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/* Copyright (C) 2018 Wildfire Games.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
/*
* DDS (DirectDraw Surface) codec.
*/
#include "precompiled.h"
#include "lib/byte_order.h"
#include "lib/bits.h"
#include "lib/timer.h"
#include "lib/allocators/shared_ptr.h"
#include "tex_codec.h"
// NOTE: the convention is bottom-up for DDS, but there's no way to tell.
//-----------------------------------------------------------------------------
// S3TC decompression
//-----------------------------------------------------------------------------
// note: this code may not be terribly efficient. it's only used to
// emulate hardware S3TC support - if that isn't available, performance
// will suffer anyway due to increased video memory usage.
// for efficiency, we precalculate as much as possible about a block
// and store it here.
class S3tcBlock
{
public:
S3tcBlock(size_t dxt, const u8* RESTRICT block)
: m_Dxt(dxt)
{
// (careful, 'dxt != 1' doesn't work - there's also DXT1a)
const u8* a_block = block;
const u8* c_block = (dxt == 3 || dxt == 5)? block+8 : block;
PrecalculateAlpha(dxt, a_block);
PrecalculateColor(dxt, c_block);
}
void WritePixel(size_t pixel_idx, u8* RESTRICT out) const
{
ENSURE(pixel_idx < 16);
// pixel index -> color selector (2 bit) -> color
const size_t c_selector = access_bit_tbl(c_selectors, pixel_idx, 2);
for(int i = 0; i < 3; i++)
out[i] = (u8)c[c_selector][i];
// if no alpha, done
if(m_Dxt == 1)
return;
size_t a;
if(m_Dxt == 3)
{
// table of 4-bit alpha entries
a = access_bit_tbl(a_bits, pixel_idx, 4);
a |= a << 4; // expand to 8 bits (replicate high into low!)
}
else if(m_Dxt == 5)
{
// pixel index -> alpha selector (3 bit) -> alpha
const size_t a_selector = access_bit_tbl(a_bits, pixel_idx, 3);
a = dxt5_a_tbl[a_selector];
}
// (m_Dxt == DXT1A)
else
a = c[c_selector][A];
out[A] = (u8)(a & 0xFF);
}
private:
// pixel colors are stored as size_t[4]. size_t rather than u8 protects from
// overflow during calculations, and padding to an even size is a bit
// more efficient (even though we don't need the alpha component).
enum RGBA { R, G, B, A };
static inline void mix_2_3(size_t dst[4], size_t c0[4], size_t c1[4])
{
for(int i = 0; i < 3; i++) dst[i] = (c0[i]*2 + c1[i] + 1)/3;
}
static inline void mix_avg(size_t dst[4], size_t c0[4], size_t c1[4])
{
for(int i = 0; i < 3; i++) dst[i] = (c0[i]+c1[i])/2;
}
template<typename T>
static inline size_t access_bit_tbl(T tbl, size_t idx, size_t bit_width)
{
size_t val = (tbl >> (idx*bit_width)) & bit_mask<T>(bit_width);
return val;
}
// extract a range of bits and expand to 8 bits (by replicating
// MS bits - see http://www.mindcontrol.org/~hplus/graphics/expand-bits.html ;
// this is also the algorithm used by graphics cards when decompressing S3TC).
// used to convert 565 to 32bpp RGB.
