unity/crnlib/crn_pixel_format.h

// File: crn_pixel_format.h
// See Copyright Notice and license at the end of inc/crnlib.h
#pragma once
#include "crn_dxt.h"
#include "../inc/crnlib.h"
#include "../inc/dds_defs.h"

namespace crnlib {
namespace pixel_format_helpers {
uint get_num_formats();
pixel_format get_pixel_format_by_index(uint index);

const char* get_pixel_format_string(pixel_format fmt);

const char* get_crn_format_string(crn_format fmt);

inline bool is_grayscale(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_L8:
    case PIXEL_FMT_A8L8:
      return true;
    default:
      break;
  }
  return false;
}

inline bool is_dxt1(pixel_format fmt) {
  return (fmt == PIXEL_FMT_DXT1) || (fmt == PIXEL_FMT_DXT1A);
}

// has_alpha() should probably be called "has_opacity()" - it indicates if the format encodes opacity
// because some swizzled DXT5 formats do not encode opacity.
inline bool has_alpha(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_DXT1A:
    case PIXEL_FMT_DXT2:
    case PIXEL_FMT_DXT3:
    case PIXEL_FMT_DXT4:
    case PIXEL_FMT_DXT5:
    case PIXEL_FMT_DXT5A:
    case PIXEL_FMT_A8R8G8B8:
    case PIXEL_FMT_A8:
    case PIXEL_FMT_A8L8:
    case PIXEL_FMT_DXT5_AGBR:
      return true;
    default:
      break;
  }
  return false;
}

inline bool is_alpha_only(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_A8:
    case PIXEL_FMT_DXT5A:
      return true;
    default:
      break;
  }
  return false;
}

inline bool is_normal_map(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_3DC:
    case PIXEL_FMT_DXN:
    case PIXEL_FMT_DXT5_xGBR:
    case PIXEL_FMT_DXT5_xGxR:
    case PIXEL_FMT_DXT5_AGBR:
      return true;
    default:
      break;
  }
  return false;
}

inline int is_dxt(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_DXT1:
    case PIXEL_FMT_DXT1A:
    case PIXEL_FMT_DXT2:
    case PIXEL_FMT_DXT3:
    case PIXEL_FMT_DXT4:
    case PIXEL_FMT_DXT5:
    case PIXEL_FMT_3DC:
    case PIXEL_FMT_DXT5A:
    case PIXEL_FMT_DXN:
    case PIXEL_FMT_DXT5_CCxY:
    case PIXEL_FMT_DXT5_xGxR:
    case PIXEL_FMT_DXT5_xGBR:
    case PIXEL_FMT_DXT5_AGBR:
    case PIXEL_FMT_ETC1:
      return true;
    default:
      break;
  }
  return false;
}

inline int get_fundamental_format(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_DXT1A:
      return PIXEL_FMT_DXT1;
    case PIXEL_FMT_DXT5_CCxY:
    case PIXEL_FMT_DXT5_xGxR:
    case PIXEL_FMT_DXT5_xGBR:
    case PIXEL_FMT_DXT5_AGBR:
      return PIXEL_FMT_DXT5;
    default:
      break;
  }
  return fmt;
}

inline dxt_format get_dxt_format(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_DXT1:
      return cDXT1;
    case PIXEL_FMT_DXT1A:
      return cDXT1A;
    case PIXEL_FMT_DXT2:
      return cDXT3;
    case PIXEL_FMT_DXT3:
      return cDXT3;
    case PIXEL_FMT_DXT4:
      return cDXT5;
    case PIXEL_FMT_DXT5:
      return cDXT5;
    case PIXEL_FMT_3DC:
      return cDXN_YX;
    case PIXEL_FMT_DXT5A:
      return cDXT5A;
    case PIXEL_FMT_DXN:
      return cDXN_XY;
    case PIXEL_FMT_DXT5_CCxY:
      return cDXT5;
    case PIXEL_FMT_DXT5_xGxR:
      return cDXT5;
    case PIXEL_FMT_DXT5_xGBR:
      return cDXT5;
    case PIXEL_FMT_DXT5_AGBR:
      return cDXT5;
    case PIXEL_FMT_ETC1:
      return cETC1;
    default:
      break;
  }
  return cDXTInvalid;
}

