vg_camera.c

   1 #include "vg_camera.h"
   2 #include "vg_m.h"
   3 #include "vg_engine.h"
   4
   5 void vg_camera_lerp_angles( v3f a, v3f b, f32 t, v3f d )
   6 {
   7    d[0] = vg_alerpf( a[0], b[0], t );
   8    d[1] = vg_lerpf(  a[1], b[1], t );
   9    d[2] = vg_lerpf(  a[2], b[2], t );
  10 }
  11
  12 /* lerp position, fov, and angles */
  13 void vg_camera_lerp( vg_camera *a, vg_camera *b, f32 t, vg_camera *d )
  14 {
  15    v3_lerp( a->pos, b->pos, t, d->pos );
  16    vg_camera_lerp_angles( a->angles, b->angles, t, d->angles );
  17    d->fov = vg_lerpf( a->fov, b->fov, t );
  18 }
  19
  20 void vg_camera_copy( vg_camera *a, vg_camera *d )
  21 {
  22    v3_copy( a->pos, d->pos );
  23    v3_copy( a->angles, d->angles );
  24    d->fov = a->fov;
  25 }
  26
  27 void vg_m4x3_transform_camera( m4x3f m, vg_camera *cam )
  28 {
  29    m4x3_mulv( m, cam->pos, cam->pos );
  30
  31    v3f v0;
  32    v3_angles_vector( cam->angles, v0 );
  33    m3x3_mulv( m, v0, v0 );
  34    v3_normalize( v0 );
  35    v3_angles( v0, cam->angles );
  36 }
  37
  38 /*
  39  * 1) [angles, pos] -> transform
  40  */
  41 void vg_camera_update_transform( vg_camera *cam )
  42 {
  43    v4f qyaw, qpitch, qcam;
  44    q_axis_angle( qyaw,   (v3f){ 0.0f, 1.0f, 0.0f }, -cam->angles[0] );
  45    q_axis_angle( qpitch, (v3f){ 1.0f, 0.0f, 0.0f }, -cam->angles[1] );
  46
  47    q_mul( qyaw, qpitch, qcam );
  48    q_m3x3( qcam, cam->transform );
  49    v3_copy( cam->pos, cam->transform[3] );
  50 }
  51
  52 /*
  53  * 2) [transform] -> transform_inverse, view matrix
  54  */
  55 void vg_camera_update_view( vg_camera *cam )
  56 {
  57    m4x4_copy( cam->mtx.v,  cam->mtx_prev.v );
  58    m4x3_invert_affine( cam->transform, cam->transform_inverse );
  59    m4x3_expand( cam->transform_inverse, cam->mtx.v );
  60 }
  61
  62 /*
  63  * 3) [fov,nearz,farz] -> projection matrix
  64  */
  65 void vg_camera_update_projection( vg_camera *cam )
  66 {
  67    m4x4_copy( cam->mtx.p,  cam->mtx_prev.p );
  68    m4x4_projection( cam->mtx.p, cam->fov,
  69                     (float)vg.window_x / (float)vg.window_y,
  70                     cam->nearz, cam->farz );
  71 }
  72
  73 /*
  74  * 4) [projection matrix, view matrix] -> previous pv, new pv
  75  */
  76 void vg_camera_finalize( vg_camera *cam )
  77 {
  78    m4x4_copy( cam->mtx.pv, cam->mtx_prev.pv );
  79    m4x4_mul( cam->mtx.p, cam->mtx.v, cam->mtx.pv );
  80 }