Problems in spotlight

Scripting Issues
1

There are always problems in spotlight. I have set various configurations of spotlight, but still can’t form a spot! Why is that? This is my code, and renderings. In addition, there are model files.

import direct.directbase.DirectStart  
from panda3d.core import *
from direct.task import Task
try:
    window = WindowProperties()
    window.setTitle('House')
    window.setSize(1200, 800)
    base.win.requestProperties(window)
    base.setBackgroundColor(0.4, 0.6, 0.7, 0.5)
    envir = loader.loadModel('house')
    envir.reparentTo(render)
    base.cam.setPos(0, -29000, 7500)
    base.cam.setHpr(0, -15, 0)   
    sun = loader.loadModel('sphere')
    sun.setColor((0.7, 0.6, 0.4, 1))
    sun.setScale(300)
    sun.setPos(-6510, -6000, 0)
    sunLight = sun.attachNewNode(DirectionalLight("SUN"))
    sunLight.setH(-60)
    sunLight.node().setColor((1, 1, 1, 1))
    sunLight.node().setShadowCaster(True)
    sunLight.node().show_frustum()
    sunLight.node().setScene(render)
    sunLight.node().getLens().setFilmSize(60, 80)
    sunLight.node().getLens().setNearFar(10, 30)
    render.setShaderAuto(True)
    sunLightHelper = render.attachNewNode('change')
    sunLightHelper.setPos(0, 0, 0)
    sun.reparentTo(sunLightHelper)
    sunLightHelper.hprInterval(20, (0, 0, 360)).loop()
    #envir.setLight(sunLight)
    lamp = loader.loadModel('lamp')
    lamp.reparentTo(render)
    lamp.getChild(0).setHpr(90, 90, 0)
    lamp.setPos(-1000, -800, 0)
    lamp.setScale(350)
    lampLight = envir.attachNewNode(PointLight("lamp"))
    lampLight.node().setColor((1,1,1,1))
    lampLight.node().setAttenuation((0,0,0.0000004))
    lampLight.setPos(-1000, -800, 1800)
    envir.setLight(lampLight)
    state = {"ON": False}
    def Change_state(direction, sated):
        state[direction] = sated
        if state["ON"]:
            envir.setLight(lampLight)
        else:
            envir.setLightOff(lampLight)
    base.accept('q', Change_state, ['ON', True])
    base.accept('w', Change_state, ['ON', False])
    base.accept('FW', Change_state, ['ON', True])
    base.accept('KW', Change_state, ['ON', False])
    def autoLight(task):
        if not(sunLightHelper.getR() > 20 and sunLightHelper.getR() < 160):
            messenger.send('FW')
        else:
            messenger.send('KW')
        return task.cont
    taskMgr.add(autoLight, 'auto')
    spota = loader.loadModel('spot')
    spota.reparentTo(render)
    spota.setScale(10)
    spota.setPos(0,4000,10)
    spotLight = spota.attachNewNode(Spotlight("spot"))
    spotLight.node().setColor((0.8, 0.4, 0.7, 1))
    #spotLight.node().setAttenuation((0, 0.0003, 0))
    lens = PerspectiveLens()
    lens.setFov(2)
    spotLight.node().setLens(lens)
    spotLight.node().showFrustum()
    spotLight.setPos(0, -500, 1000)
    spotLight.setHpr(0,-90,0)
    spotLight.node().getLens().setNearFar(200, 350)
    spotLight.node().getLens().setFilmSize(10)
    spotLight.node().setScene(render)
    spotLight.node().setExponent(20)
    #spotLight.hprInterval(10, (-180, 0, 0), (-60, 0, 0)).loop()
    envir.setLight(spotLight)
    base.run() 
except Exception as e:
    print(e)
    base.destroy()

image
image691×649 36.8 KB

lamp.egg (22.1 KB)
sphere.egg.pz (48.5 KB)

2

One thing that I notice is that you place your spotlight at a z-position of 1000, but give its lens a far-distance of only 350. It may simply be that the spotlight is too far from the environment for the light to be visible.

A quick way to test this might be to lower your spotlight to about 100 (relative to the environment), and see whether the light becomes visible.

I do also note that you have a scale applied to the parent-node of the spotlight. I honestly don’t know what effect that might have; it might be worth testing whether removing that scaling-factor changes anything.

Finally, I don’t know the size of your environment; are you sure that having the spotlight’s parent-node be placed at a y-coordinate of 4000 and the spotlight itself be placed at a y-coordinate of -500 relative to that parent-node results in the the spotlight being located within the environment?

4

It seems that the key to the problem is to find out the scaling problem at the parent node. What’s more, I found that the spotlight only follows the scaling of the parent node, and what I reset later doesn’t work. In this case, how can I use the setting method to modify the scaling of spotlight?
This is the effect of this situation

    spotLight.node().getLens().setFilmSize(0.6,0.8)

image
image1078×675 50.2 KB

This is the effect of another situation

    spotLight.node().getLens().setFilmSize(30,40)

image
image1048×556 52.2 KB

5

It should, I think, be possible to set a counter-scale on the spotlight that negates the scaling of its parent-node. Note that because scales (like positions and rotations) are compounded through parent-child relationships, you can’t just set the final scale that you want the spotlight to have; you have to set a scale that also takes into account the scaling of the parent-node (and any nodes above it that might also be scaled).

So, for example, if you want the spotlight to have an effective scale of 1 (i.e. no scale), and the parent has a scale of 5, you would have to set the spotlight’s scale to 0.2 (i.e. 1/5).

That said, I think that the easier solution might be to just have the spotlight no longer be a child of a scaled node.

Now, I imagine that you want the spotlight to move with the lamp-model held in the parent-node. Thus I see two potential solutions, offhand:

First: You could give the lamp-model and the spotlight a common parent NodePath, and use that common parent to place them. Thus the lamp-model would no longer be the parent of the spotlight, and therefore it’s scaling would not affect the light.

Second: When you load a model, the model itself is usually not held in the NodePath that is returned from “loadModel”, but instead in one or more child-NodePaths. Thus, you could potentially set your scale on those child-NodePaths, rather than the NodePath returned by “loadModel”, allowing you to keep your current parentage without having a scaling factor apply to the spotlight.

6

Well, I see, thank you very much!

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