mutter-performance-source/clutter/cogl/gles/cogl-gles2-wrapper.c

/*
 * Cogl
 *
 * An object oriented GL/GLES Abstraction/Utility Layer
 *
 * Copyright (C) 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, 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 <clutter/clutter-fixed.h>
#include <string.h>
#include <math.h>

/* We don't want to get the remaps from the gl* functions to the
   cogl_wrap_gl* functions in this file because we need to be able to
   call the base version */
#define COGL_GLES2_WRAPPER_NO_REMAP 1

#include "cogl.h"
#include "cogl-gles2-wrapper.h"
#include "cogl-fixed-vertex-shader.h"
#include "cogl-fixed-fragment-shader.h"
#include "cogl-context.h"
#include "cogl-shader-private.h"
#include "cogl-program.h"
#include "cogl-internal.h"

#define _COGL_GET_GLES2_WRAPPER(wvar, retval)			\
  CoglGles2Wrapper *wvar;					\
  {								\
    CoglContext *__ctxvar = _cogl_context_get_default ();	\
    if (__ctxvar == NULL) return retval;			\
    wvar = &__ctxvar->gles2;					\
  }

#define _COGL_GLES2_CHANGE_SETTING(w, var, val)	\
  do						\
    if ((w)->settings.var != (val))		\
      {						\
	(w)->settings.var = (val);		\
	(w)->settings_dirty = TRUE;		\
      }						\
  while (0)

#define _COGL_GLES2_CHANGE_UNIFORM(w, flag, var, val)		\
  do								\
    if ((w)->var != (val))					\
      {								\
	(w)->var = (val);					\
	(w)->dirty_uniforms |= COGL_GLES2_DIRTY_ ## flag;	\
      }								\
  while (0)

#define COGL_GLES2_WRAPPER_VERTEX_ATTRIB    0
#define COGL_GLES2_WRAPPER_COLOR_ATTRIB     1
#define COGL_GLES2_WRAPPER_NORMAL_ATTRIB    2


static GLuint
cogl_gles2_wrapper_create_shader (GLenum type, const char *source)
{
  GLuint shader;
  GLint source_len = strlen (source);
  GLint status;

  shader = glCreateShader (type);
  glShaderSource (shader, 1, &source, &source_len);
  glCompileShader (shader);

  glGetShaderiv (shader, GL_COMPILE_STATUS, &status);

  if (!status)
    {
      char shader_log[1024];
      GLint len;

      glGetShaderInfoLog (shader, sizeof (shader_log) - 1, &len, shader_log);
      shader_log[len] = '\0';

      g_critical ("%s", shader_log);

      glDeleteShader (shader);

      return 0;
    }

  return shader;
}

static void
initialize_texture_units (CoglGles2Wrapper *w)
{
  /* We save the active texture unit since we may need to temporarily
   * change this to initialise each new texture unit and we want to
   * restore the active unit afterwards */
  int initial_active_unit = w->active_texture_unit;
  GLint prev_mode;
  int i;

  /* We will need to set the matrix mode to GL_TEXTURE to
   * initialise any new texture units, so we save the current
   * mode for restoring afterwards */
  GE( cogl_wrap_glGetIntegerv (CGL_MATRIX_MODE, &prev_mode));

  for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
    {
      CoglGles2WrapperTextureUnit *new_unit;

      new_unit = w->texture_units + i;
      memset (new_unit, 0, sizeof (CoglGles2WrapperTextureUnit));

      w->active_texture_unit = i;
      GE( cogl_wrap_glMatrixMode (GL_TEXTURE));
      GE( cogl_wrap_glLoadIdentity ());
    }

  GE( cogl_wrap_glMatrixMode ((GLenum) prev_mode));

  w->settings.texture_units = 0;

  w->active_texture_unit = initial_active_unit;
}

void
cogl_gles2_wrapper_init (CoglGles2Wrapper *wrapper)
{
  GLfloat default_fog_color[4] = { 0, 0, 0, 0 };

  memset (wrapper, 0, sizeof (CoglGles2Wrapper));

  /* Initialize the stacks */
  cogl_wrap_glMatrixMode (GL_PROJECTION);
  cogl_wrap_glLoadIdentity ();
  cogl_wrap_glMatrixMode (GL_MODELVIEW);
  cogl_wrap_glLoadIdentity ();

  /* The gl*ActiveTexture wrappers will initialise the texture
   * stack for the texture unit when it's first activated */
  cogl_wrap_glActiveTexture (GL_TEXTURE0);
  cogl_wrap_glClientActiveTexture (GL_TEXTURE0);

  /* Initialize the fogging options */
  cogl_wrap_glDisable (GL_FOG);
  cogl_wrap_glFogf (GL_FOG_MODE, GL_LINEAR);
  cogl_wrap_glFogf (GL_FOG_DENSITY, 1.0);
  cogl_wrap_glFogf (GL_FOG_START, 0);
  cogl_wrap_glFogf (GL_FOG_END, 1);
  cogl_wrap_glFogfv (GL_FOG_COLOR, default_fog_color);

  /* Initialize alpha testing */
  cogl_wrap_glDisable (GL_ALPHA_TEST);
  cogl_wrap_glAlphaFunc (GL_ALWAYS, 0.0f);

  initialize_texture_units (wrapper);
}

static gboolean
cogl_gles2_settings_equal (const CoglGles2WrapperSettings *a,
			   const CoglGles2WrapperSettings *b,
			   gboolean vertex_tests,
			   gboolean fragment_tests)
{
  if (a->texture_units != b->texture_units)
    return FALSE;

  if (fragment_tests)
    {
      if (a->alpha_test_enabled != b->alpha_test_enabled)
	return FALSE;
      if (a->alpha_test_enabled && a->alpha_test_func != b->alpha_test_func)
	return FALSE;
    }

  if (a->fog_enabled != b->fog_enabled)
    return FALSE;

  if (vertex_tests && a->fog_enabled && a->fog_mode != b->fog_mode)
    return FALSE;

  return TRUE;
}

static CoglGles2WrapperShader *
cogl_gles2_get_vertex_shader (const CoglGles2WrapperSettings *settings)
{
  GString *shader_source;
  GLuint shader_obj;
  CoglGles2WrapperShader *shader;
  GSList *node;
  int i;
  int n_texture_units = 0;

  _COGL_GET_GLES2_WRAPPER (w, NULL);

