lg_camera.h

/*
 *      LibGame - Copyright (C) Emmanuel Thomas-Maurin 2011-2026
 *      All rights reserved
 */
 
#ifndef LG_CAMERA_H
#define LG_CAMERA_H
 
/* Global default camera values */
 
#define LG_CAMERA_ORIGIN        0.0, 0.0, 0.0           /* Initial camera or "eye" position */
#define LG_CAMERA_TARGET        0.0, 0.0, -1.0
#define LG_CAMERA_UP            0.0, 1.0, 0.0
 
#define LG_V_FOV                45
#define LG_Z_NEAR               0.1                     /* Usually in range [0.1, 1.0] */
#define LG_Z_FAR                1000.0                  /* Usually >= 100.0 */
 
/*
 * Forward vec3 = normalized(target - position)
 */
typedef struct {
        vec3_t          position;       /* Or "eye" position in world coords */
        LG_Quat         orientation;    /* Must update target after setting/changing orientation */
        vec3_t          target;         /* Target position in world coords - SHOULD ALWAYS ONLY BE UPDATED FROM ORIENTATION QUAT - exception for lg_camera_look_at() */
        vec3_t          up;             /* Must be normalized */
        float           v_fov;          /* Vertical field of view in deg */
        float           z_near;         /* Clipping plane along the Z axis, always > 0 */
        float           z_far;          /* Clipping plane along the Z axis, always > 0 */
        mat4_t          view_m;         /* View/proj matrices - must be updated when position or orientation changes */
        mat4_t          proj_m;
        mat4_t          view_proj_m;
        zboolean        new_view;       /* Dirty flag */
        zboolean        new_proj;
        LG_InputState   input_state;    /* To capture user input */
} LG_Camera;
 
/*
 * Need to redefine this more precisely:
 * a * x + b * y + c * z + d = 0
 * v3(a, b, c) = normal
 * d = distance to origin
 */
typedef struct {
        float   a, b, c, d;
} LG_Plane;
 
typedef struct {
        LG_Plane        left;
        LG_Plane        right;
        LG_Plane        bottom;
        LG_Plane        top;
        LG_Plane        near;
        LG_Plane        far;
} LG_Frustum;
 
LG_Camera       lg_camera();
 
int             lg_camera_init(LG_Camera *);
 
int             lg_camera_set_all(LG_Camera *, vec3_t, vec3_t, vec3_t, float, float, float);
 
int             lg_camera_reset(LG_Camera *);
 
mat4_t          lg_camera_compute_view_matrix_RH(LG_Camera *);
 
mat4_t          lg_camera_compute_proj_matrix_RH(LG_Camera *);
 
mat4_t          lg_camera_compute_view_proj_matrix_RH(LG_Camera *);
 
void            lg_update_all_cam_m(LG_Camera *);
 
mat4_t          lg_camera_compute_ortho_matrix_RH(LG_Camera *);
 
mat4_t          lg_camera_compute_view_ortho_matrix_RH(LG_Camera *);
 
int             lg_camera_move_to(LG_Camera *, vec3_t);
 
int             lg_camera_look_at(LG_Camera *, vec3_t);
 
int             lg_camera_look_at_by_k(LG_Camera *, vec3_t, float);
 
int             lg_camera_rotate_by_eu(LG_Camera *, LG_EulerAng, const char *);
 
int             lg_camera_rotate_by_quat(LG_Camera *, LG_Quat);
 
int             lg_camera_set_rot_by_eu(LG_Camera *, LG_EulerAng, const char *);
 
int             lg_camera_set_rot_by_quat(LG_Camera *, LG_Quat);
 
void            lg_camera_orbit_around(LG_Camera *, vec3_t, float, float);
 
void            lg_camera_get_frustum(LG_Camera *, LG_Frustum *);
 
zboolean        is_in_frustum(vec3_t *, LG_Frustum *);
 
zboolean        lg_cuboid_is_in_frustum(LG_Cuboid *, LG_Frustum *, zboolean);
 
zboolean        lg_mesh_is_in_frustum(LG_Mesh *, LG_Frustum *, zboolean);
 
void            lg_camera_override_znear(LG_Camera *, float);
 
void            lg_camera_override_zfar(LG_Camera *, float);
 
void            reset_orbit_cam_yaw_and_pitch();
 
int             lg_plane_normalize(LG_Plane *);
 
float           lg_point_to_plane_distance(vec3_t *, LG_Plane *);
 
float           lg_point_to_norm_plane_distance(vec3_t *, LG_Plane *);
 
void            lg_camera_info(LG_Camera *);
 
void            lg_frustum_info(LG_Frustum *);
 
#endif /* LG_CAMERA_H */