axmol/cocos/renderer/backend/Texture.cpp

/****************************************************************************
 Copyright (c) 2018-2019 Xiamen Yaji Software Co., Ltd.
 Copyright (c) 2020 c4games.com

 http://www.cocos2d-x.org

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
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 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

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 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 ****************************************************************************/
 
#include "Texture.h"
#include <cassert>
CC_BACKEND_BEGIN

#define byte(n) ((n) * 8)
#define bit(n) (n)
namespace
{
    // !!!FIXME: GPU supported compression texture formats, bpp could be ignore and doesn't to set, leave it=0
    // ASTC have float bpp, such as ASTC6x6 3.56 BPP
    static uint8_t computeBitsPerElement(PixelFormat textureFormat)
    {
        switch (textureFormat)
        {
            case PixelFormat::RGBA8888:
            case PixelFormat::BGRA8888:
                return byte(4);
            case PixelFormat::RGB888:
                return byte(3);
            case PixelFormat::RGBA4444:
                return byte(2);
            case PixelFormat::A8:
                return byte(1);
            case PixelFormat::I8:
                return byte(1);
            case PixelFormat::RGB565:
                return byte(2);
            case PixelFormat::RGB5A1:
                return byte(2);
            case PixelFormat::AI88:
                return byte(2);
            case PixelFormat::ATC_RGB:
                return bit(4);
            case PixelFormat::ATC_EXPLICIT_ALPHA:
                return byte(1);
            case PixelFormat::ATC_INTERPOLATED_ALPHA:
                return byte(1);
            case PixelFormat::PVRTC2:
                return bit(2);
            case PixelFormat::PVRTC2A:
                return bit(2);
            case PixelFormat::PVRTC4:
                return bit(4);
            case PixelFormat::PVRTC4A:
                return bit(4);
            case PixelFormat::S3TC_DXT1:
                return bit(4);
            case PixelFormat::S3TC_DXT3:
                return byte(1);
            case PixelFormat::S3TC_DXT5:
                return byte(1);
            case PixelFormat::MTL_BGR5A1:
                return byte(2);
            case PixelFormat::MTL_B5G6R5:
                return byte(2);
            case PixelFormat::MTL_ABGR4:
                return byte(2);
            case PixelFormat::D24S8:
#if (CC_TARGET_PLATFORM == CC_PLATFORM_IOS)
                //ios use MTLPixelFormatDepth32Float_Stencil8 as DepthStencil combined format, its 64 bits
                return byte(8);
#else
                //mac and opengl use Depth24_Stnicl8 combined format, its 32 bits
                return byte(4);
#endif
            default:
                return byte(0); //"textureFormat pixel size in bytes not defined!";
        }
        return 0;
    }
}

TextureBackend::~TextureBackend()
{}

void TextureBackend::updateTextureDescriptor(const cocos2d::backend::TextureDescriptor &descriptor, int /*index*/)
{
    _bitsPerElement = computeBitsPerElement(descriptor.textureFormat);
    _textureType = descriptor.textureType;
    _textureFormat = descriptor.textureFormat;
    _textureUsage = descriptor.textureUsage;
    _width = descriptor.width;
    _height = descriptor.height;
}

CC_BACKEND_END