OpenGLES到金属迁移

Question

在OpenGLES中，裁剪和裁剪很简单。通过使用直通着色器缩放像素缓冲区，然后设置

glViewport(0, 0, srcDimensions.width, srcDimensions.height)

然后设置纹理＆amp;顶点坐标使用cropRect，然后设置

进行适当的坐标

        glActiveTexture( GLenum(GL_TEXTURE0) )
        glBindTexture( CVOpenGLESTextureGetTarget( dstTexture! ), CVOpenGLESTextureGetName( dstTexture! ) )
        glTexParameteri( GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_MIN_FILTER), GL_LINEAR )
        glTexParameteri( GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_MAG_FILTER), GL_LINEAR )
        glTexParameteri( GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_WRAP_S), GL_CLAMP_TO_EDGE )
        glTexParameteri( GLenum(GL_TEXTURE_2D), GLenum(GL_TEXTURE_WRAP_T), GL_CLAMP_TO_EDGE )
        glFramebufferTexture2D( GLenum(GL_FRAMEBUFFER), GLenum(GL_COLOR_ATTACHMENT0), CVOpenGLESTextureGetTarget( dstTexture! ), CVOpenGLESTextureGetName( dstTexture! ), 0 ) 

Metal中同样的东西的等效设置是什么？