3D Libraries (2/15/2002)

2002)

Doc taken from the OZ Developement kit. See section III for Credits on this file and on the whole library

I. Introduction

The 3D Libraries include a standard set of functions for making your own 3D functions. This document is a reference for these functions.

II. Reference

The following is a reference for the available functions in lib3d.lib. Please note that you will have to include “lib3d.h” in order to use these functions in your code.

Rotate a vector

void ozrotatepointx(Vector_t *v, int rot)
void ozrotatepointy(Vector_t *v, int rot)
void ozrotatepointz(Vector_t *v, int rot)

Use these functions to rotate a vector around the origin. The variable ‘rot’ is the rotation factor in degrees (?), not radians (? × p ÷ 180).

Note: Do not rotate the original coordinates! This will distort an object after a few times of use. Use ozcopyvector() to first copy the coordinates into a temporary variable and rotate them there.

Example:

...
Vector_t v;
...
v.x = 10;
v.y = 10;
v.z = 10;
ozrotatepointx(&v, 90);
ozrotatepointy(&v, 90);
ozrotatepointz(&v, 90);
...

Copy a vector

void ozcopyvector(Vector_t *dest, Vector_t *src)

This function copies a vector’s X, Y, and Z coordinates from *src to *dest.

Example:

...
Vector_t v1;
Vector_t v2;
...
ozcopyvector(&v2, &v1);
...

Translate a vector

void oztranslatevector(Vector_t *v, Vector_t *offset)

Offset a vector by using this function. It will add the X, Y and Z coordinates from *offset to *v.

Example:

...
Vector_t v1;
Vector_t v2;
...
oztranslatevector(&v2, &v1);
...

3D to 2D vector conversion

void ozplotpointcam(Vector_t *v, Cam_t *c, Point_t *p)

This function will convert 3D vectors (X, Y, Z) into 2D Points (X, Y). This will even compensate for camera’s position and angle. If you do not wish to use a camera in your program, use ozplotpoint() instead (see next function.)

Example:

...
Vector_t v;
Point_t p;
Cam_t mycam;
...
ozplotpointcam(&v, &mycam, &p);
...

Fast 3D to 2D vector conversion

void ozplotpoint(Vector_t *v, Point_t *p)

This function converts 3D vectors to 2D points without compensating for camera’s position, thus it is much faster.

Example:

...
Vector_t v;
Point_t p;
...
ozplotpoint(&v, &p);
...

III. Credits/Acknowledgements

Vector rotation optimizations performed by Lawrence Chitty.

Wonderful Sine and Cosine enhancements done by Alexander Pruss.

Many thanks to on-line tutorials, Alexander Pruss and Benjamin Green for helping me with 3D concepts. I certainly learned a lot from this experience.