/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
              2015 James Canete

This file is part of Quake III Arena source code.

Quake III Arena source code 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; either version 2 of the License,
or (at your option) any later version.

Quake III Arena source code 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 Quake III Arena source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "../renderercommon/tr_common.h"

typedef unsigned int   ui32_t;

typedef struct ddsHeader_s
{
	ui32_t headerSize;
	ui32_t flags;
	ui32_t height;
	ui32_t width;
	ui32_t pitchOrFirstMipSize;
	ui32_t volumeDepth;
	ui32_t numMips;
	ui32_t reserved1[11];
	ui32_t always_0x00000020;
	ui32_t pixelFormatFlags;
	ui32_t fourCC;
	ui32_t rgbBitCount;
	ui32_t rBitMask;
	ui32_t gBitMask;
	ui32_t bBitMask;
	ui32_t aBitMask;
	ui32_t caps;
	ui32_t caps2;
	ui32_t caps3;
	ui32_t caps4;
	ui32_t reserved2;
}
ddsHeader_t;

// flags:
#define _DDSFLAGS_REQUIRED     0x001007
#define _DDSFLAGS_PITCH        0x8
#define _DDSFLAGS_MIPMAPCOUNT  0x20000
#define _DDSFLAGS_FIRSTMIPSIZE 0x80000
#define _DDSFLAGS_VOLUMEDEPTH  0x800000

// pixelFormatFlags:
#define DDSPF_ALPHAPIXELS 0x1
#define DDSPF_ALPHA       0x2
#define DDSPF_FOURCC      0x4
#define DDSPF_RGB         0x40
#define DDSPF_YUV         0x200
#define DDSPF_LUMINANCE   0x20000

// caps:
#define DDSCAPS_COMPLEX  0x8
#define DDSCAPS_MIPMAP   0x400000
#define DDSCAPS_REQUIRED 0x1000

// caps2:
#define DDSCAPS2_CUBEMAP 0xFE00
#define DDSCAPS2_VOLUME  0x200000

typedef struct ddsHeaderDxt10_s
{
	ui32_t dxgiFormat;
	ui32_t dimensions;
	ui32_t miscFlags;
	ui32_t arraySize;
	ui32_t miscFlags2;
}
ddsHeaderDxt10_t;

