axmol/core/renderer/backend/metal/UtilsMTL.h

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 Copyright (c) 2018-2019 Xiamen Yaji Software Co., Ltd.

 https://axys1.github.io/

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#pragma once

#include "../Macros.h"
#include "../Types.h"
#include "../PixelBufferDescriptor.h"
#import <Metal/Metal.h>
#include <functional>

NS_AX_BACKEND_BEGIN

class TextureBackend;

/**
 * @addtogroup _metal
 * @{
 */

/**
 * create and manager default depth and stencil attachment.
 * generate mipmaps.
 * read pixles from texture.
 */
struct UtilsMTL
{
    /*
     * init GPU texture supported formats
     */
    static void initGPUTextureFormats();

    /**
     * Update default color attachment texture.
     * @param texture Specifies the texture to be setted to the color attachemnt.
     */
    static void updateDefaultColorAttachmentTexture(id<MTLTexture> texture);
    static void resizeDefaultAttachmentTexture(std::size_t width, std::size_t height);

    /**
     * Get the default combined depth and stencil texture.
     * @return The default combined depth and stencil texture.
     */
    static id<MTLTexture> getDefaultDepthStencilTexture();

    /**
     * Convert backend::PixelFormat to MTLPixelFormat.
     * @param textureFormat Specifies a pixel format to be converted.
     * @return A MTLPixelFormat.
     */
    static MTLPixelFormat toMTLPixelFormat(PixelFormat textureFormat);

    /**
     * Generate a complete set of mipmaps in given texture.
     * @param texture Specifies a texture to generate mipmap.
     */
    static void generateMipmaps(id<MTLTexture> texture);

    /**
     * Swizzle the iamge form the given format to MTLPixelFormatRGBA8Unorm.
     * @param image Specifies the image to be swizzled.
     * @param width Specifies the width of the image.
     * @param heigth Specifies the height of the image.
     * @param format Specifies the format of the image.
     */
    static void swizzleImage(unsigned char* image, std::size_t width, std::size_t height, MTLPixelFormat format);

private:
    static id<MTLTexture> createDepthStencilAttachmentTexture();

    static id<MTLTexture> _defaultColorAttachmentTexture;
    static id<MTLTexture> _defaultDepthStencilAttachmentTexture;
};

// end of _metal group
/// @}
NS_AX_BACKEND_END