Hmm it works but the problem is it is always giving a positive angle because of Squareing and Squarerooting. I worked out a similar problem before so i will work this one out. It's just a matter of comparing signs of the vectors. Thanks Stevie!
Here's the code i have now(mess left over from previous tests):
Use WASDFC to move camera, and insert,home,pgup,pgdn,delete,end to move the 4th vertex.
Here's the code i have now(mess left over from previous tests):
Use WASDFC to move camera, and insert,home,pgup,pgdn,delete,end to move the 4th vertex.
Open in online IDEGraphics3D 800,600,0,2 Global vectorx# Global vectory# Global vectorz# Global vectorw# Const UPS=60 cam=CreateCamera() PositionEntity cam, 0,5,-15 l=CreateLight() period=1000/UPS time=MilliSecs()-period v1=CreateSphere() ScaleEntity v1,0.5,0.5,0.5 v2=CreateSphere() ScaleEntity v2,0.5,0.5,0.5 v3=CreateSphere() ScaleEntity v3,0.5,0.5,0.5 v4=CreateSphere() ScaleEntity v4,0.5,0.5,0.5 cp1=CreateSphere();cross product marker ScaleEntity cp1,0.5,0.5,0.5 EntityColor cp1, 0,0,250 cp2=CreateSphere() ScaleEntity cp2,0.5,0.5,0.5 EntityColor cp2, 0,0,250 smesh = CreateMesh() ssurf = CreateSurface(smesh) v1x#=-6;left v1y#=4 v1z#=2 v2x#=0;middle front v2y#=1 v2z#=4 v3x#=0;middle back v3y#=1 v3z#=0 v4x#=6;right v4y#=1 v4z#=2 v1v = AddVertex (ssurf, v1x,v1y,v1z) v2v = AddVertex (ssurf, v2x,v2y,v2z) v3v = AddVertex (ssurf, v3x,v3y,v3z) v4v = AddVertex (ssurf, v4x,v4y,v4z) AddTriangle (ssurf, v1v,v2v,v3v) AddTriangle (ssurf, v2v,v4v,v3v) PositionEntity v1, v1x,v1y,v1z PositionEntity v2, v2x,v2y,v2z PositionEntity v3, v3x,v3y,v3z PositionEntity v4, v4x,v4y,v4z Repeat Repeat elapsed=MilliSecs()-time Until elapsed ticks=elapsed/period tween#=Float(elapsed Mod period)/Float(period) msp# = 0.2 If KeyDown(17) Then MoveEntity cam, 0,0,msp If KeyDown(31) Then MoveEntity cam, 0,0,-msp If KeyDown(33) Then MoveEntity cam, 0,msp,0 If KeyDown(46) Then MoveEntity cam, 0,-msp,0 If KeyDown(32) Then MoveEntity cam, msp,0,0 If KeyDown(30) Then MoveEntity cam, -msp,0,0 If KeyDown (203) Then TurnEntity cam, 0,msp*5,0 If KeyDown (205) Then TurnEntity cam, 0,-msp*5,0 If KeyDown (200) Then TurnEntity cam, msp*5,0,0 If KeyDown (208) Then TurnEntity cam, -msp*5,0,0 If KeyDown (199) Then v4y = v4y + msp If KeyDown (207) Then v4y = v4y - msp If KeyDown (210) Then v4z = v4z + msp If KeyDown (201) Then v4z = v4z - msp If KeyDown (209) Then v4x = v4x + msp If KeyDown (211) Then v4x = v4x - msp ;update verts VertexCoords ssurf, v4v,v4x,v4y,v4z ;update spheres representing verts PositionEntity v1, v1x,v1y,v1z PositionEntity v2, v2x,v2y,v2z PositionEntity v3, v3x,v3y,v3z PositionEntity v4, v4x,v4y,v4z ax#=v1x-v2x