palette.cpp

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/*
 * This file is part of OpenTTD.
 * OpenTTD 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 Foundation, version 2.
 * OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "stdafx.h"
#include "blitter/base.hpp"
#include "blitter/factory.hpp"
#include "fileio_func.h"
#include "gfx_type.h"
#include "landscape_type.h"
#include "palette_func.h"
#include "settings_type.h"
#include "thread.h"
 
#include "table/palettes.h"
 
#include "safeguards.h"
 
Palette _cur_palette;
 
byte _colour_gradient[COLOUR_END][8];
 
static std::recursive_mutex _palette_mutex; 
 
const uint PALETTE_BITS = 6;
const uint PALETTE_SHIFT = 8 - PALETTE_BITS;
const uint PALETTE_BITS_MASK = ((1U << PALETTE_BITS) - 1) << PALETTE_SHIFT;
const uint PALETTE_BITS_OR = (1U << (PALETTE_SHIFT - 1));
 
/* Palette and reshade lookup table. */
using PaletteLookup = std::array<uint8_t, 1U << (PALETTE_BITS * 3)>;
static PaletteLookup _palette_lookup{};
 
inline uint CrunchColour(uint c)
{
  return (c & PALETTE_BITS_MASK) | PALETTE_BITS_OR;
}
 
static uint CalculateColourDistance(const Colour &col1, int r2, int g2, int b2)
{
  /* Euclidean colour distance for sRGB based on https://en.wikipedia.org/wiki/Color_difference#sRGB */
  int r = (int)col1.r - (int)r2;
  int g = (int)col1.g - (int)g2;
  int b = (int)col1.b - (int)b2;
 
  int avgr = (col1.r + r2) / 2;
  return ((2 + (avgr / 256.0)) * r * r) + (4 * g * g) + ((2 + ((255 - avgr) / 256.0)) * b * b);
}
 
/* Palette indexes for conversion. See docs/palettes/palette_key.png */
const uint8_t PALETTE_INDEX_CC_START = 198; 
const uint8_t PALETTE_INDEX_CC_END = PALETTE_INDEX_CC_START + 8; 
const uint8_t PALETTE_INDEX_START = 1; 
const uint8_t PALETTE_INDEX_END = 215; 
 
static uint8_t FindNearestColourIndex(uint8_t r, uint8_t g, uint8_t b)
{
  r = CrunchColour(r);
  g = CrunchColour(g);
  b = CrunchColour(b);
 
  uint best_index = 0;
  uint best_distance = UINT32_MAX;
 
  for (uint i = PALETTE_INDEX_START; i < PALETTE_INDEX_CC_START; i++) {
    if (uint distance = CalculateColourDistance(_palette.palette[i], r, g, b); distance < best_distance) {
      best_index = i;
      best_distance = distance;
    }
  }
  /* There's a hole in the palette reserved for company colour remaps. */
  for (uint i = PALETTE_INDEX_CC_END; i < PALETTE_INDEX_END; i++) {
    if (uint distance = CalculateColourDistance(_palette.palette[i], r, g, b); distance < best_distance) {
      best_index = i;
      best_distance = distance;
    }
  }
  return best_index;
}
 
uint8_t GetNearestColourIndex(uint8_t r, uint8_t g, uint8_t b)
{
  uint32_t key = (r >> PALETTE_SHIFT) | (g >> PALETTE_SHIFT) << PALETTE_BITS | (b >> PALETTE_SHIFT) << (PALETTE_BITS * 2);
  if (_palette_lookup[key] == 0) _palette_lookup[key] = FindNearestColourIndex(r, g, b);
  return _palette_lookup[key];
}
 
void DoPaletteAnimations();
 
void GfxInitPalettes()
{
  std::lock_guard<std::recursive_mutex> lock(_palette_mutex);
  memcpy(&_cur_palette, &_palette, sizeof(_cur_palette));
  DoPaletteAnimations();
}
 
bool CopyPalette(Palette &local_palette, bool force_copy)
{
  std::lock_guard<std::recursive_mutex> lock(_palette_mutex);
 
  if (!force_copy && _cur_palette.count_dirty == 0) return false;
 
  local_palette = _cur_palette;
  _cur_palette.count_dirty = 0;
 
  if (force_copy) {
    local_palette.first_dirty = 0;
    local_palette.count_dirty = 256;
  }
 
  return true;
}
 
#define EXTR(p, q) (((uint16_t)(palette_animation_counter * (p)) * (q)) >> 16)
#define EXTR2(p, q) (((uint16_t)(~palette_animation_counter * (p)) * (q)) >> 16)
 
void DoPaletteAnimations()
{
  std::lock_guard<std::recursive_mutex> lock(_palette_mutex);
 
  /* Animation counter for the palette animation. */
  static int palette_animation_counter = 0;
  palette_animation_counter += 8;
 
