math/bounds.h

#include <modkit/math/bounds.h>25 functions · 5 structs · 1 enums · 6 typedefs

Bounding volumes + intersection / picking.

AABB, sphere, ray, plane and frustum types with the intersection tests games actually need: ray casts (mouse picking), overlap tests (broad-phase), and frustum culling. Pairs with the existing mk_screen_to_ray / mk_project_* helpers in math/project.h. Most functions are header-only. Frustum extraction and mk_ray_from_screen live in math.c because they depend on the backend clip-space convention ([-1,1] OpenGL vs [0,1] D3D/Vulkan/Metal). Naming note: the bare names mk_sphere / mk_plane are already the draw3d quick shapes (mk_draw3d's mk_sphere(), mk_plane()), so the bounding-volume types are mk_bsphere and mk_bplane. AABB, ray and frustum keep their standard names. Plane convention: dot(normal, p) + d >= 0 means "in front" (inside, for frustum planes whose normals point inward).

Functions

`mk__mat4_point`function

mk_vec3 mk__mat4_point(const mk_mat4 *m, mk_vec3 p)

Transform a point by a column-major mk_mat4 (w=1, no perspective divide).

Parameter	Type	Description
`m`	`const mk_mat4 *`	Value for m.
`p`	`mk_vec3`	Value for p.

Returns The resulting value.

`mk__plane_dist`function

float mk__plane_dist(const mk_bplane *pl, mk_vec3 p)

Perform the plane dist operation.

Parameter	Type	Description
`pl`	`const mk_bplane *`	Value for pl.
`p`	`mk_vec3`	Value for p.

Returns The resulting value.

`mk__vmax`function

float mk__vmax(float a, float b)

Perform the vmax operation.

Parameter	Type	Description
`a`	`float`	Value for a.
`b`	`float`	Value for b.

Returns The resulting value.

`mk__vmin`function

float mk__vmin(float a, float b)

Perform the vmin operation.

Parameter	Type	Description
`a`	`float`	Value for a.
`b`	`float`	Value for b.

Returns The resulting value.

`mk_aabb_center`function

mk_vec3 mk_aabb_center(mk_aabb b)

Perform the aabb center operation.

Parameter	Type	Description
`b`	`mk_aabb`	Value for b.

Returns The resulting value.

`mk_aabb_contains_point`function

bool mk_aabb_contains_point(mk_aabb b, mk_vec3 p)

Perform the aabb contains point operation.

Parameter	Type	Description
`b`	`mk_aabb`	Value for b.
`p`	`mk_vec3`	Value for p.

Returns True when the operation succeeds.

`mk_aabb_extents`function

mk_vec3 mk_aabb_extents(mk_aabb b)

Perform the aabb extents operation.

Parameter	Type	Description
`b`	`mk_aabb`	Value for b.

Returns The resulting value.

`mk_aabb_from_center_extents`function

mk_aabb mk_aabb_from_center_extents(mk_vec3 center, mk_vec3 half)

Perform the aabb from center extents operation.

Parameter	Type	Description
`center`	`mk_vec3`	Value for center.
`half`	`mk_vec3`	Value for half.

Returns The resulting value.

`mk_aabb_from_points`function

mk_aabb mk_aabb_from_points(const mk_vec3 *pts, int count)

Perform the aabb from points operation.

Parameter	Type	Description
`pts`	`const mk_vec3 *`	Value for pts.
`count`	`int`	Number of entries.

Returns The resulting value.

`mk_aabb_make`function

mk_aabb mk_aabb_make(mk_vec3 min, mk_vec3 max)

Perform the aabb make operation.

Parameter	Type	Description
`min`	`mk_vec3`	Value for min.
`max`	`mk_vec3`	Value for max.

Returns The resulting value.

`mk_aabb_merge`function

mk_aabb mk_aabb_merge(mk_aabb a, mk_aabb b)

Perform the aabb merge operation.

Parameter	Type	Description
`a`	`mk_aabb`	Value for a.
`b`	`mk_aabb`	Value for b.

Returns The resulting value.

`mk_aabb_overlaps_aabb`function

bool mk_aabb_overlaps_aabb(mk_aabb a, mk_aabb b)

Perform the aabb overlaps aabb operation.

Parameter	Type	Description
`a`	`mk_aabb`	Value for a.
`b`	`mk_aabb`	Value for b.

Returns True when the operation succeeds.