  /* Check if we already have a vertex shader for these settings */
  for (node = w->compiled_vertex_shaders; node; node = node->next)
    if (cogl_gles2_settings_equal (settings,
				   &((CoglGles2WrapperShader *)
				     node->data)->settings,
				   TRUE, FALSE))
      return (CoglGles2WrapperShader *) node->data;

  /* Otherwise create a new shader */
  shader_source = g_string_new (cogl_fixed_vertex_shader_per_vertex_attribs);

  for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
    if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
      g_string_append_printf (shader_source,
			      "attribute vec4 multi_tex_coord_attrib%d;\n",
			      i);

  /* Find the biggest enabled texture unit index */
  for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
    if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
      n_texture_units = i + 1;

  g_string_append (shader_source, cogl_fixed_vertex_shader_transform_matrices);
  g_string_append (shader_source, cogl_fixed_vertex_shader_output_variables);

  if (n_texture_units > 0)
    {
      g_string_append_printf (shader_source,
                              "uniform mat4	      texture_matrix[%d];\n",
                              n_texture_units);

      g_string_append_printf (shader_source,
                              "varying vec2       tex_coord[%d];",
                              n_texture_units);
    }

  g_string_append (shader_source, cogl_fixed_vertex_shader_fogging_options);
  g_string_append (shader_source, cogl_fixed_vertex_shader_main_start);

  for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
    if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
      {
        g_string_append_printf (shader_source,
                                "transformed_tex_coord = "
                                "texture_matrix[%d] "
                                " * multi_tex_coord_attrib%d;\n",
                                i, i);
        g_string_append_printf (shader_source,
                                "tex_coord[%d] = transformed_tex_coord.st "
                                " / transformed_tex_coord.q;\n",
                                i);
      }

  g_string_append (shader_source, cogl_fixed_vertex_shader_frag_color_start);

  if (settings->fog_enabled)
    {
      g_string_append (shader_source, cogl_fixed_vertex_shader_fog_start);

      switch (settings->fog_mode)
	{
	case GL_EXP:
	  g_string_append (shader_source, cogl_fixed_vertex_shader_fog_exp);
	  break;

	case GL_EXP2:
	  g_string_append (shader_source, cogl_fixed_vertex_shader_fog_exp2);
	  break;

	default:
	  g_string_append (shader_source, cogl_fixed_vertex_shader_fog_linear);
	  break;
	}

      g_string_append (shader_source, cogl_fixed_vertex_shader_fog_end);
    }

  g_string_append (shader_source, cogl_fixed_vertex_shader_end);

  shader_obj = cogl_gles2_wrapper_create_shader (GL_VERTEX_SHADER,
						 shader_source->str);

  g_string_free (shader_source, TRUE);

  if (shader_obj == 0)
    return NULL;

  shader = g_slice_new (CoglGles2WrapperShader);
  shader->shader = shader_obj;
  shader->settings = *settings;

  w->compiled_vertex_shaders = g_slist_prepend (w->compiled_vertex_shaders,
						shader);

  return shader;
}

static CoglGles2WrapperShader *
cogl_gles2_get_fragment_shader (const CoglGles2WrapperSettings *settings)
{
  GString *shader_source;
  GLuint shader_obj;
  CoglGles2WrapperShader *shader;
  GSList *node;
  int i;
  int n_texture_units = 0;

  _COGL_GET_GLES2_WRAPPER (w, NULL);

  /* Check if we already have a fragment shader for these settings */
  for (node = w->compiled_fragment_shaders; node; node = node->next)
    if (cogl_gles2_settings_equal (settings,
				   &((CoglGles2WrapperShader *)
				     node->data)->settings,
				   FALSE, TRUE))
      return (CoglGles2WrapperShader *) node->data;

  /* Otherwise create a new shader */
  shader_source = g_string_new (cogl_fixed_fragment_shader_variables_start);

  /* Find the biggest enabled texture unit index */
  for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
    if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
      n_texture_units = i + 1;

  g_string_append (shader_source, cogl_fixed_fragment_shader_inputs);

  if (n_texture_units > 0)
    {
      g_string_append_printf (shader_source,
                              "varying vec2       tex_coord[%d];\n",
                              n_texture_units);

      g_string_append (shader_source, cogl_fixed_fragment_shader_texturing_options);
      g_string_append_printf (shader_source,
                              "uniform sampler2D  texture_unit[%d];\n",
                              n_texture_units);
    }

  g_string_append (shader_source, cogl_fixed_fragment_shader_fogging_options);

  g_string_append (shader_source, cogl_fixed_fragment_shader_main_declare);

  g_string_append (shader_source, cogl_fixed_fragment_shader_main_start);

  /* This pointless extra variable is needed to work around an
     apparent bug in the PowerVR drivers. Without it the alpha
     blending seems to stop working */
  g_string_append (shader_source,
		   "vec4 frag_color_copy = frag_color;\n");
  g_string_append (shader_source, "gl_FragColor = frag_color;\n");

  for (i = 0; i < n_texture_units; i++)
    if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
      {
        if (COGL_GLES2_TEXTURE_UNIT_IS_ALPHA_ONLY (settings->texture_units, i))
          /* If the texture only has an alpha channel (eg, with the textures
             from the pango renderer) then the RGB components will be
             black. We want to use the RGB from the current color in that
             case */
          g_string_append_printf (shader_source,
                                  "gl_FragColor.a *= "
                                  "texture2D (texture_unit[%d], "
                                  "tex_coord[%d]).a;\n",
                                  i, i);
        else
          g_string_append_printf (shader_source,
                                  "gl_FragColor *= "
                                  "texture2D (texture_unit[%d], "
                                  "tex_coord[%d]);\n",
                                  i, i);
      }

  if (settings->fog_enabled)
    g_string_append (shader_source, cogl_fixed_fragment_shader_fog);

  if (settings->alpha_test_enabled)
    switch (settings->alpha_test_func)
      {
      case GL_NEVER:
	g_string_append (shader_source,
			 cogl_fixed_fragment_shader_alpha_never);
	break;
      case GL_LESS:
	g_string_append (shader_source,
			 cogl_fixed_fragment_shader_alpha_less);
	break;
      case GL_EQUAL:
	g_string_append (shader_source,
			 cogl_fixed_fragment_shader_alpha_equal);
	break;
      case GL_LEQUAL:
	g_string_append (shader_source,
			 cogl_fixed_fragment_shader_alpha_lequal);
	break;
      case GL_GREATER:
	g_string_append (shader_source,
			 cogl_fixed_fragment_shader_alpha_greater);
	break;
      case GL_NOTEQUAL:
	g_string_append (shader_source,
			 cogl_fixed_fragment_shader_alpha_notequal);
	break;
      case GL_GEQUAL:
	g_string_append (shader_source,
			 cogl_fixed_fragment_shader_alpha_gequal);
      }

