/*  RetroArch - A frontend for libretro.
 *  Copyright (C) 2010-2014 - Hans-Kristian Arntzen
 *  Copyright (C) 2013-2014 - Tobias Jakobi
 *
 *  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/>.
 */

#include "../../driver.h"
#include <stdlib.h>
#include <string.h>
#include "../../general.h"
#include "../../retroarch.h"
#include <gfx/scaler/scaler.h>
#include "../video_viewport.h"
#include "../video_monitor.h"
#include "../video_context_driver.h"
#include "../font_renderer_driver.h"

#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <fcntl.h>
#include <unistd.h>
#include <ctype.h>
#include <assert.h>

#include <sys/mman.h>
#include <linux/omapfb.h>

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

typedef struct omapfb_page
{
  unsigned yoffset;
  void *buf;
  bool used;
} omapfb_page_t;

typedef struct omapfb_state
{
  struct omapfb_plane_info pi;
  struct omapfb_mem_info mi;
  struct fb_var_screeninfo si;
  void* mem;
} omapfb_state_t;

typedef struct omapfb_data
{
  const char* fbname;
  int fd;

  void *fb_mem;
  unsigned fb_framesize;

  omapfb_page_t *pages;
  int num_pages;
  omapfb_page_t *cur_page;
  omapfb_page_t *old_page;

  /* current and saved (for later restore) states */
  omapfb_state_t* current_state;
  omapfb_state_t* saved_state;

  /* native screen size */
  unsigned nat_w, nat_h;

  /* bytes per pixel */
  unsigned bpp;

  bool sync;
} omapfb_data_t;


static const char *get_fb_device(void)
{
  static char fbname[12];
  const int fbidx = g_settings.video.monitor_index;

  if (fbidx == 0)
     return "/dev/fb0";

  snprintf(fbname, sizeof(fbname), "/dev/fb%d", fbidx - 1);
  RARCH_LOG("video_omap: Using %s as framebuffer device\n", fbname);
  return fbname;
}

static omapfb_page_t *get_page(omapfb_data_t *pdata)
{
   unsigned i;
   omapfb_page_t *page = NULL;

   for (i = 0; i < pdata->num_pages; ++i)
   {
      if (&pdata->pages[i] == pdata->cur_page)
         continue;
      if (&pdata->pages[i] == pdata->old_page)
         continue;

      if (!pdata->pages[i].used)
      {
         page = &pdata->pages[i];
         break;
      }
   }

   return page;
}

static void page_flip(omapfb_data_t *pdata)
{
  if (pdata->sync)
     ioctl(pdata->fd, OMAPFB_WAITFORGO);

  /* TODO: should we use the manual update feature of the OMAP here? */

  pdata->current_state->si.yoffset = pdata->cur_page->yoffset;
  ioctl(pdata->fd, FBIOPAN_DISPLAY, &pdata->current_state->si);

  if (pdata->old_page)
    pdata->old_page->used = false;
}

static int read_sysfs(const char *fname, char *buff, size_t size)
{
  int ret;
  FILE *f = fopen(fname, "r");

  if (f == NULL)
     return -1;

  ret = fread(buff, 1, size - 1, f);
  fclose(f);

  if (ret <= 0)
     return -1;

  buff[ret] = 0;
  for (ret--; ret >= 0 && isspace(buff[ret]); ret--)
    buff[ret] = 0;

  return 0;
}

static inline void put_pixel_rgb565(uint16_t *p,
      unsigned r, unsigned g, unsigned b)
{
   *p = (((r  >> 3) & 0x1f) << 11) | (((g >> 2) & 0x3f) << 5) | ((b  >> 3) & 0x1f);
}

static inline void put_pixel_argb8888(uint32_t *p,
      unsigned r, unsigned g, unsigned b)
{
  *p = ((r << 16) & 0xff0000) | ((g << 8) & 0x00ff00) | ((b << 0) & 0x0000ff);
}

static int omapfb_detect_screen(omapfb_data_t *pdata)
{
  struct stat status;
  int i, ret;
  int w, h;
  FILE *f;
  int fb_id, overlay_id = -1, display_id = -1;
  char buff[64], manager_name[64], display_name[64];

