dump纹理数据

在排查渲染模块的渲染问题时，需要查看纹理数据是否正常，此时需要dump纹理数据来排查问题。

以 Android 平台为例，dump OES texture 和普通 texture 的代码

FILE* file_handler_{nullptr};
file_handler_ = fopen(yuv_file_name.c_str(), "wb");

static void save_texture(int texture_id, bool is_texture_2d, int width, int height, FILE* file_handler) {
    GLint old_fbo;
    glGetIntegerv(GL_FRAMEBUFFER_BINDING, &old_fbo);

    GLuint tmp_fbo;
    glGenFramebuffers(1, &tmp_fbo);
    glBindFramebuffer(GL_FRAMEBUFFER, tmp_fbo);

    if (is_texture_2d) {
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                               texture_id, 0);
    } else {
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_EXTERNAL_OES,
                               texture_id, 0);
    }
    std::unique_ptr<uint8_t []> outRgbaBuf(new uint8_t[width*height*4]);
    glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_BYTE, outRgbaBuf.get());
    {
        fwrite(outRgbaBuf.get(), 1, width * height * 4, file_handler);
    }
    glBindFramebuffer(GL_FRAMEBUFFER, old_fbo);
    glDeleteFramebuffers(1, &tmp_fbo);
}

参考：https://blog.csdn.net/weixin_43931399/article/details/106638116