/* tex3d.h - a small 3D library for the GXT120P (MGA-1164SG): textured, lit, Z-buffered
 * triangles at any size up to 640x480x16, and frame readback through IDUMP.
 * Claude Opus 5.5, 2026-10-14. Drawing code from ../texmap/texmap.c. X must be stopped. */
#ifndef TEX3D_H
#define TEX3D_H

typedef struct { double x, y, z, r, g, b, s, t, q; } t3_vtx;   /* s, t, q already divided by w */

/* flags for t3_bind */
#define T3_PERSP   1        /* perspective correction (else affine) */
#define T3_MODUL   2        /* multiply texels by the vertex colour */
#define T3_CLAMP   4        /* clamp instead of repeat */

int  t3_open(int w, int h);                 /* take the card; 0 = ok */
void t3_close(void);
void t3_clear(unsigned int rgb565);         /* colour and Z */
int  t3_texture(const unsigned short *tex, int size);   /* upload size x size 565; returns handle */
void t3_bind(int tex, int flags);
void t3_tri(t3_vtx a, t3_vtx b, t3_vtx c);  /* integer x, y; textured, Z-tested (less) */
int  t3_finish(void);                       /* wait for the engine; 0 = ok */
void t3_read(unsigned int *dst);            /* IDUMP the frame: w*h 16-bit pixels, native order,
                                               two per word, first pixel in the high half */
extern int t3_nodraw;                       /* 1: compute everything, write no registers */
#endif