// Copyright NVIDIA Corporation 2007 -- Ignacio Castano <icastano@nvidia.com>
// 
// 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.

#include "BlockDXT.h"
#include "ColorBlock.h"

#include "nvcore/Stream.h"
#include "nvcore/Utils.h" // swap
#include "nvmath/Half.h"
#include "nvmath/Vector.inl"

#include "bc6h/zoh.h"
#include "bc7/avpcl.h"


using namespace nv;


/*----------------------------------------------------------------------------
BlockDXT1
----------------------------------------------------------------------------*/

uint BlockDXT1::evaluatePalette(Color32 color_array[4], bool d3d9/*= false*/) const
{
    // Does bit expansion before interpolation.
    color_array[0].b = (col0.b << 3) | (col0.b >> 2);
    color_array[0].g = (col0.g << 2) | (col0.g >> 4);
    color_array[0].r = (col0.r << 3) | (col0.r >> 2);
    color_array[0].a = 0xFF;

    // @@ Same as above, but faster?
    //	Color32 c;
    //	c.u = ((col0.u << 3) & 0xf8) | ((col0.u << 5) & 0xfc00) | ((col0.u << 8) & 0xf80000);
    //	c.u |= (c.u >> 5) & 0x070007;
    //	c.u |= (c.u >> 6) & 0x000300;
    //	color_array[0].u = c.u;

    color_array[1].r = (col1.r << 3) | (col1.r >> 2);
    color_array[1].g = (col1.g << 2) | (col1.g >> 4);
    color_array[1].b = (col1.b << 3) | (col1.b >> 2);
    color_array[1].a = 0xFF;

    // @@ Same as above, but faster?
    //	c.u = ((col1.u << 3) & 0xf8) | ((col1.u << 5) & 0xfc00) | ((col1.u << 8) & 0xf80000);
    //	c.u |= (c.u >> 5) & 0x070007;
    //	c.u |= (c.u >> 6) & 0x000300;
    //	color_array[1].u = c.u;

    if( col0.u > col1.u ) {
        // Four-color block: derive the other two colors.
        color_array[2].r = (2 * color_array[0].r + color_array[1].r + d3d9) / 3;
        color_array[2].g = (2 * color_array[0].g + color_array[1].g + d3d9) / 3;
        color_array[2].b = (2 * color_array[0].b + color_array[1].b + d3d9) / 3;
        color_array[2].a = 0xFF;

        color_array[3].r = (2 * color_array[1].r + color_array[0].r + d3d9) / 3;
        color_array[3].g = (2 * color_array[1].g + color_array[0].g + d3d9) / 3;
        color_array[3].b = (2 * color_array[1].b + color_array[0].b + d3d9) / 3;
        color_array[3].a = 0xFF;

        return 4;
    }
    else {
        // Three-color block: derive the other color.
        color_array[2].r = (color_array[0].r + color_array[1].r) / 2;
        color_array[2].g = (color_array[0].g + color_array[1].g) / 2;
        color_array[2].b = (color_array[0].b + color_array[1].b) / 2;
        color_array[2].a = 0xFF;

        // Set all components to 0 to match DXT specs.
        color_array[3].r = 0x00; // color_array[2].r;
        color_array[3].g = 0x00; // color_array[2].g;
        color_array[3].b = 0x00; // color_array[2].b;
        color_array[3].a = 0x00;

        return 3;
    }
}


uint BlockDXT1::evaluatePaletteNV5x(Color32 color_array[4]) const
{
    // Does bit expansion before interpolation.
    color_array[0].r = (3 * col0.r * 22) / 8;
    color_array[0].g = (col0.g << 2) | (col0.g >> 4);
    color_array[0].b = (3 * col0.b * 22) / 8;
    color_array[0].a = 0xFF;

    color_array[1].r = (3 * col1.r * 22) / 8;
    color_array[1].g = (col1.g << 2) | (col1.g >> 4);
    color_array[1].b = (3 * col1.b * 22) / 8;
    color_array[1].a = 0xFF;

    int gdiff = color_array[1].g - color_array[0].g;