  Blitter *blitter = BlitterFactory::GetCurrentBlitter();
  const Colour *s;
  const ExtraPaletteValues *ev = &_extra_palette_values;
  Colour old_val[PALETTE_ANIM_SIZE];
  const uint old_tc = palette_animation_counter;
  uint j;
 
  if (blitter != nullptr && blitter->UsePaletteAnimation() == Blitter::PALETTE_ANIMATION_NONE) {
    palette_animation_counter = 0;
  }
 
  Colour *palette_pos = &_cur_palette.palette[PALETTE_ANIM_START];  // Points to where animations are taking place on the palette
  /* Makes a copy of the current animation palette in old_val,
   * so the work on the current palette could be compared, see if there has been any changes */
  memcpy(old_val, palette_pos, sizeof(old_val));
 
  /* Fizzy Drink bubbles animation */
  s = ev->fizzy_drink;
  j = EXTR2(512, EPV_CYCLES_FIZZY_DRINK);
  for (uint i = 0; i != EPV_CYCLES_FIZZY_DRINK; i++) {
    *palette_pos++ = s[j];
    j++;
    if (j == EPV_CYCLES_FIZZY_DRINK) j = 0;
  }
 
  /* Oil refinery fire animation */
  s = ev->oil_refinery;
  j = EXTR2(512, EPV_CYCLES_OIL_REFINERY);
  for (uint i = 0; i != EPV_CYCLES_OIL_REFINERY; i++) {
    *palette_pos++ = s[j];
    j++;
    if (j == EPV_CYCLES_OIL_REFINERY) j = 0;
  }
 
  /* Radio tower blinking */
  {
    byte i = (palette_animation_counter >> 1) & 0x7F;
    byte v;
 
    if (i < 0x3f) {
      v = 255;
    } else if (i < 0x4A || i >= 0x75) {
      v = 128;
    } else {
      v = 20;
    }
    palette_pos->r = v;
    palette_pos->g = 0;
    palette_pos->b = 0;
    palette_pos++;
 
    i ^= 0x40;
    if (i < 0x3f) {
      v = 255;
    } else if (i < 0x4A || i >= 0x75) {
      v = 128;
    } else {
      v = 20;
    }
    palette_pos->r = v;
    palette_pos->g = 0;
    palette_pos->b = 0;
    palette_pos++;
  }
 
  /* Handle lighthouse and stadium animation */
  s = ev->lighthouse;
  j = EXTR(256, EPV_CYCLES_LIGHTHOUSE);
  for (uint i = 0; i != EPV_CYCLES_LIGHTHOUSE; i++) {
    *palette_pos++ = s[j];
    j++;
    if (j == EPV_CYCLES_LIGHTHOUSE) j = 0;
  }
 
  /* Dark blue water */
  s = (_settings_game.game_creation.landscape == LT_TOYLAND) ? ev->dark_water_toyland : ev->dark_water;
  j = EXTR(320, EPV_CYCLES_DARK_WATER);
  for (uint i = 0; i != EPV_CYCLES_DARK_WATER; i++) {
    *palette_pos++ = s[j];
    j++;
    if (j == EPV_CYCLES_DARK_WATER) j = 0;
  }
 
  /* Glittery water */
  s = (_settings_game.game_creation.landscape == LT_TOYLAND) ? ev->glitter_water_toyland : ev->glitter_water;
  j = EXTR(128, EPV_CYCLES_GLITTER_WATER);
  for (uint i = 0; i != EPV_CYCLES_GLITTER_WATER / 3; i++) {
    *palette_pos++ = s[j];
    j += 3;
    if (j >= EPV_CYCLES_GLITTER_WATER) j -= EPV_CYCLES_GLITTER_WATER;
  }
 
  if (blitter != nullptr && blitter->UsePaletteAnimation() == Blitter::PALETTE_ANIMATION_NONE) {
    palette_animation_counter = old_tc;
  } else if (_cur_palette.count_dirty == 0 && memcmp(old_val, &_cur_palette.palette[PALETTE_ANIM_START], sizeof(old_val)) != 0) {
    /* Did we changed anything on the palette? Seems so.  Mark it as dirty */
    _cur_palette.first_dirty = PALETTE_ANIM_START;
    _cur_palette.count_dirty = PALETTE_ANIM_SIZE;
  }
}
 
TextColour GetContrastColour(uint8_t background, uint8_t threshold)
{
  Colour c = _cur_palette.palette[background];
  /* Compute brightness according to http://www.w3.org/TR/AERT#color-contrast.
   * The following formula computes 1000 * brightness^2, with brightness being in range 0 to 255. */
  uint sq1000_brightness = c.r * c.r * 299 + c.g * c.g * 587 + c.b * c.b * 114;
  /* Compare with threshold brightness which defaults to 128 (50%) */
  return sq1000_brightness < ((uint) threshold) * ((uint) threshold) * 1000 ? TC_WHITE : TC_BLACK;
}