glm/test/external/gli/core/flip.inl
2016-11-18 23:16:29 +01:00

339 lines
9.9 KiB
C++

namespace gli{
namespace detail
{
inline void flip(image ImageDst, image ImageSrc, size_t BlockSize)
{
size_t const LineSize = BlockSize * ImageDst.extent().x;
for(int y = 0; y < ImageDst.extent().y; ++y)
{
size_t OffsetDst = LineSize * y;
size_t OffsetSrc = ImageSrc.size() - (LineSize * (y + 1));
memcpy(
ImageDst.data<glm::byte>() + OffsetDst,
ImageSrc.data<glm::byte>() + OffsetSrc,
LineSize);
}
}
struct dxt1_block
{
uint16_t Color0;
uint16_t Color1;
uint8_t Row0;
uint8_t Row1;
uint8_t Row2;
uint8_t Row3;
};
struct dxt3_block
{
uint16_t AlphaRow0;
uint16_t AlphaRow1;
uint16_t AlphaRow2;
uint16_t AlphaRow3;
uint16_t Color0;
uint16_t Color1;
uint8_t Row0;
uint8_t Row1;
uint8_t Row2;
uint8_t Row3;
};
struct dxt5_block
{
uint8_t Alpha0;
uint8_t Alpha1;
uint8_t AlphaR0;
uint8_t AlphaR1;
uint8_t AlphaR2;
uint8_t AlphaR3;
uint8_t AlphaR4;
uint8_t AlphaR5;
uint16_t Color0;
uint16_t Color1;
uint8_t Row0;
uint8_t Row1;
uint8_t Row2;
uint8_t Row3;
};
inline void flip_block_s3tc(uint8_t* BlockDst, uint8_t* BlockSrc, format Format, bool HeightTwo)
{
// There is no distinction between RGB and RGBA in DXT-compressed textures,
// it is used only to tell OpenGL how to interpret the data.
// Moreover, in DXT1 (which does not contain an alpha channel), transparency can be emulated
// using Color0 and Color1 on a per-compression-block basis.
// There is no difference in how textures with and without transparency are laid out in the file,
// so they can be flipped using the same method.
if(Format == FORMAT_RGB_DXT1_UNORM_BLOCK8 || Format == FORMAT_RGB_DXT1_SRGB_BLOCK8
|| Format == FORMAT_RGBA_DXT1_UNORM_BLOCK8 || Format == FORMAT_RGBA_DXT1_SRGB_BLOCK8)
{
dxt1_block* Src = reinterpret_cast<dxt1_block*>(BlockSrc);
dxt1_block* Dst = reinterpret_cast<dxt1_block*>(BlockDst);
if(HeightTwo)
{
Dst->Color0 = Src->Color0;
Dst->Color1 = Src->Color1;
Dst->Row0 = Src->Row1;
Dst->Row1 = Src->Row0;
Dst->Row2 = Src->Row2;
Dst->Row3 = Src->Row3;
return;
}
Dst->Color0 = Src->Color0;
Dst->Color1 = Src->Color1;
Dst->Row0 = Src->Row3;
Dst->Row1 = Src->Row2;
Dst->Row2 = Src->Row1;
Dst->Row3 = Src->Row0;
return;
}
// DXT3
if(Format == FORMAT_RGBA_DXT3_UNORM_BLOCK16 || Format == FORMAT_RGBA_DXT3_SRGB_BLOCK16)
{
dxt3_block* Src = reinterpret_cast<dxt3_block*>(BlockSrc);
dxt3_block* Dst = reinterpret_cast<dxt3_block*>(BlockDst);
if(HeightTwo)
{
Dst->AlphaRow0 = Src->AlphaRow1;
Dst->AlphaRow1 = Src->AlphaRow0;
Dst->AlphaRow2 = Src->AlphaRow2;
Dst->AlphaRow3 = Src->AlphaRow3;
Dst->Color0 = Src->Color0;
Dst->Color1 = Src->Color1;
Dst->Row0 = Src->Row1;
Dst->Row1 = Src->Row0;
Dst->Row2 = Src->Row2;
Dst->Row3 = Src->Row3;
return;
}
Dst->AlphaRow0 = Src->AlphaRow3;
Dst->AlphaRow1 = Src->AlphaRow2;
Dst->AlphaRow2 = Src->AlphaRow1;
Dst->AlphaRow3 = Src->AlphaRow0;
Dst->Color0 = Src->Color0;
Dst->Color1 = Src->Color1;
Dst->Row0 = Src->Row3;
Dst->Row1 = Src->Row2;
Dst->Row2 = Src->Row1;
Dst->Row3 = Src->Row0;
return;
}
// DXT5
if(Format == FORMAT_RGBA_DXT5_UNORM_BLOCK16 || Format == FORMAT_RGBA_DXT5_SRGB_BLOCK16)
{
dxt5_block* Src = reinterpret_cast<dxt5_block*>(BlockSrc);
dxt5_block* Dst = reinterpret_cast<dxt5_block*>(BlockDst);
if(HeightTwo)
{
Dst->Alpha0 = Src->Alpha0;
Dst->Alpha1 = Src->Alpha1;
// operator+ has precedence over operator>> and operator<<, hence the parentheses. very important!
