/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2013 - Hans-Kristian Arntzen
 * 
 *  RetroArch is free software: you can redistribute it and/or modify it under the terms
 *  of the GNU General Public License as published by the Free Software Found-
 *  ation, either version 3 of the License, or (at your option) any later version.
 *
 *  RetroArch 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along with RetroArch.
 *  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef __GL_COMMON_H
#define __GL_COMMON_H

#include "../general.h"
#include "fonts/fonts.h"
#include "math/matrix.h"
#include "gfx_context.h"
#include "scaler/scaler.h"
#include "fonts/gl_font.h"

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

#include <string.h>

#ifdef HAVE_EGL
#include <EGL/egl.h>
#include <EGL/eglext.h>
#endif

#if defined(IOS)
#include <OpenGLES/ES2/gl.h>
#include <OpenGLES/ES2/glext.h>
#elif defined(__APPLE__)
#include <OpenGL/gl.h>
#include <OpenGL/glext.h>
#elif defined(HAVE_PSGL)
#include <PSGL/psgl.h>
#include <PSGL/psglu.h>
#include <GLES/glext.h>
#elif defined(HAVE_OPENGL_MODERN)
#include <GL3/gl3.h>
#include <GL3/gl3ext.h>
#elif defined(HAVE_OPENGLES2)
#include <GLES2/gl2.h>
#include <GLES2/gl2ext.h>
#elif defined(HAVE_OPENGLES1)
#include <GLES/gl.h>
#include <GLES/glext.h>
#else
#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glext.h>
#endif


#if defined(ANDROID) && defined(HAVE_GRIFFIN)
#include "../griffin/hook_context.h"
#else
#define gl_shader_use_func(vid, num)                 gl_shader_use(vid, num)
#define gl_shader_num_func(vid)                      gl_shader_num(vid)
#define gl_shader_set_params_func(vid, width, height, \
      tex_width, tex_height, out_width, out_height, \
      frame_count, info, prev_info, fbo_info, fbo_info_cnt) \
         gl_shader_set_params(vid, width, height, tex_width, tex_height, \
               out_width, out_height, frame_count, info, prev_info, fbo_info, fbo_info_cnt)
#define gl_shader_set_coords_func(vid, coords, mat)  gl_shader_set_coords(vid, coords, mat)

#define context_get_video_size_func(win, height)     gl->ctx_driver->get_video_size(win, height)
#define context_update_window_title_func(var)        gl->ctx_driver->update_window_title(var)
#define context_destroy_func()                       gl->ctx_driver->destroy()
#define context_set_fbo_func(var)                    gl->ctx_driver->set_fbo(var)
#define context_get_available_resolutions_func()     gl->ctx_driver->get_available_resolutions()
#define context_translate_aspect_func(width, height) gl->ctx_driver->translate_aspect(width, height)
#define context_set_resize_func(width, height)       gl->ctx_driver->set_resize(width, height)
#define context_swap_buffers_func()                  gl->ctx_driver->swap_buffers()
#define context_post_render_func(gl)                 gl->ctx_driver->post_render(gl)
#define context_swap_interval_func(var)              gl->ctx_driver->swap_interval(var)
#define context_has_focus_func()                     gl->ctx_driver->has_focus()
#define context_check_window_func(quit, resize, width, height, frame_count) \
   gl->ctx_driver->check_window(quit, resize, width, height, frame_count)

#define context_update_window_title_func(var)        gl->ctx_driver->update_window_title(var)
#define context_set_video_mode_func(width, height, fullscreen) gl->ctx_driver->set_video_mode(width, height, fullscreen)
#define context_input_driver_func(input, input_data) gl->ctx_driver->input_driver(input, input_data)

#ifdef HAVE_RMENU
#define context_rmenu_init_func()                    gl->ctx_driver->rmenu_init()
#define context_rmenu_frame_func(ctx)                gl->ctx_driver->rmenu_frame(ctx)
#define context_rmenu_free_func()                    gl->ctx_driver->rmenu_free()
#endif

