Unexpected behaviour of projectTexture!

Scripting Issues
1

Hi,
Just noticed a weird behaviour of projectTexture.
Look at the following example: I load two pandas into a scene and have a projector set in order to project a texture onto the bottom part of Panda1 (at least that’s the intent :wink: ).

What happens is that:
(1) Panda1 gets fully illuminated by the projector
(2) Panda2 who stands completely out of the projector frustum gets illuminated too!

import direct.directbase.DirectStart
from direct.actor import Actor
from pandac.PandaModules import *
from direct.showbase.DirectObject import DirectObject

class World(DirectObject):
   def __init__(self):
      # load and position PANDAS into scene
      panda1 = Actor.Actor('panda.egg')
      panda1.setScale(0.8)
      panda1.reparentTo(render)
      panda1.setPos(0, 0, 0)

      panda2 = Actor.Actor('panda.egg')
      panda2.setScale(0.8)
      panda2.reparentTo(render)
      panda2.setPos(5, 15, 0)

      # prepare texture projector
      proj = render.attachNewNode(LensNode('proj'))
      lens = PerspectiveLens()
      proj.node().setLens(lens)
      proj.reparentTo(render)
      proj.setPos(-6, 0, 3.5)
      proj.setHpr(-90, 0, 0)
      proj.node().showFrustum()

      # texture to be projected onto part of Panda1
      tex = loader.loadTexture('maps/envir-bamboo.png')
      ts  = TextureStage('ts')

      # now project!
      panda1.projectTexture(ts, tex, proj)
      panda2.projectTexture(ts, tex, proj)

w =   World()
run()

Any explanation???

2

I believe the texture will wrap even outside of the bounds of the lens. Try something like this to set outside the border black:

tex.setWrapU(Texture.WMBorderColor)
tex.setWrapV(Texture.WMBorderColor)
tex.setBorderColor(VBase4(0, 0, 0, 1))
3

Thank you so much! I won’t have been able to find the trick by myself reading the docs…

BTW. doing so generates another unexpected side effect: the remaining of the zones are now black (ie the initial textures have been cancelled). Is there any way to simply alter the area under the spot?

4

Use the MDecal mode, or so, and make the border colour transparent.

5

Thank you rdb,

For common interest here is the working code:

import direct.directbase.DirectStart
from direct.actor import Actor
from pandac.PandaModules import *
from direct.showbase.DirectObject import DirectObject

class World(DirectObject):
   def __init__(self):
      # load and position PANDAS into scene
      panda1 = Actor.Actor('panda.egg')
      panda1.setScale(0.8)
      panda1.reparentTo(render)
      panda1.setPos(0, 0, 0)

      panda2 = Actor.Actor('panda.egg')
      panda2.setScale(0.8)
      panda2.reparentTo(render)
      panda2.setPos(5, 15, 0)

      # prepare texture projector
      proj = render.attachNewNode(LensNode('proj'))
      lens = PerspectiveLens()
      proj.node().setLens(lens)
      proj.reparentTo(render)
      proj.setPos(-6, 0, 3.5)
      proj.setHpr(-90, 0, 0)
      proj.node().showFrustum()

      # texture to be projected onto part of Panda1
      tex = loader.loadTexture('maps/envir-bamboo.png')
      ts  = TextureStage('ts')
      ts.setSort(1)
      ts.setMode(TextureStage.MDecal)

      tex.setWrapU(Texture.WMBorderColor)
      tex.setWrapV(Texture.WMBorderColor)
      tex.setBorderColor(VBase4(0, 0, 0, 0))
	  
      # now project!
      panda1.projectTexture(ts, tex, proj)
      panda2.projectTexture(ts, tex, proj) # panda2 is not hit by the ray!

w =   World()
run()