  /* Find out the native screen resolution, which is needed to 
   * properly center the scaled image data. */
  ret = stat(pdata->fbname, &status);

  if (ret != 0)
  {
    RARCH_ERR("video_omap: can't stat %s\n", pdata->fbname);
    return -1;
  }
  fb_id = minor(status.st_rdev);

  snprintf(buff, sizeof(buff), "/sys/class/graphics/fb%d/overlays", fb_id);
  f = fopen(buff, "r");
  if (f == NULL)
  {
    RARCH_ERR("video_omap: can't open %s\n", buff);
    return -1;
  }

  ret = fscanf(f, "%d", &overlay_id);
  fclose(f);
  if (ret != 1)
  {
    RARCH_ERR("video_omap: can't parse %s\n", buff);
    return -1;
  }

  snprintf(buff, sizeof(buff), "/sys/devices/platform/omapdss/overlay%d/manager", overlay_id);
  ret = read_sysfs(buff, manager_name, sizeof(manager_name));
  if (ret < 0)
  {
    RARCH_ERR("video_omap: can't read manager name\n");
    return -1;
  }

  for (i = 0; ; i++)
  {
    snprintf(buff, sizeof(buff), "/sys/devices/platform/omapdss/manager%d/name", i);
    ret = read_sysfs(buff, buff, sizeof(buff));

    if (ret < 0)
       break;

    if (!strcmp(manager_name, buff))
    {
      snprintf(buff, sizeof(buff), "/sys/devices/platform/omapdss/manager%d/display", i);
      ret = read_sysfs(buff, display_name, sizeof(display_name));

      if (ret < 0)
      {
         RARCH_ERR("video_omap: can't read display name\n");
         return -1;
      }

      break;
    }
  }

  if (ret < 0)
  {
    RARCH_ERR("video_omap: couldn't find manager\n");
    return -1;
  }

  for (i = 0; ; i++)
  {
    snprintf(buff, sizeof(buff), "/sys/devices/platform/omapdss/display%d/name", i);
    ret = read_sysfs(buff, buff, sizeof(buff));

    if (ret < 0)
       break;

    if (!strcmp(display_name, buff))
    {
      display_id = i;
      break;
    }
  }

  if (display_id < 0)
  {
    RARCH_ERR("video_omap: couldn't find display\n");
    return -1;
  }

  snprintf(buff, sizeof(buff), "/sys/devices/platform/omapdss/display%d/timings", display_id);
  f = fopen(buff, "r");
  if (f == NULL)
  {
    RARCH_ERR("video_omap: can't open %s\n", buff);
    return -1;
  }

  ret = fscanf(f, "%*d,%d/%*d/%*d/%*d,%d/%*d/%*d/%*d", &w, &h);
  fclose(f);
  if (ret != 2)
  {
    RARCH_ERR("video_omap: can't parse %s (%d)\n", buff, ret);
    return -1;
  }

  if (w <= 0 || h <= 0)
  {
    RARCH_ERR("video_omap: unsane dimensions detected (%dx%d)\n", w, h);
    return -1;
  }

  RARCH_LOG("video_omap: detected %dx%d '%s' (%d) display attached to fb %d and overlay %d\n",
            w, h, display_name, display_id, fb_id, overlay_id);

  pdata->nat_w = w;
  pdata->nat_h = h;

  return 0;
}

static int omapfb_setup_pages(omapfb_data_t *pdata)
{
  int i;

  if (pdata->pages == NULL)
  {
    pdata->pages = calloc(pdata->num_pages, sizeof(omapfb_page_t));

    if (pdata->pages == NULL)
    {
      RARCH_ERR("video_omap: pages allocation failed\n");
      return -1;
    }
  }

  for (i = 0; i < pdata->num_pages; ++i)
  {
    pdata->pages[i].yoffset = i * pdata->current_state->si.yres;
    pdata->pages[i].buf = pdata->fb_mem + (i * pdata->fb_framesize);
    pdata->pages[i].used = false;
  }

  pdata->old_page = NULL;
  pdata->cur_page = &pdata->pages[0];

  memset(pdata->cur_page->buf, 0, pdata->fb_framesize);

  page_flip(pdata);
  pdata->cur_page->used = true;

  return 0;
}

static int omapfb_mmap(omapfb_data_t *pdata)
{
  assert(pdata->fb_mem == NULL);

  pdata->fb_mem = mmap(NULL, pdata->current_state->mi.size, PROT_WRITE,
                       MAP_SHARED, pdata->fd, 0);