    if( col0.u > col1.u ) {
        // Four-color block: derive the other two colors.
        color_array[2].r = ((2 * col0.r + col1.r) * 22) / 8;
        color_array[2].g = (256 * color_array[0].g + gdiff / 4 + 128 + gdiff * 80) / 256;
        color_array[2].b = ((2 * col0.b + col1.b) * 22) / 8;
        color_array[2].a = 0xFF;

        color_array[3].r = ((2 * col1.r + col0.r) * 22) / 8;
        color_array[3].g = (256 * color_array[1].g - gdiff / 4 + 128 - gdiff * 80) / 256;
        color_array[3].b = ((2 * col1.b + col0.b) * 22) / 8;
        color_array[3].a = 0xFF;

        return 4;
    }
    else {
        // Three-color block: derive the other color.
        color_array[2].r = ((col0.r + col1.r) * 33) / 8;
        color_array[2].g = (256 * color_array[0].g + gdiff / 4 + 128 + gdiff * 128) / 256;
        color_array[2].b = ((col0.b + col1.b) * 33) / 8;
        color_array[2].a = 0xFF;

        // Set all components to 0 to match DXT specs.
        color_array[3].r = 0x00;
        color_array[3].g = 0x00;
        color_array[3].b = 0x00;
        color_array[3].a = 0x00;

        return 3;
    }
}

// Evaluate palette assuming 3 color block.
void BlockDXT1::evaluatePalette3(Color32 color_array[4], bool d3d9) const
{
    color_array[0].b = (col0.b << 3) | (col0.b >> 2);
    color_array[0].g = (col0.g << 2) | (col0.g >> 4);
    color_array[0].r = (col0.r << 3) | (col0.r >> 2);
    color_array[0].a = 0xFF;

    color_array[1].r = (col1.r << 3) | (col1.r >> 2);
    color_array[1].g = (col1.g << 2) | (col1.g >> 4);
    color_array[1].b = (col1.b << 3) | (col1.b >> 2);
    color_array[1].a = 0xFF;

    // Three-color block: derive the other color.
    color_array[2].r = (color_array[0].r + color_array[1].r) / 2;
    color_array[2].g = (color_array[0].g + color_array[1].g) / 2;
    color_array[2].b = (color_array[0].b + color_array[1].b) / 2;
    color_array[2].a = 0xFF;

    // Set all components to 0 to match DXT specs.
    color_array[3].r = 0x00;
    color_array[3].g = 0x00;
    color_array[3].b = 0x00;
    color_array[3].a = 0x00;
}

// Evaluate palette assuming 4 color block.
void BlockDXT1::evaluatePalette4(Color32 color_array[4], bool d3d9) const
{
    color_array[0].b = (col0.b << 3) | (col0.b >> 2);
    color_array[0].g = (col0.g << 2) | (col0.g >> 4);
    color_array[0].r = (col0.r << 3) | (col0.r >> 2);
    color_array[0].a = 0xFF;

    color_array[1].r = (col1.r << 3) | (col1.r >> 2);
    color_array[1].g = (col1.g << 2) | (col1.g >> 4);
    color_array[1].b = (col1.b << 3) | (col1.b >> 2);
    color_array[1].a = 0xFF;

    int bias = 0;
    if (d3d9) bias = 1;

    // Four-color block: derive the other two colors.
    color_array[2].r = (2 * color_array[0].r + color_array[1].r + bias) / 3;
    color_array[2].g = (2 * color_array[0].g + color_array[1].g + bias) / 3;
    color_array[2].b = (2 * color_array[0].b + color_array[1].b + bias) / 3;
    color_array[2].a = 0xFF;

    color_array[3].r = (2 * color_array[1].r + color_array[0].r + bias) / 3;
    color_array[3].g = (2 * color_array[1].g + color_array[0].g + bias) / 3;
    color_array[3].b = (2 * color_array[1].b + color_array[0].b + bias) / 3;
    color_array[3].a = 0xFF;
}


void BlockDXT1::decodeBlock(ColorBlock * block, bool d3d9/*= false*/) const
{
    nvDebugCheck(block != NULL);

    // Decode color block.
    Color32 color_array[4];
    evaluatePalette(color_array, d3d9);