// dxgiFormat
// from http://msdn.microsoft.com/en-us/library/windows/desktop/bb173059%28v=vs.85%29.aspx
typedef enum DXGI_FORMAT {
	DXGI_FORMAT_UNKNOWN = 0,
	DXGI_FORMAT_R32G32B32A32_TYPELESS = 1,
	DXGI_FORMAT_R32G32B32A32_FLOAT = 2,
	DXGI_FORMAT_R32G32B32A32_UINT = 3,
	DXGI_FORMAT_R32G32B32A32_SINT = 4,
	DXGI_FORMAT_R32G32B32_TYPELESS = 5,
	DXGI_FORMAT_R32G32B32_FLOAT = 6,
	DXGI_FORMAT_R32G32B32_UINT = 7,
	DXGI_FORMAT_R32G32B32_SINT = 8,
	DXGI_FORMAT_R16G16B16A16_TYPELESS = 9,
	DXGI_FORMAT_R16G16B16A16_FLOAT = 10,
	DXGI_FORMAT_R16G16B16A16_UNORM = 11,
	DXGI_FORMAT_R16G16B16A16_UINT = 12,
	DXGI_FORMAT_R16G16B16A16_SNORM = 13,
	DXGI_FORMAT_R16G16B16A16_SINT = 14,
	DXGI_FORMAT_R32G32_TYPELESS = 15,
	DXGI_FORMAT_R32G32_FLOAT = 16,
	DXGI_FORMAT_R32G32_UINT = 17,
	DXGI_FORMAT_R32G32_SINT = 18,
	DXGI_FORMAT_R32G8X24_TYPELESS = 19,
	DXGI_FORMAT_D32_FLOAT_S8X24_UINT = 20,
	DXGI_FORMAT_R32_FLOAT_X8X24_TYPELESS = 21,
	DXGI_FORMAT_X32_TYPELESS_G8X24_UINT = 22,
	DXGI_FORMAT_R10G10B10A2_TYPELESS = 23,
	DXGI_FORMAT_R10G10B10A2_UNORM = 24,
	DXGI_FORMAT_R10G10B10A2_UINT = 25,
	DXGI_FORMAT_R11G11B10_FLOAT = 26,
	DXGI_FORMAT_R8G8B8A8_TYPELESS = 27,
	DXGI_FORMAT_R8G8B8A8_UNORM = 28,
	DXGI_FORMAT_R8G8B8A8_UNORM_SRGB = 29,
	DXGI_FORMAT_R8G8B8A8_UINT = 30,
	DXGI_FORMAT_R8G8B8A8_SNORM = 31,
	DXGI_FORMAT_R8G8B8A8_SINT = 32,
	DXGI_FORMAT_R16G16_TYPELESS = 33,
	DXGI_FORMAT_R16G16_FLOAT = 34,
	DXGI_FORMAT_R16G16_UNORM = 35,
	DXGI_FORMAT_R16G16_UINT = 36,
	DXGI_FORMAT_R16G16_SNORM = 37,
	DXGI_FORMAT_R16G16_SINT = 38,
	DXGI_FORMAT_R32_TYPELESS = 39,
	DXGI_FORMAT_D32_FLOAT = 40,
	DXGI_FORMAT_R32_FLOAT = 41,
	DXGI_FORMAT_R32_UINT = 42,
	DXGI_FORMAT_R32_SINT = 43,
	DXGI_FORMAT_R24G8_TYPELESS = 44,
	DXGI_FORMAT_D24_UNORM_S8_UINT = 45,
	DXGI_FORMAT_R24_UNORM_X8_TYPELESS = 46,
	DXGI_FORMAT_X24_TYPELESS_G8_UINT = 47,
	DXGI_FORMAT_R8G8_TYPELESS = 48,
	DXGI_FORMAT_R8G8_UNORM = 49,
	DXGI_FORMAT_R8G8_UINT = 50,
	DXGI_FORMAT_R8G8_SNORM = 51,
	DXGI_FORMAT_R8G8_SINT = 52,
	DXGI_FORMAT_R16_TYPELESS = 53,
	DXGI_FORMAT_R16_FLOAT = 54,
	DXGI_FORMAT_D16_UNORM = 55,
	DXGI_FORMAT_R16_UNORM = 56,
	DXGI_FORMAT_R16_UINT = 57,
	DXGI_FORMAT_R16_SNORM = 58,
	DXGI_FORMAT_R16_SINT = 59,
	DXGI_FORMAT_R8_TYPELESS = 60,
	DXGI_FORMAT_R8_UNORM = 61,
	DXGI_FORMAT_R8_UINT = 62,
	DXGI_FORMAT_R8_SNORM = 63,
	DXGI_FORMAT_R8_SINT = 64,
	DXGI_FORMAT_A8_UNORM = 65,
	DXGI_FORMAT_R1_UNORM = 66,
	DXGI_FORMAT_R9G9B9E5_SHAREDEXP = 67,
	DXGI_FORMAT_R8G8_B8G8_UNORM = 68,
	DXGI_FORMAT_G8R8_G8B8_UNORM = 69,
	DXGI_FORMAT_BC1_TYPELESS = 70,
	DXGI_FORMAT_BC1_UNORM = 71,
	DXGI_FORMAT_BC1_UNORM_SRGB = 72,
	DXGI_FORMAT_BC2_TYPELESS = 73,
	DXGI_FORMAT_BC2_UNORM = 74,
	DXGI_FORMAT_BC2_UNORM_SRGB = 75,
	DXGI_FORMAT_BC3_TYPELESS = 76,
	DXGI_FORMAT_BC3_UNORM = 77,
	DXGI_FORMAT_BC3_UNORM_SRGB = 78,
	DXGI_FORMAT_BC4_TYPELESS = 79,
	DXGI_FORMAT_BC4_UNORM = 80,
	DXGI_FORMAT_BC4_SNORM = 81,
	DXGI_FORMAT_BC5_TYPELESS = 82,
	DXGI_FORMAT_BC5_UNORM = 83,
	DXGI_FORMAT_BC5_SNORM = 84,
	DXGI_FORMAT_B5G6R5_UNORM = 85,
	DXGI_FORMAT_B5G5R5A1_UNORM = 86,
	DXGI_FORMAT_B8G8R8A8_UNORM = 87,
	DXGI_FORMAT_B8G8R8X8_UNORM = 88,
	DXGI_FORMAT_R10G10B10_XR_BIAS_A2_UNORM = 89,
	DXGI_FORMAT_B8G8R8A8_TYPELESS = 90,
	DXGI_FORMAT_B8G8R8A8_UNORM_SRGB = 91,
	DXGI_FORMAT_B8G8R8X8_TYPELESS = 92,
	DXGI_FORMAT_B8G8R8X8_UNORM_SRGB = 93,
	DXGI_FORMAT_BC6H_TYPELESS = 94,
	DXGI_FORMAT_BC6H_UF16 = 95,
	DXGI_FORMAT_BC6H_SF16 = 96,
	DXGI_FORMAT_BC7_TYPELESS = 97,
	DXGI_FORMAT_BC7_UNORM = 98,
	DXGI_FORMAT_BC7_UNORM_SRGB = 99,
	DXGI_FORMAT_AYUV = 100,
	DXGI_FORMAT_Y410 = 101,
	DXGI_FORMAT_Y416 = 102,
	DXGI_FORMAT_NV12 = 103,
	DXGI_FORMAT_P010 = 104,
	DXGI_FORMAT_P016 = 105,
	DXGI_FORMAT_420_OPAQUE = 106,
	DXGI_FORMAT_YUY2 = 107,
	DXGI_FORMAT_Y210 = 108,
	DXGI_FORMAT_Y216 = 109,
	DXGI_FORMAT_NV11 = 110,
	DXGI_FORMAT_AI44 = 111,
	DXGI_FORMAT_IA44 = 112,
	DXGI_FORMAT_P8 = 113,
	DXGI_FORMAT_A8P8 = 114,
	DXGI_FORMAT_B4G4R4A4_UNORM = 115,
	DXGI_FORMAT_FORCE_UINT = 0xffffffffUL
} DXGI_FORMAT;

