/**************************************************************************
 *
 * Copyright 2008 VMware, Inc.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/

#include "pipe/p_format.h"
#include "pipe/p_defines.h"
#include "pipe/p_screen.h"

#include "util/u_format.h"
#include "util/u_debug.h"
#include "util/u_memory.h"

#include "stw_icd.h"
#include "stw_device.h"
#include "stw_pixelformat.h"
#include "stw_tls.h"


struct stw_pf_color_info
{
   enum pipe_format format;
   struct {
      unsigned char red;
      unsigned char green;
      unsigned char blue;
      unsigned char alpha;
   } bits;
   struct {
      unsigned char red;
      unsigned char green;
      unsigned char blue;
      unsigned char alpha;
   } shift;
};

struct stw_pf_depth_info
{
   enum pipe_format format;
   struct {
      unsigned char depth;
      unsigned char stencil;
   } bits;
};


/* NOTE: order matters, since in otherwise equal circumstances the first
 * format listed will get chosen */

static const struct stw_pf_color_info
stw_pf_color[] = {
   /* no-alpha */
   { PIPE_FORMAT_B8G8R8X8_UNORM,    { 8,  8,  8,  0}, {16,  8,  0,  0} },
   { PIPE_FORMAT_X8R8G8B8_UNORM,    { 8,  8,  8,  0}, { 8, 16, 24,  0} },
   /* alpha */
   { PIPE_FORMAT_B8G8R8A8_UNORM,    { 8,  8,  8,  8}, {16,  8,  0, 24} },
   { PIPE_FORMAT_A8R8G8B8_UNORM,    { 8,  8,  8,  8}, { 8, 16, 24,  0} },
   /* shallow bit depths */
   { PIPE_FORMAT_B5G6R5_UNORM,      { 5,  6,  5,  0}, {11,  5,  0,  0} },
#if 0
   { PIPE_FORMAT_R10G10B10A2_UNORM, {10, 10, 10,  2}, { 0, 10, 20, 30} },
#endif
   { PIPE_FORMAT_B5G5R5A1_UNORM,    { 5,  5,  5,  1}, {10,  5,  0, 15} },
   { PIPE_FORMAT_B4G4R4A4_UNORM,    { 4,  4,  4,  4}, {16,  4,  0, 12} }
};

static const struct stw_pf_color_info
stw_pf_color_extended[] = {
   { PIPE_FORMAT_R32G32B32A32_FLOAT, {32, 32, 32, 32}, {0, 32, 64, 96} }
};

static const struct stw_pf_depth_info
stw_pf_depth_stencil[] = {
   /* pure depth */
   { PIPE_FORMAT_Z32_UNORM,   {32, 0} },
   { PIPE_FORMAT_X8Z24_UNORM, {24, 0} },
   { PIPE_FORMAT_Z24X8_UNORM, {24, 0} },
   { PIPE_FORMAT_Z16_UNORM,   {16, 0} },
   /* combined depth-stencil */
   { PIPE_FORMAT_Z24_UNORM_S8_UINT, {24, 8} },
   { PIPE_FORMAT_S8_UINT_Z24_UNORM, {24, 8} }
};


static const boolean
stw_pf_doublebuffer[] = {
   FALSE,
   TRUE,
};


const unsigned
stw_pf_multisample[] = {
   0,
   4,
   8,
   16
};


static void
stw_pixelformat_add(struct stw_device *stw_dev,
                    boolean extended,
                    const struct stw_pf_color_info *color,
                    const struct stw_pf_depth_info *depth,
                    unsigned accum,
                    boolean doublebuffer,
                    unsigned samples)
{
   struct stw_pixelformat_info *pfi;

   assert(stw_dev->pixelformat_extended_count < STW_MAX_PIXELFORMATS);
   if (stw_dev->pixelformat_extended_count >= STW_MAX_PIXELFORMATS)
      return;

   assert(util_format_get_component_bits(color->format, UTIL_FORMAT_COLORSPACE_RGB, 0) == color->bits.red);
   assert(util_format_get_component_bits(color->format, UTIL_FORMAT_COLORSPACE_RGB, 1) == color->bits.green);
   assert(util_format_get_component_bits(color->format, UTIL_FORMAT_COLORSPACE_RGB, 2) == color->bits.blue);
   assert(util_format_get_component_bits(color->format, UTIL_FORMAT_COLORSPACE_RGB, 3) == color->bits.alpha);
   assert(util_format_get_component_bits(depth->format, UTIL_FORMAT_COLORSPACE_ZS, 0) == depth->bits.depth);
   assert(util_format_get_component_bits(depth->format, UTIL_FORMAT_COLORSPACE_ZS, 1) == depth->bits.stencil);

   pfi = &stw_dev->pixelformats[stw_dev->pixelformat_extended_count];

   memset(pfi, 0, sizeof *pfi);

   pfi->pfd.nSize = sizeof pfi->pfd;
   pfi->pfd.nVersion = 1;

   pfi->pfd.dwFlags = PFD_SUPPORT_OPENGL;

