textures.c

#include <stdlib.h>
#include <stdio.h>
#ifdef WIN32
# include <windows.h>
# include <wingdi.h>
# define glBindTextureEXT  glBindTexture
# define glGenTexturesEXT  glGenTextures
#endif /*WIN32*/
#include <GL/gl.h>
#include <GL/glu.h>
#include <string.h>
#include "textures.h"
#include "shmem.h"
#include "findfile.h"

#if CAVE
#include "vd_util.h"
#endif

extern int mg_inhaletexture( Texture *tx, int rgba );

int my_txcontext(void)
{
#if CAVE
    /* assume virdir */
    int id = CAT_get_display_slot();
    if(id < 0 || id >= MAXGLCTX) id = MAXGLCTX-1;
    return id;
#else /* stand-alone -- single GLX context */
    return 0;
#endif
}

int txbind( Texture *tx, int *enabled )
{
  static GLint format[5] =
	{ 0, GL_LUMINANCE, GL_LUMINANCE_ALPHA, GL_RGB, GL_RGBA };
  static GLfloat minfilts[] = {
	GL_NEAREST, GL_LINEAR,
	GL_NEAREST, GL_LINEAR,
	GL_NEAREST_MIPMAP_NEAREST, GL_NEAREST_MIPMAP_LINEAR, 
	GL_LINEAR_MIPMAP_NEAREST, GL_LINEAR_MIPMAP_LINEAR
  };
  static int ctx = -1;
  static int txenv = -1;
  static int blendmode = -1;
  int ena = -1;
  int mustload;
  int wanted, wantenv;


  if(tx == NULL || txload(tx) == 0) {
    /* reset state, invalidate cache */
    glBindTextureEXT( GL_TEXTURE_2D, 0 );
    glDisable( GL_TEXTURE_2D );
    txenv = blendmode = -1;
    if(enabled) *enabled = 0;
    return 0;
  }

  if(ctx < 0)
    ctx = my_txcontext();
  mustload = (tx->txid[ctx] == 0);


  wantenv =
	  tx->apply == TXF_DECAL ? GL_DECAL
	: tx->apply == TXF_BLEND ? GL_BLEND
				 : GL_MODULATE;

  if(txenv != wantenv) {
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, wantenv);
    txenv = wantenv;
  }

  if(!mustload && *enabled == tx->txid[ctx])
    return *enabled;		/* short-circuit! */

  if(mustload) {
    GLuint id;
    glGenTexturesEXT( 1, &id );
    tx->txid[ctx] = id;
  }


  wanted = tx->txid[ctx];

  glBindTextureEXT( GL_TEXTURE_2D, wanted );

  if(mustload) {
    if(tx->data == NULL) {
	fprintf(stderr,
	    "Hey! Why are we having to reload the data for texture \"%s\"?\n",
	    tx->filename);
	tx->loaded = 0;
	txload(tx);
	wanted = (tx->data != NULL);
    }


    if(wanted) {
	static float black[4] = {0,0,0,0};
	char *txdata = tx->data;
	int channels = tx->channels;

	if((tx->flags&TXF_INTENSITY) && (channels == 1 || channels == 3)) {
	    int npix = tx->xsize * tx->ysize;
	    int k;
	    char *ip, *op;
	    channels++;
	    txdata = (char *)malloc( npix * channels );
	    k = npix, ip = tx->data, op = txdata;
	    switch(channels) {
	    case 2:
		do {
		    op[1] = *ip++;
		    op[0] = 255;
		    op += 2;
		} while(--k > 0);
		break;
	    case 4:
		do {
		    op[3] = 77*ip[0] + 150*ip[1] + 28*ip[2];
		    op[0] = ip[0]>op[3] ? 255 : ip[0]/op[3];
		    op[1] = ip[1]>op[3] ? 255 : ip[0]/op[3];
		    op[2] = ip[2]>op[3] ? 255 : ip[2]/op[3];
		    ip += 3;
		    op += 4;
		} while(--k > 0);
		break;
	    }
	}

	gluBuild2DMipmaps( GL_TEXTURE_2D, channels,
		    tx->xsize, tx->ysize,
		    channels==1 && (tx->flags&TXF_ALPHA)
			? GL_ALPHA : format[channels],
		    GL_UNSIGNED_BYTE,
		    txdata);

	if(txdata != tx->data)
	    free(txdata);

	glTexParameterfv(GL_TEXTURE_2D, GL_TEXTURE_BORDER_COLOR,
	    black);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S,
	    (tx->flags & TXF_SCLAMP) ? GL_CLAMP : GL_REPEAT);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T,
	    (tx->flags & TXF_TCLAMP) ? GL_CLAMP : GL_REPEAT);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
	    minfilts[tx->qualflags & 0x07]);
	glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
	    (tx->qualflags&0x07) ? GL_LINEAR : GL_NEAREST);

#if !CAVE
	/* We won't need texture data again -- opengl has it now */
	Free(tx->data);
	tx->data = NULL;
#endif

    }
  }

  if(wanted != *enabled) {
    if(wanted) glEnable(GL_TEXTURE_2D);
    else glDisable(GL_TEXTURE_2D);
    *enabled = wanted = tx->txid[ctx];
  }
  return wanted;
}

Texture *txmake( char *fname, int apply, int txflags, int qualflags )
{
  Texture *tx = NewN( Texture, 1 );
  memset(tx, 0, sizeof(*tx));
  tx->tfm = Tidentity;
  tx->filename = fname;
  tx->apply = apply;
  tx->flags = txflags;
  tx->qualflags = qualflags;
  return tx; 
}

int txload( Texture *tx )
{
  if(tx == NULL || tx->loaded < 0) return 0;
  if(tx->loaded == 1) return 1; /* already loaded */
  if(tx->loaded == 2) return 0;	/* busy loading now! */
  tx->loaded = 2;	/* set this to make multiprocess collisions unlikely */
  if(mg_inhaletexture( tx, TXF_RGBA ) <= 0) {
    tx->loaded = -1;
    return 0;
  }
  tx->loaded = 1;
  return 1;
}

int txaddentry( Texture ***tp, int *ntextures, char *fromfile,
		int txno, char *txfname, int apply, int txflags, int qualflags )
{
  char *realfname;
  if(txno < 0) {
    fprintf(stderr, "Texture indices must be >= 0 (texture %d %s)\n", txno, txfname);
    return 0;
  }

  realfname = findfile(fromfile, txfname);
  if(realfname == NULL) {
    fprintf(stderr, "Can't find texture file \"%s\", ignoring it.\n", txfname);
    return 0;
  }
  
  if(txno >= *ntextures) {
    int ontex = *ntextures;
    if(*ntextures == 0) {
	*ntextures = txno + 62;
	*tp = NewN( Texture *, *ntextures );
    } else {
	*ntextures = (txno > ontex*2+1 ? txno+ontex : ontex*2+1);
	*tp = RenewN( *tp, Texture *, *ntextures );
    }
    memset(&(*tp)[ontex], 0, (*ntextures - ontex) * sizeof(Texture *));
  }
  (*tp)[txno] = txmake( shmstrdup(realfname), apply, txflags, qualflags );
  return txno;
}