static inline size_t unpack_to_8(u16 c, size_t bits_below, size_t num_bits)
{
const size_t num_filler_bits = 8-num_bits;
const size_t field = (size_t)bits(c, bits_below, bits_below+num_bits-1);
const size_t filler = field >> (num_bits-num_filler_bits);
return (field << num_filler_bits) | filler;
}
void PrecalculateAlpha(size_t dxt, const u8* RESTRICT a_block)
{
// read block contents
const u8 a0 = a_block[0], a1 = a_block[1];
a_bits = read_le64(a_block); // see below
if(dxt == 5)
{
// skip a0,a1 bytes (data is little endian)
a_bits >>= 16;
const bool is_dxt5_special_combination = (a0 <= a1);
u8* a = dxt5_a_tbl; // shorthand
if(is_dxt5_special_combination)
{
a[0] = a0;
a[1] = a1;
a[2] = (4*a0 + 1*a1 + 2)/5;
a[3] = (3*a0 + 2*a1 + 2)/5;
a[4] = (2*a0 + 3*a1 + 2)/5;
a[5] = (1*a0 + 4*a1 + 2)/5;
a[6] = 0;
a[7] = 255;
}
else
{
a[0] = a0;
a[1] = a1;
a[2] = (6*a0 + 1*a1 + 3)/7;
a[3] = (5*a0 + 2*a1 + 3)/7;
a[4] = (4*a0 + 3*a1 + 3)/7;
a[5] = (3*a0 + 4*a1 + 3)/7;
a[6] = (2*a0 + 5*a1 + 3)/7;
a[7] = (1*a0 + 6*a1 + 3)/7;
}
}
}
void PrecalculateColor(size_t dxt, const u8* RESTRICT c_block)
{
// read block contents
// .. S3TC reference colors (565 format). the color table is generated
// from some combination of these, depending on their ordering.
u16 rc[2];
for(int i = 0; i < 2; i++)
rc[i] = read_le16(c_block + 2*i);
// .. table of 2-bit color selectors
c_selectors = read_le32(c_block+4);
const bool is_dxt1_special_combination = (dxt == 1 || dxt == DXT1A) && rc[0] <= rc[1];
// c0 and c1 are the values of rc[], converted to 32bpp
for(int i = 0; i < 2; i++)
{
c[i][R] = unpack_to_8(rc[i], 11, 5);
c[i][G] = unpack_to_8(rc[i], 5, 6);
c[i][B] = unpack_to_8(rc[i], 0, 5);
}
// c2 and c3 are combinations of c0 and c1:
if(is_dxt1_special_combination)
{
mix_avg(c[2], c[0], c[1]); // c2 = (c0+c1)/2
for(int i = 0; i < 3; i++) c[3][i] = 0; // c3 = black
c[3][A] = (dxt == DXT1A)? 0 : 255; // (transparent iff DXT1a)
}
else
{
mix_2_3(c[2], c[0], c[1]); // c2 = 2/3*c0 + 1/3*c1
mix_2_3(c[3], c[1], c[0]); // c3 = 1/3*c0 + 2/3*c1
}
}
// the 4 color choices for each pixel (RGBA)
size_t c[4][4]; // c[i][RGBA_component]
// (DXT5 only) the 8 alpha choices
u8 dxt5_a_tbl[8];
// alpha block; interpretation depends on dxt.
u64 a_bits;
// table of 2-bit color selectors
u32 c_selectors;
size_t m_Dxt;
};
struct S3tcDecompressInfo
{
size_t dxt;
size_t s3tc_block_size;
size_t out_Bpp;
u8* out;
};
static void s3tc_decompress_level(size_t UNUSED(level), size_t level_w, size_t level_h,
const u8* RESTRICT level_data, size_t level_data_size, void* RESTRICT cbData)
{
S3tcDecompressInfo* di = (S3tcDecompressInfo*)cbData;
const size_t dxt = di->dxt;
const size_t s3tc_block_size = di->s3tc_block_size;
// note: 1x1 images are legitimate (e.g. in mipmaps). they report their
// width as such for glTexImage, but the S3TC data is padded to
// 4x4 pixel block boundaries.