inline pixel_format from_dxt_format(dxt_format dxt_fmt) {
  switch (dxt_fmt) {
    case cDXT1:
      return PIXEL_FMT_DXT1;
    case cDXT1A:
      return PIXEL_FMT_DXT1A;
    case cDXT3:
      return PIXEL_FMT_DXT3;
    case cDXT5:
      return PIXEL_FMT_DXT5;
    case cDXN_XY:
      return PIXEL_FMT_DXN;
    case cDXN_YX:
      return PIXEL_FMT_3DC;
    case cDXT5A:
      return PIXEL_FMT_DXT5A;
    case cETC1:
      return PIXEL_FMT_ETC1;
    default:
      break;
  }
  CRNLIB_ASSERT(false);
  return PIXEL_FMT_INVALID;
}

inline bool is_pixel_format_non_srgb(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_3DC:
    case PIXEL_FMT_DXN:
    case PIXEL_FMT_DXT5A:
    case PIXEL_FMT_DXT5_CCxY:
    case PIXEL_FMT_DXT5_xGxR:
    case PIXEL_FMT_DXT5_xGBR:
    case PIXEL_FMT_DXT5_AGBR:
      return true;
    default:
      break;
  }
  return false;
}

inline bool is_crn_format_non_srgb(crn_format fmt) {
  switch (fmt) {
    case cCRNFmtDXN_XY:
    case cCRNFmtDXN_YX:
    case cCRNFmtDXT5A:
    case cCRNFmtDXT5_CCxY:
    case cCRNFmtDXT5_xGxR:
    case cCRNFmtDXT5_xGBR:
    case cCRNFmtDXT5_AGBR:
      return true;
    default:
      break;
  }
  return false;
}

inline uint get_bpp(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_DXT1:
      return 4;
    case PIXEL_FMT_DXT1A:
      return 4;
    case PIXEL_FMT_ETC1:
      return 4;
    case PIXEL_FMT_DXT2:
      return 8;
    case PIXEL_FMT_DXT3:
      return 8;
    case PIXEL_FMT_DXT4:
      return 8;
    case PIXEL_FMT_DXT5:
      return 8;
    case PIXEL_FMT_3DC:
      return 8;
    case PIXEL_FMT_DXT5A:
      return 4;
    case PIXEL_FMT_R8G8B8:
      return 24;
    case PIXEL_FMT_A8R8G8B8:
      return 32;
    case PIXEL_FMT_A8:
      return 8;
    case PIXEL_FMT_L8:
      return 8;
    case PIXEL_FMT_A8L8:
      return 16;
    case PIXEL_FMT_DXN:
      return 8;
    case PIXEL_FMT_DXT5_CCxY:
      return 8;
    case PIXEL_FMT_DXT5_xGxR:
      return 8;
    case PIXEL_FMT_DXT5_xGBR:
      return 8;
    case PIXEL_FMT_DXT5_AGBR:
      return 8;
    default:
      break;
  }
  CRNLIB_ASSERT(false);
  return 0;
};

inline uint get_dxt_bytes_per_block(pixel_format fmt) {
  switch (fmt) {
    case PIXEL_FMT_DXT1:
      return 8;
    case PIXEL_FMT_DXT1A:
      return 8;
    case PIXEL_FMT_DXT5A:
      return 8;
    case PIXEL_FMT_ETC1:
      return 8;
    case PIXEL_FMT_DXT2:
      return 16;
    case PIXEL_FMT_DXT3:
      return 16;
    case PIXEL_FMT_DXT4:
      return 16;
    case PIXEL_FMT_DXT5:
      return 16;
    case PIXEL_FMT_3DC:
      return 16;
    case PIXEL_FMT_DXN:
      return 16;
    case PIXEL_FMT_DXT5_CCxY:
      return 16;
    case PIXEL_FMT_DXT5_xGxR:
      return 16;
    case PIXEL_FMT_DXT5_xGBR:
      return 16;
    case PIXEL_FMT_DXT5_AGBR:
      return 16;
    default:
      break;
  }
  CRNLIB_ASSERT(false);
  return 0;
}

enum component_flags {
  cCompFlagRValid = 1,
  cCompFlagGValid = 2,
  cCompFlagBValid = 4,
  cCompFlagAValid = 8,

  cCompFlagGrayscale = 16,
  cCompFlagNormalMap = 32,
  cCompFlagLumaChroma = 64,

  cDefaultCompFlags = cCompFlagRValid | cCompFlagGValid | cCompFlagBValid | cCompFlagAValid
};

component_flags get_component_flags(pixel_format fmt);

crn_format convert_pixel_format_to_best_crn_format(pixel_format crn_fmt);

pixel_format convert_crn_format_to_pixel_format(crn_format fmt);

}  // namespace pixel_format_helpers

}  // namespace crnlib