;
  22 };
  23
  24 static void camera_lerp_angles( v3f a, v3f b, float t, v3f d ){
  25    d[0] = vg_alerpf( a[0], b[0], t );
  26    d[1] = vg_lerpf(  a[1], b[1], t );
  27    d[2] = vg_lerpf(  a[2], b[2], t );
  28 }
  29
  30 /* lerp position, fov, and angles */
  31 static void camera_lerp( camera *a, camera *b, float t, camera *d ){
  32    v3_lerp( a->pos, b->pos, t, d->pos );
  33    camera_lerp_angles( a->angles, b->angles, t, d->angles );
  34    d->fov = vg_lerpf( a->fov, b->fov, t );
  35 }
  36
  37 static void camera_copy( camera *a, camera *d ){
  38    v3_copy( a->pos, d->pos );
  39    v3_copy( a->angles, d->angles );
  40    d->fov = a->fov;
  41 }
  42
  43 static void m4x3_transform_camera( m4x3f m, camera *cam ){
  44    m4x3_mulv( m, cam->pos, cam->pos );
  45
  46    v3f v0;
  47    v3_angles_vector( cam->angles, v0 );
  48    m3x3_mulv( m, v0, v0 );
  49    v3_normalize( v0 );
  50    v3_angles( v0, cam->angles );
  51 }
  52
  53 /*
  54  * 1) [angles, pos] -> transform
  55  */
  56 static void camera_update_transform( camera *cam )
  57 {
  58    v4f qyaw, qpitch, qcam;
  59    q_axis_angle( qyaw,   (v3f){ 0.0f, 1.0f, 0.0f }, -cam->angles[0] );
  60    q_axis_angle( qpitch, (v3f){ 1.0f, 0.0f, 0.0f }, -cam->angles[1] );
  61
  62    q_mul( qyaw, qpitch, qcam );
  63    q_m3x3( qcam, cam->transform );
  64    v3_copy( cam->pos, cam->transform[3] );
  65 }
  66
  67 /*
  68  * 2) [transform] -> transform_inverse, view matrix
  69  */
  70 static void camera_update_view( camera *cam )
  71 {
  72    m4x4_copy( cam->mtx.v,  cam->mtx_prev.v );
  73    m4x3_invert_affine( cam->transform, cam->transform_inverse );
  74    m4x3_expand( cam->transform_inverse, cam->mtx.v );
  75 }
  76
  77 /*
  78  * 3) [fov,nearz,farz] -> projection matrix
  79  */
  80 static void camera_update_projection( camera *cam )
  81 {
  82    m4x4_copy( cam->mtx.p,  cam->mtx_prev.p );
  83    m4x4_projection( cam->mtx.p, cam->fov,
  84                     (float)vg.window_x / (float)vg.window_y,
  85                     cam->nearz, cam->farz );
  86 }
  87
  88 /*
  89  * 4) [projection matrix, view matrix] -> previous pv, new pv
  90  */
  91 static void camera_finalize( camera *cam )
  92 {
  93    m4x4_copy( cam->mtx.pv, cam->mtx_prev.pv );
  94    m4x4_mul( cam->mtx.p, cam->mtx.v, cam->mtx.pv );
  95 }
  96 #endif