// the values below are bitmasks used to retrieve alpha values according to the DXT specification
// 0xF0 == 0b11110000 and 0xF == 0b1111
Dst->AlphaR0 = ((Src->AlphaR1 & 0xF0) >> 4) + ((Src->AlphaR2 & 0xF) << 4);
Dst->AlphaR1 = ((Src->AlphaR2 & 0xF0) >> 4) + ((Src->AlphaR0 & 0xF) << 4);
Dst->AlphaR2 = ((Src->AlphaR0 & 0xF0) >> 4) + ((Src->AlphaR1 & 0xF) << 4);
Dst->AlphaR3 = Src->AlphaR3;
Dst->AlphaR4 = Src->AlphaR4;
Dst->AlphaR5 = Src->AlphaR5;
Dst->Color0 = Src->Color0;
Dst->Color1 = Src->Color1;
Dst->Row0 = Src->Row1;
Dst->Row1 = Src->Row0;
Dst->Row2 = Src->Row2;
Dst->Row3 = Src->Row3;
return;
}
Dst->Alpha0 = Src->Alpha0;
Dst->Alpha1 = Src->Alpha1;
// operator+ has precedence over operator>> and operator<<, hence the parentheses. very important!
// the values below are bitmasks used to retrieve alpha values according to the DXT specification
// 0xF0 == 0b11110000 and 0xF == 0b1111
Dst->AlphaR0 = ((Src->AlphaR4 & 0xF0) >> 4) + ((Src->AlphaR5 & 0xF) << 4);
Dst->AlphaR1 = ((Src->AlphaR5 & 0xF0) >> 4) + ((Src->AlphaR3 & 0xF) << 4);
Dst->AlphaR2 = ((Src->AlphaR3 & 0xF0) >> 4) + ((Src->AlphaR4 & 0xF) << 4);
Dst->AlphaR3 = ((Src->AlphaR1 & 0xF0) >> 4) + ((Src->AlphaR2 & 0xF) << 4);
Dst->AlphaR4 = ((Src->AlphaR2 & 0xF0) >> 4) + ((Src->AlphaR0 & 0xF) << 4);
Dst->AlphaR5 = ((Src->AlphaR0 & 0xF0) >> 4) + ((Src->AlphaR1 & 0xF) << 4);
Dst->Color0 = Src->Color0;
Dst->Color1 = Src->Color1;
Dst->Row0 = Src->Row3;
Dst->Row1 = Src->Row2;
Dst->Row2 = Src->Row1;
Dst->Row3 = Src->Row0;
return;
}
// invalid format specified (unknown S3TC format?)
