godot/thirdparty/etc2comp/EtcBlock4x4EncodingBits.h

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/*
* Copyright 2015 The Etc2Comp Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <assert.h>
namespace Etc
{
// ################################################################################
// Block4x4EncodingBits
// Base class for Block4x4EncodingBits_XXXX
// ################################################################################
class Block4x4EncodingBits
{
public:
enum class Format
{
UNKNOWN,
//
RGB8,
RGBA8,
R11,
RG11,
RGB8A1,
//
FORMATS
};
static unsigned int GetBytesPerBlock(Format a_format)
{
switch (a_format)
{
case Format::RGB8:
case Format::R11:
case Format::RGB8A1:
return 8;
break;
case Format::RGBA8:
case Format::RG11:
return 16;
break;
default:
return 0;
break;
}
}
};
// ################################################################################
// Block4x4EncodingBits_RGB8
// Encoding bits for the RGB portion of ETC1, RGB8, RGB8A1 and RGBA8
// ################################################################################
class Block4x4EncodingBits_RGB8
{
public:
static const unsigned int BYTES_PER_BLOCK = 8;
inline Block4x4EncodingBits_RGB8(void)
{
assert(sizeof(Block4x4EncodingBits_RGB8) == BYTES_PER_BLOCK);
for (unsigned int uiByte = 0; uiByte < BYTES_PER_BLOCK; uiByte++)
{
auc[uiByte] = 0;
}
}
typedef struct
{
unsigned red2 : 4;
unsigned red1 : 4;
//
unsigned green2 : 4;
unsigned green1 : 4;
//
unsigned blue2 : 4;
unsigned blue1 : 4;
//
unsigned flip : 1;
unsigned diff : 1;
unsigned cw2 : 3;
unsigned cw1 : 3;
//
unsigned int selectors;
} Individual;
typedef struct
{
signed dred2 : 3;
unsigned red1 : 5;
//
signed dgreen2 : 3;
unsigned green1 : 5;
//
signed dblue2 : 3;
unsigned blue1 : 5;
//
unsigned flip : 1;
unsigned diff : 1;
unsigned cw2 : 3;
unsigned cw1 : 3;
//
unsigned int selectors;
} Differential;
typedef struct
{
unsigned red1b : 2;
unsigned detect2 : 1;
unsigned red1a : 2;
unsigned detect1 : 3;
//
unsigned blue1 : 4;
unsigned green1 : 4;
//
unsigned green2 : 4;
unsigned red2 : 4;
//
unsigned db : 1;
unsigned diff : 1;
unsigned da : 2;
unsigned blue2 : 4;
//
unsigned int selectors;
} T;
typedef struct
{
unsigned green1a : 3;
unsigned red1 : 4;
unsigned detect1 : 1;
//
unsigned blue1b : 2;
unsigned detect3 : 1;
unsigned blue1a : 1;
unsigned green1b : 1;
unsigned detect2 : 3;
//
unsigned green2a : 3;
unsigned red2 : 4;
unsigned blue1c : 1;
//
unsigned db : 1;
unsigned diff : 1;
unsigned da : 1;
unsigned blue2 : 4;
unsigned green2b : 1;
//
unsigned int selectors;
} H;
typedef struct
{
unsigned originGreen1 : 1;
unsigned originRed : 6;
unsigned detect1 : 1;
//
unsigned originBlue1 : 1;
unsigned originGreen2 : 6;
unsigned detect2 : 1;
//
unsigned originBlue3 : 2;
unsigned detect4 : 1;
unsigned originBlue2 : 2;
unsigned detect3 : 3;
//
unsigned horizRed2 : 1;
unsigned diff : 1;
unsigned horizRed1 : 5;
unsigned originBlue4 : 1;
//
unsigned horizBlue1: 1;
unsigned horizGreen : 7;
//
unsigned vertRed1 : 3;
unsigned horizBlue2 : 5;
//
unsigned vertGreen1 : 5;
unsigned vertRed2 : 3;
//
unsigned vertBlue : 6;
unsigned vertGreen2 : 2;
} Planar;
union
{
unsigned char auc[BYTES_PER_BLOCK];
unsigned long int ul;
Individual individual;
Differential differential;
T t;
H h;
Planar planar;
};
};
// ################################################################################
// Block4x4EncodingBits_A8
// Encoding bits for the A portion of RGBA8
// ################################################################################
class Block4x4EncodingBits_A8
{
public:
static const unsigned int BYTES_PER_BLOCK = 8;
static const unsigned int SELECTOR_BYTES = 6;
typedef struct
{
unsigned base : 8;
unsigned table : 4;
unsigned multiplier : 4;
unsigned selectors0 : 8;
unsigned selectors1 : 8;
unsigned selectors2 : 8;
unsigned selectors3 : 8;
unsigned selectors4 : 8;
unsigned selectors5 : 8;
} Data;
Data data;
};
// ################################################################################
// Block4x4EncodingBits_R11
// Encoding bits for the R portion of R11
// ################################################################################
class Block4x4EncodingBits_R11
{
public:
static const unsigned int BYTES_PER_BLOCK = 8;
static const unsigned int SELECTOR_BYTES = 6;
typedef struct
{
unsigned base : 8;
unsigned table : 4;
unsigned multiplier : 4;
unsigned selectors0 : 8;
unsigned selectors1 : 8;
unsigned selectors2 : 8;
unsigned selectors3 : 8;
unsigned selectors4 : 8;
unsigned selectors5 : 8;
} Data;
Data data;
};
class Block4x4EncodingBits_RG11
{
public:
static const unsigned int BYTES_PER_BLOCK = 16;
static const unsigned int SELECTOR_BYTES = 12;
typedef struct
{
//Red portion
unsigned baseR : 8;
unsigned tableIndexR : 4;
unsigned multiplierR : 4;
unsigned selectorsR0 : 8;
unsigned selectorsR1 : 8;
unsigned selectorsR2 : 8;
unsigned selectorsR3 : 8;
unsigned selectorsR4 : 8;
unsigned selectorsR5 : 8;
//Green portion
unsigned baseG : 8;
unsigned tableIndexG : 4;
unsigned multiplierG : 4;
unsigned selectorsG0 : 8;
unsigned selectorsG1 : 8;
unsigned selectorsG2 : 8;
unsigned selectorsG3 : 8;
unsigned selectorsG4 : 8;
unsigned selectorsG5 : 8;
} Data;
Data data;
};
}