/*
 * Cogl
 *
 * An object oriented GL/GLES Abstraction/Utility Layer
 *
 * Copyright (C) 2007,2008,2009 Intel Corporation.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 *
 *
 * Authors:
 *  Matthew Allum  <mallum@openedhand.com>
 *  Neil Roberts   <neil@linux.intel.com>
 *  Robert Bragg   <robert@linux.intel.com>
 */

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

#include "cogl-private.h"
#include "cogl-util.h"
#include "cogl-bitmap.h"
#include "cogl-bitmap-private.h"
#include "cogl-texture-private.h"
#include "cogl-pipeline.h"
#include "cogl-pipeline-opengl-private.h"
#include "cogl-context-private.h"
#include "cogl-handle.h"
#include "cogl-primitives.h"

#include <string.h>
#include <stdlib.h>
#include <math.h>

#ifndef GL_TEXTURE_3D
#define GL_TEXTURE_3D 0x806F
#endif
#ifndef GL_MAX_3D_TEXTURE_SIZE_OES
#define GL_MAX_3D_TEXTURE_SIZE_OES 0x8073
#endif

static void
_cogl_texture_driver_gen (CoglContext *ctx,
                          GLenum gl_target,
                          GLsizei n,
                          GLuint *textures)
{
  unsigned int i;

  GE (ctx, glGenTextures (n, textures));

  for (i = 0; i < n; i++)
    {
      _cogl_bind_gl_texture_transient (gl_target, textures[i], FALSE);

      switch (gl_target)
        {
        case GL_TEXTURE_2D:
        case GL_TEXTURE_3D:
          /* GL_TEXTURE_MAG_FILTER defaults to GL_LINEAR, no need to set it */
          GE( ctx, glTexParameteri (gl_target,
                                    GL_TEXTURE_MIN_FILTER,
                                    GL_LINEAR) );
          break;

        default:
          g_assert_not_reached();
        }
    }
}

static void
_cogl_texture_driver_prep_gl_for_pixels_upload (CoglContext *context,
                                                int pixels_rowstride,
                                                int pixels_bpp)
{
  _cogl_texture_prep_gl_alignment_for_pixels_upload (pixels_rowstride);
}

static void
_cogl_texture_driver_prep_gl_for_pixels_download (CoglContext *ctx,
                                                  int pixels_rowstride,
                                                  int pixels_bpp)
{
  _cogl_texture_prep_gl_alignment_for_pixels_download (pixels_rowstride);
}

static CoglBitmap *
prepare_bitmap_alignment_for_upload (CoglContext *ctx,
                                     CoglBitmap *src_bmp)
{
  CoglPixelFormat format = cogl_bitmap_get_format (src_bmp);
  int bpp = _cogl_pixel_format_get_bytes_per_pixel (format);
  int src_rowstride = cogl_bitmap_get_rowstride (src_bmp);
  int width = cogl_bitmap_get_width (src_bmp);
  int alignment = 1;

  if (src_rowstride == 0)
    return cogl_object_ref (src_bmp);

  /* Work out the alignment of the source rowstride */
  alignment = 1 << (_cogl_util_ffs (src_rowstride) - 1);
  alignment = MIN (alignment, 8);

  /* If the aligned data equals the rowstride then we can upload from
     the bitmap directly using GL_UNPACK_ALIGNMENT */
  if (((width * bpp + alignment - 1) & ~(alignment - 1)) == src_rowstride)
    return cogl_object_ref (src_bmp);
  /* Otherwise we need to copy the bitmap to pack the alignment
     because GLES has no GL_ROW_LENGTH */
  else
    return _cogl_bitmap_copy (src_bmp);
}

static void
_cogl_texture_driver_upload_subregion_to_gl (CoglContext *ctx,
                                             GLenum       gl_target,
                                             GLuint       gl_handle,
                                             gboolean     is_foreign,
                                             int          src_x,
                                             int          src_y,
                                             int          dst_x,
                                             int          dst_y,
                                             int          width,
                                             int          height,
                                             CoglBitmap  *source_bmp,
				             GLuint       source_gl_format,
				             GLuint       source_gl_type)
{
  guint8 *data;
  CoglPixelFormat source_format = cogl_bitmap_get_format (source_bmp);
  int bpp = _cogl_pixel_format_get_bytes_per_pixel (source_format);
  CoglBitmap *slice_bmp;
  int rowstride;

  /* If we are copying a sub region of the source bitmap then we need
     to copy it because GLES does not support GL_UNPACK_ROW_LENGTH */
  if (src_x != 0 || src_y != 0 ||
      width != cogl_bitmap_get_width (source_bmp) ||
      height != cogl_bitmap_get_height (source_bmp))
    {
      slice_bmp =
        _cogl_bitmap_new_with_malloc_buffer (ctx,
                                             width, height,
                                             source_format);
      _cogl_bitmap_copy_subregion (source_bmp,
                                   slice_bmp,
                                   src_x, src_y,
                                   0, 0, /* dst_x/y */
                                   width, height);
    }
  else
    slice_bmp = prepare_bitmap_alignment_for_upload (ctx, source_bmp);

  rowstride = cogl_bitmap_get_rowstride (slice_bmp);

