mutter/clutter/cogl/gles/cogl-texture.c

/*
 * Clutter COGL
 *
 * A basic GL/GLES Abstraction/Utility Layer
 *
 * Authored By Matthew Allum  <mallum@openedhand.com>
 *
 * Copyright (C) 2007 OpenedHand
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "cogl.h"
#include "cogl-internal.h"
#include "cogl-util.h"
#include "cogl-bitmap.h"
#include "cogl-texture.h"
#include "cogl-context.h"
#include "cogl-handle.h"

#include <string.h>
#include <stdlib.h>
/*
#define COGL_DEBUG 1

#define GE(x) \
{ \
  glGetError(); x; \
  GLuint err = glGetError(); \
  if (err != 0) \
    printf("err: 0x%x\n", err); \
} */

struct _CoglSpanIter
{
  gint              index;
  GArray           *array;
  CoglTexSliceSpan *span;
  ClutterFixed      pos;
  ClutterFixed      next_pos;
  ClutterFixed      origin;
  ClutterFixed      cover_start;
  ClutterFixed      cover_end;
  ClutterFixed      intersect_start;
  ClutterFixed      intersect_end;
  ClutterFixed      intersect_start_local;
  ClutterFixed      intersect_end_local;
  gboolean          intersects;
};

static void _cogl_texture_free (CoglTexture *tex);

COGL_HANDLE_DEFINE (Texture, texture, texture_handles);

CoglHandle
_cogl_texture_handle_from_pointer (CoglTexture *tex)
{
  return (CoglHandle) tex;
}

static void
_cogl_texture_bitmap_free (CoglTexture *tex)
{
  if (tex->bitmap.data != NULL && tex->bitmap_owner)
    g_free (tex->bitmap.data);
  
  tex->bitmap.data = NULL;
  tex->bitmap_owner = FALSE;
}

static void
_cogl_texture_bitmap_swap (CoglTexture     *tex,
			   CoglBitmap      *new_bitmap)
{
  if (tex->bitmap.data != NULL && tex->bitmap_owner)
    g_free (tex->bitmap.data);
  
  tex->bitmap = *new_bitmap;
  tex->bitmap_owner = TRUE;
}

static void
_cogl_span_iter_update (CoglSpanIter *iter)
{
  /* Pick current span */
  iter->span = &g_array_index (iter->array,
			       CoglTexSliceSpan,
			       iter->index);
  
  /* Offset next position by span size */
  iter->next_pos = iter->pos +
    CLUTTER_INT_TO_FIXED (iter->span->size - iter->span->waste);
  
  /* Check if span intersects the area to cover */
  if (iter->next_pos <= iter->cover_start ||
      iter->pos >= iter->cover_end)
    {
      /* Intersection undefined */
      iter->intersects = FALSE;
      return;
    }
  
  iter->intersects = TRUE;
  
  /* Clip start position to coverage area */
  if (iter->pos < iter->cover_start)
    iter->intersect_start = iter->cover_start;
  else
    iter->intersect_start = iter->pos;
  
  /* Clip end position to coverage area */
  if (iter->next_pos > iter->cover_end)
    iter->intersect_end = iter->cover_end;
  else
    iter->intersect_end = iter->next_pos;
}

static void
_cogl_span_iter_begin (CoglSpanIter  *iter,
		       GArray        *array,
		       ClutterFixed   origin,
		       ClutterFixed   cover_start,
		       ClutterFixed   cover_end)
{
  /* Copy info */
  iter->index = 0;
  iter->array = array;
  iter->span = NULL;
  iter->origin = origin;
  iter->cover_start = cover_start;
  iter->cover_end = cover_end;
  iter->pos = iter->origin;
  
  /* Update intersection */
  _cogl_span_iter_update (iter);
}

void
_cogl_span_iter_next (CoglSpanIter *iter)
{
  /* Move current position */
  iter->pos = iter->next_pos;
  
  /* Pick next slice (wrap when last reached) */
  iter->index = (iter->index + 1) % iter->array->len;
  
  /* Update intersection */
  _cogl_span_iter_update (iter);
}

static gboolean
_cogl_span_iter_end (CoglSpanIter *iter)
{
  /* End reached when whole area covered */
  return iter->pos >= iter->cover_end;
}

static gboolean
_cogl_texture_upload_to_gl (CoglTexture *tex)
{
  CoglTexSliceSpan  *x_span;
  CoglTexSliceSpan  *y_span;
  GLuint             gl_handle;
  gint               bpp;
  gint               x,y;
  CoglBitmap         slice_bmp;
  
  /* FIXME: might optimize by not copying to intermediate slice
     bitmap when source rowstride = bpp * width and the texture
     image is not sliced */
  
  bpp = _cogl_get_format_bpp (tex->bitmap.format);
  
  /* Iterate vertical slices */
  for (y = 0; y < tex->slice_y_spans->len; ++y)
    {
      y_span = &g_array_index (tex->slice_y_spans, CoglTexSliceSpan, y);
	
      /* Iterate horizontal slices */
      for (x = 0; x < tex->slice_x_spans->len; ++x)
	{
	  x_span = &g_array_index (tex->slice_x_spans, CoglTexSliceSpan, x);
	  
	  /* Pick the gl texture object handle */
	  gl_handle = g_array_index (tex->slice_gl_handles, GLuint,
				     y * tex->slice_x_spans->len + x);
	  
	  /* Setup temp bitmap for slice subregion */
	  slice_bmp.format = tex->bitmap.format;
	  slice_bmp.width  = x_span->size - x_span->waste;
	  slice_bmp.height = y_span->size - y_span->waste;
	  slice_bmp.rowstride = bpp * slice_bmp.width;
	  slice_bmp.data = (guchar*) g_malloc (slice_bmp.rowstride *
					     slice_bmp.height);
	  
	  /* Copy subregion data */
	  _cogl_bitmap_copy_subregion (&tex->bitmap,
				       &slice_bmp,
				       x_span->start,
				       y_span->start,
				       0, 0,
				       slice_bmp.width,
				       slice_bmp.height);
	  
	  /* Upload new image data */
	  GE( glBindTexture (tex->gl_target, gl_handle) );

	  GE( glPixelStorei (GL_UNPACK_ALIGNMENT, 1) );
	  
	  GE( glTexSubImage2D (tex->gl_target, 0, 0, 0,
			       slice_bmp.width,
			       slice_bmp.height,
			       tex->gl_format, tex->gl_type,
			       slice_bmp.data) );
	  
	  /* Free temp bitmap */
	  g_free (slice_bmp.data);
	}
    }
  
  return TRUE;
}

static gboolean
_cogl_texture_download_from_gl (CoglTexture *tex,
				CoglBitmap  *target_bmp,
				GLuint       target_gl_format,
				GLuint       target_gl_type)
{
  gint               bpp;
  GLint              viewport[4];
  CoglHandle         handle;
  ClutterColor       cback = {0x0, 0x0, 0x0, 0x0};
  ClutterColor       cwhite = {0xFF, 0xFF, 0xFF, 0xFF};
  CoglBitmap         rect_bmp;
  ClutterFixed       rx1, ry1;
  ClutterFixed       rx2, ry2;
  ClutterFixed       tx1, ty1;
  ClutterFixed       tx2, ty2;
  int                bw,  bh;
  
  handle = _cogl_texture_handle_from_pointer (tex);
  bpp = _cogl_get_format_bpp (COGL_PIXEL_FORMAT_RGBA_8888);
  
  /* Viewport needs to have some size and be inside the window for this */
  GE( glGetIntegerv (GL_VIEWPORT, viewport) );
  
  if (viewport[0] <  0 || viewport[1] <  0 ||
      viewport[2] <= 0 || viewport[3] <= 0)
    return FALSE;
  
  /* Setup orthographic projection into current viewport
     (0,0 in bottom-left corner to draw the texture
     upside-down so we match the way glReadPixels works) */
  
  GE( glMatrixMode (GL_PROJECTION) );
  GE( glPushMatrix () );
  GE( glLoadIdentity () );
  