  if (pdata->fb_mem == MAP_FAILED)
  {
    pdata->fb_mem = NULL;
    RARCH_ERR("video_omap: framebuffer mmap failed\n");

    return -1;
  }

  return 0;
}

static int omapfb_backup_state(omapfb_data_t *pdata)
{
  void* mem;

  assert(pdata->saved_state == NULL);

  pdata->saved_state = calloc(1, sizeof(omapfb_state_t));
  if (!pdata->saved_state) return -1;

  if (ioctl(pdata->fd, OMAPFB_QUERY_PLANE, &pdata->saved_state->pi) != 0)
  {
    RARCH_ERR("video_omap: backup layer (plane) failed\n");
    return -1;
  }

  if (ioctl(pdata->fd, OMAPFB_QUERY_MEM, &pdata->saved_state->mi) != 0)
  {
    RARCH_ERR("video_omap: backup layer (mem) failed\n");
    return -1;
  }

  if (ioctl(pdata->fd, FBIOGET_VSCREENINFO, &pdata->saved_state->si) != 0)
  {
    RARCH_ERR("video_omap: backup layer (screeninfo) failed\n");
    return -1;
  }

  pdata->saved_state->mem = malloc(pdata->saved_state->mi.size);
  mem = mmap(NULL, pdata->saved_state->mi.size, PROT_WRITE|PROT_READ,
             MAP_SHARED, pdata->fd, 0);
  if (pdata->saved_state->mem == NULL || mem == MAP_FAILED)
  {
    RARCH_ERR("video_omap: backup layer (mem backup) failed\n");
    munmap(mem, pdata->saved_state->mi.size);
    return -1;
  }
  memcpy(pdata->saved_state->mem, mem, pdata->saved_state->mi.size);
  munmap(mem, pdata->saved_state->mi.size);

  return 0;
}

static int omapfb_alloc_mem(omapfb_data_t *pdata)
{
  struct omapfb_plane_info pi;
  struct omapfb_mem_info mi;
  const struct retro_game_geometry *geom;
  unsigned mem_size;
  void* mem;

  assert(pdata->current_state == NULL);

  pdata->current_state = calloc(1, sizeof(omapfb_state_t));
  if (!pdata->current_state) return -1;

  if (ioctl(pdata->fd, OMAPFB_QUERY_PLANE, &pi) != 0)
  {
    RARCH_ERR("video_omap: alloc mem (query plane) failed\n");
    return -1;
  }

  if (ioctl(pdata->fd, OMAPFB_QUERY_MEM, &mi) != 0)
  {
    RARCH_ERR("video_omap: alloc mem (query mem) failed\n");
    return -1;
  }

  /* disable plane when changing memory allocation */
  if (pi.enabled)
  {
    pi.enabled = 0;
    if (ioctl(pdata->fd, OMAPFB_SETUP_PLANE, &pi) != 0)
    {
      RARCH_ERR("video_omap: alloc mem (disable plane) failed\n");
      return -1;
    }
  }

  geom = &g_extern.system.av_info.geometry;
  mem_size = geom->max_width * geom->max_height *
             pdata->bpp * pdata->num_pages;

  mi.size = mem_size;

  if (ioctl(pdata->fd, OMAPFB_SETUP_MEM, &mi) != 0)
  {
    RARCH_ERR("video_omap: allocation of %u bytes of VRAM failed\n", mem_size);
    return -1;
  }

  mem = mmap(NULL, mi.size, PROT_WRITE|PROT_READ, MAP_SHARED, pdata->fd, 0);
  if (mem == MAP_FAILED)
  {
    RARCH_ERR("video_omap: zeroing framebuffer failed\n");
    return -1;
  }
  memset(mem, 0, mi.size);
  munmap(mem, mi.size);

  pdata->current_state->mi = mi;

  /* Don't re-enable the plane here (setup not yet complete) */

  return 0;
}

static int omapfb_setup_screeninfo(omapfb_data_t *pdata, int width, int height)
{
  omapfb_state_t* state = pdata->current_state;

  state->si.xres = width;
  state->si.yres = height;
  state->si.xres_virtual = width;
  state->si.yres_virtual = height * pdata->num_pages;

  state->si.xoffset = 0;
  state->si.yoffset = 0;

  state->si.bits_per_pixel = pdata->bpp * 8;

