// Texture Manager

#include "engine/tinygl/zgl.h"

static GLTexture *find_texture(GLContext *c, int h) {
	GLTexture *t;

	t = c->shared_state.texture_hash_table[h % TEXTURE_HASH_TABLE_SIZE];
	while (t != NULL) {
		if (t->handle == h)
			return t;
		t = t->next;
	}
	return NULL;
}

static void free_texture(GLContext *c, int h) {
	GLTexture *t, **ht;
	GLImage *im;
	int i;

	t = find_texture(c, h);
	if (t->prev == NULL) {
		ht = &c->shared_state.texture_hash_table[t->handle % TEXTURE_HASH_TABLE_SIZE];
		*ht = t->next;
	} else {
		t->prev->next = t->next;
	}
	if (t->next != NULL)
		t->next->prev = t->prev;

	for (i = 0; i < MAX_TEXTURE_LEVELS; i++) {
		im = &t->images[i];
		if (im->pixmap != NULL)
			gl_free(im->pixmap);
	}

	gl_free(t);
}

GLTexture *alloc_texture(GLContext *c,int h)
{
  GLTexture *t,**ht;
  
  t=(GLTexture *)gl_zalloc(sizeof(GLTexture));

  ht=&c->shared_state.texture_hash_table[h % TEXTURE_HASH_TABLE_SIZE];

  t->next=*ht;
  t->prev=NULL;
  if (t->next != NULL) t->next->prev=t;
  *ht=t;

  t->handle=h;
  
  return t;
}


void glInitTextures(GLContext *c)
{
  /* textures */

  c->texture_2d_enabled=0;
  c->current_texture=find_texture(c,0);
}

void tglGenTextures(int n, unsigned int *textures)
{
  GLContext *c=gl_get_context();
  int max,i;
  GLTexture *t;

  max=0;
  for(i=0;i<TEXTURE_HASH_TABLE_SIZE;i++) {
    t=c->shared_state.texture_hash_table[i];
    while (t!=NULL) {
      if (t->handle>max) max=t->handle;
      t=t->next;
    }

  }
  for(i=0;i<n;i++) {
    textures[i]=max+i+1;
  }
}


void tglDeleteTextures(int n, const unsigned int *textures)
{
  GLContext *c=gl_get_context();
  int i;
  GLTexture *t;

  for(i=0;i<n;i++) {
    t=find_texture(c,textures[i]);
    if (t!=NULL && t!=0) {
      if (t==c->current_texture) {
	tglBindTexture(TGL_TEXTURE_2D,0);
      }
      free_texture(c,textures[i]);
    }
  }
}


void glopBindTexture(GLContext *c,TGLParam *p)
{
  int target=p[1].i;
  int texture=p[2].i;
  GLTexture *t;

  assert(target == TGL_TEXTURE_2D && texture >= 0);

  t=find_texture(c,texture);
  if (t==NULL) {
    t=alloc_texture(c,texture);
  }
  c->current_texture=t;
}

void glopTexImage2D(GLContext *c, TGLParam *p) {
	int target = p[1].i;
	int level = p[2].i;
	int components = p[3].i;
	int width = p[4].i;
	int height = p[5].i;
	int border = p[6].i;
	int format = p[7].i;
	int type = p[8].i;
	void *pixels = p[9].p;
	GLImage *im;
	unsigned char *pixels1;
	int do_free;

	if (!(target == TGL_TEXTURE_2D && level == 0 && components == 3 && 
			border == 0 && format == TGL_RGBA &&
			type == TGL_UNSIGNED_BYTE)) {
		gl_fatal_error("glTexImage2D: combination of parameters not handled");
	}
  
	do_free = 0;
	if (width != 256 || height != 256) {
		pixels1 = (unsigned char *)gl_malloc(256 * 256 * 4);
		// no interpolation is done here to respect the original image aliasing !
		//gl_resizeImageNoInterpolate(pixels1, 256, 256, (unsigned char *)pixels, width, height);
		// used interpolation anyway, it look much better :) --- aquadran
		gl_resizeImage(pixels1, 256, 256, (unsigned char *)pixels, width, height);
		do_free = 1;
		width = 256;
		height = 256;
  } else {
		pixels1 = (unsigned char *)pixels;
  }

  im = &c->current_texture->images[level];
  im->xsize = width;
  im->ysize = height;
  if (im->pixmap)
	  gl_free(im->pixmap);
  im->pixmap = gl_malloc(width * height * 3);
  if (im->pixmap)
		gl_convertRGB_to_5R6G5B8A((unsigned short *)im->pixmap, pixels1, width, height);
  if (do_free)
		gl_free(pixels1);
}


/* TODO: not all tests are done */
void glopTexEnv(GLContext *,TGLParam *p)
{
  int target=p[1].i;
  int pname=p[2].i;
  int param=p[3].i;

  if (target != TGL_TEXTURE_ENV) {
  error:
    gl_fatal_error("glTexParameter: unsupported option");
  }

  if (pname != TGL_TEXTURE_ENV_MODE) goto error;

  if (param != TGL_DECAL) goto error;
}

/* TODO: not all tests are done */
void glopTexParameter(GLContext *,TGLParam *p)
{
  int target=p[1].i;
  int pname=p[2].i;
  int param=p[3].i;
  
  if (target != TGL_TEXTURE_2D) {
  error:
    gl_fatal_error("glTexParameter: unsupported option");
  }

  switch(pname) {
  case TGL_TEXTURE_WRAP_S:
  case TGL_TEXTURE_WRAP_T:
    if (param != TGL_REPEAT) goto error;
    break;
  }
}

void glopPixelStore(GLContext *,TGLParam *p)
{
  int pname=p[1].i;
  int param=p[2].i;

  if (pname != TGL_UNPACK_ALIGNMENT ||
      param != 1) {
    gl_fatal_error("glPixelStore: unsupported option");
  }
}