  GE( glOrthox (0, CLUTTER_INT_TO_FIXED (viewport[2]),
		0, CLUTTER_INT_TO_FIXED (viewport[3]),
		CLUTTER_INT_TO_FIXED (0),
		CLUTTER_INT_TO_FIXED (100)) );
  
  GE( glMatrixMode (GL_MODELVIEW) );
  GE( glPushMatrix () );
  GE( glLoadIdentity () );
  
  /* Draw to all channels */
  cogl_draw_buffer (COGL_WINDOW_BUFFER | COGL_MASK_BUFFER, 0);
  
  
  /* If whole image fits into the viewport and target buffer
     has got no special rowstride, we can do it in one pass */
  if (tex->bitmap.width < viewport[2] - viewport[0] &&
      tex->bitmap.height < viewport[3] - viewport[1] &&
      tex->bitmap.rowstride == bpp * tex->bitmap.width)
    {
      /* Clear buffer with transparent black, draw with white
         for direct copy to framebuffer */
      cogl_paint_init (&cback);
      cogl_color (&cwhite);
      
      /* Draw the texture image */
      cogl_texture_rectangle (handle,
			      0, 0,
			      CLUTTER_INT_TO_FIXED (tex->bitmap.width),
			      CLUTTER_INT_TO_FIXED (tex->bitmap.height),
			      0, 0, CFX_ONE, CFX_ONE);
      
      /* Read into target bitmap */
      GE( glPixelStorei (GL_PACK_ALIGNMENT, 1) );
      GE( glReadPixels (viewport[0], viewport[1],
			tex->bitmap.width,
			tex->bitmap.height,
			GL_RGBA, GL_UNSIGNED_BYTE,
			target_bmp->data) );
    }
  else
    {
      ry1 = 0; ry2 = 0;
      ty1 = 0; ty2 = 0;
      
#define CFIX CLUTTER_INT_TO_FIXED
      
      /* Walk Y axis until whole bitmap height consumed */
      for (bh = tex->bitmap.height; bh > 0; bh -= viewport[3])
	{
	  /* Rectangle Y coords */
	  ry1 = ry2;
	  ry2 += (bh < viewport[3]) ? bh : viewport[3];
	  
	  /* Normalized texture Y coords */
	  ty1 = ty2;
	  ty2 = CFX_QDIV (CFIX (ry2), CFIX (tex->bitmap.height));
	  
	  rx1 = 0; rx2 = 0;
	  tx1 = 0; tx2 = 0;
	  
	  /* Walk X axis until whole bitmap width consumed */
	  for (bw = tex->bitmap.width; bw > 0; bw-=viewport[2])
	    {
	      /* Rectangle X coords */
	      rx1 = rx2;
	      rx2 += (bw < viewport[2]) ? bw : viewport[2];
	      
	      /* Normalized texture X coords */
	      tx1 = tx2;
	      tx2 = CFX_QDIV (CFIX (rx2), CFIX (tex->bitmap.width));
	      
	      /* Clear buffer with transparent black, draw with white
		 for direct copy to framebuffer */
	      cogl_paint_init (&cback);
	      cogl_color (&cwhite);
	      
	      /* Draw a portion of texture */
	      cogl_texture_rectangle (handle,
				      0, 0,
				      CFIX (rx2 - rx1),
				      CFIX (ry2 - ry1),
				      tx1, ty1,
				      tx2, ty2);
	      
	      /* Read into a temporary bitmap */
	      rect_bmp.format = COGL_PIXEL_FORMAT_RGBA_8888;
	      rect_bmp.width = rx2 - rx1;
	      rect_bmp.height = ry2 - ry1;
	      rect_bmp.rowstride = bpp * rect_bmp.width;
	      rect_bmp.data = (guchar*) g_malloc (rect_bmp.rowstride *
						  rect_bmp.height);
	      
	      GE( glPixelStorei (GL_PACK_ALIGNMENT, 1) );
	      GE( glReadPixels (viewport[0], viewport[1],
				rect_bmp.width,
				rect_bmp.height,
				GL_RGBA, GL_UNSIGNED_BYTE,
				rect_bmp.data) );
	      
	      /* Copy to target bitmap */
	      _cogl_bitmap_copy_subregion (&rect_bmp,
					   target_bmp,
					   0,0,
					   rx1,ry1,
					   rect_bmp.width,
					   rect_bmp.height);
	      
	      /* Free temp bitmap */
	      g_free (rect_bmp.data);
	    }
	}
      
#undef CFIX
    }
  
  glMatrixMode (GL_PROJECTION);
  glPopMatrix ();
  glMatrixMode (GL_MODELVIEW);
  glPopMatrix ();
  
  cogl_draw_buffer (COGL_WINDOW_BUFFER, 0);
  
  return TRUE;
}

static void
_cogl_texture_set_alignment_for_rowstride (gint rowstride)
{
  gint alignment = 1;

  while ((rowstride & 1) == 0 && alignment < 8)
    {
      alignment <<= 1;
      rowstride >>= 1;
    }

  GE( glPixelStorei (GL_UNPACK_ALIGNMENT, alignment) );
}

static gboolean
_cogl_texture_upload_subregion_to_gl (CoglTexture *tex,
				      gint         src_x,
				      gint         src_y,
				      gint         dst_x,
				      gint         dst_y,
				      gint         width,
				      gint         height,
				      CoglBitmap  *source_bmp,
				      GLuint       source_gl_format,
				      GLuint       source_gl_type)
{
  gint         bpp;
  CoglSpanIter x_iter;
  CoglSpanIter y_iter;
  GLuint       gl_handle;
  gint         source_x = 0, source_y = 0;
  gint         inter_w = 0, inter_h = 0;
  gint         local_x = 0, local_y = 0;
  CoglBitmap   slice_bmp;
  
  bpp = _cogl_get_format_bpp (source_bmp->format);
  
  /* FIXME: might optimize by not copying to intermediate slice
     bitmap when source rowstride = bpp * width and the texture
     image is not sliced */
  
  /* Iterate vertical spans */
  for (source_y = src_y,
       _cogl_span_iter_begin (&y_iter, tex->slice_y_spans,
			      0, CLUTTER_INT_TO_FIXED (dst_y),
			      CLUTTER_INT_TO_FIXED (dst_y + height));
       
       !_cogl_span_iter_end (&y_iter);
       
       _cogl_span_iter_next (&y_iter),
       source_y += inter_h )
    {
      /* Skip non-intersecting ones */
      if (!y_iter.intersects)
	{
	  inter_h = 0;
	  continue;
	}
      
      /* Iterate horizontal spans */
      for (source_x = src_x,
	   _cogl_span_iter_begin (&x_iter, tex->slice_x_spans,
				  0, CLUTTER_INT_TO_FIXED (dst_x),
				  CLUTTER_INT_TO_FIXED (dst_x + width));
	   
	   !_cogl_span_iter_end (&x_iter);
	   
	   _cogl_span_iter_next (&x_iter),
	   source_x += inter_w )
        {
	  /* Skip non-intersecting ones */
	  if (!x_iter.intersects)
	    {
	      inter_w = 0;
	      continue;
	    }
	  
	  /* Pick intersection width and height */
	  inter_w = CLUTTER_FIXED_TO_INT (x_iter.intersect_end -
					  x_iter.intersect_start);
	  inter_h = CLUTTER_FIXED_TO_INT (y_iter.intersect_end -
					  y_iter.intersect_start);
	  
	  /* Localize intersection top-left corner to slice*/
	  local_x = CLUTTER_FIXED_TO_INT (x_iter.intersect_start -
					  x_iter.pos);
	  local_y = CLUTTER_FIXED_TO_INT (y_iter.intersect_start -
					  y_iter.pos);
	  
	  /* Pick slice GL handle */
	  gl_handle = g_array_index (tex->slice_gl_handles, GLuint,
				     y_iter.index * tex->slice_x_spans->len +
				     x_iter.index);
	  
	  /* Setup temp bitmap for slice subregion */
	  slice_bmp.format = tex->bitmap.format;
	  slice_bmp.width  = inter_w;
	  slice_bmp.height = inter_h;
	  slice_bmp.rowstride = bpp * slice_bmp.width;
	  slice_bmp.data = (guchar*) g_malloc (slice_bmp.rowstride *
					     slice_bmp.height);
	  