   /* TODO: also support non-native pixel formats */
   if (!extended) {
      pfi->pfd.dwFlags |= PFD_DRAW_TO_WINDOW;
   }

   /* See http://www.opengl.org/pipeline/article/vol003_7/ */
   pfi->pfd.dwFlags |= PFD_SUPPORT_COMPOSITION;

   if (doublebuffer)
      pfi->pfd.dwFlags |= PFD_DOUBLEBUFFER | PFD_SWAP_EXCHANGE;

   pfi->pfd.iPixelType = PFD_TYPE_RGBA;

   pfi->pfd.cColorBits =
      color->bits.red + color->bits.green + color->bits.blue + color->bits.alpha;
   pfi->pfd.cRedBits = color->bits.red;
   pfi->pfd.cRedShift = color->shift.red;
   pfi->pfd.cGreenBits = color->bits.green;
   pfi->pfd.cGreenShift = color->shift.green;
   pfi->pfd.cBlueBits = color->bits.blue;
   pfi->pfd.cBlueShift = color->shift.blue;
   pfi->pfd.cAlphaBits = color->bits.alpha;
   pfi->pfd.cAlphaShift = color->shift.alpha;
   pfi->pfd.cAccumBits = 4*accum;
   pfi->pfd.cAccumRedBits = accum;
   pfi->pfd.cAccumGreenBits = accum;
   pfi->pfd.cAccumBlueBits = accum;
   pfi->pfd.cAccumAlphaBits = accum;
   pfi->pfd.cDepthBits = depth->bits.depth;
   pfi->pfd.cStencilBits = depth->bits.stencil;
   pfi->pfd.cAuxBuffers = 0;
   pfi->pfd.iLayerType = 0;
   pfi->pfd.bReserved = 0;
   pfi->pfd.dwLayerMask = 0;
   pfi->pfd.dwVisibleMask = 0;
   pfi->pfd.dwDamageMask = 0;

   /*
    * since state trackers can allocate depth/stencil/accum buffers, we provide
    * only color buffers here
    */
   pfi->stvis.buffer_mask = ST_ATTACHMENT_FRONT_LEFT_MASK;
   if (doublebuffer)
      pfi->stvis.buffer_mask |= ST_ATTACHMENT_BACK_LEFT_MASK;

   pfi->stvis.color_format = color->format;
   pfi->stvis.depth_stencil_format = depth->format;

   pfi->stvis.accum_format = (accum) ?
      PIPE_FORMAT_R16G16B16A16_SNORM : PIPE_FORMAT_NONE;

   pfi->stvis.samples = samples;
   pfi->stvis.render_buffer = ST_ATTACHMENT_INVALID;

   /* WGL_ARB_render_texture */
   if (color->bits.alpha)
      pfi->bindToTextureRGBA = TRUE;

   pfi->bindToTextureRGB = TRUE;

   ++stw_dev->pixelformat_extended_count;

   if (!extended) {
      ++stw_dev->pixelformat_count;
      assert(stw_dev->pixelformat_count == stw_dev->pixelformat_extended_count);
   }
}


/**
 * Add the depth/stencil/accum/ms variants for a list of color formats.
 */
static unsigned
add_color_format_variants(const struct stw_pf_color_info *color_formats,
                          unsigned num_color_formats, boolean extended)
{
   struct pipe_screen *screen = stw_dev->screen;
   unsigned cfmt, ms, db, ds, acc;
   unsigned bind_flags = PIPE_BIND_RENDER_TARGET;
   unsigned num_added = 0;
   int force_samples = 0;

   /* Since GLUT for Windows doesn't support MSAA we have an env var
    * to force all pixel formats to have a particular number of samples.
    */
   {
      const char *samples= getenv("SVGA_FORCE_MSAA");
      if (samples)
         force_samples = atoi(samples);
   }

   if (!extended) {
      bind_flags |= PIPE_BIND_DISPLAY_TARGET;
   }

   for (ms = 0; ms < ARRAY_SIZE(stw_pf_multisample); ms++) {
      unsigned samples = stw_pf_multisample[ms];

      if (force_samples && samples != force_samples)
         continue;

      for (cfmt = 0; cfmt < num_color_formats; cfmt++) {
         if (!screen->is_format_supported(screen, color_formats[cfmt].format,
                                          PIPE_TEXTURE_2D, samples,
                                          bind_flags)) {
            continue;
         }

         for (db = 0; db < ARRAY_SIZE(stw_pf_doublebuffer); db++) {
            unsigned doublebuffer = stw_pf_doublebuffer[db];

            for (ds = 0; ds < ARRAY_SIZE(stw_pf_depth_stencil); ds++) {
               const struct stw_pf_depth_info *depth = &stw_pf_depth_stencil[ds];

               if (!screen->is_format_supported(screen, depth->format,
                                                PIPE_TEXTURE_2D, samples,
                                                PIPE_BIND_DEPTH_STENCIL)) {
                  continue;
               }

               for (acc = 0; acc < 2; acc++) {
                  stw_pixelformat_add(stw_dev, extended, &color_formats[cfmt],
                                      depth,
                                      acc * 16, doublebuffer, samples);
                  num_added++;
               }
            }
         }
      }
   }

   return num_added;
}


void
stw_pixelformat_init(void)
{
   unsigned num_formats;

   assert(!stw_dev->pixelformat_count);
   assert(!stw_dev->pixelformat_extended_count);

