For each 2 clip space vertices output by the vertex shader draw a line connecting the 2 points. If we had points A,B,C,D,E,F then we'd get 3 lines. Read more
屏幕上只画出一条线,是因为 LINES 模式下,每两个顶点之间只画一条线,点不会被复用,而我们传入了3个点,所以只画出一条线,比如有 A,B,C,D,E,F 六个顶点,那么只画出 AB,CD,EF 两条线。阅读更多