Fixed Jeremy McGrath Supercross 2000: missing jauge line in menu #274
This game sets coordinates of lines vertices via modify_vtx.
modify_vtx set screen coordinates for the vertex.
Screen coordinates must be converted back to normalized device coordinates (NDC)
to apply viewport transformation. Unfortunately, the screen coordinates set are out of current viewport
and just clipped after transformation to NDC coordinates and viewport transformation.
Solution: use fullscreen viewport for modified vertex coordinates and
transform coordinates according to this viewport.
The game copies current frame buffer to the area, which initially allocated for depth buffer.
Game read camera data from that area, not from normal frame buffer.
That's why 'copy color buffer to RDRAM' option does not help there.
Special code needed to process that. Looks ugly, but works.
