OpenRCT2/src/openrct2/interface/Colour.cpp

/*****************************************************************************
 * Copyright (c) 2014-2019 OpenRCT2 developers
 *
 * For a complete list of all authors, please refer to contributors.md
 * Interested in contributing? Visit https://github.com/OpenRCT2/OpenRCT2
 *
 * OpenRCT2 is licensed under the GNU General Public License version 3.
 *****************************************************************************/

#include "Colour.h"

#include "../drawing/Drawing.h"
#include "../sprites.h"

#include <algorithm>
#include <cmath>

rct_colour_map ColourMapA[COLOUR_COUNT] = {};

enum
{
    INDEX_COLOUR_0 = 243,
    INDEX_COLOUR_1 = 245,
    INDEX_DARKEST = 245,
    INDEX_DARKER = 246,
    INDEX_DARK = 247,
    INDEX_MID_DARK = 248,
    INDEX_MID_LIGHT = 249,
    INDEX_LIGHT = 250,
    INDEX_LIGHTER = 251,
    INDEX_LIGHTEST = 252,
    INDEX_COLOUR_10 = 253,
    INDEX_COLOUR_11 = 254,
};

void colours_init_maps()
{
    // Get colour maps from g1
    for (int32_t i = 0; i < COLOUR_COUNT; i++)
    {
        const rct_g1_element* g1 = gfx_get_g1_element(SPR_PALETTE_2_START + i);
        if (g1 != nullptr)
        {
            ColourMapA[i].colour_0 = g1->offset[INDEX_COLOUR_0];
            ColourMapA[i].colour_1 = g1->offset[INDEX_COLOUR_1];
            ColourMapA[i].darkest = g1->offset[INDEX_DARKEST];
            ColourMapA[i].darker = g1->offset[INDEX_DARKER];
            ColourMapA[i].dark = g1->offset[INDEX_DARK];
            ColourMapA[i].mid_dark = g1->offset[INDEX_MID_DARK];
            ColourMapA[i].mid_light = g1->offset[INDEX_MID_LIGHT];
            ColourMapA[i].light = g1->offset[INDEX_LIGHT];
            ColourMapA[i].lighter = g1->offset[INDEX_LIGHTER];
            ColourMapA[i].lightest = g1->offset[INDEX_LIGHTEST];
            ColourMapA[i].colour_10 = g1->offset[INDEX_COLOUR_10];
            ColourMapA[i].colour_11 = g1->offset[INDEX_COLOUR_11];
        }
    }
}

#ifndef NO_TTF
static uint8_t BlendColourMap[PALETTE_COUNT][PALETTE_COUNT] = { 0 };

static uint8_t findClosestPaletteIndex(uint8_t red, uint8_t green, uint8_t blue)
{
    int16_t closest = -1;
    int32_t closestDistance = INT32_MAX;

    for (int i = PALETTE_INDEX_0; i < PALETTE_INDEX_230; i++)
    {
        const int32_t distance = std::pow(gPalette[i].red - red, 2) + std::pow(gPalette[i].green - green, 2)
            + std::pow(gPalette[i].blue - blue, 2);

        if (distance < closestDistance)
        {
            closest = i;
            closestDistance = distance;
        }
    }

    return closest;
}

uint8_t blendColours(const uint8_t paletteIndex1, const uint8_t paletteIndex2)
{
    const uint8_t cMin = std::min(paletteIndex1, paletteIndex2);
    const uint8_t cMax = std::max(paletteIndex1, paletteIndex2);

    if (BlendColourMap[cMin][cMax] != 0)
    {
        return BlendColourMap[cMin][cMax];
    }

    uint8_t red = (gPalette[cMin].red + gPalette[cMax].red) / 2;
    uint8_t green = (gPalette[cMin].green + gPalette[cMax].green) / 2;
    uint8_t blue = (gPalette[cMin].blue + gPalette[cMax].blue) / 2;

    BlendColourMap[cMin][cMax] = findClosestPaletteIndex(red, green, blue);
    return BlendColourMap[cMin][cMax];
}
#endif