	  /* Copy subregion data */
	  _cogl_bitmap_copy_subregion (source_bmp,
				       &slice_bmp,
				       source_x,
				       source_y,
				       0, 0,
				       slice_bmp.width,
				       slice_bmp.height);
	  
	  /* Upload new image data */
	  GE( glPixelStorei (GL_UNPACK_ALIGNMENT, 1) );
	  
	  GE( glBindTexture (tex->gl_target, gl_handle) );
	  
	  GE( glTexSubImage2D (tex->gl_target, 0,
			       local_x, local_y,
			       inter_w, inter_h,
			       source_gl_format,
			       source_gl_type,
			       slice_bmp.data) );
	  
	  /* Free temp bitmap */
	  g_free (slice_bmp.data);
	}
    }
  
  return TRUE;
}

static gint
_cogl_pot_slices_for_size (gint     size_to_fill,
			   gint     max_span_size,
			   gint     max_waste,
			   GArray  *out_spans)
{
  gint             n_spans = 0;
  CoglTexSliceSpan span;
  
  /* Init first slice span */
  span.start = 0;
  span.size = max_span_size;
  span.waste = 0;
  
  /* Fix invalid max_waste */
  if (max_waste < 0) max_waste = 0;
  
  while (TRUE)
    {
      /* Is the whole area covered? */
      if (size_to_fill > span.size)
	{
	  /* Not yet - add a span of this size */
	  if (out_spans) g_array_append_val (out_spans, span);
	  span.start   += span.size;
	  size_to_fill -= span.size;
	  n_spans++;
	}
      else if (span.size - size_to_fill <= max_waste)
	{
	  /* Yes and waste is small enough */
	  span.waste = span.size - size_to_fill;
	  if (out_spans) g_array_append_val (out_spans, span);
	  return ++n_spans;
	}
      else
	{
	  /* Yes but waste is too large */
	  while (span.size - size_to_fill > max_waste)
	    {
	      span.size /= 2;
	      g_assert (span.size > 0);
	    }
	}
    }
  
  /* Can't get here */
  return 0;
}

static gboolean
_cogl_texture_size_supported (GLenum gl_target,
			      GLenum gl_format,
			      GLenum gl_type,
			      int    width,
			      int    height)
{
  return TRUE;
}

static gboolean
_cogl_texture_slices_create (CoglTexture *tex)
{  
  gint              bpp;
  gint              max_width;
  gint              max_height;
  GLuint           *gl_handles;
  gint              n_x_slices;
  gint              n_y_slices;
  gint              n_slices;
  gint              x, y;
  CoglTexSliceSpan *x_span;
  CoglTexSliceSpan *y_span;
  
  gint   (*slices_for_size) (gint, gint, gint, GArray*);
  
  bpp = _cogl_get_format_bpp (tex->bitmap.format);
  
  /* Initialize size of largest slice according to supported features */
  max_width = cogl_util_next_p2 (tex->bitmap.width);
  max_height = cogl_util_next_p2 (tex->bitmap.height);
  tex->gl_target = GL_TEXTURE_2D;
  slices_for_size = _cogl_pot_slices_for_size;
  
  /* Negative number means no slicing forced by the user */
  if (tex->max_waste <= -1)
    {
      CoglTexSliceSpan span;
      
      /* Check if size supported else bail out */
      if (!_cogl_texture_size_supported (tex->gl_target,
					tex->gl_format,
					tex->gl_type,
					max_width,
					max_height))
	{
	  return FALSE;
	}
      
      n_x_slices = 1;
      n_y_slices = 1;
      
      /* Init span arrays */      
      tex->slice_x_spans = g_array_sized_new (FALSE, FALSE,
					      sizeof (CoglTexSliceSpan),
					      1);
      
      tex->slice_y_spans = g_array_sized_new (FALSE, FALSE,
					      sizeof (CoglTexSliceSpan),
					      1);
      
      /* Add a single span for width and height */
      span.start = 0;
      span.size = max_width;
      span.waste = max_width - tex->bitmap.width;
      g_array_append_val (tex->slice_x_spans, span);
      
      span.size = max_height;
      span.waste = max_height - tex->bitmap.height;
      g_array_append_val (tex->slice_y_spans, span);
    }
  else
    {
      /* Decrease the size of largest slice until supported by GL */
      while (!_cogl_texture_size_supported (tex->gl_target,
					    tex->gl_format,
					    tex->gl_type,
					    max_width,
					    max_height))
	{
	  /* Alternate between width and height */
	  if (max_width > max_height)
	    max_width /= 2;
	  else
	    max_height /= 2;
	  
	  if (max_width == 0 || max_height == 0)
	    return FALSE;
	}
      
      /* Determine the slices required to cover the bitmap area */
      n_x_slices = slices_for_size (tex->bitmap.width,
				    max_width, tex->max_waste,
				    NULL);
      
      n_y_slices = slices_for_size (tex->bitmap.height,
				    max_height, tex->max_waste,
				    NULL);
      
      /* Init span arrays with reserved size */
      tex->slice_x_spans = g_array_sized_new (FALSE, FALSE,
					      sizeof (CoglTexSliceSpan),
					      n_x_slices);
      
      tex->slice_y_spans = g_array_sized_new (FALSE, FALSE,
					      sizeof (CoglTexSliceSpan),
					      n_y_slices);
      
      /* Fill span arrays with info */
      slices_for_size (tex->bitmap.width,
		       max_width, tex->max_waste,
		       tex->slice_x_spans);
      
      slices_for_size (tex->bitmap.height,
		       max_height, tex->max_waste,
		       tex->slice_y_spans);
    }
  
  /* Init and resize GL handle array */
  n_slices = n_x_slices * n_y_slices;
  
  tex->slice_gl_handles = g_array_sized_new (FALSE, FALSE,
					     sizeof (GLuint),
					     n_slices);
  
  g_array_set_size (tex->slice_gl_handles, n_slices);
  
  /* Generate a "working set" of GL texture objects
   * (some implementations might supported faster
   *  re-binding between textures inside a set) */
  gl_handles = (GLuint*) tex->slice_gl_handles->data;
  
  GE( glGenTextures (n_slices, gl_handles) );
  
  
  /* Init each GL texture object */
  for (y = 0; y < n_y_slices; ++y)
    {
      y_span = &g_array_index (tex->slice_y_spans, CoglTexSliceSpan, y);
      
      for (x = 0; x < n_x_slices; ++x)
	{
	  x_span = &g_array_index (tex->slice_x_spans, CoglTexSliceSpan, x);
	  
#if COGL_DEBUG
	  printf ("CREATE SLICE (%d,%d)\n", x,y);
	  printf ("size: (%d x %d)\n",
	    x_span->size - x_span->waste,
	    y_span->size - y_span->waste);
#endif
	  /* Setup texture parameters */
	  GE( glBindTexture   (tex->gl_target, gl_handles[y * n_x_slices + x]) );
	  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_MAG_FILTER, tex->mag_filter) );
	  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_MIN_FILTER, tex->min_filter) );
	  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE) );
	  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE) );
	  
	  /* Pass NULL data to init size and internal format */
	  GE( glTexImage2D (tex->gl_target, 0, tex->gl_intformat,
			    x_span->size, y_span->size, 0,
			    tex->gl_format, tex->gl_type, 0) );
	}
    }
  
  return TRUE;
}

static void
_cogl_texture_slices_free (CoglTexture *tex)
{ 
  if (tex->slice_x_spans != NULL)
    g_array_free (tex->slice_x_spans, TRUE);
  
  if (tex->slice_y_spans != NULL)
    g_array_free (tex->slice_y_spans, TRUE);
  
  if (tex->slice_gl_handles != NULL)
    {
      if (tex->is_foreign == FALSE)
	{
	  GE( glDeleteTextures (tex->slice_gl_handles->len,
				(GLuint*) tex->slice_gl_handles->data) );
	}
      
      g_array_free (tex->slice_gl_handles, TRUE);
    }
}

static gboolean
_cogl_pixel_format_from_gl_internal (GLenum            gl_int_format,
				     CoglPixelFormat  *out_format)
{
  /* It doesn't really matter we convert to exact same
     format (some have no cogl match anyway) since format
     is re-matched against cogl when getting or setting
     texture image data.
  */
  
  switch (gl_int_format)
    {
    case GL_ALPHA:
      