  /* Setup gl alignment to match rowstride and top-left corner */
  _cogl_texture_driver_prep_gl_for_pixels_upload (ctx, rowstride, bpp);

  data = _cogl_bitmap_bind (slice_bmp, COGL_BUFFER_ACCESS_READ, 0);

  _cogl_bind_gl_texture_transient (gl_target, gl_handle, is_foreign);

  GE( ctx, glTexSubImage2D (gl_target, 0,
                            dst_x, dst_y,
                            width, height,
                            source_gl_format,
                            source_gl_type,
                            data) );

  _cogl_bitmap_unbind (slice_bmp);

  cogl_object_unref (slice_bmp);
}

static void
_cogl_texture_driver_upload_to_gl (CoglContext *ctx,
                                   GLenum       gl_target,
                                   GLuint       gl_handle,
                                   gboolean     is_foreign,
                                   CoglBitmap  *source_bmp,
                                   GLint        internal_gl_format,
                                   GLuint       source_gl_format,
                                   GLuint       source_gl_type)
{
  CoglPixelFormat source_format = cogl_bitmap_get_format (source_bmp);
  int bpp = _cogl_pixel_format_get_bytes_per_pixel (source_format);
  int rowstride;
  int bmp_width = cogl_bitmap_get_width (source_bmp);
  int bmp_height = cogl_bitmap_get_height (source_bmp);
  CoglBitmap *bmp;
  guint8 *data;

  bmp = prepare_bitmap_alignment_for_upload (ctx, source_bmp);
  rowstride = cogl_bitmap_get_rowstride (bmp);

  /* Setup gl alignment to match rowstride and top-left corner */
  _cogl_texture_driver_prep_gl_for_pixels_upload (ctx, rowstride, bpp);

  _cogl_bind_gl_texture_transient (gl_target, gl_handle, is_foreign);

  data = _cogl_bitmap_bind (bmp, COGL_BUFFER_ACCESS_READ, 0);

  GE( ctx, glTexImage2D (gl_target, 0,
                         internal_gl_format,
                         bmp_width, bmp_height,
                         0,
                         source_gl_format,
                         source_gl_type,
                         data) );

  _cogl_bitmap_unbind (bmp);

  cogl_object_unref (bmp);
}

static void
_cogl_texture_driver_upload_to_gl_3d (CoglContext *ctx,
                                      GLenum       gl_target,
                                      GLuint       gl_handle,
                                      gboolean     is_foreign,
                                      GLint        height,
                                      GLint        depth,
                                      CoglBitmap  *source_bmp,
                                      GLint        internal_gl_format,
                                      GLuint       source_gl_format,
                                      GLuint       source_gl_type)
{
  CoglPixelFormat source_format = cogl_bitmap_get_format (source_bmp);
  int bpp = _cogl_pixel_format_get_bytes_per_pixel (source_format);
  int rowstride = cogl_bitmap_get_rowstride (source_bmp);
  int bmp_width = cogl_bitmap_get_width (source_bmp);
  int bmp_height = cogl_bitmap_get_height (source_bmp);
  guint8 *data;

  _cogl_bind_gl_texture_transient (gl_target, gl_handle, is_foreign);

  /* If the rowstride or image height can't be specified with just
     GL_ALIGNMENT alone then we need to copy the bitmap because there
     is no GL_ROW_LENGTH */
  if (rowstride / bpp != bmp_width ||
      height != bmp_height / depth)
    {
      CoglBitmap *bmp;
      int image_height = bmp_height / depth;
      CoglPixelFormat source_bmp_format = cogl_bitmap_get_format (source_bmp);
      int i;

      _cogl_texture_driver_prep_gl_for_pixels_upload (ctx, bmp_width * bpp, bpp);

      /* Initialize the texture with empty data and then upload each
         image with a sub-region update */

      GE( ctx, glTexImage3D (gl_target,
                             0, /* level */
                             internal_gl_format,
                             bmp_width,
                             height,
                             depth,
                             0,
                             source_gl_format,
                             source_gl_type,
                             NULL) );

      bmp = _cogl_bitmap_new_with_malloc_buffer (ctx,
                                                 bmp_width,
                                                 height,
                                                 source_bmp_format);

      for (i = 0; i < depth; i++)
        {
          _cogl_bitmap_copy_subregion (source_bmp,
                                       bmp,
                                       0, image_height * i,
                                       0, 0,
                                       bmp_width,
                                       height);

          data = _cogl_bitmap_bind (bmp,
                                    COGL_BUFFER_ACCESS_READ, 0);