assert(false);
}
inline void flip_s3tc(image ImageDst, image ImageSrc, format Format)
{
if(ImageSrc.extent().y == 1)
{
memcpy(ImageDst.data(),
ImageSrc.data(),
ImageSrc.size());
return;
}
std::size_t const XBlocks = ImageSrc.extent().x <= 4 ? 1 : ImageSrc.extent().x / 4;
if(ImageSrc.extent().y == 2)
{
for(std::size_t i_block = 0; i_block < XBlocks; ++i_block)
flip_block_s3tc(ImageDst.data<uint8_t>() + i_block * block_size(Format), ImageSrc.data<uint8_t>() + i_block * block_size(Format), Format, true);
return;
}
std::size_t const MaxYBlock = ImageSrc.extent().y / 4 - 1;
for(std::size_t i_row = 0; i_row <= MaxYBlock; ++i_row)
for(std::size_t i_block = 0; i_block < XBlocks; ++i_block)
flip_block_s3tc(ImageDst.data<uint8_t>() + (MaxYBlock - i_row) * block_size(Format) * XBlocks + i_block * block_size(Format), ImageSrc.data<uint8_t>() + i_row * block_size(Format) * XBlocks + i_block * block_size(Format), Format, false);
}
}//namespace detail
/*
template <>
inline image flip(image const & Image)
{
}
*/
template <>
inline texture2d flip(texture2d const& Texture)
{
GLI_ASSERT(!gli::is_compressed(Texture.format()) || gli::is_s3tc_compressed(Texture.format()));
texture2d Flip(Texture.format(), Texture.extent(), Texture.levels());
if(!is_compressed(Texture.format()))
{
texture2d::size_type const BlockSize = block_size(Texture.format());
for(texture2d::size_type Level = 0; Level < Flip.levels(); ++Level)
detail::flip(Flip[Level], Texture[Level], BlockSize);
}
else
for(texture2d::size_type Level = 0; Level < Flip.levels(); ++Level)
detail::flip_s3tc(Flip[Level], Texture[Level], Texture.format());
return Flip;
}
template <>
inline texture2d_array flip(texture2d_array const& Texture)
{
GLI_ASSERT(!gli::is_compressed(Texture.format()) || gli::is_s3tc_compressed(Texture.format()));
texture2d_array Flip(Texture.format(), Texture.extent(), Texture.layers(), Texture.levels());
if(!gli::is_compressed(Texture.format()))
{
texture2d_array::size_type const BlockSize = block_size(Texture.format());
for(texture2d_array::size_type Layer = 0; Layer < Flip.layers(); ++Layer)
for(texture2d_array::size_type Level = 0; Level < Flip.levels(); ++Level)
detail::flip(Flip[Layer][Level], Texture[Layer][Level], BlockSize);
}
else
for(texture2d_array::size_type Layer = 0; Layer < Flip.layers(); ++Layer)
for(texture2d_array::size_type Level = 0; Level < Flip.levels(); ++Level)
detail::flip_s3tc(Flip[Layer][Level], Texture[Layer][Level], Texture.format());
return Flip;
}
template <>
inline texture_cube flip(texture_cube const & Texture)
{
GLI_ASSERT(!gli::is_compressed(Texture.format()) || gli::is_s3tc_compressed(Texture.format()));
texture_cube Flip(Texture.format(), Texture.extent(), Texture.levels());
if(!gli::is_compressed(Texture.format()))
{
texture_cube::size_type const BlockSize = block_size(Texture.format());
for(texture_cube::size_type Face = 0; Face < Flip.faces(); ++Face)
for(texture_cube::size_type Level = 0; Level < Flip.levels(); ++Level)
detail::flip(Flip[Face][Level], Texture[Face][Level], BlockSize);
}
else
for(texture_cube::size_type Face = 0; Face < Flip.faces(); ++Face)
for(texture_cube::size_type Level = 0; Level < Flip.levels(); ++Level)
detail::flip_s3tc(Flip[Face][Level], Texture[Face][Level], Texture.format());
return Flip;
}
template <>
inline texture_cube_array flip(texture_cube_array const & Texture)
{
assert(!is_compressed(Texture.format()) || is_s3tc_compressed(Texture.format()));
texture_cube_array Flip(Texture.format(), Texture.extent(), Texture.layers(), Texture.levels());
if(!is_compressed(Texture.format()))
{
gli::size_t const BlockSize = block_size(Texture.format());
for(std::size_t Layer = 0; Layer < Flip.layers(); ++Layer)
for(std::size_t Face = 0; Face < Flip.faces(); ++Face)
for(std::size_t Level = 0; Level < Flip.levels(); ++Level)
detail::flip(Flip[Layer][Face][Level], Texture[Layer][Face][Level], BlockSize);
}
else
for(std::size_t Layer = 0; Layer < Flip.layers(); ++Layer)
for(std::size_t Face = 0; Face < Flip.faces(); ++Face)
for(std::size_t Level = 0; Level < Flip.levels(); ++Level)
detail::flip_s3tc(Flip[Layer][Face][Level], Texture[Layer][Face][Level], Texture.format());
return Flip;
}
template <>
inline texture flip(texture const & Texture)
{
switch(Texture.target())
{
case TARGET_2D:
return flip(texture2d(Texture));
case TARGET_2D_ARRAY:
return flip(texture2d_array(Texture));
case TARGET_CUBE:
return flip(texture_cube(Texture));
case TARGET_CUBE_ARRAY:
return flip(texture_cube_array(Texture));
default:
assert(false && "Texture target does not support flipping.");
return Texture;
}
}
}//namespace gli