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#pragma once
#include "mat4.h"
#include "vec3.h"
/// An object in 3D space.
typedef struct Spatial3 {
vec3 p; // Position.
vec3 r; // Right vector.
vec3 u; // Up vector.
vec3 f; // Forward vector.
} Spatial3;
/// Construct a spatial with position 0 and canonical direction vectors.
static inline Spatial3 spatial3_make() {
return (Spatial3){.p = zero3(), .r = right3(), .u = up3(), .f = forward3()};
}
/// Return the spatial's transformation matrix (from local to world
/// coordinates).
static inline mat4 spatial3_transform(const Spatial3* spatial) {
const vec3 p = spatial->p;
const vec3 r = spatial->r;
const vec3 u = spatial->u;
const vec3 f = spatial->f;
return mat4_make(r.x, u.x, -f.x, p.x, r.y, u.y, -f.y, p.y, r.z, u.z, -f.z,
p.z, 0.0, 0.0, 0.0, 1.0f);
}
/// Return the spatial's inverse transformation matrix (from world to local
/// coordinates).
static inline mat4 spatial3_inverse_transform(const Spatial3* spatial) {
return mat4_inverse_transform(spatial3_transform(spatial));
}
/// Move the spatial by the given vector.
static inline void spatial3_move(Spatial3* spatial, vec3 v) {
spatial->p = vec3_add(spatial->p, v);
}
/// Move the spatial along its forward vector.
static inline void spatial3_move_forwards(Spatial3* spatial, R speed) {
spatial->p = vec3_add(spatial->p, vec3_scale(spatial->f, speed));
}
/// Move the spatial along its backwards vector.
static inline void spatial3_move_backwards(Spatial3* spatial, R speed) {
spatial->p = vec3_add(spatial->p, vec3_scale(spatial->f, -speed));
}
/// Move the spatial along its left vector.
static inline void spatial3_move_left(Spatial3* spatial, R speed) {
spatial->p = vec3_add(spatial->p, vec3_scale(spatial->r, -speed));
}
/// Move the spatial along its right vector.
static inline void spatial3_move_right(Spatial3* spatial, R speed) {
spatial->p = vec3_add(spatial->p, vec3_scale(spatial->r, speed));
}
/// Move the spatial along the global up vector.
static inline void spatial3_move_up(Spatial3* spatial, R speed) {
spatial->p = vec3_add(spatial->p, vec3_scale(up3(), speed));
}
/// Move the spatial along the global down vector.
static inline void spatial3_move_down(Spatial3* spatial, R speed) {
spatial->p = vec3_add(spatial->p, vec3_scale(up3(), -speed));
}
/// Rotate the spatial about the given axis by the given angle.
static inline void spatial3_rotate(Spatial3* spatial, vec3 axis, R angle) {
mat4 transf = spatial3_transform(spatial);
const vec3 local_axis =
vec3_normalize(mat4_mul_vec3(mat4_inverse_transform(transf), axis, 0.0));
transf = mat4_mul(transf, mat4_rot(local_axis, angle));
spatial->r = vec3_normalize(mat4_v0(transf));
spatial->u = vec3_normalize(mat4_v1(transf));
spatial->f = vec3_normalize(vec3_neg(mat4_v2(transf)));
}
/// Rotate the spatial about its local y axis.
static inline void spatial3_yaw(Spatial3* spatial, const R angle) {
const R sa = sin(angle);
const R ca = cos(angle);
spatial->f = vec3_normalize(
vec3_sub(vec3_scale(spatial->f, ca), vec3_scale(spatial->r, sa)));
spatial->r = vec3_normalize(vec3_cross(spatial->f, spatial->u));
}
/// Rotate the spatial about its local x axis.