#define EncodeFourCC(x) ((((ui32_t)((x)[0]))      ) | \
                         (((ui32_t)((x)[1])) << 8 ) | \
                         (((ui32_t)((x)[2])) << 16) | \
                         (((ui32_t)((x)[3])) << 24) )


void R_LoadDDS ( const char *filename, byte **pic, int *width, int *height, GLenum *picFormat, int *numMips )
{
	union {
		byte *b;
		void *v;
	} buffer;
	int len;
	ddsHeader_t *ddsHeader = NULL;
	ddsHeaderDxt10_t *ddsHeaderDxt10 = NULL;
	byte *data;

	if (!picFormat)
	{
		ri.Printf(PRINT_ERROR, "R_LoadDDS() called without picFormat parameter!");
		return;
	}

	if (width)
		*width = 0;
	if (height)
		*height = 0;
	if (picFormat)
		*picFormat = GL_RGBA8;
	if (numMips)
		*numMips = 1;

	*pic = NULL;

	//
	// load the file
	//
	len = ri.FS_ReadFile( ( char * ) filename, &buffer.v);
	if (!buffer.b || len < 0) {
		return;
	}

	//
	// reject files that are too small to hold even a header
	//
	if (len < 4 + sizeof(*ddsHeader))
	{
		ri.Printf(PRINT_ALL, "File %s is too small to be a DDS file.\n", filename);
		ri.FS_FreeFile(buffer.v);
		return;
	}