      *out_format = COGL_PIXEL_FORMAT_A_8;
      return TRUE;
      
    case GL_LUMINANCE:
      
      *out_format = COGL_PIXEL_FORMAT_G_8;
      return TRUE;
      
    case GL_RGB:
      
      *out_format = COGL_PIXEL_FORMAT_RGB_888;
      return TRUE;
      
    case GL_RGBA:
      
      *out_format = COGL_PIXEL_FORMAT_RGBA_8888;
      return TRUE;
    }
  
  return FALSE;
}

static CoglPixelFormat
_cogl_pixel_format_to_gl (CoglPixelFormat  format,
			  GLenum          *out_glintformat,
			  GLenum          *out_glformat,
			  GLenum          *out_gltype)
{
  CoglPixelFormat required_format = format;
  GLenum          glintformat = 0;
  GLenum          glformat = 0;
  GLenum          gltype = 0;
  
  /* No premultiplied formats accepted  by GL
   * (FIXME: latest hardware?) */
  
  if (format & COGL_PREMULT_BIT)
    format = (format & COGL_UNPREMULT_MASK);
  
  /* Find GL equivalents */
  switch (format)
    {
    case COGL_PIXEL_FORMAT_A_8:
      glintformat = GL_ALPHA;
      glformat = GL_ALPHA;
      gltype = GL_UNSIGNED_BYTE;
      break;
    case COGL_PIXEL_FORMAT_G_8:
      glintformat = GL_LUMINANCE;
      glformat = GL_LUMINANCE;
      gltype = GL_UNSIGNED_BYTE;
      break;
      
      /* Just one 24-bit ordering supported */
    case COGL_PIXEL_FORMAT_RGB_888:
    case COGL_PIXEL_FORMAT_BGR_888:
      glintformat = GL_RGB;
      glformat = GL_RGB;
      gltype = GL_UNSIGNED_BYTE;
      required_format = COGL_PIXEL_FORMAT_RGB_888;
      break;
      
      /* Just one 32-bit ordering supported */
    case COGL_PIXEL_FORMAT_RGBA_8888:
    case COGL_PIXEL_FORMAT_BGRA_8888:
    case COGL_PIXEL_FORMAT_ARGB_8888:
    case COGL_PIXEL_FORMAT_ABGR_8888:
      glintformat = GL_RGBA;
      glformat = GL_RGBA;
      gltype = GL_UNSIGNED_BYTE;
      required_format = COGL_PIXEL_FORMAT_RGBA_8888;
      break;
      
      /* The following three types of channel ordering
       * are always defined using system word byte
       * ordering (even according to GLES spec) */
    case COGL_PIXEL_FORMAT_RGB_565:
      glintformat = GL_RGB;
      glformat = GL_RGB;
      gltype = GL_UNSIGNED_SHORT_5_6_5;
      break;
    case COGL_PIXEL_FORMAT_RGBA_4444:
      glintformat = GL_RGBA;
      glformat = GL_RGBA;
      gltype = GL_UNSIGNED_SHORT_4_4_4_4;
      break;
    case COGL_PIXEL_FORMAT_RGBA_5551:
      glintformat = GL_RGBA;
      glformat = GL_RGBA;
      gltype = GL_UNSIGNED_SHORT_5_5_5_1;
      break;
      
      /* FIXME: check extensions for YUV support */
    default:
      break;
    }
  
  if (out_glintformat != NULL)
    *out_glintformat = glintformat;
  if (out_glformat != NULL)
    *out_glformat = glformat;
  if (out_gltype != NULL)
    *out_gltype = gltype;
  
  return required_format;
}

static gboolean
_cogl_texture_bitmap_prepare (CoglTexture     *tex,
			      CoglPixelFormat  internal_format)
{
  CoglBitmap        new_bitmap;
  CoglPixelFormat   new_data_format;
  gboolean          success;
  
  /* Was there any internal conversion requested? */
  if (internal_format == COGL_PIXEL_FORMAT_ANY)
    internal_format = tex->bitmap.format;

  /* Find closest format accepted by GL */
  new_data_format = _cogl_pixel_format_to_gl (internal_format,
					      &tex->gl_intformat,
					      &tex->gl_format,
					      &tex->gl_type);
  
  /* Convert to internal format */
  if (new_data_format != tex->bitmap.format)
    {
      success = _cogl_bitmap_convert_and_premult (&tex->bitmap,
						  &new_bitmap,
						  new_data_format);
      
      if (!success)
	return FALSE;
      
      /* Update texture with new data */
      _cogl_texture_bitmap_swap (tex, &new_bitmap);
    }
  
  return TRUE;
}

static void
_cogl_texture_free (CoglTexture *tex)
{
  /* Frees texture resources but its handle is not
     released! Do that separately before this! */
  _cogl_texture_bitmap_free (tex);
  _cogl_texture_slices_free (tex);
  g_free (tex);
}

CoglHandle
cogl_texture_new_with_size (guint           width,
			    guint           height,
			    gint            max_waste,
			    CoglPixelFormat internal_format)
{
  CoglTexture *tex;
  gint         bpp;
  gint         rowstride;
  
  /* Since no data, we need some internal format */
  if (internal_format == COGL_PIXEL_FORMAT_ANY)
    return COGL_INVALID_HANDLE;
  
  /* Rowstride from width */
  bpp = _cogl_get_format_bpp (internal_format);
  rowstride = width * bpp;
  
  /* Init texture with empty bitmap */
  tex = (CoglTexture*) g_malloc (sizeof (CoglTexture));

  tex->ref_count = 1;
  COGL_HANDLE_DEBUG_NEW (texture, tex);
  
  tex->is_foreign = FALSE;
  
  tex->bitmap.width = width;
  tex->bitmap.height = height;
  tex->bitmap.format = internal_format;
  tex->bitmap.rowstride = rowstride;
  tex->bitmap.data = NULL;
  tex->bitmap_owner = FALSE;
  
  tex->slice_x_spans = NULL;
  tex->slice_y_spans = NULL;
  tex->slice_gl_handles = NULL;
  
  tex->max_waste = max_waste;
  tex->min_filter = CGL_NEAREST;
  tex->mag_filter = CGL_NEAREST;
  
  /* Find closest GL format match */
  tex->bitmap.format =
    _cogl_pixel_format_to_gl (internal_format,
			      &tex->gl_intformat,
			      &tex->gl_format,
			      &tex->gl_type);
  
  if (!_cogl_texture_slices_create (tex))
    {
      _cogl_texture_free (tex);
      return COGL_INVALID_HANDLE;
    }
  
  return _cogl_texture_handle_new (tex);
}

CoglHandle
cogl_texture_new_from_data (guint              width,
			    guint              height,
			    gint               max_waste,
			    CoglPixelFormat    format,
			    CoglPixelFormat    internal_format,
			    guint              rowstride,
			    const guchar      *data)
{
  CoglTexture *tex;
  gint         bpp;
  
  if (format == COGL_PIXEL_FORMAT_ANY)
    return COGL_INVALID_HANDLE;
  
  if (data == NULL)
    return COGL_INVALID_HANDLE;
  
  /* Rowstride from width if not given */
  bpp = _cogl_get_format_bpp (format);
  if (rowstride == 0) rowstride = width * bpp;
  
  /* Create new texture and fill with given data */
  tex = (CoglTexture*) g_malloc (sizeof (CoglTexture));
  
  tex->ref_count = 1;
  COGL_HANDLE_DEBUG_NEW (texture, tex);
  
  tex->is_foreign = FALSE;

  tex->bitmap.width = width;
  tex->bitmap.height = height;
  tex->bitmap.data = (guchar*)data;
  tex->bitmap.format = format;
  tex->bitmap.rowstride = rowstride;
  tex->bitmap_owner = FALSE;
  
  tex->slice_x_spans = NULL;
  tex->slice_y_spans = NULL;
  tex->slice_gl_handles = NULL;
  
  tex->max_waste = max_waste;
  tex->min_filter = CGL_NEAREST;
  tex->mag_filter = CGL_NEAREST;
  