const size_t blocks_w = DivideRoundUp(level_w, size_t(4));
const size_t blocks_h = DivideRoundUp(level_h, size_t(4));
const u8* s3tc_data = level_data;
ENSURE(level_data_size % s3tc_block_size == 0);
for(size_t block_y = 0; block_y < blocks_h; block_y++)
{
for(size_t block_x = 0; block_x < blocks_w; block_x++)
{
S3tcBlock block(dxt, s3tc_data);
s3tc_data += s3tc_block_size;
size_t pixel_idx = 0;
for(int y = 0; y < 4; y++)
{
// this is ugly, but advancing after x, y and block_y loops
// is no better.
u8* out = (u8*)di->out + ((block_y*4+y)*blocks_w*4 + block_x*4) * di->out_Bpp;
for(int x = 0; x < 4; x++)
{
block.WritePixel(pixel_idx, out);
out += di->out_Bpp;
pixel_idx++;
}
}
}
}
ENSURE(s3tc_data == level_data + level_data_size);
di->out += blocks_w*blocks_h * 16 * di->out_Bpp;
}
// decompress the given image (which is known to be stored as DXTn)
// effectively in-place. updates Tex fields.
static Status s3tc_decompress(Tex* t)
{
// alloc new image memory
// notes:
// - dxt == 1 is the only non-alpha case.
// - adding or stripping alpha channels during transform is not
// our job; we merely output the same pixel format as given
// (tex.cpp's plain transform could cover it, if ever needed).
const size_t dxt = t->m_Flags & TEX_DXT;
const size_t out_bpp = (dxt != 1)? 32 : 24;
const size_t out_size = t->img_size() * out_bpp / t->m_Bpp;
shared_ptr<u8> decompressedData;
AllocateAligned(decompressedData, out_size, g_PageSize);
const size_t s3tc_block_size = (dxt == 3 || dxt == 5)? 16 : 8;
S3tcDecompressInfo di = { dxt, s3tc_block_size, out_bpp/8, decompressedData.get() };
const u8* s3tc_data = t->get_data();
const int levels_to_skip = (t->m_Flags & TEX_MIPMAPS)? 0 : TEX_BASE_LEVEL_ONLY;
tex_util_foreach_mipmap(t->m_Width, t->m_Height, t->m_Bpp, s3tc_data, levels_to_skip, 4, s3tc_decompress_level, &di);
t->m_Data = decompressedData;
t->m_DataSize = out_size;
t->m_Ofs = 0;
t->m_Bpp = out_bpp;
t->m_Flags &= ~TEX_DXT;
return INFO::OK;
}
//-----------------------------------------------------------------------------
// DDS file format
//-----------------------------------------------------------------------------
// bit values and structure definitions taken from
// http://msdn.microsoft.com/en-us/library/ee417785(VS.85).aspx
#pragma pack(push, 1)
// DDS_PIXELFORMAT.dwFlags
// we've seen some DXT3 files that don't have this set (which is nonsense;
// any image lacking alpha should be stored as DXT1). it's authoritative
// if fourcc is DXT1 (there's no other way to tell DXT1 and DXT1a apart)
// and ignored otherwise.