    // Write color block.
    for( uint j = 0; j < 4; j++ ) {
        for( uint i = 0; i < 4; i++ ) {
            uint idx = (row[j] >> (2 * i)) & 3;
            block->color(i, j) = color_array[idx];
        }
    }	
}

void BlockDXT1::decodeBlockNV5x(ColorBlock * block) const
{
    nvDebugCheck(block != NULL);

    // Decode color block.
    Color32 color_array[4];
    evaluatePaletteNV5x(color_array);

    // Write color block.
    for( uint j = 0; j < 4; j++ ) {
        for( uint i = 0; i < 4; i++ ) {
            uint idx = (row[j] >> (2 * i)) & 3;
            block->color(i, j) = color_array[idx];
        }
    }
}

void BlockDXT1::setIndices(int * idx)
{
    indices = 0;
    for(uint i = 0; i < 16; i++) {
        indices |= (idx[i] & 3) << (2 * i);
    }
}


/// Flip DXT1 block vertically.
inline void BlockDXT1::flip4()
{
    swap(row[0], row[3]);
    swap(row[1], row[2]);
}

/// Flip half DXT1 block vertically.
inline void BlockDXT1::flip2()
{
    swap(row[0], row[1]);
}


/*----------------------------------------------------------------------------
BlockDXT3
----------------------------------------------------------------------------*/

void BlockDXT3::decodeBlock(ColorBlock * block, bool d3d9/*= false*/) const
{
    nvDebugCheck(block != NULL);

    // Decode color.
    color.decodeBlock(block, d3d9);

    // Decode alpha.
    alpha.decodeBlock(block, d3d9);
}

void BlockDXT3::decodeBlockNV5x(ColorBlock * block) const
{
    nvDebugCheck(block != NULL);

    color.decodeBlockNV5x(block);
    alpha.decodeBlock(block);
}

void AlphaBlockDXT3::decodeBlock(ColorBlock * block, bool d3d9/*= false*/) const
{
    nvDebugCheck(block != NULL);

    block->color(0x0).a = (alpha0 << 4) | alpha0;
    block->color(0x1).a = (alpha1 << 4) | alpha1;
    block->color(0x2).a = (alpha2 << 4) | alpha2;
    block->color(0x3).a = (alpha3 << 4) | alpha3;
    block->color(0x4).a = (alpha4 << 4) | alpha4;
    block->color(0x5).a = (alpha5 << 4) | alpha5;
    block->color(0x6).a = (alpha6 << 4) | alpha6;
    block->color(0x7).a = (alpha7 << 4) | alpha7;
    block->color(0x8).a = (alpha8 << 4) | alpha8;
    block->color(0x9).a = (alpha9 << 4) | alpha9;
    block->color(0xA).a = (alphaA << 4) | alphaA;
    block->color(0xB).a = (alphaB << 4) | alphaB;
    block->color(0xC).a = (alphaC << 4) | alphaC;
    block->color(0xD).a = (alphaD << 4) | alphaD;
    block->color(0xE).a = (alphaE << 4) | alphaE;
    block->color(0xF).a = (alphaF << 4) | alphaF;
}

/// Flip DXT3 alpha block vertically.
void AlphaBlockDXT3::flip4()
{
    swap(row[0], row[3]);
    swap(row[1], row[2]);
}

/// Flip half DXT3 alpha block vertically.
void AlphaBlockDXT3::flip2()
{
    swap(row[0], row[1]);
}

/// Flip DXT3 block vertically.
void BlockDXT3::flip4()
{
    alpha.flip4();
    color.flip4();
}

/// Flip half DXT3 block vertically.
void BlockDXT3::flip2()
{
    alpha.flip2();
    color.flip2();
}


/*----------------------------------------------------------------------------
BlockDXT5
----------------------------------------------------------------------------*/

void AlphaBlockDXT5::evaluatePalette(uint8 alpha[8], bool d3d9) const
{
    if (alpha0 > alpha1) {
        evaluatePalette8(alpha, d3d9);
    }
    else {
        evaluatePalette6(alpha, d3d9);
    }
}

void AlphaBlockDXT5::evaluatePalette8(uint8 alpha[8], bool d3d9) const
{
    int bias = 0;
    if (d3d9) bias = 3;