  g_string_append (shader_source, cogl_fixed_fragment_shader_end);

  shader_obj = cogl_gles2_wrapper_create_shader (GL_FRAGMENT_SHADER,
						 shader_source->str);

  g_string_free (shader_source, TRUE);

  if (shader_obj == 0)
    return NULL;

  shader = g_slice_new (CoglGles2WrapperShader);
  shader->shader = shader_obj;
  shader->settings = *settings;

  w->compiled_fragment_shaders = g_slist_prepend (w->compiled_fragment_shaders,
						  shader);

  return shader;
}

static void
cogl_gles2_wrapper_get_locations (GLuint program,
				  CoglGles2WrapperSettings *settings,
				  CoglGles2WrapperUniforms *uniforms,
				  CoglGles2WrapperAttributes *attribs)
{
  int i;

  uniforms->mvp_matrix_uniform
    = glGetUniformLocation (program, "mvp_matrix");
  uniforms->modelview_matrix_uniform
    = glGetUniformLocation (program, "modelview_matrix");

  for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
    if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (settings->texture_units, i))
      {
        char *matrix_var_name = g_strdup_printf ("texture_matrix[%d]", i);
        char *sampler_var_name = g_strdup_printf ("texture_unit[%d]", i);
        char *tex_coord_var_name =
          g_strdup_printf ("multi_tex_coord_attrib%d", i);

        uniforms->texture_matrix_uniforms[i]
          = glGetUniformLocation (program, matrix_var_name);
        uniforms->texture_sampler_uniforms[i]
          = glGetUniformLocation (program, sampler_var_name);
        attribs->multi_texture_coords[i]
          = glGetAttribLocation (program, tex_coord_var_name);

        g_free (tex_coord_var_name);
        g_free (sampler_var_name);
        g_free (matrix_var_name);
      }
    else
      {
        uniforms->texture_matrix_uniforms[i] = -1;
        uniforms->texture_sampler_uniforms[i] = -1;
        attribs->multi_texture_coords[i] = -1;
      }

  uniforms->fog_density_uniform
    = glGetUniformLocation (program, "fog_density");
  uniforms->fog_start_uniform
    = glGetUniformLocation (program, "fog_start");
  uniforms->fog_end_uniform
    = glGetUniformLocation (program, "fog_end");
  uniforms->fog_color_uniform
    = glGetUniformLocation (program, "fog_color");

  uniforms->alpha_test_ref_uniform
    = glGetUniformLocation (program, "alpha_test_ref");
}

static void
cogl_gles2_wrapper_bind_attributes (GLuint program)
{
  glBindAttribLocation (program, COGL_GLES2_WRAPPER_VERTEX_ATTRIB,
			"vertex_attrib");
  glBindAttribLocation (program, COGL_GLES2_WRAPPER_COLOR_ATTRIB,
			"color_attrib");
  glBindAttribLocation (program, COGL_GLES2_WRAPPER_NORMAL_ATTRIB,
			"normal_attrib");
}

static CoglGles2WrapperProgram *
cogl_gles2_wrapper_get_program (const CoglGles2WrapperSettings *settings)
{
  GSList *node;
  CoglGles2WrapperProgram *program;
  CoglGles2WrapperShader *vertex_shader, *fragment_shader;
  GLint status;
  gboolean custom_vertex_shader = FALSE, custom_fragment_shader = FALSE;
  CoglProgram *user_program = NULL;
  int i;

  _COGL_GET_GLES2_WRAPPER (w, NULL);

  /* Check if we've already got a program for these settings */
  for (node = w->compiled_programs; node; node = node->next)
    {
      program = (CoglGles2WrapperProgram *) node->data;

      if (cogl_gles2_settings_equal (settings, &program->settings, TRUE, TRUE)
	  && program->settings.user_program == settings->user_program)
	return (CoglGles2WrapperProgram *) node->data;
    }

  /* Otherwise create a new program */

  /* Check whether the currently used custom program has vertex and
     fragment shaders */
  if (w->settings.user_program != COGL_INVALID_HANDLE)
    {
      user_program
	= _cogl_program_pointer_from_handle (w->settings.user_program);

      for (node = user_program->attached_shaders; node; node = node->next)
	{
	  CoglShader *shader
	    = _cogl_shader_pointer_from_handle ((CoglHandle) node->data);

	  if (shader->type == COGL_SHADER_TYPE_VERTEX)
	    custom_vertex_shader = TRUE;
	  else if (shader->type == COGL_SHADER_TYPE_FRAGMENT)
	    custom_fragment_shader = TRUE;
	}
    }

  /* Get or create the fixed functionality shaders for these settings
     if there is no custom replacement */
  if (!custom_vertex_shader)
    {
      vertex_shader = cogl_gles2_get_vertex_shader (settings);
      if (vertex_shader == NULL)
	return NULL;
    }
  if (!custom_fragment_shader)
    {
      fragment_shader = cogl_gles2_get_fragment_shader (settings);
      if (fragment_shader == NULL)
	return NULL;
    }

  program = g_slice_new (CoglGles2WrapperProgram);

  program->program = glCreateProgram ();
  if (!custom_vertex_shader)
    glAttachShader (program->program, vertex_shader->shader);
  if (!custom_fragment_shader)
    glAttachShader (program->program, fragment_shader->shader);
  if (user_program)
    for (node = user_program->attached_shaders; node; node = node->next)
      {
	CoglShader *shader
	  = _cogl_shader_pointer_from_handle ((CoglHandle) node->data);
	glAttachShader (program->program, shader->gl_handle);
      }
  cogl_gles2_wrapper_bind_attributes (program->program);
  glLinkProgram (program->program);

  glGetProgramiv (program->program, GL_LINK_STATUS, &status);

  if (!status)
    {
      char shader_log[1024];
      GLint len;

      glGetProgramInfoLog (program->program, sizeof (shader_log) - 1, &len, shader_log);
      shader_log[len] = '\0';

      g_critical ("%s", shader_log);

      glDeleteProgram (program->program);
      g_slice_free (CoglGles2WrapperProgram, program);

      return NULL;
    }

  program->settings = *settings;

  cogl_gles2_wrapper_get_locations (program->program,
				    &program->settings,
				    &program->uniforms,
				    &program->attributes);

