X-Git-Url: https://harrygodden.com/git/?p=vg.git;a=blobdiff_plain;f=vg_camera.h;fp=vg_camera.h;h=9fd660bbd0ac1c133191b3f8685fa1c3b35e62ab;hp=0000000000000000000000000000000000000000;hb=1c305409e8eca9cf8449d681df73208956ce14df;hpb=1abb54856257b10f6a20a4980a31930c59e3d37c

diff --git a/vg_camera.h b/vg_camera.h
new file mode 100644
index 0000000..9fd660b
--- /dev/null
+++ b/vg_camera.h
@@ -0,0 +1,91 @@
+#pragma once
+#include "vg_m.h"
+
+typedef struct vg_camera vg_camera;
+struct vg_camera{
+   /* Input */
+   v3f angles;
+   v3f pos;
+   f32 fov, nearz, farz;
+
+   /* Output */
+   m4x3f transform,
+         transform_inverse;
+
+   struct vg_camera_mtx{
+      m4x4f p,
+            v,
+            pv;
+   }
+   mtx,
+   mtx_prev;
+};
+
+static void vg_camera_lerp_angles( v3f a, v3f b, f32 t, v3f d ){
+   d[0] = vg_alerpf( a[0], b[0], t );
+   d[1] = vg_lerpf(  a[1], b[1], t );
+   d[2] = vg_lerpf(  a[2], b[2], t );
+}
+
+/* lerp position, fov, and angles */
+static void vg_camera_lerp( vg_camera *a, vg_camera *b, f32 t, vg_camera *d ){
+   v3_lerp( a->pos, b->pos, t, d->pos );
+   vg_camera_lerp_angles( a->angles, b->angles, t, d->angles );
+   d->fov = vg_lerpf( a->fov, b->fov, t );
+}
+
+static void vg_camera_copy( vg_camera *a, vg_camera *d ){
+   v3_copy( a->pos, d->pos );
+   v3_copy( a->angles, d->angles );
+   d->fov = a->fov;
+}
+
+static void vg_m4x3_transform_camera( m4x3f m, vg_camera *cam ){
+   m4x3_mulv( m, cam->pos, cam->pos );
+
+   v3f v0;
+   v3_angles_vector( cam->angles, v0 );
+   m3x3_mulv( m, v0, v0 );
+   v3_normalize( v0 );
+   v3_angles( v0, cam->angles );
+}
+
+/*
+ * 1) [angles, pos] -> transform 
+ */
+static void vg_camera_update_transform( vg_camera *cam ){
+   v4f qyaw, qpitch, qcam;
+   q_axis_angle( qyaw,   (v3f){ 0.0f, 1.0f, 0.0f }, -cam->angles[0] );
+   q_axis_angle( qpitch, (v3f){ 1.0f, 0.0f, 0.0f }, -cam->angles[1] );
+
+   q_mul( qyaw, qpitch, qcam );
+   q_m3x3( qcam, cam->transform );
+   v3_copy( cam->pos, cam->transform[3] );
+}
+
+/*
+ * 2) [transform] -> transform_inverse, view matrix
+ */
+static void vg_camera_update_view( vg_camera *cam ){
+   m4x4_copy( cam->mtx.v,  cam->mtx_prev.v );
+   m4x3_invert_affine( cam->transform, cam->transform_inverse );
+   m4x3_expand( cam->transform_inverse, cam->mtx.v );
+}
+
+/*
+ * 3) [fov,nearz,farz] -> projection matrix
+ */
+static void vg_camera_update_projection( vg_camera *cam ){
+   m4x4_copy( cam->mtx.p,  cam->mtx_prev.p );
+   m4x4_projection( cam->mtx.p, cam->fov,
+                    (float)vg.window_x / (float)vg.window_y, 
+                    cam->nearz, cam->farz );
+}
+
+/*
+ * 4) [projection matrix, view matrix] -> previous pv, new pv 
+ */
+static void vg_camera_finalize( vg_camera *cam ){
+   m4x4_copy( cam->mtx.pv, cam->mtx_prev.pv );
+   m4x4_mul( cam->mtx.p, cam->mtx.v, cam->mtx.pv );
+}