///////////////////////////////////////////////////////////
//
//
//	CGL-Pal.cpp - OpenGL palette support
//
//
#include <windows.h>
#include "util.h"

#include "cgl.h"

///////////////////////////////////////////////////////////
//
// RGBA Palette support code
//
unsigned char CGL::m_threeto8[8] = {
    0, 0111>>1, 0222>>1, 0333>>1, 0444>>1, 0555>>1, 0666>>1, 0377
};
unsigned char CGL::m_twoto8[4] = {
   0, 0x55, 0xaa, 0xff
};
unsigned char CGL::m_oneto8[2] = {
    0, 255
};

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

PALETTEENTRY CGL::m_defaultPalEntry[20] = {
    { 0,   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 }, //7

    { 192, 220, 192,  0 }, //8
    { 166, 202, 240,  0 },
    { 255, 251, 240,  0 },
    { 160, 160, 164,  0 }, //11

    { 0x80,0x80,0x80, 0 }, //12
    { 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 }  //19
  };

///////////////////////////////////////////////////////////
//
// Color Component From Index
//
unsigned char CGL::ComponentFromIndex(int i, UINT nbits, UINT shift)
{
    unsigned char val = (unsigned char) (i >> shift);
    switch (nbits) {

    case 1:
        val &= 0x1;
        return m_oneto8[val];

    case 2:
        val &= 0x3;
        return m_twoto8[val];

    case 3:
        val &= 0x7;
        return m_threeto8[val];

    default:
        return 0;
    }
}

///////////////////////////////////////////////////////////
//
// CreateRGBPalette
//
BOOL CGL::CreatePalette()
{
	//
	// Check to see if we need a palette
	//
   PIXELFORMATDESCRIPTOR pfd;
   int n = ::GetPixelFormat(m_hdc);
   ::DescribePixelFormat(m_hdc, n, sizeof(PIXELFORMATDESCRIPTOR), &pfd);
	
	// Palette needed for color index mode.
	BOOL bColorIndex = (pfd.iPixelType & PFD_TYPE_COLORINDEX) ;
	if (bColorIndex)
	{
		// Color index mode not supported.
		return FALSE ;
	}

	// Palette needed for 8bpp DIBs. PFD_NEED_PALETTE is not set.
	BOOL b8bppDIB = (pfd.cColorBits == 8) ;
	if ( (pfd.dwFlags & PFD_NEED_PALETTE) || 
		 (b8bppDIB) ||
		 (bColorIndex))
	{
		TRACE0("Creating palette\r\n") ;
		// allocate a log pal and fill it with the color table info
		int iPalSize = sizeof(LOGPALETTE) + 256 * sizeof(PALETTEENTRY) ;
		LOGPALETTE* pPal = (LOGPALETTE*) malloc(iPalSize);
		memset(pPal, 0, iPalSize) ;

		if (!pPal) 
		{
		return FALSE;
		}
		pPal->palVersion = 0x300; // Windows 3.0
		pPal->palNumEntries = 256; // table size

		// --- Create RGB Palette ---
		ASSERT( pfd.cColorBits == 8) ;
		n = 1 << pfd.cColorBits;
		for (int 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 color table with system colors. ---
		if ((pfd.cColorBits == 8)							&&
			(pfd.cRedBits   == 3) && (pfd.cRedShift   == 0) &&
			(pfd.cGreenBits == 3) && (pfd.cGreenShift == 3) &&
			(pfd.cBlueBits  == 2) && (pfd.cBlueShift  == 6)
			)
		{
			for (int j = 1 ; j <= 12 ; j++)
			{
				pPal->palPalEntry[m_defaultOverride[j]] = m_defaultPalEntry[j];
			}
		}

		// Delete any existing GDI palette
		if (m_hPal)
		{
			::DeleteObject(m_hPal) ;
		}

		m_hPal = ::CreatePalette(pPal) ;
		free (pPal);

		if (m_hPal == NULL)
		{
			return FALSE ;
		}

		// Select and Realize Palette
		return TRUE;
	}
	else
		return FALSE ;
}