  /* FIXME: If upload fails we should set some kind of
   * error flag but still return texture handle (this
   * is to keep the behavior equal to _new_from_file;
   * see below) */
  
  if (!_cogl_texture_bitmap_prepare (tex, internal_format))
    {
      _cogl_texture_free (tex);
      return COGL_INVALID_HANDLE;
    }
  
  if (!_cogl_texture_slices_create (tex))
    {
      _cogl_texture_free (tex);
      return COGL_INVALID_HANDLE;
    }
  
  if (!_cogl_texture_upload_to_gl (tex))
    {
      _cogl_texture_free (tex);
      return COGL_INVALID_HANDLE;
    }
  
  _cogl_texture_bitmap_free (tex);
  
  return _cogl_texture_handle_new (tex);;
}

CoglHandle
cogl_texture_new_from_file (const gchar     *filename,
			    gint             max_waste,
			    CoglPixelFormat  internal_format,
			    GError         **error)
{
  CoglBitmap   bmp;
  CoglTexture *tex;
  
  g_return_val_if_fail (error == NULL || *error == NULL, COGL_INVALID_HANDLE);

  /* Try loading with imaging backend */
  if (!_cogl_bitmap_from_file (&bmp, filename, error))
    {
      /* Try fallback */
      if (!_cogl_bitmap_fallback_from_file (&bmp, filename))
	return COGL_INVALID_HANDLE;
      else if (error && *error)
	{
	  g_error_free (*error);
	  *error = NULL;
	}
    }
  
  /* Create new texture and fill with loaded data */
  tex = (CoglTexture*) g_malloc ( sizeof (CoglTexture));
  
  tex->ref_count = 1;
  COGL_HANDLE_DEBUG_NEW (texture, tex);
  
  tex->is_foreign = FALSE;

  tex->bitmap = bmp;
  tex->bitmap_owner = TRUE;  
  
  tex->slice_x_spans = NULL;
  tex->slice_y_spans = NULL;
  tex->slice_gl_handles = NULL;
  
  tex->max_waste = max_waste;
  tex->min_filter = CGL_NEAREST;
  tex->mag_filter = CGL_NEAREST;
  
  /* FIXME: If upload fails we should set some kind of
   * error flag but still return texture handle if the
   * user decides to destroy another texture and upload
   * this one instead (reloading from file is not needed
   * in that case). As a rule then, everytime a valid
   * CoglHandle is returned, it should also be destroyed
   * with cogl_texture_unref at some point! */
  
  if (!_cogl_texture_bitmap_prepare (tex, internal_format))
    {
      _cogl_texture_free (tex);
      return COGL_INVALID_HANDLE;
    }
  
  if (!_cogl_texture_slices_create (tex))
    {
      _cogl_texture_free (tex);
      return COGL_INVALID_HANDLE;
    }
  
  if (!_cogl_texture_upload_to_gl (tex))
    {
      _cogl_texture_free (tex);
      return COGL_INVALID_HANDLE;
    }
  
  _cogl_texture_bitmap_free (tex);
  
  return _cogl_texture_handle_new (tex);
}

CoglHandle
cogl_texture_new_from_foreign (GLuint           gl_handle,
			       GLenum           gl_target,
			       GLuint           width,
			       GLuint           height,
			       GLuint           x_pot_waste,
			       GLuint           y_pot_waste,
			       CoglPixelFormat  format)
{
  GLenum           gl_error = 0;
  GLboolean        gl_istexture;
  GLint            gl_min_filter;
  GLint            gl_mag_filter;
  guint            bpp;
  CoglTexture     *tex;
  CoglTexSliceSpan x_span;
  CoglTexSliceSpan y_span;
  
  /* Allow 2-dimensional textures only */
  if (gl_target != GL_TEXTURE_2D)
    return COGL_INVALID_HANDLE;
  
  /* Make sure it is a valid GL texture object */
  gl_istexture = GE( glIsTexture (gl_handle) );
  if (gl_istexture == GL_FALSE)
    return COGL_INVALID_HANDLE;
  
  /* Make sure binding succeeds */
  gl_error = glGetError ();
  glBindTexture (gl_target, gl_handle);
  if (glGetError () != GL_NO_ERROR)
    return COGL_INVALID_HANDLE;
  
  /* Obtain texture parameters
     (only level 0 we are interested in) */
  
  /* These are not queriable in GLES :(
  GE( glGetTexLevelParameteriv (gl_target, 0,
				GL_TEXTURE_COMPRESSED,
				&gl_compressed) );
  
  GE( glGetTexLevelParameteriv (gl_target, 0,
				GL_TEXTURE_INTERNAL_FORMAT,
				&gl_int_format) );
  */
  GE( glGetTexParameteriv (gl_target,
			   GL_TEXTURE_MIN_FILTER,
			   &gl_min_filter));
  
  GE( glGetTexParameteriv (gl_target,
			   GL_TEXTURE_MAG_FILTER,
			   &gl_mag_filter));
  
  /* Validate width and height */
  if (width <= 0 || height <= 0)
    return COGL_INVALID_HANDLE;
  
  /* Validate pot waste */
  if (x_pot_waste < 0 || x_pot_waste >= width ||
      y_pot_waste < 0 || y_pot_waste >= height)
    return COGL_INVALID_HANDLE;
  
  /* Create new texture */
  tex = (CoglTexture*) g_malloc ( sizeof (CoglTexture));
  
  tex->ref_count = 1;
  COGL_HANDLE_DEBUG_NEW (texture, tex);
  
  /* Setup bitmap info */
  tex->is_foreign = TRUE;
  
  bpp = _cogl_get_format_bpp (format);
  tex->bitmap.format = format;
  tex->bitmap.width = width;
  tex->bitmap.height = height;
  tex->bitmap.rowstride = tex->bitmap.width * bpp;
  tex->bitmap_owner = FALSE;
  
  tex->gl_target = gl_target;
  tex->gl_intformat = 0;
  tex->gl_format = 0;
  tex->gl_type = 0;
  
  tex->min_filter = gl_min_filter;
  tex->mag_filter = gl_mag_filter;
  tex->max_waste = 0;
  
  /* Create slice arrays */
  tex->slice_x_spans =
    g_array_sized_new (FALSE, FALSE,
		       sizeof (CoglTexSliceSpan), 1);
  
  tex->slice_y_spans =
    g_array_sized_new (FALSE, FALSE,
		       sizeof (CoglTexSliceSpan), 1);
  
  tex->slice_gl_handles =
    g_array_sized_new (FALSE, FALSE,
		       sizeof (GLuint), 1);
  
  /* Store info for a single slice */
  x_span.start = 0;
  x_span.size = width + x_pot_waste;
  x_span.waste = x_pot_waste;
  g_array_append_val (tex->slice_x_spans, x_span);
  
  y_span.start = 0;
  y_span.size = height + x_pot_waste;
  y_span.waste = y_pot_waste;
  g_array_append_val (tex->slice_y_spans, y_span);
  
  g_array_append_val (tex->slice_gl_handles, gl_handle);
  
  /* Replace mipmap min filter modes with single level ones */
  if (gl_min_filter != GL_NEAREST && gl_min_filter != GL_LINEAR)
    {
      if (gl_min_filter == GL_NEAREST_MIPMAP_NEAREST)
	{
	  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_MIN_FILTER, GL_NEAREST) );
	  tex->min_filter = CGL_NEAREST;
	}
      else
	{
	  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_MIN_FILTER, GL_LINEAR) );
	  tex->min_filter = CGL_LINEAR;
	}
    }
  
  /* Force appropriate wrap parameter */
  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE) );
  GE( glTexParameteri (tex->gl_target, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE) );
  
  return _cogl_texture_handle_new (tex);
}

void
cogl_texture_get_properties (CoglHandle       handle,
			     guint           *out_width,
			     guint           *out_height,
			     CoglPixelFormat *out_format,
			     guint           *out_rowstride,
			     guint           *out_max_waste)
{
  CoglTexture *tex;
  