#ifdef HAVE_EGL
#define context_init_egl_image_buffer_func(video)    gl->ctx_driver->init_egl_image_buffer(video)
#define context_write_egl_image_func(frame, width, height, pitch, base_size, tex_index, img) \
   gl->ctx_driver->write_egl_image(frame, width, height, pitch, base_size, tex_index,img)
#endif
#endif

static inline bool gl_query_extension(const char *ext)
{
   const char *str = (const char*)glGetString(GL_EXTENSIONS);
   bool ret = str && strstr(str, ext);
   RARCH_LOG("Querying GL extension: %s => %s\n",
         ext, ret ? "exists" : "doesn't exist");

   return ret;
}

static inline bool gl_check_error(void)
{
   int error = glGetError();
   switch (error)
   {
      case GL_INVALID_ENUM:
         RARCH_ERR("GL: Invalid enum.\n");
         break;
      case GL_INVALID_VALUE:
         RARCH_ERR("GL: Invalid value.\n");
         break;
      case GL_INVALID_OPERATION:
         RARCH_ERR("GL: Invalid operation.\n");
         break;
      case GL_OUT_OF_MEMORY:
         RARCH_ERR("GL: Out of memory.\n");
         break;
      case GL_NO_ERROR:
         return true;
      default:
         RARCH_ERR("Non specified GL error.\n");
   }

   return false;
}

static inline unsigned get_alignment(unsigned pitch)
{
   if (pitch & 1)
      return 1;
   if (pitch & 2)
      return 2;
   if (pitch & 4)
      return 4;
   return 8;
}

struct gl_fbo_rect
{
   unsigned img_width;
   unsigned img_height;
   unsigned max_img_width;
   unsigned max_img_height;
   unsigned width;
   unsigned height;
};

enum gl_scale_type
{
   RARCH_SCALE_ABSOLUTE,
   RARCH_SCALE_INPUT,
   RARCH_SCALE_VIEWPORT
};

struct gl_fbo_scale
{
   bool fp_fbo;
   enum gl_scale_type type_x;
   enum gl_scale_type type_y;
   float scale_x;
   float scale_y;
   unsigned abs_x;
   unsigned abs_y;
   bool valid;
};

struct gl_ortho
{
   GLfloat left;
   GLfloat right;
   GLfloat bottom;
   GLfloat top;
   GLfloat znear;
   GLfloat zfar;
};

struct gl_tex_info
{
   GLuint tex;
   GLfloat input_size[2];
   GLfloat tex_size[2];
   GLfloat coord[8];
};

struct gl_coords
{
   const GLfloat *vertex;
   const GLfloat *color;
   const GLfloat *tex_coord;
   const GLfloat *lut_tex_coord;
};

typedef struct gl_shader_backend gl_shader_backend_t;

#define MAX_SHADERS 16

#if (defined(HAVE_GLSL) || defined(HAVE_CG))
#define TEXTURES 8
#else
#define TEXTURES 1
#endif
#define TEXTURES_MASK (TEXTURES - 1)

typedef struct gl
{
   const gfx_ctx_driver_t *ctx_driver;
   const gl_shader_backend_t *shader;

   bool vsync;
   GLuint texture[TEXTURES];
   unsigned tex_index; // For use with PREV.
   struct gl_tex_info prev_info[TEXTURES];
   GLuint tex_filter;

   void *empty_buf;

   void *conv_buffer;
   struct scaler_ctx scaler;

   unsigned frame_count;

#ifdef HAVE_FBO
   // Render-to-texture, multipass shaders
   GLuint fbo[MAX_SHADERS];
   GLuint fbo_texture[MAX_SHADERS];
   struct gl_fbo_rect fbo_rect[MAX_SHADERS];
   struct gl_fbo_scale fbo_scale[MAX_SHADERS];
   int fbo_pass;
   bool fbo_inited;

   GLuint hw_render_fbo[TEXTURES];
   GLuint hw_render_depth[TEXTURES];
   GLuint hw_render_stencil[TEXTURES];
   bool hw_render_fbo_init;
   bool hw_render_depth_init;
   bool hw_render_stencil_init;
#endif

   bool should_resize;
   bool quitting;
   bool fullscreen;
   bool keep_aspect;
   unsigned rotation;

   unsigned full_x, full_y;

   unsigned win_width;
   unsigned win_height;
   struct rarch_viewport vp;
   unsigned vp_out_width;
   unsigned vp_out_height;
   unsigned last_width[TEXTURES];
   unsigned last_height[TEXTURES];
   unsigned tex_w, tex_h;
   GLfloat tex_coords[8];
   math_matrix mvp, mvp_no_rot;

   struct gl_coords coords;

   GLuint pbo;

   GLenum internal_fmt;
   GLenum texture_type; // RGB565 or ARGB
   GLenum texture_fmt;
   GLenum border_type;
   unsigned base_size; // 2 or 4

   // Fonts
   void *font;
   const gl_font_renderer_t *font_ctx;
   const font_renderer_driver_t *font_driver;
   GLuint font_tex;
   int font_tex_w, font_tex_h;
   uint16_t *font_tex_buf;
   char font_last_msg[256];
   int font_last_width, font_last_height;
   GLfloat font_color[16];
   GLfloat font_color_dark[16];

   bool egl_images;

