I hate the game :) However the ball bounce stuff was all worked out here some time ago by the likes of SSwift. Still on the forums if you search for it. I have changed your code to include it, and tried adding paddle forces, but that bit needs improving.
Open in online IDEGraphics3D 640,480,16,1 HidePointer() camera=CreateCamera() light=CreateLight() LightColor light,100,100,100 RotateEntity light,180,0,0 Const CUBE_COL=1 Const SPHERE_COL=2 ;create ball Global ball=CreateSphere(12) ScaleEntity ball,3,3,3 EntityColor ball,100,100,255 EntityShininess ball,.5 maxballspd#=5 ;create paddle Global p1=CreateCube() ScaleEntity p1,20,3,2 EntityColor p1,200,200,0 ;setup Collisions table EntityType ball,SPHERE_COL EntityType p1, CUBE_COL Collisions SPHERE_COL,CUBE_COL,2,2 arena=CreateCube() EntityColor arena,200,100,0 FlipMesh arena : ScaleEntity arena,200,150,5 EntityType arena,CUBE_COL Local vx#=2,vy#=2 While Not KeyHit(1) x1#=x1#+MouseXSpeed()*0.5 MoveMouse GraphicsWidth()/2,GraphicsHeight()/2 oldx#=EntityX(p1) If x1#<-180 Then x1#=-180 If x1#>180 Then x1#=180 PositionEntity p1,x1#,122,0 PFx#=EntityX(p1)-oldx PositionEntity camera,0,0,200 RotateEntity camera,180,0,0 If EntityCollided(ball,CUBE_COL) Then Nx# = CollisionNX(ball, 1) Ny# = CollisionNY(ball, 1) ; Compute the dot product of the entity's motion vector and the normal of the surface collided with. VdotN# = Vx# * Nx# + Vy# * Ny# ; Calculate the normal force. NFx# = -2.0 * Nx# * VdotN# NFy# = -2.0 * Ny# * VdotN# ; Add the normal force to the direction vector. ; if coll with paddle include some paddle force If CollisionEntity(ball,1)=p1 Then Vx# = Vx# + NFx# + PFx#*0.5 Vy# = Vy# + NFy# - Abs(PFx#*0.1) Else Vx# = Vx# + NFx# Vy# = Vy# + NFy# EndIf EndIf ;limit ballspeed ballspd# = Sqr(Vx# * Vx# + Vy# * Vy#) If ballspd# > maxballspd# Then Vx# = Vx# / ballspd# * maxballspd# Vy# = Vy# / ballspd# * maxballspd# EndIf TranslateEntity ball,Vx,Vy,0 PositionEntity ball,EntityX(ball),EntityY(ball),0 ; stay at the same Z UpdateWorld RenderWorld Flip Wend End