    // 8-alpha block:  derive the other six alphas.
    // Bit code 000 = alpha0, 001 = alpha1, others are interpolated.
    alpha[0] = alpha0;
    alpha[1] = alpha1;
    alpha[2] = (6 * alpha[0] + 1 * alpha[1] + bias) / 7;    // bit code 010
    alpha[3] = (5 * alpha[0] + 2 * alpha[1] + bias) / 7;    // bit code 011
    alpha[4] = (4 * alpha[0] + 3 * alpha[1] + bias) / 7;    // bit code 100
    alpha[5] = (3 * alpha[0] + 4 * alpha[1] + bias) / 7;    // bit code 101
    alpha[6] = (2 * alpha[0] + 5 * alpha[1] + bias) / 7;    // bit code 110
    alpha[7] = (1 * alpha[0] + 6 * alpha[1] + bias) / 7;    // bit code 111
}

void AlphaBlockDXT5::evaluatePalette6(uint8 alpha[8], bool d3d9) const
{
    int bias = 0;
    if (d3d9) bias = 2;

    // 6-alpha block.
    // Bit code 000 = alpha0, 001 = alpha1, others are interpolated.
    alpha[0] = alpha0;
    alpha[1] = alpha1;
    alpha[2] = (4 * alpha[0] + 1 * alpha[1] + bias) / 5;    // Bit code 010
    alpha[3] = (3 * alpha[0] + 2 * alpha[1] + bias) / 5;    // Bit code 011
    alpha[4] = (2 * alpha[0] + 3 * alpha[1] + bias) / 5;    // Bit code 100
    alpha[5] = (1 * alpha[0] + 4 * alpha[1] + bias) / 5;    // Bit code 101
    alpha[6] = 0x00;                                        // Bit code 110
    alpha[7] = 0xFF;                                        // Bit code 111
}

void AlphaBlockDXT5::indices(uint8 index_array[16]) const
{
    index_array[0x0] = bits0;
    index_array[0x1] = bits1;
    index_array[0x2] = bits2;
    index_array[0x3] = bits3;
    index_array[0x4] = bits4;
    index_array[0x5] = bits5;
    index_array[0x6] = bits6;
    index_array[0x7] = bits7;
    index_array[0x8] = bits8;
    index_array[0x9] = bits9;
    index_array[0xA] = bitsA;
    index_array[0xB] = bitsB;
    index_array[0xC] = bitsC;
    index_array[0xD] = bitsD;
    index_array[0xE] = bitsE;
    index_array[0xF] = bitsF;
}

uint AlphaBlockDXT5::index(uint index) const
{
    nvDebugCheck(index < 16);

    int offset = (3 * index + 16);
    return uint((this->u >> offset) & 0x7);
}

void AlphaBlockDXT5::setIndex(uint index, uint value)
{
    nvDebugCheck(index < 16);
    nvDebugCheck(value < 8);

    int offset = (3 * index + 16);
    uint64 mask = uint64(0x7) << offset;
    this->u = (this->u & ~mask) | (uint64(value) << offset);
}

void AlphaBlockDXT5::decodeBlock(ColorBlock * block, bool d3d9/*= false*/) const
{
    nvDebugCheck(block != NULL);

    uint8 alpha_array[8];
    evaluatePalette(alpha_array, d3d9);

    uint8 index_array[16];
    indices(index_array);

    for(uint i = 0; i < 16; i++) {
        block->color(i).a = alpha_array[index_array[i]];
    }
}

void AlphaBlockDXT5::decodeBlock(AlphaBlock4x4 * block, bool d3d9/*= false*/) const
{
    nvDebugCheck(block != NULL);

    uint8 alpha_array[8];
    evaluatePalette(alpha_array, d3d9);

    uint8 index_array[16];
    indices(index_array);

    for(uint i = 0; i < 16; i++) {
        block->alpha[i] = alpha_array[index_array[i]];
    }
}


void AlphaBlockDXT5::flip4()
{
    uint64 * b = (uint64 *)this;

