#include "stdafx.h"
#include "InitOpenGL.h"

static HPALETTE  ghpalOld, ghPalette;

static unsigned char threeto8[8] = {
    0, 0111>>1, 0222>>1, 0333>>1, 0444>>1, 0555>>1, 0666>>1, 0377
};

static unsigned char twoto8[4] = {
    0, 0x55, 0xaa, 0xff
};

static unsigned char oneto8[2] = {
    0, 255
};

static int defaultOverride[13] = {
    0, 3, 24, 27, 64, 67, 88, 173, 181, 236, 247, 164, 91
};

static PALETTEENTRY defaultPalEntry[20] = {
    { 0,   0,   0,    0 },
    { 0x80,0,   0,    0 },
    { 0,   0x80,0,    0 },
    { 0x80,0x80,0,    0 },
    { 0,   0,   0x80, 0 },
    { 0x80,0,   0x80, 0 },
    { 0,   0x80,0x80, 0 },
    { 0xC0,0xC0,0xC0, 0 },

    { 192, 220, 192,  0 },
    { 166, 202, 240,  0 },
    { 255, 251, 240,  0 },
    { 160, 160, 164,  0 },

    { 0x80,0x80,0x80, 0 },
    { 0xFF,0,   0,    0 },
    { 0,   0xFF,0,    0 },
    { 0xFF,0xFF,0,    0 },
    { 0,   0,   0xFF, 0 },
    { 0xFF,0,   0xFF, 0 },
    { 0,   0xFF,0xFF, 0 },
    { 0xFF,0xFF,0xFF, 0 }
};

char ComponentFromIndex(int i, UINT nbits, UINT shift)
{
    unsigned char val;

    val = (unsigned char) (i >> shift);
    switch (nbits) {

    case 1:
        val &= 0x1;
        return oneto8[val];

    case 2:
        val &= 0x3;
        return twoto8[val];

    case 3:
        val &= 0x7;
        return threeto8[val];

    default:
        return 0;
    }
}

void CreateRGBPalette(HDC hDC)
{
    PIXELFORMATDESCRIPTOR pfd;
    LOGPALETTE *pPal;
    int n, i;

    n = GetPixelFormat(hDC);
    DescribePixelFormat(hDC, n, sizeof(PIXELFORMATDESCRIPTOR), &pfd);

    if (pfd.dwFlags & PFD_NEED_PALETTE) {
        n = 1 << pfd.cColorBits;
        pPal = (PLOGPALETTE)LocalAlloc(LMEM_FIXED, sizeof(LOGPALETTE) +
                n * sizeof(PALETTEENTRY));
        pPal->palVersion = 0x300;
        pPal->palNumEntries = n;
        for(i=0; i<n; i++) {
            pPal->palPalEntry[i].peRed =
                    ComponentFromIndex(i, pfd.cRedBits, pfd.cRedShift);
            pPal->palPalEntry[i].peGreen =
                    ComponentFromIndex(i, pfd.cGreenBits, pfd.cGreenShift);
            pPal->palPalEntry[i].peBlue =
                    ComponentFromIndex(i, pfd.cBlueBits, pfd.cBlueShift);
            pPal->palPalEntry[i].peFlags = 0;
        }

        // fix up the palette to include the default GDI palette 
        if ((pfd.cColorBits == 8)                           &&
            (pfd.cRedBits   == 3) && (pfd.cRedShift   == 0) &&
            (pfd.cGreenBits == 3) && (pfd.cGreenShift == 3) &&
            (pfd.cBlueBits  == 2) && (pfd.cBlueShift  == 6)
           ) {
            for (i = 1 ; i <= 12 ; i++)
                pPal->palPalEntry[defaultOverride[i]] = defaultPalEntry[i];
        }

        ghPalette = CreatePalette(pPal);
        LocalFree(pPal);

        ghpalOld = SelectPalette(hDC, ghPalette, FALSE);
        n = RealizePalette(hDC);
    }
}