  /* We haven't tried to get a location for any of the custom uniforms
     yet */
  for (i = 0; i < COGL_GLES2_NUM_CUSTOM_UNIFORMS; i++)
    program->custom_uniforms[i] = COGL_GLES2_UNBOUND_CUSTOM_UNIFORM;

  w->compiled_programs = g_slist_append (w->compiled_programs, program);

  return program;
}

void
cogl_gles2_wrapper_deinit (CoglGles2Wrapper *wrapper)
{
  GSList *node, *next;
  int i;

  for (node = wrapper->compiled_programs; node; node = next)
    {
      next = node->next;
      glDeleteProgram (((CoglGles2WrapperProgram *) node->data)->program);
      g_slist_free1 (node);
    }
  wrapper->compiled_programs = NULL;

  for (node = wrapper->compiled_vertex_shaders; node; node = next)
    {
      next = node->next;
      glDeleteShader (((CoglGles2WrapperShader *) node->data)->shader);
      g_slist_free1 (node);
    }
  wrapper->compiled_vertex_shaders = NULL;

  for (node = wrapper->compiled_fragment_shaders; node; node = next)
    {
      next = node->next;
      glDeleteShader (((CoglGles2WrapperShader *) node->data)->shader);
      g_slist_free1 (node);
    }
  wrapper->compiled_fragment_shaders = NULL;

  for (i = 0; i < COGL_GLES2_NUM_CUSTOM_UNIFORMS; i++)
    if (wrapper->custom_uniforms[i].count > 1)
      g_free (wrapper->custom_uniforms[i].v.array);
}

static void
cogl_gles2_wrapper_update_matrix (CoglGles2Wrapper *wrapper, GLenum matrix_num)
{
  CoglGles2WrapperTextureUnit *texture_unit;

  switch (matrix_num)
    {
    default:
    case GL_MODELVIEW:
      wrapper->dirty_uniforms |= COGL_GLES2_DIRTY_MVP_MATRIX
	| COGL_GLES2_DIRTY_MODELVIEW_MATRIX;
      break;

    case GL_PROJECTION:
      wrapper->dirty_uniforms |= COGL_GLES2_DIRTY_MVP_MATRIX;
      break;

    case GL_TEXTURE:
      wrapper->dirty_uniforms |= COGL_GLES2_DIRTY_TEXTURE_MATRICES;
      texture_unit = wrapper->texture_units + wrapper->active_texture_unit;
      texture_unit->dirty_matrix = 1;
      break;
    }
}

void
cogl_wrap_glPushMatrix ()
{
  const float *src;
  float *dst;

  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  /* Get a pointer to the old and new matrix position and increment
     the stack pointer */
  switch (w->matrix_mode)
    {
    default:
    case GL_MODELVIEW:
      src = w->modelview_stack + w->modelview_stack_pos * 16;
      w->modelview_stack_pos = (w->modelview_stack_pos + 1)
	& (COGL_GLES2_MODELVIEW_STACK_SIZE - 1);
      dst = w->modelview_stack + w->modelview_stack_pos * 16;
      break;

    case GL_PROJECTION:
      src = w->projection_stack + w->projection_stack_pos * 16;
      w->projection_stack_pos = (w->projection_stack_pos + 1)
	& (COGL_GLES2_PROJECTION_STACK_SIZE - 1);
      dst = w->projection_stack + w->projection_stack_pos * 16;
      break;

    case GL_TEXTURE:
      {
	CoglGles2WrapperTextureUnit *texture_unit;
	texture_unit = w->texture_units + w->active_texture_unit;
	src = texture_unit->texture_stack
	      + texture_unit->texture_stack_pos * 16;
	texture_unit->texture_stack_pos = (texture_unit->texture_stack_pos + 1)
	  & (COGL_GLES2_TEXTURE_STACK_SIZE - 1);
	dst = texture_unit->texture_stack
	      + texture_unit->texture_stack_pos * 16;
	break;
      }
    }

  /* Copy the old matrix to the new position */
  memcpy (dst, src, sizeof (float) * 16);
}

void
cogl_wrap_glPopMatrix ()
{
  CoglGles2WrapperTextureUnit *texture_unit;
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  /* Decrement the stack pointer */
  switch (w->matrix_mode)
    {
    default:
    case GL_MODELVIEW:
      w->modelview_stack_pos = (w->modelview_stack_pos - 1)
	& (COGL_GLES2_MODELVIEW_STACK_SIZE - 1);
      break;

    case GL_PROJECTION:
      w->projection_stack_pos = (w->projection_stack_pos - 1)
	& (COGL_GLES2_PROJECTION_STACK_SIZE - 1);
      break;

    case GL_TEXTURE:
      texture_unit = w->texture_units + w->active_texture_unit;
      texture_unit->texture_stack_pos = (texture_unit->texture_stack_pos - 1)
	& (COGL_GLES2_TEXTURE_STACK_SIZE - 1);
      break;
    }

  /* Update the matrix in the program object */
  cogl_gles2_wrapper_update_matrix (w, w->matrix_mode);
}

void
cogl_wrap_glMatrixMode (GLenum mode)
{
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  w->matrix_mode = mode;
}

static float *
cogl_gles2_get_matrix_stack_top (CoglGles2Wrapper *wrapper)
{
  CoglGles2WrapperTextureUnit *texture_unit;

  switch (wrapper->matrix_mode)
    {
    default:
    case GL_MODELVIEW:
      return wrapper->modelview_stack + wrapper->modelview_stack_pos * 16;

    case GL_PROJECTION:
      return wrapper->projection_stack + wrapper->projection_stack_pos * 16;

    case GL_TEXTURE:
      texture_unit = wrapper->texture_units + wrapper->active_texture_unit;
      return texture_unit->texture_stack
	+ texture_unit->texture_stack_pos * 16;
    }
}

void
cogl_wrap_glLoadIdentity ()
{
  float *matrix;