#ifdef HAVE_OVERLAY
   // Overlay rendering
   bool overlay_enable;
   bool overlay_full_screen;
   GLuint tex_overlay;
   GLfloat overlay_tex_coord[8];
   GLfloat overlay_vertex_coord[8];
   GLfloat overlay_alpha_mod;
#endif

#if !defined(HAVE_OPENGLES) && defined(HAVE_FFMPEG)
   // PBOs used for asynchronous viewport readbacks.
   GLuint pbo_readback[4];
   bool pbo_readback_enable;
   bool pbo_readback_valid;
   unsigned pbo_readback_index;
   struct scaler_ctx pbo_readback_scaler;
#endif

#ifdef HAVE_RGUI
   GLuint rgui_texture;
   const void *rgui_data;
#endif

} gl_t;

// Windows ... <_<
#ifdef _WIN32
extern PFNGLCLIENTACTIVETEXTUREPROC pglClientActiveTexture;
extern PFNGLACTIVETEXTUREPROC pglActiveTexture;
#else
#define pglClientActiveTexture glClientActiveTexture
#define pglActiveTexture glActiveTexture
#endif

#if defined(HAVE_PSGL)
#define RARCH_GL_INTERNAL_FORMAT32 GL_ARGB_SCE
#define RARCH_GL_INTERNAL_FORMAT16 GL_RGB5
#define RARCH_GL_TEXTURE_TYPE32 GL_BGRA
#define RARCH_GL_TEXTURE_TYPE16 GL_BGRA
#define RARCH_GL_FORMAT32 GL_UNSIGNED_INT_8_8_8_8_REV
#define RARCH_GL_FORMAT16 GL_RGB5
#elif defined(HAVE_OPENGLES)
// Imgtec/SGX headers have this missing.
#ifndef GL_BGRA_EXT
#define GL_BGRA_EXT 0x80E1
#endif
#ifdef IOS
#define RARCH_GL_INTERNAL_FORMAT32 GL_RGBA // Stupid Apple
#else
#define RARCH_GL_INTERNAL_FORMAT32 GL_BGRA_EXT
#endif
#define RARCH_GL_INTERNAL_FORMAT16 GL_RGB
#define RARCH_GL_TEXTURE_TYPE32 GL_BGRA_EXT
#define RARCH_GL_TEXTURE_TYPE16 GL_RGB
#define RARCH_GL_FORMAT32 GL_UNSIGNED_BYTE
#define RARCH_GL_FORMAT16 GL_UNSIGNED_SHORT_5_6_5
#else
// On desktop, we always use 32-bit.
#define RARCH_GL_INTERNAL_FORMAT32 GL_RGBA
#define RARCH_GL_INTERNAL_FORMAT16 GL_RGBA
#define RARCH_GL_TEXTURE_TYPE32 GL_BGRA
#define RARCH_GL_TEXTURE_TYPE16 GL_BGRA
#define RARCH_GL_FORMAT32 GL_UNSIGNED_INT_8_8_8_8_REV
#define RARCH_GL_FORMAT16 GL_UNSIGNED_INT_8_8_8_8_REV
#endif

// Platform specific workarounds/hacks.
#if defined(__CELLOS_LV2__)
#define NO_GL_READ_VIEWPORT
#endif

#if defined(HAVE_OPENGL_MODERN) || defined(HAVE_OPENGLES2) || defined(HAVE_PSGL)
#define NO_GL_FF_VERTEX
#endif

#if defined(HAVE_OPENGL_MODERN) || defined(HAVE_OPENGLES2) || defined(HAVE_PSGL)
#define NO_GL_FF_MATRIX
#endif

#if defined(HAVE_OPENGLES2) // TODO: Figure out exactly what.
#define NO_GL_CLAMP_TO_BORDER
#endif

#if defined(HAVE_OPENGLES2) // It's an extension. Don't bother checking for it atm.
#undef GL_UNPACK_ROW_LENGTH
#endif

extern const GLfloat vertexes_flipped[];
extern const GLfloat white_color[];

void gl_shader_use(void *data, unsigned index);
void gl_set_projection(void *data, struct gl_ortho *ortho, bool allow_rotate);
void gl_set_viewport(void *data, unsigned width, unsigned height, bool force_full, bool allow_rotate);
void gl_shader_set_coords(void *data, const struct gl_coords *coords, const math_matrix *mat);

void gl_init_fbo(void *data, unsigned width, unsigned height);
void gl_deinit_fbo(void *data);

#endif