`mk_aabb_overlaps_sphere`function

bool mk_aabb_overlaps_sphere(mk_aabb b, mk_bsphere s)

Perform the aabb overlaps sphere operation.

Parameter	Type	Description
`b`	`mk_aabb`	Value for b.
`s`	`mk_bsphere`	Value for s.

Returns True when the operation succeeds.

`mk_aabb_transform`function

mk_aabb mk_aabb_transform(mk_aabb b, const mk_mat4 *m)

Transform an AABB by a matrix and re-fit an axis-aligned box around it.

Parameter	Type	Description
`b`	`mk_aabb`	Value for b.
`m`	`const mk_mat4 *`	Value for m.

Returns The resulting value.

`mk_frustum_contains_point`function

bool mk_frustum_contains_point(const mk_frustum *f, mk_vec3 p)

Perform the frustum contains point operation.

Parameter	Type	Description
`f`	`const mk_frustum *`	Value for f.
`p`	`mk_vec3`	Value for p.

Returns True when the operation succeeds.

`mk_frustum_from_vp`function

mk_frustum mk_frustum_from_vp(const mk_mat4 *view_proj)

Extract the six frustum planes from a view-projection matrix (Gribb-Hartmann).

Normals point inward and are normalized; backend clip range handled internally.

Parameter	Type	Description
`view_proj`	`const mk_mat4 *`	Value for view proj.

Returns The resulting value.

`mk_frustum_test_aabb`function

mk_containment mk_frustum_test_aabb(const mk_frustum *f, mk_aabb b)

Perform the frustum test aabb operation.

Parameter	Type	Description
`f`	`const mk_frustum *`	Value for f.
`b`	`mk_aabb`	Value for b.

Returns The resulting value.

`mk_frustum_test_sphere`function

mk_containment mk_frustum_test_sphere(const mk_frustum *f, mk_bsphere s)

Perform the frustum test sphere operation.

Parameter	Type	Description
`f`	`const mk_frustum *`	Value for f.
`s`	`mk_bsphere`	Value for s.

Returns The resulting value.

`mk_ray_from_screen`function

mk_ray mk_ray_from_screen(float screen_x, float screen_y, const mk_camera *camera, const mk_vec4 *viewport)

Build a world-space picking ray from screen coordinates.

Parameter	Type	Description
`screen_x`	`float`	Value for screen x.
`screen_y`	`float`	Value for screen y.
`camera`	`const mk_camera *`	Value for camera.
`viewport`	`const mk_vec4 *`	Value for viewport.

Returns The resulting value.

`mk_ray_hit_aabb`function

bool mk_ray_hit_aabb(mk_ray r, mk_aabb b, float *out_t)

Ray vs AABB (slab method).

Parameter	Type	Description
`r`	`mk_ray`	Value for r.
`b`	`mk_aabb`	Value for b.
`out_t`	`float *`	Receives the t.

Returns True when the operation succeeds.

`mk_ray_hit_plane`function

bool mk_ray_hit_plane(mk_ray r, mk_bplane p, float *out_t)

Ray vs plane.

Parameter	Type	Description
`r`	`mk_ray`	Value for r.
`p`	`mk_bplane`	Value for p.
`out_t`	`float *`	Receives the t.

Returns True when the operation succeeds.

`mk_ray_hit_sphere`function

bool mk_ray_hit_sphere(mk_ray r, mk_bsphere s, float *out_t)

Ray vs sphere.

Parameter	Type	Description
`r`	`mk_ray`	Value for r.
`s`	`mk_bsphere`	Value for s.
`out_t`	`float *`	Receives the t.

Returns True when the operation succeeds.

`mk_ray_hit_triangle`function

bool mk_ray_hit_triangle(mk_ray r, mk_vec3 a, mk_vec3 b, mk_vec3 c, float *out_t)

Ray vs triangle (Moller-Trumbore), two-sided.

Parameter	Type	Description
`r`	`mk_ray`	Value for r.
`a`	`mk_vec3`	Value for a.
`b`	`mk_vec3`	Value for b.
`c`	`mk_vec3`	Value for c.
`out_t`	`float *`	Receives the t.

Returns True when the operation succeeds.

`mk_sphere_from_aabb`function

mk_bsphere mk_sphere_from_aabb(mk_aabb b)

Perform the sphere from aabb operation.

Parameter	Type	Description
`b`	`mk_aabb`	Value for b.

Returns The resulting value.

`mk_sphere_overlaps_sphere`function

bool mk_sphere_overlaps_sphere(mk_bsphere a, mk_bsphere b)

Perform the sphere overlaps sphere operation.

