PhysicsRayNY# ( world )

Parameters

world - physics-world handle returned by CreatePhysicsWorld

Description

Returns the Y component of the last cast hit's surface normal.

One component of the unit surface normal - see PhysicsRayNX for the family overview. For a downward ground probe this reads the slope: close to 1 is flat, walkable ground, smaller values mean steeper terrain.

Valid only while a hit is stored: a miss clears the result and the getters raise a runtime error, so check the cast's returned handle first.

Requires Extended mode.

See also: PhysicsRayCast, PhysicsRayNX, PhysicsRayNZ, PhysicsRayY, PhysicsRayFraction.

Example

; PhysicsRayNY Example
; --------------------
; Requires Extended mode.

Graphics3D 640,480,0,2
SetBuffer BackBuffer()

Const PHYSICS_STATIC=0

camera=CreateCamera()
PositionEntity camera,0,7,-8
RotateEntity camera,30,0,0

light=CreateLight()
RotateEntity light,45,-30,0
AmbientLight 50,50,50

world=CreatePhysicsWorld()

; A ring of static pillars for the ray to hit
For i=1 To 5
    pillar=CreateCylinder()
    ScaleEntity pillar,0.5,1.5,0.5
    PositionEntity pillar,Cos(i*72)*(2.5+i*0.5),1.5,Sin(i*72)*(2.5+i*0.5),True
    EntityColor pillar,80,160,255
    pillar_body=CreatePhysicsBody(world,pillar,PHYSICS_STATIC)
    pillar_shape=PhysicsBodyCapsule(pillar_body,1,3,0)
Next

; The ray emitter at the centre of the scene
emitter=CreateSphere(8)
ScaleEntity emitter,0.3,0.3,0.3
PositionEntity emitter,0,1,0,True
EntityColor emitter,255,255,255

; A thin cylinder visualises the ray itself
beam=CreateCylinder(8)
EntityColor beam,255,120,70

; Red marker for the hit point
marker=CreateSphere(8)
ScaleEntity marker,0.15,0.15,0.15
EntityColor marker,255,60,60
HideEntity marker

angle#=0
ray_len#=9

While Not KeyDown(1)

    ; A / D keys sweep the ray around the emitter
    If KeyDown(30) Then angle=angle-1.5
    If KeyDown(32) Then angle=angle+1.5
    dx#=Cos(angle)*ray_len
    dz#=Sin(angle)*ray_len

    ; Cast the ray and read the hit data back
    hit_shape=PhysicsRayCast(world,0,1,0,dx,0,dz)
    If hit_shape<>0
        hit_x#=PhysicsRayX(world)
        hit_y#=PhysicsRayY(world)
        hit_z#=PhysicsRayZ(world)
        normal_x#=PhysicsRayNX(world)
        normal_y#=PhysicsRayNY(world)
        normal_z#=PhysicsRayNZ(world)
        fraction#=PhysicsRayFraction(world)
        beam_len#=fraction*ray_len
        PositionEntity marker,hit_x,hit_y,hit_z,True
        ShowEntity marker
    Else
        beam_len=ray_len
        HideEntity marker
    EndIf

    ; Stretch the beam cylinder from the emitter towards the hit
    ScaleEntity beam,0.05,beam_len/2,0.05
    AlignToVector beam,dx,0,dz,2
    PositionEntity beam,Cos(angle)*beam_len/2,1,Sin(angle)*beam_len/2,True

    ; Arrow keys move the camera
    If KeyDown(200) Then MoveEntity camera,0,0,0.1
    If KeyDown(208) Then MoveEntity camera,0,0,-0.1
    If KeyDown(203) Then TurnEntity camera,0,1,0
    If KeyDown(205) Then TurnEntity camera,0,-1,0

    RenderWorld

    Text 0,0,"A / D: sweep the ray   Arrow keys: move camera   Esc: exit"
    Text 0,20,"PhysicsRayNY(world) = "+normal_y
    Text 0,40,"Hit point: "+hit_x+", "+hit_y+", "+hit_z
    Text 0,60,"Normal: "+normal_x+", "+normal_y+", "+normal_z+"   Fraction: "+fraction

    Flip

Wend

FreePhysicsWorld world
End

Index

Blitz3D+ Command Reference

PhysicsRayNY# ( world )

Parameters

Description

Example