  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  matrix = cogl_gles2_get_matrix_stack_top (w);
  memset (matrix, 0, sizeof (float) * 16);
  matrix[0] = 1.0f;
  matrix[5] = 1.0f;
  matrix[10] = 1.0f;
  matrix[15] = 1.0f;

  cogl_gles2_wrapper_update_matrix (w, w->matrix_mode);
}

static void
cogl_gles2_wrapper_mult_matrix (float *dst, const float *a, const float *b)
{
  int i, j, k;

  for (i = 0; i < 4; i++)
    for (j = 0; j < 4; j++)
      {
	float sum = 0.0f;
	for (k = 0; k < 4; k++)
	  sum += a[k * 4 + j] * b[i * 4 + k];
	dst[i * 4 + j] = sum;
      }
}

static void
cogl_wrap_glMultMatrix (const float *m)
{
  float new_matrix[16];
  float *old_matrix;

  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  old_matrix = cogl_gles2_get_matrix_stack_top (w);

  cogl_gles2_wrapper_mult_matrix (new_matrix, old_matrix, m);

  memcpy (old_matrix, new_matrix, sizeof (float) * 16);

  cogl_gles2_wrapper_update_matrix (w, w->matrix_mode);
}

void
cogl_wrap_glMultMatrixf (const GLfloat *m)
{
  cogl_wrap_glMultMatrix (m);
}

void
cogl_wrap_glLoadMatrixf (const GLfloat *m)
{
  float *old_matrix;

  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  old_matrix = cogl_gles2_get_matrix_stack_top (w);

  memcpy (old_matrix, m, sizeof (float) * 16);

  cogl_gles2_wrapper_update_matrix (w, w->matrix_mode);
}

void
cogl_wrap_glFrustumf (GLfloat left, GLfloat right,
		      GLfloat bottom, GLfloat top,
		      GLfloat z_near, GLfloat z_far)
{
  float matrix[16];
  float two_near =  (2 * z_near);

  memset (matrix, 0, sizeof (matrix));

  matrix[0] = two_near /  (right - left);
  matrix[5] = two_near /  (top - bottom);
  matrix[8] =  (right + left)
    /  (right - left);
  matrix[9] =  (top + bottom)
    /  (top - bottom);
  matrix[10] = - (z_far + z_near)
    /  (z_far - z_near);
  matrix[11] = -1.0f;
  matrix[14] = -two_near *  (z_far)
    /  (z_far - z_near);

  cogl_wrap_glMultMatrix (matrix);
}

void
cogl_wrap_glScalef (GLfloat x, GLfloat y, GLfloat z)
{
  float matrix[16];

  memset (matrix, 0, sizeof (matrix));
  matrix[0] =  (x);
  matrix[5] =  (y);
  matrix[10] =  (z);
  matrix[15] = 1.0f;

  cogl_wrap_glMultMatrix (matrix);
}

void
cogl_wrap_glTranslatef (GLfloat x, GLfloat y, GLfloat z)
{
  float matrix[16];

  memset (matrix, 0, sizeof (matrix));
  matrix[0] = 1.0f;
  matrix[5] = 1.0f;
  matrix[10] = 1.0f;
  matrix[12] =  (x);
  matrix[13] =  (y);
  matrix[14] =  (z);
  matrix[15] = 1.0f;

  cogl_wrap_glMultMatrix (matrix);
}

void
cogl_wrap_glRotatef (GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
{
  float matrix[16];
  float xf =  (x);
  float yf =  (y);
  float zf =  (z);
  float anglef =  (angle) * G_PI / 180.0f;
  float c = cosf (anglef);
  float s = sinf (anglef);

  matrix[0]  = xf * xf * (1.0f - c) + c;
  matrix[1]  = yf * xf * (1.0f - c) + zf * s;
  matrix[2]  = xf * zf * (1.0f - c) - yf * s;
  matrix[3]  = 0.0f;

  matrix[4]  = xf * yf * (1.0f - c) - zf * s;
  matrix[5]  = yf * yf * (1.0f - c) + c;
  matrix[6]  = yf * zf * (1.0f - c) + xf * s;
  matrix[7]  = 0.0f;

  matrix[8]  = xf * zf * (1.0f - c) + yf * s;
  matrix[9]  = yf * zf * (1.0f - c) - xf * s;
  matrix[10] = zf * zf * (1.0f - c) + c;
  matrix[11] = 0.0f;

  matrix[12] = 0.0f;
  matrix[13] = 0.0f;
  matrix[14] = 0.0f;
  matrix[15] = 1.0f;

  cogl_wrap_glMultMatrix (matrix);
}

void
cogl_wrap_glOrthof (GLfloat left, GLfloat right, GLfloat bottom, GLfloat top,
		    GLfloat near, GLfloat far)
{
  float matrix[16];
  float xrange =  (right - left);
  float yrange =  (top - bottom);
  float zrange =  (far - near);

  memset (matrix, 0, sizeof (matrix));
  matrix[0] = 2.0f / xrange;
  matrix[5] = 2.0f / yrange;
  matrix[10] = 2.0f / zrange;
  matrix[12] =  (right + left) / xrange;
  matrix[13] =  (top + bottom) / yrange;
  matrix[14] =  (far + near) / zrange;
  matrix[15] = 1.0f;

  cogl_wrap_glMultMatrix (matrix);
}

void
cogl_wrap_glVertexPointer (GLint size, GLenum type, GLsizei stride,
			   const GLvoid *pointer)
{
  glVertexAttribPointer (COGL_GLES2_WRAPPER_VERTEX_ATTRIB, size, type,
			 GL_FALSE, stride, pointer);
}

void
cogl_wrap_glTexCoordPointer (GLint size, GLenum type, GLsizei stride,
			     const GLvoid *pointer)
{
  int active_unit;
  CoglGles2WrapperTextureUnit *texture_unit;
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  active_unit = w->active_client_texture_unit;

  texture_unit = w->texture_units + active_unit;
  texture_unit->texture_coords_size = size;
  texture_unit->texture_coords_type = type;
  texture_unit->texture_coords_stride = stride;
  texture_unit->texture_coords_pointer = pointer;

  w->dirty_attribute_pointers
    |= COGL_GLES2_DIRTY_TEX_COORD_VERTEX_ATTRIB;
}

void
cogl_wrap_glColorPointer (GLint size, GLenum type, GLsizei stride,
			  const GLvoid *pointer)
{
  glVertexAttribPointer (COGL_GLES2_WRAPPER_COLOR_ATTRIB, size, type,
			 GL_TRUE, stride, pointer);
}

