lg_math_extra.c File Reference

Functions
zboolean	lg_raycast_bsphere (LG_Camera *cam, LG_BSphere bsphere, float *inters_dist, int *click_type, zboolean flush_clicks)
vec4_t	vec4 (float x, float y, float z, float w)
vec4_t	m4_mul_v4 (mat4_t m, vec4_t v)
float	m4_det (mat4_t mat)
mat4_t	m4_invert (mat4_t mat)

Detailed Description

=== Ray casting ===

Also implement extra mat4 funcs: vec4 x mat4, determinant, and inverse

Sources:

https://github.com/capnramses/antons_opengl_tutorials_book/tree/master https://github.com/capnramses/antons_opengl_tutorials_book/blob/master/07_ray_picking/main.cpp https://github.com/capnramses/antons_opengl_tutorials_book/blob/master/07_ray_picking/maths_funcs.cpp

Function Documentation

lg_raycast_bsphere()

zboolean lg_raycast_bsphere	(	LG_Camera *	cam,
		LG_BSphere	bsphere,
		float *	inters_dist,
		int *	click_type,
		zboolean	flush_clicks
	)

Ray casting

Check intersection of ray (emitted from mouse pointer location on left/right-click) with sphere

Parameters

cam
bsphere
inters_dist	Intersection distance, set if intersection occurs
click_type	Set to RAYCAST_LEFT_CLICK, RAYCAST_RIGHT_CLICK, or RAYCAST_NO_CLICK
flush_clicks	If TRUE, call lg_flush_in_clicks() after intersection occurs and before returning

Returns

TRUE if intersection occurs, FALSE otherwise

vec4()

vec4_t vec4	(	float	x,
		float	y,
		float	z,
		float	w
	)

Create a vec4_t

Parameters

x
y
z
w

Returns

A new vec4_t

m4_mul_v4()

vec4_t m4_mul_v4	(	mat4_t	m,
		vec4_t	v
	)

Multiply 4x4 matrix by vec4 ("apply" mat4 to vec4)

Parameters

m	4x4 matrix
v	Vec4

Returns

Result as a vec4_t

m4_det()

float m4_det

(

mat4_t

mat

)

Get determinant of a 4x4 matrix

Source: http://www.euclideanspace.com/maths/algebra/matrix/functions/determinant/fourD/index.htm

Parameters

m

Matrix

Returns

Determinant of matrix

m4_invert()

mat4_t m4_invert

(

mat4_t

mat

)

Invert a 4x4 matrix if invertible, ie if its determinant is != 0

Source: http://www.euclideanspace.com/maths/algebra/matrix/functions/inverse/fourD/index.htm

Parameters

m

Matrix

Returns

Inverted matrix if OK, unchanged matrix if not invertible