如何在SDL2中实现自定义混合模式？

#include <SDL2/SDL.h>

int main() {
    SDL_Init(SDL_INIT_VIDEO);

    SDL_Window* window = SDL_CreateWindow("SDL2 Custom Blend Mode", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_SHOWN);
    SDL_Renderer* renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);

    SDL_Texture* texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_TARGET, 800, 600);

    SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_ADD); // 设置混合模式为加法混合

    SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255); // 设置绘制颜色为黑色

    SDL_RenderClear(renderer); // 清空渲染器

    // 绘制图像到纹理上
    SDL_SetRenderTarget(renderer, texture);
    SDL_SetRenderDrawColor(renderer, 255, 0, 0, 128); // 设置绘制颜色为半透明红色
    SDL_RenderFillRect(renderer, NULL); // 绘制一个矩形填充整个纹理
    SDL_SetRenderTarget(renderer, NULL);

    SDL_RenderCopy(renderer, texture, NULL, NULL); // 将纹理复制到渲染器上

    SDL_RenderPresent(renderer); // 更新窗口显示

    SDL_Delay(3000); // 延迟3秒

    SDL_DestroyTexture(texture);
    SDL_DestroyRenderer(renderer);
    SDL_DestroyWindow(window);

    SDL_Quit();

    return 0;
}