    // @@ The masks might have to be byte swapped.
    uint64 tmp = (*b & POSH_U64(0x000000000000FFFF));
    tmp |= (*b & POSH_U64(0x000000000FFF0000)) << 36;
    tmp |= (*b & POSH_U64(0x000000FFF0000000)) << 12;
    tmp |= (*b & POSH_U64(0x000FFF0000000000)) >> 12;
    tmp |= (*b & POSH_U64(0xFFF0000000000000)) >> 36;

    *b = tmp;
}

void AlphaBlockDXT5::flip2()
{
    uint * b = (uint *)this;

    // @@ The masks might have to be byte swapped.
    uint tmp = (*b & 0xFF000000);
    tmp |=  (*b & 0x00000FFF) << 12;
    tmp |= (*b & 0x00FFF000) >> 12;

    *b = tmp;
}

void BlockDXT5::decodeBlock(ColorBlock * block, bool d3d9/*= false*/) const
{
    nvDebugCheck(block != NULL);

    // Decode color.
    color.decodeBlock(block, d3d9);

    // Decode alpha.
    alpha.decodeBlock(block, d3d9);
}

void BlockDXT5::decodeBlockNV5x(ColorBlock * block) const
{
    nvDebugCheck(block != NULL);

    // Decode color.
    color.decodeBlockNV5x(block);

    // Decode alpha.
    alpha.decodeBlock(block);
}

/// Flip DXT5 block vertically.
void BlockDXT5::flip4()
{
    alpha.flip4();
    color.flip4();
}

/// Flip half DXT5 block vertically.
void BlockDXT5::flip2()
{
    alpha.flip2();
    color.flip2();
}


/// Decode ATI1 block.
void BlockATI1::decodeBlock(ColorBlock * block, bool d3d9/*= false*/) const
{
    uint8 alpha_array[8];
    alpha.evaluatePalette(alpha_array, d3d9);

    uint8 index_array[16];
    alpha.indices(index_array);

    for(uint i = 0; i < 16; i++) {
        Color32 & c = block->color(i);
        c.b = c.g = c.r = alpha_array[index_array[i]];
        c.a = 255;
    }
}

/// Flip ATI1 block vertically.
void BlockATI1::flip4()
{
    alpha.flip4();
}

/// Flip half ATI1 block vertically.
void BlockATI1::flip2()
{
    alpha.flip2();
}


/// Decode ATI2 block.
void BlockATI2::decodeBlock(ColorBlock * block, bool d3d9/*= false*/) const
{
    uint8 alpha_array[8];
    uint8 index_array[16];

    x.evaluatePalette(alpha_array, d3d9);
    x.indices(index_array);

    for(uint i = 0; i < 16; i++) {
        Color32 & c = block->color(i);
        c.r = alpha_array[index_array[i]];
    }

    y.evaluatePalette(alpha_array, d3d9);
    y.indices(index_array);

    for(uint i = 0; i < 16; i++) {
        Color32 & c = block->color(i);
        c.g = alpha_array[index_array[i]];
        c.b = 0;
        c.a = 255;
    }
}

/// Flip ATI2 block vertically.
void BlockATI2::flip4()
{
    x.flip4();
    y.flip4();
}

/// Flip half ATI2 block vertically.
void BlockATI2::flip2()
{
    x.flip2();
    y.flip2();
}


void BlockCTX1::evaluatePalette(Color32 color_array[4]) const
{
    // Does bit expansion before interpolation.
    color_array[0].b = 0x00;
    color_array[0].g = col0[1];
    color_array[0].r = col0[0];
    color_array[0].a = 0xFF;

    color_array[1].r = 0x00;
    color_array[1].g = col0[1];
    color_array[1].b = col1[0];
    color_array[1].a = 0xFF;

    color_array[2].r = 0x00;
    color_array[2].g = (2 * color_array[0].g + color_array[1].g) / 3;
    color_array[2].b = (2 * color_array[0].b + color_array[1].b) / 3;
    color_array[2].a = 0xFF;

    color_array[3].r = 0x00;
    color_array[3].g = (2 * color_array[1].g + color_array[0].g) / 3;
    color_array[3].b = (2 * color_array[1].b + color_array[0].b) / 3;
    color_array[3].a = 0xFF;
}

void BlockCTX1::decodeBlock(ColorBlock * block) const
{
    nvDebugCheck(block != NULL);

