is vertex visible ?

Sorry for double-posting, but I found an algo in the archive (by birdie) that determines CW/CCW for a 2d triangle. And it works:

 	;setup graphics
	Graphics3D 800, 600, 0, 2
	SetBuffer BackBuffer()
	
	;enable wireframe	
	WireFrame 1

	;create camera	
	camera = CreateCamera()
	MoveEntity camera, 0, 0, -5
	
	;create pivot for camera	
	campiv = CreatePivot()
	EntityParent camera, campiv
	
	;create cube	
	cube = CreateCube()
	UpdateNormals cube
	surf = GetSurface(cube, 1)
	
	Repeat
		
		;turn camera
		TurnEntity campiv, 0, 1, 0
		RenderWorld
		
		;loop through all triangles		
		For i = 0 To CountTriangles(surf) - 1
		
			;get vertices from triangle			
			v0 = TriangleVertex(surf, i, 0)		
			v1 = TriangleVertex(surf, i, 1)
			v2 = TriangleVertex(surf, i, 2)
			
			;get coordinates from vertices
			v0x# = VertexX(surf, v0)
			v0y# = VertexY(surf, v0)
			v0z# = VertexZ(surf, v0)
			
			v1x# = VertexX(surf, v1)
			v1y# = VertexY(surf, v1)
			v1z# = VertexZ(surf, v1)
			
			v2x# = VertexX(surf, v2)
			v2y# = VertexY(surf, v2)
			v2z# = VertexZ(surf, v2)
			
			;project vertices to screen			
			CameraProject camera, v0x, v0y, v0z
			v0x# = ProjectedX()
			v0y# = ProjectedY()
							
			CameraProject camera, v1x, v1y, v1z
			v1x# = ProjectedX()
			v1y# = ProjectedY()
							
			CameraProject camera, v2x, v2y, v2z
			v2x# = ProjectedX()
			v2y# = ProjectedY()
			
			;check if triangle is CW			
			If ((v0x - v1x) * (v2y - v1y) - (v0y - v1y) * (v2x - v1x)) < 0 Then
				
				;if it is, draw vertices
				Color 255, 0, 0
				Oval v0x - 1, v0y - 1, 3, 3
				Oval v1x - 1, v1y - 1, 3, 3
				Oval v2x - 1, v2y - 1, 3, 3
				
			End If
			
		Next
							
		Flip
		
	Until KeyHit(1)
	
	End

Still, it is not exactly what I want. I think I should try projecting every triangle, and then checking if the projected vertex coordinate is behind any of the triangles from the cameras view.