   /* normal, displayable formats */
   num_formats = add_color_format_variants(stw_pf_color,
                                           ARRAY_SIZE(stw_pf_color), FALSE);
   assert(num_formats > 0);

   /* extended, pbuffer-only formats */
   add_color_format_variants(stw_pf_color_extended,
                             ARRAY_SIZE(stw_pf_color_extended), TRUE);

   assert(stw_dev->pixelformat_count <= stw_dev->pixelformat_extended_count);
   assert(stw_dev->pixelformat_extended_count <= STW_MAX_PIXELFORMATS);
}


uint
stw_pixelformat_get_count(void)
{
   return stw_dev->pixelformat_count;
}


uint
stw_pixelformat_get_extended_count(void)
{
   return stw_dev->pixelformat_extended_count;
}


const struct stw_pixelformat_info *
stw_pixelformat_get_info(int iPixelFormat)
{
   unsigned index;

   if (iPixelFormat <= 0) {
      return NULL;
   }

   index = iPixelFormat - 1;
   if (index >= stw_dev->pixelformat_extended_count) {
      return NULL;
   }

   return &stw_dev->pixelformats[index];
}


LONG APIENTRY
DrvDescribePixelFormat(HDC hdc, INT iPixelFormat, ULONG cjpfd,
                       PIXELFORMATDESCRIPTOR *ppfd)
{
   uint count;
   const struct stw_pixelformat_info *pfi;

   (void) hdc;

   if (!stw_dev)
      return 0;

   count = stw_pixelformat_get_count();

   if (ppfd == NULL)
      return count;

   if (cjpfd != sizeof(PIXELFORMATDESCRIPTOR))
      return 0;

   pfi = stw_pixelformat_get_info(iPixelFormat);
   if (!pfi) {
      return 0;
   }

   memcpy(ppfd, &pfi->pfd, sizeof(PIXELFORMATDESCRIPTOR));

   return count;
}


BOOL APIENTRY
DrvDescribeLayerPlane(HDC hdc, INT iPixelFormat, INT iLayerPlane,
                      UINT nBytes, LPLAYERPLANEDESCRIPTOR plpd)
{
   assert(0);
   return FALSE;
}


int APIENTRY
DrvGetLayerPaletteEntries(HDC hdc, INT iLayerPlane, INT iStart,
                          INT cEntries, COLORREF *pcr)
{
   assert(0);
   return 0;
}


int APIENTRY
DrvSetLayerPaletteEntries(HDC hdc, INT iLayerPlane, INT iStart,
                          INT cEntries, CONST COLORREF *pcr)
{
   assert(0);
   return 0;
}


BOOL APIENTRY
DrvRealizeLayerPalette(HDC hdc, INT iLayerPlane, BOOL bRealize)
{
   assert(0);
   return FALSE;
}


/* Only used by the wgl code, but have it here to avoid exporting the
 * pixelformat.h functionality.
 */
int
stw_pixelformat_choose(HDC hdc, CONST PIXELFORMATDESCRIPTOR *ppfd)
{
   uint count;
   uint index;
   uint bestindex;
   uint bestdelta;

   (void) hdc;

   count = stw_pixelformat_get_extended_count();
   bestindex = 0;
   bestdelta = ~0U;

   for (index = 1; index <= count; index++) {
      uint delta = 0;
      const struct stw_pixelformat_info *pfi = stw_pixelformat_get_info(index);

      if (!(ppfd->dwFlags & PFD_DOUBLEBUFFER_DONTCARE) &&
          !!(ppfd->dwFlags & PFD_DOUBLEBUFFER) !=
          !!(pfi->pfd.dwFlags & PFD_DOUBLEBUFFER))
         continue;

      /* FIXME: Take in account individual channel bits */
      if (ppfd->cColorBits != pfi->pfd.cColorBits)
         delta += 8;

      if (ppfd->cDepthBits != pfi->pfd.cDepthBits)
         delta += 4;

      if (ppfd->cStencilBits != pfi->pfd.cStencilBits)
         delta += 2;

      if (ppfd->cAlphaBits != pfi->pfd.cAlphaBits)
         delta++;

      if (delta < bestdelta) {
         bestindex = index;
         bestdelta = delta;
         if (bestdelta == 0)
            break;
      }
   }

   return bestindex;
}