void
cogl_wrap_glNormalPointer (GLenum type, GLsizei stride, const GLvoid *pointer)
{
  glVertexAttribPointer (COGL_GLES2_WRAPPER_NORMAL_ATTRIB, 1, type,
			 GL_FALSE, stride, pointer);
}

static void
cogl_gles2_do_set_uniform (GLint location, CoglBoxedValue *value)
{
  switch (value->type)
    {
    case COGL_BOXED_NONE:
      break;

    case COGL_BOXED_INT:
      {
	gint *ptr;

	if (value->count == 1)
	  ptr = value->v.int_value;
	else
	  ptr = value->v.int_array;

	switch (value->size)
	  {
	  case 1: glUniform1iv (location, value->count, ptr); break;
	  case 2: glUniform2iv (location, value->count, ptr); break;
	  case 3: glUniform3iv (location, value->count, ptr); break;
	  case 4: glUniform4iv (location, value->count, ptr); break;
	  }
      }
      break;

    case COGL_BOXED_FLOAT:
      {
	gfloat *ptr;

	if (value->count == 1)
	  ptr = value->v.float_value;
	else
	  ptr = value->v.float_array;

	switch (value->size)
	  {
	  case 1: glUniform1fv (location, value->count, ptr); break;
	  case 2: glUniform2fv (location, value->count, ptr); break;
	  case 3: glUniform3fv (location, value->count, ptr); break;
	  case 4: glUniform4fv (location, value->count, ptr); break;
	  }
      }
      break;

    case COGL_BOXED_MATRIX:
      {
	gfloat *ptr;

	if (value->count == 1)
	  ptr = value->v.matrix;
	else
	  ptr = value->v.float_array;

	switch (value->size)
	  {
	  case 2:
	    glUniformMatrix2fv (location, value->count, value->transpose, ptr);
	    break;
	  case 3:
	    glUniformMatrix3fv (location, value->count, value->transpose, ptr);
	    break;
	  case 4:
	    glUniformMatrix4fv (location, value->count, value->transpose, ptr);
	    break;
	  }
      }
      break;
    }
}

static void
cogl_wrap_prepare_for_draw (void)
{
  CoglGles2WrapperProgram *program;

  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  /* Check if we need to switch programs */
  if (w->settings_dirty)
    {
      /* Find or create a program for the current settings */
      program = cogl_gles2_wrapper_get_program (&w->settings);

      if (program == NULL)
	/* Can't compile a shader so there is nothing we can do */
	return;

      /* Start using it if we aren't already */
      if (w->current_program != program)
	{
	  glUseProgram (program->program);
	  w->current_program = program;
	  /* All of the uniforms are probably now out of date */
	  w->dirty_uniforms = COGL_GLES2_DIRTY_ALL;
	  w->dirty_custom_uniforms = (1 << COGL_GLES2_NUM_CUSTOM_UNIFORMS) - 1;
	}
      w->settings_dirty = FALSE;
    }
  else
    program = w->current_program;

  /* Make sure all of the uniforms are up to date */
  if (w->dirty_uniforms)
    {
      if ((w->dirty_uniforms & (COGL_GLES2_DIRTY_MVP_MATRIX
				| COGL_GLES2_DIRTY_MODELVIEW_MATRIX)))
	{
	  float mvp_matrix[16];
	  const float *modelview_matrix = w->modelview_stack
	    + w->modelview_stack_pos * 16;

	  cogl_gles2_wrapper_mult_matrix (mvp_matrix,
					  w->projection_stack
					  + w->projection_stack_pos * 16,
					  modelview_matrix);

	  if (program->uniforms.mvp_matrix_uniform != -1)
	    glUniformMatrix4fv (program->uniforms.mvp_matrix_uniform, 1,
				GL_FALSE, mvp_matrix);
	  if (program->uniforms.modelview_matrix_uniform != -1)
	    glUniformMatrix4fv (program->uniforms.modelview_matrix_uniform, 1,
				GL_FALSE, modelview_matrix);
	}
      if ((w->dirty_uniforms & COGL_GLES2_DIRTY_TEXTURE_MATRICES))
	{
	  int i;

	  /* TODO - we should probably have a per unit dirty flag too */

	  for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
	    {
	      CoglGles2WrapperTextureUnit *texture_unit;
	      GLint uniform = program->uniforms.texture_matrix_uniforms[i];

              texture_unit = w->texture_units + i;
	      if (uniform != -1)
		glUniformMatrix4fv (uniform, 1, GL_FALSE,
				    texture_unit->texture_stack
				      + texture_unit->texture_stack_pos * 16);
	    }
	}

      if ((w->dirty_uniforms & COGL_GLES2_DIRTY_FOG_DENSITY)
	  && program->uniforms.fog_density_uniform != -1)
	glUniform1f (program->uniforms.fog_density_uniform, w->fog_density);
      if ((w->dirty_uniforms & COGL_GLES2_DIRTY_FOG_START)
	  && program->uniforms.fog_start_uniform != -1)
	glUniform1f (program->uniforms.fog_start_uniform, w->fog_start);
      if ((w->dirty_uniforms & COGL_GLES2_DIRTY_FOG_END)
	  && program->uniforms.fog_end_uniform != -1)
	glUniform1f (program->uniforms.fog_end_uniform, w->fog_end);

      if ((w->dirty_uniforms & COGL_GLES2_DIRTY_ALPHA_TEST_REF)
	  && program->uniforms.alpha_test_ref_uniform != -1)
	glUniform1f (program->uniforms.alpha_test_ref_uniform,
		     w->alpha_test_ref);

      if ((w->dirty_uniforms & COGL_GLES2_DIRTY_TEXTURE_UNITS))
        {
          int i;

          /* TODO - we should probably have a per unit dirty flag too */

          for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
            {
              GLint uniform = program->uniforms.texture_sampler_uniforms[i];

              if (uniform != -1)
                glUniform1i (uniform, i);
            }
        }

      w->dirty_uniforms = 0;
    }

  if (w->dirty_custom_uniforms)
    {
      int i;

      if (w->settings.user_program != COGL_INVALID_HANDLE)
	{
	  CoglProgram *user_program
	    = _cogl_program_pointer_from_handle (w->settings.user_program);
	  const char *uniform_name;

	  for (i = 0; i < COGL_GLES2_NUM_CUSTOM_UNIFORMS; i++)
	    if ((w->dirty_custom_uniforms & (1 << i))
		&& (uniform_name = user_program->custom_uniform_names[i]))
	      {
		if (program->custom_uniforms[i]
		    == COGL_GLES2_UNBOUND_CUSTOM_UNIFORM)
		  program->custom_uniforms[i]
		    = glGetUniformLocation (program->program, uniform_name);
		if (program->custom_uniforms[i] >= 0)
		  cogl_gles2_do_set_uniform (program->custom_uniforms[i],
					     &w->custom_uniforms[i]);
	      }
	}

      w->dirty_custom_uniforms = 0;
    }

  if (w->dirty_attribute_pointers
      & COGL_GLES2_DIRTY_TEX_COORD_VERTEX_ATTRIB)
    {
      int i;