  /* OMAPFB_COLOR_ARGB32 for bpp=4, OMAPFB_COLOR_RGB565 for bpp=2 */
  state->si.nonstd = 0;

  if (ioctl(pdata->fd, FBIOPUT_VSCREENINFO, &state->si) != 0)
  {
    RARCH_ERR("video_omap: setup screeninfo failed\n");
    return -1;
  }

  pdata->fb_framesize = width * height * pdata->bpp;

  return 0;
}

static float omapfb_scaling(omapfb_data_t *pdata, int width, int height)
{
  const float w_factor = (float)pdata->nat_w / (float)width;
  const float h_factor = (float)pdata->nat_h / (float)height;

  return (w_factor < h_factor ? w_factor : h_factor);
}

static int omapfb_setup_plane(omapfb_data_t *pdata, int width, int height)
{
  struct omapfb_plane_info pi = {0};
  int x, y, w, h;
  float scale = omapfb_scaling(pdata, width, height);

  w = (int)(scale * width);
  h = (int)(scale * height);

  RARCH_LOG("omap_video: scaling %dx%d to %dx%d\n", width, height, w, h);

  x = pdata->nat_w / 2 - w / 2;
  y = pdata->nat_h / 2 - h / 2;

  if (width * height * pdata->bpp * pdata->num_pages > pdata->current_state->mi.size)
  {
    RARCH_ERR("omap_video: fb dimensions too large for allocated buffer\n");
    return -1;
  }

  if (ioctl(pdata->fd, OMAPFB_QUERY_PLANE, &pi) != 0)
  {
    RARCH_ERR("video_omap: setup plane (query) failed\n");
    return -1;
  }

  /* Disable the plane during setup to avoid garbage on screen. */
  pi.pos_x = x;
  pi.pos_y = y;
  pi.out_width = w;
  pi.out_height = h;
  pi.enabled = 0;

  if (ioctl(pdata->fd, OMAPFB_SETUP_PLANE, &pi) != 0)
  {
    RARCH_ERR("video_omap: setup plane (param = %d %d %d %d) failed\n", x, y, w, h);
    return -1;
  }

  pdata->current_state->pi = pi;

  return 0;
}

static int omapfb_enable_plane(omapfb_data_t *pdata)
{
  struct omapfb_plane_info pi = {0};

  if (ioctl(pdata->fd, OMAPFB_QUERY_PLANE, &pi) != 0)
  {
    RARCH_ERR("video_omap: enable plane (query) failed\n");
    return -1;
  }

  pi.enabled = 1;

  if (ioctl(pdata->fd, OMAPFB_SETUP_PLANE, &pi) != 0)
  {
    RARCH_ERR("video_omap: enable plane failed\n");
    return -1;
  }

  return 0;
}

static int omapfb_init(omapfb_data_t *pdata, unsigned bpp)
{
  const char *fbname = get_fb_device();
  int             fd = open(fbname, O_RDWR);

  if (fd == -1)
  {
    RARCH_ERR("video_omap: can't open framebuffer device\n");
    return -1;
  }

  pdata->fbname = fbname;
  pdata->fd = fd;

  if (omapfb_detect_screen(pdata))
  {
    close(fd);

    pdata->fbname = NULL;
    pdata->fd = -1;

    return -1;
  }

  /* always use triple buffering to reduce chance of tearing */
  pdata->bpp = bpp;
  pdata->num_pages = 3;

  pdata->sync = g_settings.video.vsync;

  return 0;
}

void omapfb_free(omapfb_data_t *pdata)
{
  if (pdata->sync)
     ioctl(pdata->fd, OMAPFB_WAITFORGO);

  /* unmap the framebuffer memory */
  if (pdata->fb_mem != NULL)
  {
    munmap(pdata->fb_mem, pdata->current_state->mi.size);
    pdata->fb_mem = NULL;
  }

  /* restore the framebuffer state (OMAP plane state, screen info) */
  if (pdata->saved_state != NULL)
  {
    void *mem;
    int enabled = pdata->saved_state->pi.enabled;

    /* be sure to disable while setting up */
    pdata->saved_state->pi.enabled = 0;
    ioctl(pdata->fd, OMAPFB_SETUP_PLANE, &pdata->saved_state->pi);
    ioctl(pdata->fd, OMAPFB_SETUP_MEM, &pdata->saved_state->mi);

    if (enabled)
    {
      pdata->saved_state->pi.enabled = enabled;
      ioctl(pdata->fd, OMAPFB_SETUP_PLANE, &pdata->saved_state->pi);
    }