static inline void spatial3_pitch(Spatial3* spatial, const R angle) {
const R sa = sin(angle);
const R ca = cos(angle);
spatial->f = vec3_normalize(
vec3_add(vec3_scale(spatial->f, ca), vec3_scale(spatial->u, sa)));
spatial->u = vec3_normalize(vec3_cross(spatial->r, spatial->f));
}
/// Rotate the spatial about its local z axis.
static inline void spatial3_roll(Spatial3* spatial, const R angle) {
const R sa = sin(angle);
const R ca = cos(angle);
spatial->u = vec3_normalize(
vec3_sub(vec3_scale(spatial->u, ca), vec3_scale(spatial->r, sa)));
spatial->r = vec3_normalize(vec3_cross(spatial->f, spatial->u));
}
/// Set the spatial's transformation matrix.
static inline void spatial3_set_transform(Spatial3* spatial, mat4 transform) {
spatial->r = mat4_v0(transform);
spatial->u = mat4_v1(transform);
spatial->f = mat4_v2(transform);
spatial->p = mat4_v3(transform);
}
static inline void spatial3_set_forward(Spatial3* spatial, vec3 forward) {
spatial->f = vec3_normalize(forward);
// Use aux vector to define right vector orthogonal to forward.
if (vec3_eq(vec3_abs(spatial->f), up3())) {
spatial->r = vec3_normalize(vec3_cross(spatial->f, forward3()));
} else {
spatial->r = vec3_normalize(vec3_cross(spatial->f, up3()));
}
spatial->u = vec3_normalize(vec3_cross(spatial->r, spatial->f));
}
/// Make the spatial look at the given target.
static inline void spatial3_lookat(Spatial3* spatial, vec3 target) {
spatial3_set_forward(spatial, vec3_sub(target, spatial->p));
}
/// Make the spatial look at the given target.
static inline void spatial3_lookat_spatial(Spatial3* spatial,
const Spatial3* target) {
spatial3_set_forward(spatial, vec3_sub(target->p, spatial->p));
}
/// Make the spatial orbit around the given target.
/// \param target Target position.
/// \param radius Radial distance.
/// \param azimuth Azimuthal (horizontal) angle.
/// \param zenith Polar (vertical) angle.
static inline void spatial3_orbit(Spatial3* spatial, vec3 target, R radius,
R azimuth, R zenith) {
const R sx = sin(azimuth);
const R sy = sin(zenith);
const R cx = cos(azimuth);
const R cy = cos(zenith);
spatial->p = (vec3){target.x + radius * cy * sx, target.y + radius * sy,
target.z + radius * cx * cy};
}
/// Make the spatial orbit around the given target.
/// \param target Target spatial.
/// \param radius Radial distance.
/// \param azimuth Azimuthal (horizontal) angle.
/// \param zenith Polar (vertical) angle.
static inline void spatial3_orbit_spatial(Spatial3* spatial,
const Spatial3* target, R radius,
R azimuth, R zenith) {
spatial3_orbit(spatial, target->p, radius, azimuth, zenith);
}
// The functions below are provided so that client code can work with a Spatial3
// with no assumptions on the data type's definition.
/// Return the spatial's position.
static inline vec3 spatial3_position(const Spatial3* spatial) {
return spatial->p;
}
/// Return the spatial's right vector.
static inline vec3 spatial3_right(const Spatial3* spatial) {
return spatial->r;
}
/// Return the spatial's up vector.
static inline vec3 spatial3_up(const Spatial3* spatial) { return spatial->u; }
/// Return the spatial's forward vector.
static inline vec3 spatial3_forward(const Spatial3* spatial) {
return spatial->f;
}
static inline void spatial3_set_position(Spatial3* spatial, vec3 p) {
spatial->p = p;
}
static inline void spatial3_setx(Spatial3* spatial, R x) { spatial->p.x = x; }
static inline void spatial3_sety(Spatial3* spatial, R y) { spatial->p.y = y; }
static inline void spatial3_setz(Spatial3* spatial, R z) { spatial->p.z = z; }
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