  /* Check if valid texture handle */
  if (!cogl_is_texture (handle))
    return;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  /* Output requested properties */
  if (out_width != NULL)
    *out_width = tex->bitmap.width;
  
  if (out_height != NULL)
    *out_height = tex->bitmap.height;
  
  if (out_format != NULL)
    *out_format = tex->bitmap.format;
  
  if (out_rowstride != NULL)
    *out_rowstride = tex->bitmap.rowstride;
  
  if (out_max_waste != NULL)
    *out_max_waste = tex->max_waste;
}

guint
cogl_texture_get_width (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return 0;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  return tex->bitmap.width;
}

guint
cogl_texture_get_height (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return 0;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  return tex->bitmap.height;
}

CoglPixelFormat
cogl_texture_get_format (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return COGL_PIXEL_FORMAT_ANY;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  return tex->bitmap.format;
}

guint
cogl_texture_get_rowstride (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return 0;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  return tex->bitmap.rowstride;
}

gint
cogl_texture_get_max_waste (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return 0;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  return tex->max_waste;
}

gboolean
cogl_texture_is_sliced (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return FALSE;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  if (tex->slice_gl_handles == NULL)
    return FALSE;
  
  if (tex->slice_gl_handles->len <= 1)
    return FALSE;
  
  return TRUE;
}

gboolean
cogl_texture_get_gl_texture (CoglHandle handle,
			     GLuint *out_gl_handle,
			     GLenum *out_gl_target)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return FALSE;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  if (tex->slice_gl_handles == NULL)
    return FALSE;
  
  if (tex->slice_gl_handles->len < 1)
    return FALSE;
  
  if (out_gl_handle != NULL)
    *out_gl_handle = g_array_index (tex->slice_gl_handles, GLuint, 0);
  
  if (out_gl_target != NULL)
    *out_gl_target = tex->gl_target;
  
  return TRUE;
}

COGLenum
cogl_texture_get_min_filter (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return 0;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  return tex->min_filter;
}

COGLenum
cogl_texture_get_mag_filter (CoglHandle handle)
{
  CoglTexture *tex;
  
  if (!cogl_is_texture (handle))
    return 0;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  return tex->mag_filter;
}

void
cogl_texture_set_filters (CoglHandle handle,
			  COGLenum   min_filter,
			  COGLenum   mag_filter)
{
  CoglTexture *tex;
  GLuint       gl_handle;
  int          i;
  
  if (!cogl_is_texture (handle))
    return;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  /* Store new values */
  tex->min_filter = min_filter;
  tex->mag_filter = mag_filter;
  
  /* Make sure slices were created */
  if (tex->slice_gl_handles == NULL)
    return;
  
  /* Apply new filters to every slice */
  for (i=0; i<tex->slice_gl_handles->len; ++i)
    {
      gl_handle = g_array_index (tex->slice_gl_handles, GLuint, i);
      GE( glBindTexture   (tex->gl_target, gl_handle) );
      GE( glTexParameteri (tex->gl_target, GL_TEXTURE_MAG_FILTER, tex->mag_filter) );
      GE( glTexParameteri (tex->gl_target, GL_TEXTURE_MIN_FILTER, tex->min_filter) );
    }
}

gboolean
cogl_texture_set_region (CoglHandle       handle,
			 gint             src_x,
			 gint             src_y,
			 gint             dst_x,
			 gint             dst_y,
			 guint            dst_width,
			 guint            dst_height,
			 gint             width,
			 gint             height,
			 CoglPixelFormat  format,
			 guint            rowstride,
			 const guchar    *data)
{
  CoglTexture     *tex;
  gint             bpp;
  CoglBitmap       source_bmp;
  CoglBitmap       temp_bmp;
  gboolean         source_bmp_owner = FALSE;
  CoglPixelFormat  closest_format;
  GLenum           closest_gl_format;
  GLenum           closest_gl_type;
  gboolean         success;
  
  /* Check if valid texture handle */
  if (!cogl_is_texture (handle))
    return FALSE;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  /* Check for valid format */
  if (format == COGL_PIXEL_FORMAT_ANY)
    return FALSE;
  
  /* Init source bitmap */
  source_bmp.width = width;
  source_bmp.height = height;
  source_bmp.format = format;
  source_bmp.data = (guchar*)data;
  
  /* Rowstride from width if none specified */
  bpp = _cogl_get_format_bpp (format);
  source_bmp.rowstride = (rowstride == 0) ? width * bpp : rowstride;
  
  /* Find closest format to internal that's supported by GL */
  closest_format = _cogl_pixel_format_to_gl (tex->bitmap.format,
					     NULL, /* don't need */
					     &closest_gl_format,
					     &closest_gl_type);
  
  /* If no direct match, convert */
  if (closest_format != format)
    {
      /* Convert to required format */
      success = _cogl_bitmap_convert_and_premult (&source_bmp,
						  &temp_bmp,
						  closest_format);
      
      /* Swap bitmaps if succeeded */
      if (!success) return FALSE;
      source_bmp = temp_bmp;
      source_bmp_owner = TRUE;
    }
  
  /* Send data to GL */
  _cogl_texture_upload_subregion_to_gl (tex,
					src_x, src_y,
					dst_x, dst_y,
					dst_width, dst_height,
					&source_bmp,
					closest_gl_format,
					closest_gl_type);
  
  /* Free data if owner */
  if (source_bmp_owner)
    g_free (source_bmp.data);
  
  return TRUE;
}

gint
cogl_texture_get_data (CoglHandle       handle,
		       CoglPixelFormat  format,
		       guint            rowstride,
		       guchar          *data)
{
  CoglTexture      *tex;
  gint              bpp;
  gint              byte_size;
  CoglPixelFormat   closest_format;
  gint              closest_bpp;
  GLenum            closest_gl_format;
  GLenum            closest_gl_type;
  CoglBitmap        target_bmp;
  CoglBitmap        new_bmp;
  gboolean          success;
  guchar           *src;
  guchar           *dst;
  gint              y;
  
  /* Check if valid texture handle */
  if (!cogl_is_texture (handle))
    return 0;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  /* Default to internal format if none specified */
  if (format == COGL_PIXEL_FORMAT_ANY)
    format = tex->bitmap.format;
  
  /* Rowstride from texture width if none specified */
  bpp = _cogl_get_format_bpp (format);
  if (rowstride == 0) rowstride = tex->bitmap.width * bpp;
  
  /* Return byte size if only that requested */
  byte_size =  tex->bitmap.height * rowstride;
  if (data == NULL) return byte_size;
  
  /* Find closest format that's supported by GL
     (Can't use _cogl_pixel_format_to_gl since available formats
      when reading pixels on GLES are severely limited) */
  closest_format = COGL_PIXEL_FORMAT_RGBA_8888;
  closest_gl_format = GL_RGBA;
  closest_gl_type = GL_UNSIGNED_BYTE;
  closest_bpp = _cogl_get_format_bpp (closest_format);
  
  /* Is the requested format supported? */
  if (closest_format == format)
    {
      /* Target user data directly */
      target_bmp = tex->bitmap;
      target_bmp.format = format;
      target_bmp.rowstride = rowstride;
      target_bmp.data = data;
    }
  else
    {
      /* Target intermediate buffer */
      target_bmp = tex->bitmap;
      target_bmp.format = closest_format;
      target_bmp.rowstride = target_bmp.width * closest_bpp;
      target_bmp.data = (guchar*) g_malloc (target_bmp.height
					    * target_bmp.rowstride);
    }
  
  /* Retrieve data from slices */
  _cogl_texture_download_from_gl (tex, &target_bmp,
				  closest_gl_format,
				  closest_gl_type);
  
  /* Was intermediate used? */
  if (closest_format != format)
    {
      /* Convert to requested format */
      success = _cogl_bitmap_convert_and_premult (&target_bmp,
						  &new_bmp,
						  format);
      
      /* Free intermediate data and return if failed */
      g_free (target_bmp.data);
      if (!success) return 0;
      
      /* Copy to user buffer */
      for (y = 0; y < new_bmp.height; ++y)
	{
	  src = new_bmp.data + y * new_bmp.rowstride;
	  dst = data + y * rowstride;
	  memcpy (dst, src, new_bmp.width);
	}
      
