Debugging Process

1. After tweaking the rendering of TGL_LINES and TGL_TRIANGLES several times, the first thing I did was to determine that this bug only occurs during the depth testing of TGL_LINES.
2. Keep only one TGL_LINES and one TGL_TRIANGLES element in the scene.
3. Then it was a constant process of interrupting the point to view the rendered pipeline, constantly troubleshooting every possible error. Until I troubleshooted to line 120 in the zline.cpp file (putPixel<kDepthWrite, kEnableScissor>(pixelOffset, color, x, y, z);), I started to go to see the change in the z-value before and after the z-value assignment.And I found out that if the TGL_LINES draws first, although the pixel value changed, but the z-values before and after did not change, so the problem must be in this line.
4. I then went further into this function call and found the problem with the bug.

The reason for this bug is that the TGL_LINES drawing passes the depth test and then updates the pixel values but not the depth values.