ay#=v1y-v2y az#=v1z-v2z bx#=v1x-v3x by#=v1y-v3y bz#=v1z-v3z CrossProduct(ax,ay,az,bx,by,bz) t1vx#=vectorx t1vy#=vectory t1vz#=vectorz ax#=v4x-v3x ay#=v4y-v3y az#=v4z-v3z bx#=v4x-v2x by#=v4y-v2y bz#=v4z-v2z CrossProduct(ax,ay,az,bx,by,bz) t2vx#=vectorx t2vy#=vectory t2vz#=vectorz px# = t1vx py# = t1vy pz# = t1vz qx# = t2vx qy# = t2vy qz# = t2vz MagP# = Sqr( px * px + py * py + pz * pz ) MagQ# = Sqr( qx * qx + qy * qy + qz * qz ) Theta# = ACos( ( px*qx + py*qy + pz*qz ) / ( MagP * MagQ ) ) wtf=False If t1vx <= 0 And t2vx > 0 Then wtf=True ElseIf t1vx >= 0 And t2vx < 0 Then wtf=True ElseIf t1vy <= 0 And t2vy > 0 Then wtf=True ElseIf t1vy >= 0 And t2vy < 0 Then wtf=True ElseIf t1vz <= 0 And t2vz > 0 Then wtf=True ElseIf t1vz >= 0 And t2vz < 0 Then wtf=True EndIf If Theta = NaN Then djhfsdf$="No Edge" Else djhfsdf$="Edge" End If ;update the cross product results PositionEntity cp1, v1x+t1vx,v1y+t1vy,v1z+t1vz PositionEntity cp2, v4x+t2vx,v4y+t2vy,v4z+t2vz ;show projected lines of cross product CameraProject (cam, v1x,v1y,v1z) p1x=ProjectedX() p1y=ProjectedY() CameraProject (cam, v1x+t1vx,v1y+t1vy,v1z+t1vz) pt1x=ProjectedX() pt1y=ProjectedY() CameraProject (cam, v4x,v4y,v4z) p2x=ProjectedX() p2y=ProjectedY() CameraProject (cam, v4x+t2vx,v4y+t2vy,v4z+t2vz) pt2x=ProjectedX() pt2y=ProjectedY() For k=1 To ticks time=time+period If KeyHit(1) End UpdateWorld Next RenderWorld tween Color 255,255,255 Text 10,10, t1vx + ", " + t1vy + ", " + t1vz Text 10,20, t2vx + ", " + t2vy + ", " + t2vz Text 10,30, Theta Text 10,40, djhfsdf Text 10,50, "wtf:" + wtf Color 255,00,0 ;Line p1x,p1y,pt1x,pt1y ;Line p2x,p2y,pt2x,pt2ya Flip Forever Function TriangleNormal#(Ax#,Ay#,Az#,Bx#,By#,Bz#,Cx#,Cy#,Cz#) SubVector Bx#,By#,Bz#,Ax#,Ay#,Az# ux#=VectorX() uy#=VectorY() uz#=VectorZ() SubVector Cx#,Cy#,Cz#,Bx#,By#,Bz# vx#=VectorX() vy#=VectorY() vz#=VectorZ() CrossProduct vx#,vy#,vz#,ux#,uy#,uz# ;Normalize vectorx,vectory,vectorz Return Ax#*vectorx+Ay#*vectory+Az#*vectorz End Function Function VectorX#() Return vectorx End Function Function VectorY#() Return vectory End Function Function VectorZ#() Return vectorz End Function Function VectorW#() Return vectorw End Function Function SubVector(Ax#,Ay#,Az#,Bx#,By#,Bz#) vectorx#=ax#-bx# vectory#=ay#-by# vectorz#=az#-bz# End Function Function Normalize(nx#,ny#,nz#) If nx=0 And ny=0 And nz=0 Return m#=Magnitude(nx#,ny#,nz#) vectorx#=nx#/m# vectory#=ny#/m# vectorz#=nz#/m# End Function Function CrossProduct(Ax#,Ay#,Az#,Bx#,By#,Bz#) vectorx#=Ay#*Bz#-Az#*By# vectory#=Az#*Bx#-Ax#*Bz# vectorz#=Ax#*By#-Ay#*Bx# End Function Function Magnitude(nx#,ny#,nz#) m#= Sqr( (nx*nx) + (ny*ny) + (nz*nz) ) Return m# End Function