	//
	// reject files that don't start with "DDS "
	//
	if (*((ui32_t *)(buffer.b)) != EncodeFourCC("DDS "))
	{
		ri.Printf(PRINT_ALL, "File %s is not a DDS file.\n", filename);
		ri.FS_FreeFile(buffer.v);
		return;
	}

	//
	// parse header and dx10 header if available
	//
	ddsHeader = (ddsHeader_t *)(buffer.b + 4);
	if ((ddsHeader->pixelFormatFlags & DDSPF_FOURCC) && ddsHeader->fourCC == EncodeFourCC("DX10"))
	{
		if (len < 4 + sizeof(*ddsHeader) + sizeof(*ddsHeaderDxt10))
		{
			ri.Printf(PRINT_ALL, "File %s indicates a DX10 header it is too small to contain.\n", filename);
			ri.FS_FreeFile(buffer.v);
			return;
		}

		ddsHeaderDxt10 = (ddsHeaderDxt10_t *)(buffer.b + 4 + sizeof(ddsHeader_t));
		data = buffer.b + 4 + sizeof(*ddsHeader) + sizeof(*ddsHeaderDxt10);
		len -= 4 + sizeof(*ddsHeader) + sizeof(*ddsHeaderDxt10);
	}
	else
	{
		data = buffer.b + 4 + sizeof(*ddsHeader);
		len -= 4 + sizeof(*ddsHeader);
	}

	if (width)
		*width = ddsHeader->width;
	if (height)
		*height = ddsHeader->height;

	if (numMips)
	{
		if (ddsHeader->flags & _DDSFLAGS_MIPMAPCOUNT)
			*numMips = ddsHeader->numMips;
		else
			*numMips = 1;
	}

	// FIXME: handle cube map
	//if ((ddsHeader->caps2 & DDSCAPS2_CUBEMAP) == DDSCAPS2_CUBEMAP)

	//
	// Convert DXGI format/FourCC into OpenGL format
	//
	if (ddsHeaderDxt10)
	{
		switch (ddsHeaderDxt10->dxgiFormat)
		{
			case DXGI_FORMAT_BC1_TYPELESS:
			case DXGI_FORMAT_BC1_UNORM:
				// FIXME: check for GL_COMPRESSED_RGBA_S3TC_DXT1_EXT
				*picFormat = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
				break;

			case DXGI_FORMAT_BC1_UNORM_SRGB:
				// FIXME: check for GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT1_EXT
				*picFormat = GL_COMPRESSED_SRGB_S3TC_DXT1_EXT;
				break;

			case DXGI_FORMAT_BC2_TYPELESS:
			case DXGI_FORMAT_BC2_UNORM:
				*picFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
				break;

			case DXGI_FORMAT_BC2_UNORM_SRGB:
				*picFormat = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT3_EXT;
				break;

			case DXGI_FORMAT_BC3_TYPELESS:
			case DXGI_FORMAT_BC3_UNORM:
				*picFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
				break;

			case DXGI_FORMAT_BC3_UNORM_SRGB:
				*picFormat = GL_COMPRESSED_SRGB_ALPHA_S3TC_DXT5_EXT;
				break;

			case DXGI_FORMAT_BC4_TYPELESS:
			case DXGI_FORMAT_BC4_UNORM:
				*picFormat = GL_COMPRESSED_RED_RGTC1;
				break;

			case DXGI_FORMAT_BC4_SNORM:
				*picFormat = GL_COMPRESSED_SIGNED_RED_RGTC1;
				break;

			case DXGI_FORMAT_BC5_TYPELESS:
			case DXGI_FORMAT_BC5_UNORM:
				*picFormat = GL_COMPRESSED_RG_RGTC2;
				break;

			case DXGI_FORMAT_BC5_SNORM:
				*picFormat = GL_COMPRESSED_SIGNED_RG_RGTC2;
				break;