Parameter	Type	Description
`a`	`mk_bsphere`	Value for a.
`b`	`mk_bsphere`	Value for b.

Returns True when the operation succeeds.

Structs

`mk_aabb`struct

Data for aabb.

Field	Type	Description
`min`	`mk_vec3`	Minimum corner.
`max`	`mk_vec3`	Maximum corner.

`mk_bplane`struct

Data for bplane.

Field	Type	Description
`normal`	`mk_vec3`	Plane normal.
`d`	`float`	Signed offset in dot(normal, point) + d.

`mk_bsphere`struct

Data for bsphere.

Field	Type	Description
`center`	`mk_vec3`	The center.
`radius`	`float`	The radius.

`mk_frustum`struct

Data for frustum.

Field	Type	Description
`planes`	`mk_bplane`	Left, right, bottom, top, near, and far inward planes.

`mk_ray`struct

Data for ray.

Field	Type	Description
`origin`	`mk_vec3`	Ray origin.
`dir`	`mk_vec3`	Normalized ray direction.

Enums

`mk_containment`enum

Values for containment.

Value	Description
`MK_OUTSIDE`	Selects outside.
`MK_INTERSECT`	Selects intersect.
`MK_INSIDE`	Selects inside.

Typedefs

`mk_aabb`typedef

typedef struct mk_aabb mk_aabb

Data for aabb.

`mk_bplane`typedef

typedef struct mk_bplane mk_bplane

Data for bplane.

`mk_bsphere`typedef

typedef struct mk_bsphere mk_bsphere

Data for bsphere.

`mk_containment`typedef

typedef enum mk_containment mk_containment

Values for containment.

`mk_frustum`typedef

typedef struct mk_frustum mk_frustum

Data for frustum.

`mk_ray`typedef

typedef struct mk_ray mk_ray

Data for ray.

math/bounds.h

Functions

mk__mat4_pointfunction

mk__plane_distfunction

mk__vmaxfunction

mk__vminfunction

mk_aabb_centerfunction

mk_aabb_contains_pointfunction

mk_aabb_extentsfunction

mk_aabb_from_center_extentsfunction

mk_aabb_from_pointsfunction

mk_aabb_makefunction

mk_aabb_mergefunction

mk_aabb_overlaps_aabbfunction

mk_aabb_overlaps_spherefunction

mk_aabb_transformfunction

mk_frustum_contains_pointfunction

mk_frustum_from_vpfunction

mk_frustum_test_aabbfunction

mk_frustum_test_spherefunction

mk_ray_from_screenfunction

mk_ray_hit_aabbfunction

mk_ray_hit_planefunction

mk_ray_hit_spherefunction

mk_ray_hit_trianglefunction

mk_sphere_from_aabbfunction

mk_sphere_overlaps_spherefunction

Structs

mk_aabbstruct

mk_bplanestruct

mk_bspherestruct

mk_frustumstruct

mk_raystruct

Enums

mk_containmentenum

Typedefs

mk_aabbtypedef

mk_bplanetypedef

mk_bspheretypedef

mk_containmenttypedef

mk_frustumtypedef

mk_raytypedef

`mk__mat4_point`function

`mk__plane_dist`function

`mk__vmax`function

`mk__vmin`function

`mk_aabb_center`function

`mk_aabb_contains_point`function

`mk_aabb_extents`function

`mk_aabb_from_center_extents`function

`mk_aabb_from_points`function

`mk_aabb_make`function

`mk_aabb_merge`function

`mk_aabb_overlaps_aabb`function

`mk_aabb_overlaps_sphere`function

`mk_aabb_transform`function

`mk_frustum_contains_point`function

`mk_frustum_from_vp`function

`mk_frustum_test_aabb`function

`mk_frustum_test_sphere`function

`mk_ray_from_screen`function

`mk_ray_hit_aabb`function

`mk_ray_hit_plane`function

`mk_ray_hit_sphere`function

`mk_ray_hit_triangle`function

`mk_sphere_from_aabb`function

`mk_sphere_overlaps_sphere`function

`mk_aabb`struct

`mk_bplane`struct

`mk_bsphere`struct

`mk_frustum`struct

`mk_ray`struct

`mk_containment`enum

`mk_aabb`typedef

`mk_bplane`typedef

`mk_bsphere`typedef

`mk_containment`typedef

`mk_frustum`typedef

`mk_ray`typedef