    // Decode color block.
    Color32 color_array[4];
    evaluatePalette(color_array);

    // Write color block.
    for( uint j = 0; j < 4; j++ ) {
        for( uint i = 0; i < 4; i++ ) {
            uint idx = (row[j] >> (2 * i)) & 3;
            block->color(i, j) = color_array[idx];
        }
    }	
}

void BlockCTX1::setIndices(int * idx)
{
    indices = 0;
    for(uint i = 0; i < 16; i++) {
        indices |= (idx[i] & 3) << (2 * i);
    }
}


/// Decode BC6 block.
void BlockBC6::decodeBlock(Vector4 colors[16]) const
{
    ZOH::Tile tile(4, 4);
    ZOH::decompress((const char *)data, tile);

    // Convert ZOH's tile struct to Vector3, and convert half to float.
    for (uint y = 0; y < 4; ++y)
    {
        for (uint x = 0; x < 4; ++x)
        {
            uint16 rHalf = ZOH::Tile::float2half(tile.data[y][x].x);
            uint16 gHalf = ZOH::Tile::float2half(tile.data[y][x].y);
            uint16 bHalf = ZOH::Tile::float2half(tile.data[y][x].z);
            colors[y * 4 + x].x = to_float(rHalf);
            colors[y * 4 + x].y = to_float(gHalf);
            colors[y * 4 + x].z = to_float(bHalf);
            colors[y * 4 + x].w = 1.0f;
        }
    }
}


/// Decode BC7 block.
void BlockBC7::decodeBlock(ColorBlock * block) const
{
    AVPCL::Tile tile(4, 4);
    AVPCL::decompress((const char *)data, tile);

    // Convert AVPCL's tile struct back to NVTT's.
    for (uint y = 0; y < 4; ++y)
    {
        for (uint x = 0; x < 4; ++x)
        {
            Vector4 rgba = tile.data[y][x];
            // Note: decoded rgba values are in [0, 255] range and should be an integer,
            // because BC7 never uses more than 8 bits per channel.  So no need to round.
            block->color(x, y).setRGBA(uint8(rgba.x), uint8(rgba.y), uint8(rgba.z), uint8(rgba.w));
        }
    }
}


/// Flip CTX1 block vertically.
inline void BlockCTX1::flip4()
{
    swap(row[0], row[3]);
    swap(row[1], row[2]);
}

/// Flip half CTX1 block vertically.
inline void BlockCTX1::flip2()
{
    swap(row[0], row[1]);
}




Stream & nv::operator<<(Stream & stream, BlockDXT1 & block)
{
    stream << block.col0.u << block.col1.u;
    stream.serialize(&block.indices, sizeof(block.indices));
    return stream;
}

Stream & nv::operator<<(Stream & stream, AlphaBlockDXT3 & block)
{
    stream.serialize(&block, sizeof(block));
    return stream;
}

Stream & nv::operator<<(Stream & stream, BlockDXT3 & block)
{
    return stream << block.alpha << block.color;
}

Stream & nv::operator<<(Stream & stream, AlphaBlockDXT5 & block)
{
    stream.serialize(&block, sizeof(block));
    return stream;
}

Stream & nv::operator<<(Stream & stream, BlockDXT5 & block)
{
    return stream << block.alpha << block.color;
}

Stream & nv::operator<<(Stream & stream, BlockATI1 & block)
{
    return stream << block.alpha;
}

Stream & nv::operator<<(Stream & stream, BlockATI2 & block)
{
    return stream << block.x << block.y;
}

Stream & nv::operator<<(Stream & stream, BlockCTX1 & block)
{
    stream.serialize(&block, sizeof(block));
    return stream;
}

Stream & nv::operator<<(Stream & stream, BlockBC6 & block)
{
    stream.serialize(&block, sizeof(block));
    return stream;
}

Stream & nv::operator<<(Stream & stream, BlockBC7 & block)
{
    stream.serialize(&block, sizeof(block));
    return stream;
}