			case DXGI_FORMAT_BC6H_TYPELESS:
			case DXGI_FORMAT_BC6H_UF16:
				*picFormat = GL_COMPRESSED_RGB_BPTC_UNSIGNED_FLOAT_ARB;
				break;

			case DXGI_FORMAT_BC6H_SF16:
				*picFormat = GL_COMPRESSED_RGB_BPTC_SIGNED_FLOAT_ARB;
				break;

			case DXGI_FORMAT_BC7_TYPELESS:
			case DXGI_FORMAT_BC7_UNORM:
				*picFormat = GL_COMPRESSED_RGBA_BPTC_UNORM_ARB;
				break;

			case DXGI_FORMAT_BC7_UNORM_SRGB:
				*picFormat = GL_COMPRESSED_SRGB_ALPHA_BPTC_UNORM_ARB;
				break;

			case DXGI_FORMAT_R8G8B8A8_UNORM_SRGB:
				*picFormat = GL_SRGB8_ALPHA8_EXT;
				break;

			case DXGI_FORMAT_R8G8B8A8_UNORM:
			case DXGI_FORMAT_R8G8B8A8_SNORM:
				*picFormat = GL_RGBA8;
				break;

			default:
				ri.Printf(PRINT_ALL, "DDS File %s has unsupported DXGI format %d.", filename, ddsHeaderDxt10->dxgiFormat);
				ri.FS_FreeFile(buffer.v);
				return;
				break;
		}
	}
	else
	{
		if (ddsHeader->pixelFormatFlags & DDSPF_FOURCC)
		{
			if (ddsHeader->fourCC == EncodeFourCC("DXT1"))
				*picFormat = GL_COMPRESSED_RGB_S3TC_DXT1_EXT;
			else if (ddsHeader->fourCC == EncodeFourCC("DXT2"))
				*picFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
			else if (ddsHeader->fourCC == EncodeFourCC("DXT3"))
				*picFormat = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
			else if (ddsHeader->fourCC == EncodeFourCC("DXT4"))
				*picFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
			else if (ddsHeader->fourCC == EncodeFourCC("DXT5"))
				*picFormat = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
			else if (ddsHeader->fourCC == EncodeFourCC("ATI1"))
				*picFormat = GL_COMPRESSED_RED_RGTC1;
			else if (ddsHeader->fourCC == EncodeFourCC("BC4U"))
				*picFormat = GL_COMPRESSED_RED_RGTC1;
			else if (ddsHeader->fourCC == EncodeFourCC("BC4S"))
				*picFormat = GL_COMPRESSED_SIGNED_RED_RGTC1;
			else if (ddsHeader->fourCC == EncodeFourCC("ATI2"))
				*picFormat = GL_COMPRESSED_RG_RGTC2;
			else if (ddsHeader->fourCC == EncodeFourCC("BC5U"))
				*picFormat = GL_COMPRESSED_RG_RGTC2;
			else if (ddsHeader->fourCC == EncodeFourCC("BC5S"))
				*picFormat = GL_COMPRESSED_SIGNED_RG_RGTC2;
			else
			{
				ri.Printf(PRINT_ALL, "DDS File %s has unsupported FourCC.", filename);
				ri.FS_FreeFile(buffer.v);
				return;
			}
		}
		else if (ddsHeader->pixelFormatFlags == (DDSPF_RGB | DDSPF_ALPHAPIXELS)
			&& ddsHeader->rgbBitCount == 32
			&& ddsHeader->rBitMask == 0x000000ff
			&& ddsHeader->gBitMask == 0x0000ff00
			&& ddsHeader->bBitMask == 0x00ff0000
			&& ddsHeader->aBitMask == 0xff000000)
		{
			*picFormat = GL_RGBA8;
		}
		else
		{
			ri.Printf(PRINT_ALL, "DDS File %s has unsupported RGBA format.", filename);
			ri.FS_FreeFile(buffer.v);
			return;
		}
	}

	*pic = ri.Malloc(len);
	Com_Memcpy(*pic, data, len);

	ri.FS_FreeFile(buffer.v);
}