      /* TODO - coverage test */
      for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
        if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (w->settings.texture_units, i))
          {
            GLint tex_coord_var_index;
            CoglGles2WrapperTextureUnit *texture_unit;

            texture_unit = w->texture_units + w->active_texture_unit;
            if (!texture_unit->texture_coords_enabled)
              continue;

            /* TODO - we should probably have a per unit dirty flag too */

            /* TODO - coverage test */
            tex_coord_var_index = program->attributes.multi_texture_coords[i];
            glVertexAttribPointer (tex_coord_var_index,
                                   texture_unit->texture_coords_size,
                                   texture_unit->texture_coords_type,
                                   GL_FALSE,
                                   texture_unit->texture_coords_stride,
                                   texture_unit->texture_coords_pointer);
          }
    }

  if (w->dirty_vertex_attrib_enables)
    {
      int i;

      /* TODO - coverage test */

      /* TODO - we should probably have a per unit dirty flag too */

      for (i = 0; i < COGL_GLES2_MAX_TEXTURE_UNITS; i++)
	{
	  CoglGles2WrapperTextureUnit *texture_unit
            = w->texture_units + w->active_texture_unit;
          GLint attrib = program->attributes.multi_texture_coords[i];

          if (attrib != -1)
            {
              if (texture_unit->texture_coords_enabled)
                glEnableVertexAttribArray (attrib);
              else
                glDisableVertexAttribArray (attrib);
            }
	}

      w->dirty_vertex_attrib_enables = 0;
    }
}

void
cogl_wrap_glDrawArrays (GLenum mode, GLint first, GLsizei count)
{
  cogl_wrap_prepare_for_draw ();

  glDrawArrays (mode, first, count);
}

void
cogl_wrap_glDrawElements (GLenum mode, GLsizei count, GLenum type,
                          const GLvoid *indices)
{
  cogl_wrap_prepare_for_draw ();

  glDrawElements (mode, count, type, indices);
}

void
cogl_gles2_wrapper_bind_texture (GLenum target, GLuint texture,
				 GLenum internal_format)
{
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  glBindTexture (target, texture);

  /* We need to keep track of whether the texture is alpha-only
     because the emulation of GL_MODULATE needs to work differently in
     that case */
  if (COGL_GLES2_TEXTURE_UNIT_IS_ALPHA_ONLY (w->settings.texture_units,
                                             w->active_texture_unit)
      != (internal_format == GL_ALPHA))
    {
      COGL_GLES2_TEXTURE_UNIT_SET_ALPHA_ONLY (w->settings.texture_units,
                                              w->active_texture_unit,
                                              internal_format == GL_ALPHA);
      w->settings_dirty = TRUE;
    }
}

void
cogl_wrap_glTexEnvi (GLenum target, GLenum pname, GLint param)
{
  /* This function is only used to set the texture mode once to
     GL_MODULATE. The shader is hard-coded to modulate the texture so
     nothing needs to be done here. */
}

void
cogl_wrap_glTexEnvfv (GLenum target, GLenum pname, const GLfloat *params)
{
  /* FIXME: Currently needed to support texture combining using
   * COGL_BLEND_STRING_COLOR_SOURCE_CONSTANT */
}

void
cogl_wrap_glClientActiveTexture (GLenum texture)
{
  int texture_unit_index = texture - GL_TEXTURE0;
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  if (texture_unit_index < COGL_GLES2_MAX_TEXTURE_UNITS)
    w->active_client_texture_unit = texture_unit_index;
}

void
cogl_wrap_glActiveTexture (GLenum texture)
{
  int texture_unit_index = texture - GL_TEXTURE0;
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  glActiveTexture (texture);

  if (texture_unit_index < COGL_GLES2_MAX_TEXTURE_UNITS)
    w->active_texture_unit = texture_unit_index;
}

void
cogl_wrap_glEnable (GLenum cap)
{
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  switch (cap)
    {
    case GL_TEXTURE_2D:
      if (!COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (w->settings.texture_units,
                                               w->active_texture_unit))
        {
          COGL_GLES2_TEXTURE_UNIT_SET_ENABLED (w->settings.texture_units,
                                               w->active_texture_unit,
                                               TRUE);
          w->settings_dirty = TRUE;
        }
      break;

    case GL_FOG:
      _COGL_GLES2_CHANGE_SETTING (w, fog_enabled, TRUE);
      break;

    case GL_ALPHA_TEST:
      _COGL_GLES2_CHANGE_SETTING (w, alpha_test_enabled, TRUE);
      break;

    default:
      glEnable (cap);
    }
}

void
cogl_wrap_glDisable (GLenum cap)
{
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  switch (cap)
    {
    case GL_TEXTURE_2D:
      if (COGL_GLES2_TEXTURE_UNIT_IS_ENABLED (w->settings.texture_units,
                                              w->active_texture_unit))
        {
          COGL_GLES2_TEXTURE_UNIT_SET_ENABLED (w->settings.texture_units,
                                               w->active_texture_unit,
                                               FALSE);
          w->settings_dirty = TRUE;
        }
      break;

    case GL_FOG:
      _COGL_GLES2_CHANGE_SETTING (w, fog_enabled, FALSE);
      break;

    case GL_ALPHA_TEST:
      _COGL_GLES2_CHANGE_SETTING (w, alpha_test_enabled, FALSE);
      break;

    default:
      glDisable (cap);
    }
}

void
cogl_wrap_glEnableClientState (GLenum array)
{
  CoglGles2WrapperTextureUnit *texture_unit;
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  switch (array)
    {
    case GL_VERTEX_ARRAY:
      glEnableVertexAttribArray (COGL_GLES2_WRAPPER_VERTEX_ATTRIB);
      break;
    case GL_TEXTURE_COORD_ARRAY:
      /* TODO - review if this should be in w->settings? */