    /* restore framebuffer content */
    mem = mmap(0, pdata->saved_state->mi.size, PROT_WRITE|PROT_READ,
               MAP_SHARED, pdata->fd, 0);

    if (mem != MAP_FAILED)
    {
      memcpy(mem, pdata->saved_state->mem, pdata->saved_state->mi.size);
      munmap(mem, pdata->saved_state->mi.size);
    }

    /* restore screen info */
    ioctl(pdata->fd, FBIOPUT_VSCREENINFO, &pdata->saved_state->si);

    free(pdata->saved_state->mem);
    pdata->saved_state->mem = NULL;

    free(pdata->saved_state);
    pdata->saved_state = NULL;
  }

  free(pdata->current_state);
  pdata->current_state = NULL;

  close(pdata->fd);
  pdata->fd = -1;
}

static int omapfb_set_mode(omapfb_data_t *pdata, int width, int height)
{
  if (pdata->sync) ioctl(pdata->fd, OMAPFB_WAITFORGO);

  if (omapfb_setup_plane(pdata, width, height) != 0)
    return -1;

  if (omapfb_setup_screeninfo(pdata, width, height) != 0 ||
      omapfb_setup_pages(pdata) != 0 ||
      omapfb_enable_plane(pdata) != 0)
    return -1;

  return 0;
}

static void omapfb_prepare(omapfb_data_t *pdata)
{
  omapfb_page_t *page;

  /* issue flip before getting free page */
  page_flip(pdata);
  page = get_page(pdata);
  assert(page != NULL);

  pdata->old_page = pdata->cur_page;
  pdata->cur_page = page;

  pdata->cur_page->used = true;
}

static void omapfb_blend_glyph_rgb565(omapfb_data_t *pdata,
      const uint8_t *src, uint8_t *f_rgb,
      unsigned g_width, unsigned g_height, unsigned g_pitch,
      unsigned dst_x, unsigned dst_y)
{
  unsigned x, y;
  unsigned dst_pitch;
  uint16_t *dst;
  unsigned r, g, b;

  dst_pitch = (pdata->current_state->si.xres * pdata->bpp) >> 1;
  dst = (uint16_t*)pdata->cur_page->buf + dst_y * dst_pitch + dst_x;

  for (y = 0; y < g_height; ++y, src += g_pitch, dst += dst_pitch)
  {
    for (x = 0; x < g_width; ++x)
    {
       const uint8_t blend = src[x];
       const uint16_t out  = dst[x];

       if (blend == 0)
          continue;

       if (blend == 255)
       {
          put_pixel_rgb565(&dst[x], f_rgb[0], f_rgb[1], f_rgb[2]);
          continue;
       }

       r = (out & 0xf800) >> 11;
       g = (out & 0x07e0) >> 5;
       b = (out & 0x001f) >> 0;

       r = (r << 3) | (r >> 2);
       g = (g << 2) | (g >> 4);
       b = (b << 3) | (b >> 2);

       put_pixel_rgb565(&dst[x], (r * (256 - blend) + f_rgb[0] * blend) >> 8,
             (g * (256 - blend) + f_rgb[1] * blend) >> 8,
             (b * (256 - blend) + f_rgb[2] * blend) >> 8);
    }
  }
}

static void omapfb_blend_glyph_argb8888(omapfb_data_t *pdata,
      const uint8_t *src, uint8_t *f_rgb,
      unsigned g_width, unsigned g_height, unsigned g_pitch,
      unsigned dst_x, unsigned dst_y)
{
  unsigned x, y;
  unsigned r, g, b;
  unsigned dst_pitch = (pdata->current_state->si.xres * pdata->bpp) >> 2;
  uint32_t *dst = (uint32_t*)pdata->cur_page->buf + dst_y * dst_pitch + dst_x;

  for (y = 0; y < g_height; ++y, src += g_pitch, dst += dst_pitch)
  {
    for (x = 0; x < g_width; ++x)
    {
       const uint8_t blend = src[x];
       const uint32_t out = dst[x];

       if (blend == 0)
          continue;
       if (blend == 255)
       {
          put_pixel_argb8888(&dst[x], f_rgb[0], f_rgb[1], f_rgb[2]);
          continue;
       }

       r = (out & 0xff0000) >> 16;
       g = (out & 0x00ff00) >> 8;
       b = (out & 0x0000ff) >> 0;

