position.h File Reference

#include "../_math.h"
#include <stddef.h>
#include <string.h>
#include "../str.h"

Go to the source code of this file.

Data Structures
struct	gm3Pos
	Represents a 3D position or vector. More...

Macros
#define	gm3pos(x, y, z)
	Creates a new gm3Pos struct with the given coordinates.
#define	gm3_pos_magnitude(p)
	Calculates the magnitude (length) of a gm3Pos vector.
#define	gm3_pos_distance(a, b)
	Calculates the Euclidean distance between two gm3Pos points.
#define	gm3_pos_from2(p, z)
	Creates a gm3Pos from a 2D gmPos and a Z-coordinate.
#define	gm3_pos_project_simple(p)
	Performs a simple perspective projection of a 3D point onto a 2D plane.
#define	gm3_pos_dot(a, b)
	Calculates the dot product of two gm3Pos vectors.
#define	gm3_pos_cross(a, b)
	Calculates the cross product of two gm3Pos vectors (a x b).
#define	gm3_pos_reset(p)
	Resets the coordinates of a gm3Pos struct to (0, 0, 0).

Functions
void	gm3_pos_mul (gm3Pos *res, const gm3Pos *trans)
	Multiplies the components of a gm3Pos vector by the corresponding components of another gm3Pos vector (component-wise multiplication).
void	gm3_pos_mul_scalar (gm3Pos *res, double s)
	Multiplies the components of a gm3Pos vector by a scalar value.
int	gmg_pos3 (gmStr *str, gm3Pos pos)
	Converts a gm3Pos struct to a string representation for debugging.

Macro Definition Documentation

gm3_pos_cross

#define gm3_pos_cross	(		a,
			b )

Value:

  ((gm3Pos){(a).y * (b).z - (a).z * (b).y, (a).z * (b).x - (a).x * (b).z,      \
            (a).x * (b).y - (a).y * (b).x})

Calculates the cross product of two gm3Pos vectors (a x b).

Parameters

a	The first gm3Pos vector.
b	The second gm3Pos vector.

Returns

A new gm3Pos vector representing the cross product.

gm3_pos_distance

#define gm3_pos_distance	(		a,
			b )

Value:

  sqrt(pow((a).x - (b).x, 2) + pow((a).y - (b).y, 2) + pow((a).z - (b).z, 2))

Calculates the Euclidean distance between two gm3Pos points.

Parameters

a	The first gm3Pos point.
b	The second gm3Pos point.

Returns

The distance between the two points.

gm3_pos_dot

#define gm3_pos_dot	(		a,
			b )

Value:

((a).x * (b).x + (a).y * (b).y + (a).z * (b).z)

Calculates the dot product of two gm3Pos vectors.

Parameters

a	The first gm3Pos vector.
b	The second gm3Pos vector.

Returns

The dot product (scalar value).

gm3_pos_from2

#define gm3_pos_from2	(		p,
			z )

Value:

gm3pos((p).x, (p).y, z)

Creates a gm3Pos from a 2D gmPos and a Z-coordinate.

Parameters

p	The 2D gmPos.
z	The Z-coordinate.

Returns

A new gm3Pos instance.

gm3_pos_magnitude

#define gm3_pos_magnitude

(

p

)

Value:

sqrt((p).x *(p).x + (p).y * (p).y + (p).z * (p).z)

Calculates the magnitude (length) of a gm3Pos vector.

Parameters

p	The gm3Pos vector.

Returns

The magnitude of the vector.

gm3_pos_project_simple

#define gm3_pos_project_simple

(

p

)

Value:

gmpos((p).x / (p).z, (p).y / (p).z)

Performs a simple perspective projection of a 3D point onto a 2D plane.

This macro assumes a camera at the origin looking down the Z-axis, and projects the point onto the Z=1 plane.

Parameters

p	The gm3Pos to project.

Returns

A gmPos representing the 2D projected coordinates.

gm3_pos_reset

#define gm3_pos_reset

(

p

)

Value:

memset(p, 0, sizeof(*p))

Resets the coordinates of a gm3Pos struct to (0, 0, 0).

Parameters

p	A pointer to the gm3Pos struct to reset.

gm3pos

#define gm3pos	(		x,
			y,
			z )

Value:

((gm3Pos){x, y, z})

Creates a new gm3Pos struct with the given coordinates.

Parameters

x	The X-coordinate.
y	The Y-coordinate.
z	The Z-coordinate.

Returns

A new gm3Pos instance.

Function Documentation

gm3_pos_mul()

void gm3_pos_mul	(	gm3Pos *	res,
		const gm3Pos *	trans )

Multiplies the components of a gm3Pos vector by the corresponding components of another gm3Pos vector (component-wise multiplication).

Parameters

res	A pointer to the gm3Pos vector to modify (result stored here).
trans	The gm3Pos vector to multiply by.

gm3_pos_mul_scalar()

void gm3_pos_mul_scalar	(	gm3Pos *	res,
		double	s )

Multiplies the components of a gm3Pos vector by a scalar value.

Parameters

res	A pointer to the gm3Pos vector to modify (result stored here).
s	The scalar value to multiply by.

gmg_pos3()

int gmg_pos3	(	gmStr *	str,
		gm3Pos	pos )

Converts a gm3Pos struct to a string representation for debugging.

Parameters

str	A pointer to a gmStr buffer to append the string to.
pos	The gm3Pos struct to convert.

Returns

0 on success.