      texture_unit = w->texture_units + w->active_texture_unit;
      if (texture_unit->texture_coords_enabled != 1)
	{
	  texture_unit->texture_coords_enabled = 1;
	  w->dirty_vertex_attrib_enables
	    |= COGL_GLES2_DIRTY_TEX_COORD_ATTRIB_ENABLES;
	}
      break;
    case GL_COLOR_ARRAY:
      glEnableVertexAttribArray (COGL_GLES2_WRAPPER_COLOR_ATTRIB);
      break;
    case GL_NORMAL_ARRAY:
      glEnableVertexAttribArray (COGL_GLES2_WRAPPER_NORMAL_ATTRIB);
      break;
    }
}

void
cogl_wrap_glDisableClientState (GLenum array)
{
  CoglGles2WrapperTextureUnit *texture_unit;
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  switch (array)
    {
    case GL_VERTEX_ARRAY:
      glDisableVertexAttribArray (COGL_GLES2_WRAPPER_VERTEX_ATTRIB);
      break;
    case GL_TEXTURE_COORD_ARRAY:

      texture_unit = w->texture_units + w->active_texture_unit;
      /* TODO - review if this should be in w->settings? */
      if (texture_unit->texture_coords_enabled != 0)
	{
	  texture_unit->texture_coords_enabled = 0;
	  w->dirty_vertex_attrib_enables
	    |= COGL_GLES2_DIRTY_TEX_COORD_ATTRIB_ENABLES;
	}
      break;
    case GL_COLOR_ARRAY:
      glDisableVertexAttribArray (COGL_GLES2_WRAPPER_COLOR_ATTRIB);
      break;
    case GL_NORMAL_ARRAY:
      glDisableVertexAttribArray (COGL_GLES2_WRAPPER_NORMAL_ATTRIB);
      break;
    }
}

void
cogl_wrap_glAlphaFunc (GLenum func, GLclampf ref)
{
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  if (ref < 0.0f)
    ref = 0.0f;
  else if (ref > 1.0f)
    ref = 1.0f;

  _COGL_GLES2_CHANGE_SETTING (w, alpha_test_func, func);
  _COGL_GLES2_CHANGE_UNIFORM (w, ALPHA_TEST_REF, alpha_test_ref, ref);
}

void
cogl_wrap_glColor4f (GLclampf r, GLclampf g, GLclampf b, GLclampf a)
{
  glVertexAttrib4f (COGL_GLES2_WRAPPER_COLOR_ATTRIB, r, g, b, a);
}

void
cogl_wrap_glColor4ub (GLubyte r, GLubyte g, GLubyte b, GLubyte a)
{
  glVertexAttrib4f (COGL_GLES2_WRAPPER_COLOR_ATTRIB,
                    r/255.0, g/255.0, b/255.0, a/255.0);
}

void
cogl_wrap_glClipPlanef (GLenum plane, GLfloat *equation)
{
  /* FIXME */
}

void
cogl_wrap_glGetIntegerv (GLenum pname, GLint *params)
{
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  switch (pname)
    {
    case GL_MAX_CLIP_PLANES:
      *params = 0;
      break;

    case CGL_MATRIX_MODE:
      *params = w->matrix_mode;
      break;

    default:
      glGetIntegerv (pname, params);
      break;
    }
}

void
cogl_wrap_glGetFloatv (GLenum pname, GLfloat *params)
{
  CoglGles2WrapperTextureUnit *texture_unit;

  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  switch (pname)
    {
    case GL_MODELVIEW_MATRIX:
      memcpy (params, w->modelview_stack + w->modelview_stack_pos * 16,
              sizeof (GLfloat) * 16);
      break;

    case GL_PROJECTION_MATRIX:
      memcpy (params, w->projection_stack + w->projection_stack_pos * 16,
              sizeof (GLfloat) * 16);
      break;

    case GL_TEXTURE_MATRIX:
      texture_unit = w->texture_units + w->active_texture_unit;
      memcpy (params,
              texture_unit->texture_stack
               + texture_unit->texture_stack_pos * 16,
              sizeof (GLfloat) * 16);
      break;

    case GL_VIEWPORT:
      glGetFloatv (GL_VIEWPORT, params);
      break;
    }
}

void
cogl_wrap_glFogf (GLenum pname, GLfloat param)
{
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  switch (pname)
    {
    case GL_FOG_MODE:
      _COGL_GLES2_CHANGE_SETTING (w, fog_mode, param);
      break;

    case GL_FOG_DENSITY:
      _COGL_GLES2_CHANGE_UNIFORM (w, FOG_DENSITY, fog_density,
				   (param));
      break;

    case GL_FOG_START:
      _COGL_GLES2_CHANGE_UNIFORM (w, FOG_START, fog_start,
				   (param));
      break;

    case GL_FOG_END:
      _COGL_GLES2_CHANGE_UNIFORM (w, FOG_END, fog_end,
				   (param));
      break;
    }
}

void
cogl_wrap_glFogfv (GLenum pname, const GLfloat *params)
{
  int i;
  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  if (pname == GL_FOG_COLOR)
    {
      for (i = 0; i < 4; i++)
	w->fog_color[i] =  (params[i]);

      w->dirty_uniforms |= COGL_GLES2_DIRTY_FOG_COLOR;
    }
}

void
cogl_wrap_glTexParameteri (GLenum target, GLenum pname, GLfloat param)
{
  if (pname != GL_GENERATE_MIPMAP)
    glTexParameteri (target, pname, param);
}

void
cogl_wrap_glMaterialfv (GLenum face, GLenum pname, const GLfloat *params)
{
  /* FIXME: the GLES 2 backend doesn't yet support lighting so this
     function can't do anything */
}

void
_cogl_gles2_clear_cache_for_program (CoglHandle user_program)
{
  GSList *node, *next, *last = NULL;
  CoglGles2WrapperProgram *program;

  _COGL_GET_GLES2_WRAPPER (w, NO_RETVAL);

  /* Remove any cached programs that link against this custom program */
  for (node = w->compiled_programs; node; node = next)
    {
      next = node->next;
      program = (CoglGles2WrapperProgram *) node->data;

      if (program->settings.user_program == user_program)
	{
	  glDeleteProgram (program->program);

	  if (last)
	    last->next = next;
	  else
	    w->compiled_programs = next;

	  g_slist_free1 (node);
	}
      else
	last = node;
    }
}