#define DDPF_ALPHAPIXELS 0x00000001
#define DDPF_FOURCC 0x00000004
#define DDPF_RGB 0x00000040
struct DDS_PIXELFORMAT
{
u32 dwSize; // size of structure (32)
u32 dwFlags; // indicates which fields are valid
u32 dwFourCC; // (DDPF_FOURCC) FOURCC code, "DXTn"
u32 dwRGBBitCount; // (DDPF_RGB) bits per pixel
u32 dwRBitMask;
u32 dwGBitMask;
u32 dwBBitMask;
u32 dwABitMask; // (DDPF_ALPHAPIXELS)
};
// DDS_HEADER.dwFlags (none are optional)
#define DDSD_CAPS 0x00000001
#define DDSD_HEIGHT 0x00000002
#define DDSD_WIDTH 0x00000004
#define DDSD_PITCH 0x00000008 // used when texture is uncompressed
#define DDSD_PIXELFORMAT 0x00001000
#define DDSD_MIPMAPCOUNT 0x00020000
#define DDSD_LINEARSIZE 0x00080000 // used when texture is compressed
#define DDSD_DEPTH 0x00800000
// DDS_HEADER.dwCaps
#define DDSCAPS_MIPMAP 0x00400000 // optional
#define DDSCAPS_TEXTURE 0x00001000 // required
struct DDS_HEADER
{
// (preceded by the FOURCC "DDS ")
u32 dwSize; // size of structure (124)
u32 dwFlags; // indicates which fields are valid
u32 dwHeight; // (DDSD_HEIGHT) height of main image (pixels)
u32 dwWidth; // (DDSD_WIDTH ) width of main image (pixels)
u32 dwPitchOrLinearSize; // (DDSD_LINEARSIZE) size [bytes] of top level
// (DDSD_PITCH) bytes per row (%4 = 0)
u32 dwDepth; // (DDSD_DEPTH) vol. textures: vol. depth
u32 dwMipMapCount; // (DDSD_MIPMAPCOUNT) total # levels
u32 dwReserved1[11]; // reserved
DDS_PIXELFORMAT ddpf; // (DDSD_PIXELFORMAT) surface description
u32 dwCaps; // (DDSD_CAPS) misc. surface flags
u32 dwCaps2;
u32 dwCaps3;
u32 dwCaps4;
u32 dwReserved2; // reserved
};
#pragma pack(pop)
static bool is_valid_dxt(size_t dxt)
{
switch(dxt)
{
case 0:
case 1:
case DXT1A:
case 3:
case 5:
return true;
default:
return false;
}
}
// extract all information from DDS pixel format and store in bpp, flags.
// pf points to the DDS file's header; all fields must be endian-converted
// before use.
// output parameters invalid on failure.
static Status decode_pf(const DDS_PIXELFORMAT* pf, size_t& bpp, size_t& flags)
{
bpp = 0;
flags = 0;
// check struct size
if(read_le32(&pf->dwSize) != sizeof(DDS_PIXELFORMAT))
WARN_RETURN(ERR::TEX_INVALID_SIZE);
// determine type
const size_t pf_flags = (size_t)read_le32(&pf->dwFlags);
// .. uncompressed RGB/RGBA
if(pf_flags & DDPF_RGB)
{
const size_t pf_bpp = (size_t)read_le32(&pf->dwRGBBitCount);
const size_t pf_r_mask = (size_t)read_le32(&pf->dwRBitMask);
const size_t pf_g_mask = (size_t)read_le32(&pf->dwGBitMask);
const size_t pf_b_mask = (size_t)read_le32(&pf->dwBBitMask);
const size_t pf_a_mask = (size_t)read_le32(&pf->dwABitMask);
// (checked below; must be set in case below warning is to be
// skipped)
bpp = pf_bpp;
if(pf_flags & DDPF_ALPHAPIXELS)
{
// something weird other than RGBA or BGRA
if(pf_a_mask != 0xFF000000)
WARN_RETURN(ERR::TEX_FMT_INVALID);
flags |= TEX_ALPHA;
}
// make sure component ordering is 0xBBGGRR = RGB (see below)
if(pf_r_mask != 0xFF || pf_g_mask != 0xFF00 || pf_b_mask != 0xFF0000)
{
// DDS_PIXELFORMAT in theory supports any ordering of R,G,B,A.
// we need to upload to OpenGL, which can only receive BGR(A) or
// RGB(A). the former still requires conversion (done by driver),
// so it's slower. since the very purpose of supporting uncompressed
// DDS is storing images in a format that requires no processing,
// we do not allow any weird orderings that require runtime work.
// instead, the artists must export with the correct settings.
