axmol/core/base/ktxspec_v1.h

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 Copyright (c) 2019-present Axmol Engine contributors (see AUTHORS.md).

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#pragma once

#include <stdint.h>

#define KTX_V1_HEADER_SIZE 64

#define KTX_V1_MAGIC "KTX 11"

// ktxv1 header, refer to: https://www.khronos.org/registry/KTX/specs/1.0/ktxspec_v1.html
struct KTXv1Header
{
    struct InternalFormat
    {
        enum
        {
            // ETC1
            ETC1_RGB8   = 0x8D64,
            ETC1_ALPHA8 = ETC1_RGB8,
            // ETC2
            ETC2_R11                       = 0x9270,
            ETC2_SIGNED_R11                = 0x9271,
            ETC2_RG11                      = 0x9272,
            ETC2_SIGNED_RG11               = 0x9273,
            ETC2_RGB8                      = 0x9274,
            ETC2_SRGB8                     = 0x9275,
            ETC2_RGB8A1                    = 0x9276,
            ETC2_SRGB8_PUNCHTHROUGH_ALPHA1 = 0x9277,
            ETC2_RGBA8                     = 0x9278,
            // ATITC
            ATC_RGB_AMD                     = 0x8C92,
            ATC_RGBA_EXPLICIT_ALPHA_AMD     = 0x8C93,
            ATC_RGBA_INTERPOLATED_ALPHA_AMD = 0x87EE,
        };
    };

    // enum class BaseInternalFormat
    //{
    //    ETC2_R11    = 0x1903,
    //    ETC2_RG11   = 0x8227,
    //    ETC1_RGB8   = 0x1907,
    //    ETC1_ALPHA8 = ETC1_RGB8,
    //    ETC2_RGB8   = 0x1907,
    //    ETC2_RGB8A1 = 0x1908,
    //    ETC2_RGBA8  = 0x1908,
    //};

    uint8_t identifier[12];
    uint32_t endianness;
    uint32_t glType;
    uint32_t glTypeSize;
    uint32_t glFormat;
    uint32_t glInternalFormat;
    uint32_t glBaseInternalFormat;
    uint32_t pixelWidth;
    uint32_t pixelHeight;
    uint32_t pixelDepth;
    uint32_t numberOfArrayElements;
    uint32_t numberOfFaces;
    uint32_t numberOfMipmapLevels;
    uint32_t bytesOfKeyValueData;
};