          GE( ctx, glTexSubImage3D (gl_target,
                                    0, /* level */
                                    0, /* xoffset */
                                    0, /* yoffset */
                                    i, /* zoffset */
                                    bmp_width, /* width */
                                    height, /* height */
                                    1, /* depth */
                                    source_gl_format,
                                    source_gl_type,
                                    data) );

          _cogl_bitmap_unbind (bmp);
        }

      cogl_object_unref (bmp);
    }
  else
    {
      data = _cogl_bitmap_bind (source_bmp, COGL_BUFFER_ACCESS_READ, 0);

      _cogl_texture_driver_prep_gl_for_pixels_upload (ctx, rowstride, bpp);

      GE( ctx, glTexImage3D (gl_target,
                             0, /* level */
                             internal_gl_format,
                             bmp_width,
                             height,
                             depth,
                             0,
                             source_gl_format,
                             source_gl_type,
                             data) );

      _cogl_bitmap_unbind (source_bmp);
    }
}

/* NB: GLES doesn't support glGetTexImage2D, so cogl-texture will instead
 * fallback to a generic render + readpixels approach to downloading
 * texture data. (See _cogl_texture_draw_and_read() ) */
static gboolean
_cogl_texture_driver_gl_get_tex_image (CoglContext *ctx,
                                       GLenum gl_target,
                                       GLenum dest_gl_format,
                                       GLenum dest_gl_type,
                                       guint8 *dest)
{
  return FALSE;
}

static gboolean
_cogl_texture_driver_size_supported_3d (CoglContext *ctx,
                                        GLenum gl_target,
                                        GLenum gl_format,
                                        GLenum gl_type,
                                        int width,
                                        int height,
                                        int depth)
{
  GLint max_size;

  /* GLES doesn't support a proxy texture target so let's at least
     check whether the size is greater than
     GL_MAX_3D_TEXTURE_SIZE_OES */
  GE( ctx, glGetIntegerv (GL_MAX_3D_TEXTURE_SIZE_OES, &max_size) );

  return width <= max_size && height <= max_size && depth <= max_size;
}

static gboolean
_cogl_texture_driver_size_supported (CoglContext *ctx,
                                     GLenum gl_target,
                                     GLenum gl_format,
                                     GLenum gl_type,
                                     int width,
                                     int height)
{
  GLint max_size;

  /* GLES doesn't support a proxy texture target so let's at least
     check whether the size is greater than GL_MAX_TEXTURE_SIZE */
  GE( ctx, glGetIntegerv (GL_MAX_TEXTURE_SIZE, &max_size) );

  return width <= max_size && height <= max_size;
}

static void
_cogl_texture_driver_try_setting_gl_border_color
                                            (CoglContext *ctx,
                                             GLuint gl_target,
                                             const GLfloat *transparent_color)
{
  /* FAIL! */
}

static gboolean
_cogl_texture_driver_allows_foreign_gl_target (CoglContext *ctx,
                                               GLenum gl_target)
{
  /* Allow 2-dimensional textures only */
  if (gl_target != GL_TEXTURE_2D)
    return FALSE;
  return TRUE;
}

static void
_cogl_texture_driver_gl_generate_mipmaps (CoglContext *ctx,
                                          GLenum gl_target)
{
  if (ctx->driver == COGL_DRIVER_GLES2)
    GE( ctx, glGenerateMipmap (gl_target) );
}

static CoglPixelFormat
_cogl_texture_driver_find_best_gl_get_data_format
                                            (CoglContext *context,
                                             CoglPixelFormat format,
                                             GLenum *closest_gl_format,
                                             GLenum *closest_gl_type)
{
  /* 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_gl_format = GL_RGBA;
  *closest_gl_type = GL_UNSIGNED_BYTE;
  return COGL_PIXEL_FORMAT_RGBA_8888;
}

const CoglTextureDriver
_cogl_texture_driver_gles =
  {
    _cogl_texture_driver_gen,
    _cogl_texture_driver_prep_gl_for_pixels_upload,
    _cogl_texture_driver_upload_subregion_to_gl,
    _cogl_texture_driver_upload_to_gl,
    _cogl_texture_driver_upload_to_gl_3d,
    _cogl_texture_driver_prep_gl_for_pixels_download,
    _cogl_texture_driver_gl_get_tex_image,
    _cogl_texture_driver_size_supported,
    _cogl_texture_driver_size_supported_3d,
    _cogl_texture_driver_try_setting_gl_border_color,
    _cogl_texture_driver_allows_foreign_gl_target,
    _cogl_texture_driver_gl_generate_mipmaps,
    _cogl_texture_driver_find_best_gl_get_data_format
  };