WARN_RETURN(ERR::TEX_FMT_INVALID);
}
RETURN_STATUS_IF_ERR(tex_validate_plain_format(bpp, (int)flags));
}
// .. uncompressed 8bpp greyscale
else if(pf_flags & DDPF_ALPHAPIXELS)
{
const size_t pf_bpp = (size_t)read_le32(&pf->dwRGBBitCount);
const size_t pf_a_mask = (size_t)read_le32(&pf->dwABitMask);
bpp = pf_bpp;
if(pf_bpp != 8)
WARN_RETURN(ERR::TEX_FMT_INVALID);
if(pf_a_mask != 0xFF)
WARN_RETURN(ERR::TEX_FMT_INVALID);
flags |= TEX_GREY;
RETURN_STATUS_IF_ERR(tex_validate_plain_format(bpp, (int)flags));
}
// .. compressed
else if(pf_flags & DDPF_FOURCC)
{
// set effective bpp and store DXT format in flags & TEX_DXT.
// no endian conversion necessary - FOURCC() takes care of that.
switch(pf->dwFourCC)
{
case FOURCC('D','X','T','1'):
bpp = 4;
if(pf_flags & DDPF_ALPHAPIXELS)
flags |= DXT1A | TEX_ALPHA;
else
flags |= 1;
break;
case FOURCC('D','X','T','3'):
bpp = 8;
flags |= 3;
flags |= TEX_ALPHA; // see DDPF_ALPHAPIXELS decl
break;
case FOURCC('D','X','T','5'):
bpp = 8;
flags |= 5;
flags |= TEX_ALPHA; // see DDPF_ALPHAPIXELS decl
break;
default:
WARN_RETURN(ERR::TEX_FMT_INVALID);
}
}
// .. neither uncompressed nor compressed - invalid
else
WARN_RETURN(ERR::TEX_FMT_INVALID);
return INFO::OK;
}
// extract all information from DDS header and store in w, h, bpp, flags.
// sd points to the DDS file's header; all fields must be endian-converted
// before use.
// output parameters invalid on failure.
static Status decode_sd(const DDS_HEADER* sd, size_t& w, size_t& h, size_t& bpp, size_t& flags)
{
// check header size
if(read_le32(&sd->dwSize) != sizeof(*sd))
WARN_RETURN(ERR::CORRUPTED);
// flags (indicate which fields are valid)
const size_t sd_flags = (size_t)read_le32(&sd->dwFlags);
// .. not all required fields are present
// note: we can't guess dimensions - the image may not be square.
const size_t sd_req_flags = DDSD_CAPS|DDSD_HEIGHT|DDSD_WIDTH|DDSD_PIXELFORMAT;
if((sd_flags & sd_req_flags) != sd_req_flags)
WARN_RETURN(ERR::TEX_INCOMPLETE_HEADER);
// image dimensions
h = (size_t)read_le32(&sd->dwHeight);
w = (size_t)read_le32(&sd->dwWidth);
// pixel format
RETURN_STATUS_IF_ERR(decode_pf(&sd->ddpf, bpp, flags));
// if the image is not aligned with the S3TC block size, it is stored
// with extra pixels on the bottom left to fill up the space, so we need
// to account for those when calculating how big it should be
size_t stored_h, stored_w;
if(flags & TEX_DXT)
{
stored_h = Align<4>(h);
stored_w = Align<4>(w);
}
else
{
stored_h = h;
stored_w = w;
}
// verify pitch or linear size, if given
const size_t pitch = stored_w*bpp/8;
const size_t sd_pitch_or_size = (size_t)read_le32(&sd->dwPitchOrLinearSize);
if(sd_flags & DDSD_PITCH)
{
if(sd_pitch_or_size != Align<4>(pitch))
DEBUG_WARN_ERR(ERR::CORRUPTED);
}
if(sd_flags & DDSD_LINEARSIZE)
{
// some DDS tools mistakenly store the total size of all levels,
// so allow values close to that as well
const ssize_t totalSize = ssize_t(pitch*stored_h*1.333333f);
if(sd_pitch_or_size != pitch*stored_h && abs(ssize_t(sd_pitch_or_size)-totalSize) > 64)
DEBUG_WARN_ERR(ERR::CORRUPTED);
}
// note: both flags set would be invalid; no need to check for that,
// though, since one of the above tests would fail.
