/*
 * Cogl
 *
 * An object oriented GL/GLES Abstraction/Utility Layer
 *
 * Copyright (C) 2008,2009,2010 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:
 *   Neil Roberts <neil@linux.intel.com>
 */

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

#include "cogl-context-private.h"
#include "cogl-pipeline-private.h"
#include "cogl-pipeline-state-private.h"
#include "cogl-pipeline-opengl-private.h"

#ifdef COGL_PIPELINE_VERTEND_FIXED

#include "cogl-internal.h"
#include "cogl-context-private.h"
#include "cogl-handle.h"
#include "cogl-program-private.h"

const CoglPipelineVertend _cogl_pipeline_fixed_vertend;

static gboolean
_cogl_pipeline_vertend_fixed_start (CoglPipeline *pipeline,
                                    int n_layers,
                                    unsigned long pipelines_difference,
                                    int n_tex_coord_attribs)
{
  CoglProgram *user_program;

  _COGL_GET_CONTEXT (ctx, FALSE);

  if (G_UNLIKELY (COGL_DEBUG_ENABLED (COGL_DEBUG_DISABLE_FIXED)))
    return FALSE;

  if (ctx->driver == COGL_DRIVER_GLES2)
    return FALSE;

  /* Vertex snippets are only supported in the GLSL fragend */
  if (_cogl_pipeline_has_vertex_snippets (pipeline))
    return FALSE;

  /* If there is a user program with a vertex shader then the
     appropriate backend for that language should handle it. We can
     still use the fixed vertex backend if the program only contains
     a fragment shader */
  user_program = cogl_pipeline_get_user_program (pipeline);
  if (user_program != COGL_INVALID_HANDLE &&
      _cogl_program_has_vertex_shader (user_program))
    return FALSE;

  _cogl_use_vertex_program (0, COGL_PIPELINE_PROGRAM_TYPE_FIXED);

  return TRUE;
}

static gboolean
_cogl_pipeline_vertend_fixed_add_layer (CoglPipeline *pipeline,
                                        CoglPipelineLayer *layer,
                                        unsigned long layers_difference)
{
  int unit_index = _cogl_pipeline_layer_get_unit_index (layer);
  CoglTextureUnit *unit = _cogl_get_texture_unit (unit_index);

  _COGL_GET_CONTEXT (ctx, FALSE);

  if (layers_difference & COGL_PIPELINE_LAYER_STATE_USER_MATRIX)
    {
      CoglPipelineLayerState state = COGL_PIPELINE_LAYER_STATE_USER_MATRIX;
      CoglPipelineLayer *authority =
        _cogl_pipeline_layer_get_authority (layer, state);

      _cogl_matrix_stack_set (unit->matrix_stack,
                              &authority->big_state->matrix);

      _cogl_set_active_texture_unit (unit_index);

      _cogl_matrix_stack_flush_to_gl_builtins (ctx, unit->matrix_stack,
                                               COGL_MATRIX_TEXTURE,
                                               FALSE /* enable flip */);
    }

  return TRUE;
}

static gboolean
_cogl_pipeline_vertend_fixed_end (CoglPipeline *pipeline,
                                  unsigned long pipelines_difference)
{
  _COGL_GET_CONTEXT (ctx, FALSE);

  if (pipelines_difference & COGL_PIPELINE_STATE_POINT_SIZE)
    {
      CoglPipeline *authority =
        _cogl_pipeline_get_authority (pipeline, COGL_PIPELINE_STATE_POINT_SIZE);

      GE( ctx, glPointSize (authority->big_state->point_size) );
    }

  return TRUE;
}

const CoglPipelineVertend _cogl_pipeline_fixed_vertend =
{
  _cogl_pipeline_vertend_fixed_start,
  _cogl_pipeline_vertend_fixed_add_layer,
  _cogl_pipeline_vertend_fixed_end,
  NULL, /* pipeline_change_notify */
  NULL /* layer_change_notify */
};

#endif /* COGL_PIPELINE_VERTEND_FIXED */