      /* Free converted data */
      g_free (new_bmp.data);
    }
  
  return byte_size;
}

static void
_cogl_texture_quad_sw (CoglTexture *tex,
		       ClutterFixed x1,
		       ClutterFixed y1,
		       ClutterFixed x2,
		       ClutterFixed y2,
		       ClutterFixed tx1,
		       ClutterFixed ty1,
		       ClutterFixed tx2,
		       ClutterFixed ty2)
{
  _COGL_GET_CONTEXT (ctx, NO_RETVAL);
  
  CoglSpanIter       iter_x    ,  iter_y;
  ClutterFixed       tw        ,  th;
  ClutterFixed       tqx       ,  tqy;
  ClutterFixed       first_tx  ,  first_ty;
  ClutterFixed       first_qx  ,  first_qy;
  ClutterFixed       slice_tx1 ,  slice_ty1;
  ClutterFixed       slice_tx2 ,  slice_ty2;
  ClutterFixed       slice_qx1 ,  slice_qy1;
  ClutterFixed       slice_qx2 ,  slice_qy2;
  GLfixed            tex_coords[8];
  GLfixed            quad_coords[8];
  GLuint             gl_handle;
  
#if COGL_DEBUG
  printf("=== Drawing Tex Quad (Software Tiling Mode) ===\n");
#endif
  
  /* Prepare GL state */
  gulong enable_flags = (COGL_ENABLE_TEXTURE_2D
			 | COGL_ENABLE_VERTEX_ARRAY
			 | COGL_ENABLE_TEXCOORD_ARRAY);
  
  if (ctx->color_alpha < 255
      || tex->bitmap.format & COGL_A_BIT)
    {
      enable_flags |= COGL_ENABLE_BLEND;
    }
  
  cogl_enable (enable_flags);
  
  GE( glTexCoordPointer (2, GL_FIXED, 0, tex_coords) );
  GE( glVertexPointer   (2, GL_FIXED, 0, quad_coords) );
  
  /* Scale ratio from texture to quad widths */
  tw = CLUTTER_INT_TO_FIXED (tex->bitmap.width);
  th = CLUTTER_INT_TO_FIXED (tex->bitmap.height);
  
  tqx = CFX_QDIV (x2-x1, CFX_QMUL (tw, (tx2 - tx1)));
  tqy = CFX_QDIV (y2-y1, CFX_QMUL (th, (ty2 - ty1)));

  /* Integral texture coordinate for first tile */
  first_tx = CLUTTER_INT_TO_FIXED (CLUTTER_FIXED_FLOOR (tx1));
  first_ty = CLUTTER_INT_TO_FIXED (CLUTTER_FIXED_FLOOR (ty1));
  
  /* Denormalize texture coordinates */
  first_tx = CFX_QMUL (first_tx, tw);
  first_ty = CFX_QMUL (first_ty, th);
  tx1 = CFX_QMUL (tx1, tw);
  ty1 = CFX_QMUL (ty1, th);
  tx2 = CFX_QMUL (tx2, tw);
  ty2 = CFX_QMUL (ty2, th);

  /* Quad coordinate of the first tile */
  first_qx = x1 - CFX_QMUL (tx1 - first_tx, tqx);
  first_qy = y1 - CFX_QMUL (ty1 - first_ty, tqy);
  
  
  /* Iterate until whole quad height covered */
  for (_cogl_span_iter_begin (&iter_y, tex->slice_y_spans,
			      first_ty, ty1, ty2) ;
       !_cogl_span_iter_end  (&iter_y) ;
       _cogl_span_iter_next  (&iter_y) )
    { 
      /* Discard slices out of quad early */
      if (!iter_y.intersects) continue;
      
      /* Span-quad intersection in quad coordinates */
      slice_qy1 = first_qy +
	CFX_QMUL (iter_y.intersect_start - first_ty, tqy);
      
      slice_qy2 = first_qy +
	CFX_QMUL (iter_y.intersect_end - first_ty, tqy);
      
      /* Localize slice texture coordinates */
      slice_ty1 = iter_y.intersect_start - iter_y.pos;
      slice_ty2 = iter_y.intersect_end - iter_y.pos;
      
      /* Normalize texture coordinates to current slice */
      slice_ty1 /= iter_y.span->size;
      slice_ty2 /= iter_y.span->size;
      
      
      /* Iterate until whole quad width covered */
      for (_cogl_span_iter_begin (&iter_x, tex->slice_x_spans,
				  first_tx, tx1, tx2) ;
	   !_cogl_span_iter_end  (&iter_x) ;
	   _cogl_span_iter_next  (&iter_x) )
        {
	  /* Discard slices out of quad early */
	  if (!iter_x.intersects) continue;
	  
	  /* Span-quad intersection in quad coordinates */
	  slice_qx1 = first_qx +
	    CFX_QMUL (iter_x.intersect_start - first_tx, tqx);
	  
	  slice_qx2 = first_qx +
	    CFX_QMUL (iter_x.intersect_end - first_tx, tqx);
	  
	  /* Localize slice texture coordinates */
	  slice_tx1 = iter_x.intersect_start - iter_x.pos;
	  slice_tx2 = iter_x.intersect_end - iter_x.pos;
	  
	  /* Normalize texture coordinates to current slice */
	  slice_tx1 /= iter_x.span->size;
	  slice_tx2 /= iter_x.span->size;
	  
#if COGL_DEBUG
	  printf("~~~~~ slice (%d,%d)\n", iter_x.index, iter_y.index);
	  printf("qx1: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_qx1));
	  printf("qy1: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_qy1));
	  printf("qx2: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_qx2));
	  printf("qy2: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_qy2));
	  printf("tx1: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_tx1));
	  printf("ty1: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_ty1));
	  printf("tx2: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_tx2));
	  printf("ty2: %f\n", CLUTTER_FIXED_TO_FLOAT (slice_ty2));
#endif
	  
	  /* Pick and bind opengl texture object */
	  gl_handle = g_array_index (tex->slice_gl_handles, GLuint,
				     iter_y.index * iter_x.array->len +
				     iter_x.index);
	  
	  GE( glBindTexture (tex->gl_target, gl_handle) );
	  
	  /* Draw textured quad */
	  tex_coords[0] = slice_tx1; tex_coords[1] = slice_ty1;
	  tex_coords[2] = slice_tx2; tex_coords[3] = slice_ty1;
	  tex_coords[4] = slice_tx1; tex_coords[5] = slice_ty2;
	  tex_coords[6] = slice_tx2; tex_coords[7] = slice_ty2;
	  
	  quad_coords[0] = slice_qx1; quad_coords[1] = slice_qy1;
	  quad_coords[2] = slice_qx2; quad_coords[3] = slice_qy1;
	  quad_coords[4] = slice_qx1; quad_coords[5] = slice_qy2;
	  quad_coords[6] = slice_qx2; quad_coords[7] = slice_qy2;
	  
	  GE (glDrawArrays (GL_TRIANGLE_STRIP, 0, 4) );
	}
    }
}

static void
_cogl_texture_quad_hw (CoglTexture *tex,
		       ClutterFixed x1,
		       ClutterFixed y1,
		       ClutterFixed x2,
		       ClutterFixed y2,
		       ClutterFixed tx1,
		       ClutterFixed ty1,
		       ClutterFixed tx2,
		       ClutterFixed ty2)
{
  _COGL_GET_CONTEXT (ctx, NO_RETVAL);
  
  GLfixed           tex_coords[8];
  GLfixed           quad_coords[8];
  GLuint            gl_handle;
  CoglTexSliceSpan *x_span;
  CoglTexSliceSpan *y_span;
  
#if COGL_DEBUG
  printf("=== Drawing Tex Quad (Hardware Tiling Mode) ===\n");
#endif
  
  /* Prepare GL state */
  gulong enable_flags = (COGL_ENABLE_TEXTURE_2D
			 | COGL_ENABLE_VERTEX_ARRAY
			 | COGL_ENABLE_TEXCOORD_ARRAY);
  
  if (ctx->color_alpha < 255
      || tex->bitmap.format & COGL_A_BIT)
    {
      enable_flags |= COGL_ENABLE_BLEND;
    }
  
  cogl_enable (enable_flags);
  