// mipmaps
if(sd_flags & DDSD_MIPMAPCOUNT)
{
const size_t mipmap_count = (size_t)read_le32(&sd->dwMipMapCount);
if(mipmap_count)
{
// mipmap chain is incomplete
// note: DDS includes the base level in its count, hence +1.
if(mipmap_count != ceil_log2(std::max(w,h))+1)
WARN_RETURN(ERR::TEX_FMT_INVALID);
flags |= TEX_MIPMAPS;
}
}
// check for volume textures
if(sd_flags & DDSD_DEPTH)
{
const size_t depth = (size_t)read_le32(&sd->dwDepth);
if(depth)
WARN_RETURN(ERR::NOT_SUPPORTED);
}
// check caps
// .. this is supposed to be set, but don't bail if not (pointless)
ENSURE(sd->dwCaps & DDSCAPS_TEXTURE);
// .. sanity check: warn if mipmap flag not set (don't bail if not
// because we've already made the decision).
const bool mipmap_cap = (sd->dwCaps & DDSCAPS_MIPMAP) != 0;
const bool mipmap_flag = (flags & TEX_MIPMAPS) != 0;
ENSURE(mipmap_cap == mipmap_flag);
// note: we do not check for cubemaps and volume textures (not supported)
// because the file may still have useful data we can read.
return INFO::OK;
}
//-----------------------------------------------------------------------------
bool TexCodecDds::is_hdr(const u8* file) const
{
return *(u32*)file == FOURCC('D','D','S',' ');
}
bool TexCodecDds::is_ext(const OsPath& extension) const
{
return extension == L".dds";
}
size_t TexCodecDds::hdr_size(const u8* UNUSED(file)) const
{
return 4+sizeof(DDS_HEADER);
}
Status TexCodecDds::decode(u8* RESTRICT data, size_t UNUSED(size), Tex* RESTRICT t) const
{
const DDS_HEADER* sd = (const DDS_HEADER*)(data+4);
RETURN_STATUS_IF_ERR(decode_sd(sd, t->m_Width, t->m_Height, t->m_Bpp, t->m_Flags));
return INFO::OK;
}
Status TexCodecDds::encode(Tex* RESTRICT UNUSED(t), DynArray* RESTRICT UNUSED(da)) const
{
// note: do not return ERR::NOT_SUPPORTED et al. because that would
// break tex_write (which assumes either this, 0 or errors are returned).
return INFO::TEX_CODEC_CANNOT_HANDLE;
}
TIMER_ADD_CLIENT(tc_dds_transform);
Status TexCodecDds::transform(Tex* t, size_t transforms) const
{
TIMER_ACCRUE(tc_dds_transform);
size_t mipmaps = t->m_Flags & TEX_MIPMAPS;
size_t dxt = t->m_Flags & TEX_DXT;
ENSURE(is_valid_dxt(dxt));
const size_t transform_mipmaps = transforms & TEX_MIPMAPS;
const size_t transform_dxt = transforms & TEX_DXT;
// requesting removal of mipmaps
if(mipmaps && transform_mipmaps)
{
// we don't need to actually change anything except the flag - the
// mipmap levels will just be treated as trailing junk
t->m_Flags &= ~TEX_MIPMAPS;
return INFO::OK;
}
// requesting decompression
if(dxt && transform_dxt)
{
RETURN_STATUS_IF_ERR(s3tc_decompress(t));
return INFO::OK;
}
// both are DXT (unsupported; there are no flags we can change while
// compressed) or requesting compression (not implemented) or
// both not DXT (nothing we can do) - bail.
return INFO::TEX_CODEC_CANNOT_HANDLE;
}
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