GLKView，如何blitFrameBuffer，如果可能的话

Question

这是我的设置，宽度和高度是GLKView的界限*缩放

private func initFrameBuffer() -> GLuint {
    var framebuffer_id: GLuint = 0
    glGenFramebuffers(1, &framebuffer_id)
    glBindFramebuffer(GLenum(GL_FRAMEBUFFER), framebuffer_id)
    return framebuffer_id
}

private func initRenderBuffer(_ width: GLsizei, _ height: GLsizei) -> GLuint {
    var renderBuffer_id: GLuint = 0
    glGenRenderbuffers(1, &renderBuffer_id)
    glBindRenderbuffer(GLenum(GL_RENDERBUFFER), renderBuffer_id)
    glRenderbufferStorage(GLenum(GL_RENDERBUFFER), GLenum(GL_RGBA8), width, height)
    glFramebufferRenderbuffer(GLenum(GL_FRAMEBUFFER), GLenum(GL_COLOR_ATTACHMENT0), GLenum(GL_RENDERBUFFER), renderBuffer_id)
    return renderBuffer_id
}

func blitz() {
    glBindFramebuffer(GLenum(GL_FRAMEBUFFER), frameBuffer)
    bindDrawable()
    glBlitFramebuffer(0, 0, width, height, 0, 0, width, height, GLbitfield(GL_COLOR_BUFFER_BIT), GLenum(GL_LINEAR))
}

我在draw(_ rect)中调用了draw(_ rect)，没有发生任何事情，所以当我检查错误时，它会给我一个GL_INVALID_OPERATION。

我还尝试获取ios的id并手动绑定它，而不是调用bindDrawble()，这也失败了。

Answer 1

glBlitFramebuffer将当前绑定的GL_READ_FRAMEBUFFER复制到当前绑定的GL_DRAW_FRAMEBUFFER。绑定到目标GL_FRAMEBUFFER是同时将FBO绑定到GL_READ_FRAMEBUFFER和GL_DRAW_FRAMEBUFFER的快捷方式，所以您的blit是从framebuffer到framebuffer的，这是不允许的。