  GE( glTexCoordPointer (2, GL_FIXED, 0, tex_coords) );
  GE( glVertexPointer   (2, GL_FIXED, 0, quad_coords) );
  
  /* Pick and bind opengl texture object */
  gl_handle = g_array_index (tex->slice_gl_handles, GLuint, 0);
  GE( glBindTexture (tex->gl_target, gl_handle) );
  
  /* Don't include the waste in the texture coordinates */
  x_span = &g_array_index (tex->slice_x_spans, CoglTexSliceSpan, 0);
  y_span = &g_array_index (tex->slice_y_spans, CoglTexSliceSpan, 0);
  tx1 = tx1 * (x_span->size - x_span->waste) / x_span->size;
  tx2 = tx2 * (x_span->size - x_span->waste) / x_span->size;
  ty1 = ty1 * (y_span->size - y_span->waste) / y_span->size;
  ty2 = ty2 * (y_span->size - y_span->waste) / y_span->size;

  /* Draw textured quad */
  tex_coords[0] = tx1; tex_coords[1] = ty1;
  tex_coords[2] = tx2; tex_coords[3] = ty1;
  tex_coords[4] = tx1; tex_coords[5] = ty2;
  tex_coords[6] = tx2; tex_coords[7] = ty2;
  
  quad_coords[0] = x1; quad_coords[1] = y1;
  quad_coords[2] = x2; quad_coords[3] = y1;
  quad_coords[4] = x1; quad_coords[5] = y2;
  quad_coords[6] = x2; quad_coords[7] = y2;
  
  GE (glDrawArrays (GL_TRIANGLE_STRIP, 0, 4) );
}

void
cogl_texture_rectangle (CoglHandle   handle,
			ClutterFixed x1,
			ClutterFixed y1,
			ClutterFixed x2,
			ClutterFixed y2,
			ClutterFixed tx1,
			ClutterFixed ty1,
			ClutterFixed tx2,
			ClutterFixed ty2)
{
  CoglTexture       *tex;
  ClutterFixed       tempx;
  
  /* Check if valid texture */
  if (!cogl_is_texture (handle))
    return;
  
  tex = _cogl_texture_pointer_from_handle (handle);
  
  /* Make sure we got stuff to draw */
  if (tex->slice_gl_handles == NULL)
    return;
  
  if (tex->slice_gl_handles->len == 0)
    return;
  
  if (tx1 == tx2 || ty1 == ty2)
    return;
  
  /* Fix quad coord ordering */
  if (x1 > x2)
    {
      tempx = x1;
      x1 = x2;
      x2 = tempx;
    }
  
  if (y1 > y2)
    {
      tempx = y1;
      y1 = y2;
      y2 = tempx;
    }
  
  /* Fix texture coord ordering */
  if (tx1 > tx2)
    {
      tempx = tx1;
      tx1 = tx2;
      tx2 = tempx;
    }
  
  if (ty1 > ty2)
    {
      tempx = ty1;
      ty1 = ty2;
      ty2 = tempx;
    }
  
  /* Tile textured quads */
  if (tex->slice_gl_handles->len == 1
      && tx1 >= -CFX_ONE && tx2 <= CFX_ONE
      && ty1 >= -CFX_ONE && ty2 <= CFX_ONE)
    {
      _cogl_texture_quad_hw (tex, x1,y1, x2,y2, tx1,ty1, tx2,ty2);
    }
  else
    {
      _cogl_texture_quad_sw (tex, x1,y1, x2,y2, tx1,ty1, tx2,ty2);
    }
}

void
cogl_texture_polygon (CoglHandle         handle,
		      guint              n_vertices,
		      CoglTextureVertex *vertices,
		      gboolean           use_color)
{
  CoglTexture         *tex;
  GLuint               gl_handle;
  gulong               enable_flags;
  int                  i;
  CoglTextureGLVertex *p;
  CoglTexSliceSpan    *x_span;
  CoglTexSliceSpan    *y_span;

  _COGL_GET_CONTEXT (ctx, NO_RETVAL);
  
  /* Check if valid texture */
  if (!cogl_is_texture (handle))
    return;

  tex = _cogl_texture_pointer_from_handle (handle);

  /* GL ES has no GL_CLAMP_TO_BORDER wrap mode so the method used to
     render sliced textures in the GL backend will not work. Therefore
     cogl_texture_polygon is only supported if the texture is not
     sliced */
  if (tex->slice_gl_handles->len != 1)
    {
      static gboolean shown_warning = FALSE;

      if (!shown_warning)
	{
	  g_warning ("cogl_texture_polygon does not work for "
		     "sliced textures on GL ES");
	  shown_warning = TRUE;
	}
      return;
    }

  /* Make sure there is enough space in the global texture vertex
     array. This is used so we can render the polygon with a single
     call to OpenGL but still support any number of vertices */
  if (ctx->texture_vertices_size < n_vertices)
    {
      guint nsize = ctx->texture_vertices_size;
      
      if (nsize == 0)
	nsize = 1;
      do
	nsize *= 2;
      while (nsize < n_vertices);
      
      ctx->texture_vertices_size = nsize;

      if (ctx->texture_vertices)
	ctx->texture_vertices = g_realloc (ctx->texture_vertices,
					   nsize
					   * sizeof (CoglTextureGLVertex));
      else
	ctx->texture_vertices = g_malloc (nsize
					  * sizeof (CoglTextureGLVertex));
    }
  
  /* Prepare GL state */
  enable_flags = (COGL_ENABLE_TEXTURE_2D
		  | COGL_ENABLE_VERTEX_ARRAY
		  | COGL_ENABLE_TEXCOORD_ARRAY);

  if ((tex->bitmap.format & COGL_A_BIT))
    enable_flags |= COGL_ENABLE_BLEND;
  else if (use_color)
    {
      for (i = 0; i < n_vertices; i++)
	if (vertices[i].color.alpha < 255)
	  {
	    enable_flags |= COGL_ENABLE_BLEND;
	    break;
	  }
    }
  else if (ctx->color_alpha < 255)
    enable_flags |= COGL_ENABLE_BLEND;

  if (use_color)
    {
      enable_flags |= COGL_ENABLE_COLOR_ARRAY;
      GE( glColorPointer (4, GL_FIXED, sizeof (CoglTextureGLVertex),
			  ctx->texture_vertices[0].c) );
    }
 
  GE( glVertexPointer (3, GL_FIXED, sizeof (CoglTextureGLVertex),
		       ctx->texture_vertices[0].v) );
  GE( glTexCoordPointer (2, GL_FIXED, sizeof (CoglTextureGLVertex),
			 ctx->texture_vertices[0].t) );

  cogl_enable (enable_flags);
  
  gl_handle = g_array_index (tex->slice_gl_handles, GLuint, 0);
  x_span = &g_array_index (tex->slice_x_spans, CoglTexSliceSpan, 0);
  y_span = &g_array_index (tex->slice_y_spans, CoglTexSliceSpan, 0);

  /* Convert the vertices into an array of GLfixeds ready to pass to
     OpenGL */
  for (i = 0, p = ctx->texture_vertices; i < n_vertices; i++, p++)
    {
      p->v[0] = vertices[i].x;
      p->v[1] = vertices[i].y;
      p->v[2] = vertices[i].z;
      p->t[0] = vertices[i].tx * (x_span->size - x_span->waste) / x_span->size;
      p->t[1] = vertices[i].ty * (y_span->size - y_span->waste) / y_span->size;
      p->c[0] = (vertices[i].color.red << 16) / 0xff;
      p->c[1] = (vertices[i].color.green << 16) / 0xff;
      p->c[2] = (vertices[i].color.blue << 16) / 0xff;
      p->c[3] = (vertices[i].color.alpha << 16) / 0xff;
    }

  GE( glBindTexture (tex->gl_target, gl_handle) );

  GE( glDrawArrays (GL_TRIANGLE_FAN, 0, n_vertices) );

  /* Set the last color so that the cache of the alpha value will work
     properly */
  if (use_color && n_vertices > 0)
    cogl_color (&vertices[n_vertices - 1].color);
}