       put_pixel_argb8888(&dst[x], (r * (256 - blend) + f_rgb[0] * blend) >> 8,
             (g * (256 - blend) + f_rgb[1] * blend) >> 8,
             (b * (256 - blend) + f_rgb[2] * blend) >> 8);
    }
  }
}

static void omapfb_blit_frame(omapfb_data_t *pdata, const void *src,
                              unsigned height, unsigned src_pitch)
{
   unsigned i, dst_pitch;
   void *dst = pdata->cur_page->buf;

   dst_pitch = pdata->current_state->si.xres * pdata->bpp;

   for (i = 0; i < height; i++)
      memcpy(dst + dst_pitch * i, src + src_pitch * i, dst_pitch);
}


typedef struct omap_video
{
  omapfb_data_t *omap;

  void *font;
  const font_renderer_driver_t *font_driver;
  uint8_t font_rgb[4];

  unsigned bytes_per_pixel;

  /* current dimensions */
  unsigned width;
  unsigned height;
} omap_video_t;


static void omap_gfx_free(void *data)
{
  omap_video_t *vid = data;
  if (!vid)
     return;

  omapfb_free(vid->omap);
  free(vid->omap);

  if (vid->font)
     vid->font_driver->free(vid->font);

  free(vid);
}

static void omap_init_font(omap_video_t *vid, const char *font_path, unsigned font_size)
{
   int r, g, b;

   if (!g_settings.video.font_enable)
      return;

   if (!(font_renderer_create_default(&vid->font_driver, &vid->font,
               *g_settings.video.font_path ? g_settings.video.font_path : NULL, g_settings.video.font_size)))
   {
      RARCH_LOG("video_omap: font init failed\n");
      return;
   }

   {
      r = g_settings.video.msg_color_r * 255;
      g = g_settings.video.msg_color_g * 255;
      b = g_settings.video.msg_color_b * 255;

      r = (r < 0) ? 0 : (r > 255 ? 255 : r);
      g = (g < 0) ? 0 : (g > 255 ? 255 : g);
      b = (b < 0) ? 0 : (b > 255 ? 255 : b);

      vid->font_rgb[0] = r;
      vid->font_rgb[1] = g;
      vid->font_rgb[2] = b;
   }
}

static void omap_render_msg(omap_video_t *vid, const char *msg)
{
   const struct font_atlas *atlas = NULL;
   int msg_base_x = g_settings.video.msg_pos_x * vid->width;
   int msg_base_y = (1.0 - g_settings.video.msg_pos_y) * vid->height;

   if (!vid->font)
      return;

   atlas = vid->font_driver->get_atlas(vid->font);

   for (; *msg; msg++)
   {
      int base_x, base_y;
      int glyph_width, glyph_height;
      const uint8_t *src = NULL;
      const struct font_glyph *glyph = 
         vid->font_driver->get_glyph(vid->font, (uint8_t)*msg);

      if (!glyph)
         continue;

      base_x               = msg_base_x + glyph->draw_offset_x;
      base_y               = msg_base_y + glyph->draw_offset_y;

      const int max_width  = vid->width - base_x;
      const int max_height = vid->height - base_y;

      glyph_width          = head->width;
      glyph_height         = head->height;

      src                  = atlas->buffer + glyph->atlas_offset_x + 
         glyph->atlas_offset_y * atlas->width;

      if (base_x < 0)
      {
         src -= base_x;
         glyph_width += base_x;
         base_x = 0;
      }

      if (base_y < 0)
      {
         src -= base_y * (int)atlas->width;
         glyph_height += base_y;
         base_y = 0;
      }

      if (max_width <= 0 || max_height <= 0)
         continue;

      if (glyph_width > max_width)
         glyph_width = max_width;
      if (glyph_height > max_height)
         glyph_height = max_height;

      if (vid->bytes_per_pixel == 2)
      {
         omapfb_blend_glyph_rgb565(vid->omap, src, vid->font_rgb,
               glyph_width, glyph_height,
               atlas->width, base_x, base_y);
      }
      else
      {
         omapfb_blend_glyph_argb8888(vid->omap, src, vid->font_rgb,
               glyph_width, glyph_height,
               atlas->width, base_x, base_y);
      }

      msg_base_x += glyph->advance_x;
      msg_base_y += glyph->advance_y;
   }
}

static void *omap_gfx_init(const video_info_t *video,
      const input_driver_t **input, void **input_data)
{
  omap_video_t *vid = NULL;

