guLookAtHilite

Function

guLookAtHilite

Creates the viewing matrix (fixed point) and sets the LookAt/Hilite structures

Syntax

#include <ultra64.h>        /* gu.h */
void guLookAtHilite(
        Mtx *m,
        LookAt *l,
        Hilite *h,
        float xEye,
        float yEye,
        float zEye,
        float xAt,
        float yAt,
        float zAt,
        float xUp,
        float yUp,
        float zUp,
        float xl1,
        float yl1,
        float zl1,
        float xl2,
        float yl2,
        float zl2,
        int twidth,
        int theight);

Arguments

m

Pointer to 4x4 viewing matrix resulting from calculation

l

Pointer to LookAt structure resulting from calculation

h

Pointer to Hilite structure resulting from calculation

xEye

x-coordinate of viewpoint

yEye

y-coordinate of viewpoint

zEye

z-coordinate of viewpoint

xAt

x-coordinate of lookat point

yAt

y-coordinate of lookat point

zAt

z-coordinate of lookat point

xUp

x component of upward vector

yUp

y component of upward vector

zUp

z component of upward vector

xl1

x direction for first specular highlight

yl1

y direction for first specular highlight

zl1

z direction for first specular highlight

xl2

x direction for second specular highlight

yl2

y direction for second specular highlight

zl2

z direction for second specular highlight

twidth

Width of texture for specular highlight

theight

Height of texture for specular highlight

Returned value

None

Description

This function returns a viewing matrix to the structure indicated by m. It also sets the x,y screen coordinate directions in the LookAt structure in order to render specular highlights, and it sets the texture offsets used for the rendering of two specular highlights in the Hilite structure. For details about the fixed point format, see gSPMatrix. Floating point is handled with the guLookAtHiliteF function.

The arguments that this function shares in common with guLookAt also share the same meanings. Use gDPSetHilite1Tile or gDPSetHilite2Tile to set the texture parameters (the Hilite structure) for the rendering of specular highlights. Use the gSPLookAt function to set the texture settings (the LookAt structure) for specular highlights.

For details, see Section 11.7.4 "Specular Highlights" in the N64 Programming Manual.

Note

If you are only going to render one specular highlight, be sure to set xl2, yl2, and zl2 to 0. Also, note that both twidth and theight must be powers of 2.

Comment

The Mtx structure looks like this:

typedef long  Mtx_t[4][4];
typedef union {
     Mtx_t          m;
     long long int  force_structure_alignment;
} Mtx;

The LookAt structure looks like this:

typedef struct {
     unsigned char  col[3]; /* Diffuse light value (RGBA) */
     char           pad1;
     unsigned char  colc[3]; /* Copy of diffuse light value (RGBA) */
     char           pad2;
     signed char    dir[3]; /* Direction toward light source (normalized) */
     char           pad3;   /* IMPORTANT: dir must be smaller than 127  */
} Light_t;
typedef union {
     Light_t        l;
     long long int  force_structure_alignment[2];
} Light;
typedef struct {
     Light          l[2];
} LookAt;

The Hilite structure looks like this:

typedef struct {
     int       x1, y1, x2, y2; /* Texture offsets for specular highlights */
} Hilite_t;
typedef union {
     Hilite_t  h;
     long int  force_structure_alignment[4];
} Hilite;

See also

gDPSetHilite1Tile, gDPSetHilite2Tile, gSPLookAt, gSPMatrix, guLookAt, guLookAtF, guLookAtHiliteF, guLookAtReflect, and guLookAtReflectF

Revision history

03/01/99 Completely rewritten.