  /* Don't support filters at the moment since they make estimations  *
   * on the maximum used resolution difficult.                        */
  if (g_extern.filter.active)
  {
    RARCH_ERR("video_omap: filters are not supported\n");
    return NULL;
  }

  vid = calloc(1, sizeof(omap_video_t));
  if (!vid)
     return NULL;

  vid->omap = calloc(1, sizeof(omapfb_data_t));
  if (!vid->omap)
     goto fail;

  vid->bytes_per_pixel = video->rgb32 ? 4 : 2;

  if (omapfb_init(vid->omap, vid->bytes_per_pixel) != 0)
    goto fail_omapfb;

  if (omapfb_backup_state(vid->omap) != 0 ||
      omapfb_alloc_mem(vid->omap) != 0 ||
      omapfb_mmap(vid->omap) != 0)
     goto fail_omapfb;

  if (input && input_data)
    *input = NULL;

  omap_init_font(vid, g_settings.video.font_path, g_settings.video.font_size);

  return vid;

fail_omapfb:
  omapfb_free(vid->omap);
  free(vid->omap);
fail:
  free(vid);
  RARCH_ERR("video_omap: initialization failed\n");
  return NULL;
}

static bool omap_gfx_frame(void *data, const void *frame, unsigned width,
                           unsigned height, unsigned pitch, const char *msg)
{
  omap_video_t *vid;

  if (!frame)
     return true;
  vid = data;

  if (width != vid->width || height != vid->height)
  {
    if (width == 0 || height == 0)
       return true;

    RARCH_LOG("video_omap: mode set (resolution changed by core)\n");

    if (omapfb_set_mode(vid->omap, width, height) != 0)
    {
      RARCH_ERR("video_omap: mode set failed\n");
      return false;
    }

    vid->width = width;
    vid->height = height;
  }

  omapfb_prepare(vid->omap);
  omapfb_blit_frame(vid->omap, frame, vid->height, pitch);
  if (msg)
     omap_render_msg(vid, msg);

  g_extern.frame_count++;

  return true;
}

static void omap_gfx_set_nonblock_state(void *data, bool state)
{
  omap_video_t *vid;

  if (!data)
     return;

  vid = data;
  vid->omap->sync = !state;
}

static bool omap_gfx_alive(void *data)
{
  (void)data;
  return true; /* always alive */
}

static bool omap_gfx_focus(void *data)
{
  (void)data;
  return true; /* fb device always has focus */
}

static void omap_gfx_viewport_info(void *data, struct rarch_viewport *vp)
{
  omap_video_t *vid = (omap_video_t*)data;
  
  if (!vid)
     return;

  vp->x = vp->y = 0;

  vp->width  = vp->full_width  = vid->width;
  vp->height = vp->full_height = vid->height;
}

static bool omap_gfx_suppress_screensaver(void *data, bool enable)
{
   (void)data;
   (void)enable;

   return false;
}

static bool omap_gfx_has_windowed(void *data)
{
   (void)data;

   /* TODO - implement. */
   return true;
}

static bool omap_gfx_set_shader(void *data,
      enum rarch_shader_type type, const char *path)
{
   (void)data;
   (void)type;
   (void)path;

   return false; 
}

static void omap_gfx_set_rotation(void *data, unsigned rotation)
{
   (void)data;
   (void)rotation;
}

static bool omap_gfx_read_viewport(void *data, uint8_t *buffer)
{
   (void)data;
   (void)buffer;

   return true;
}

static void omap_gfx_get_poke_interface(void *data,
      const video_poke_interface_t **iface)
{
   (void)data;
   (void)iface;
}

video_driver_t video_omap = {
  omap_gfx_init,
  omap_gfx_frame,
  omap_gfx_set_nonblock_state,
  omap_gfx_alive,
  omap_gfx_focus,
  omap_gfx_suppress_screensaver,
  omap_gfx_has_windowed,
  omap_gfx_set_shader,
  omap_gfx_free,
  "omap",

  omap_gfx_set_rotation,
  omap_gfx_viewport_info,
  omap_gfx_read_viewport,

#ifdef HAVE_OVERLAY
  NULL, /* overlay_interface */
#endif
  omap_gfx_get_poke_interface
};
