What's going on with coronas?

[VeTaL]

I'm trying to make this code works in LE 2.42 just to test it, but can see nothing

TCorona corona = CreateCorona(model);
SetCoronaRadius(corona, 10, 20);
PaintEntity(corona, LoadMaterial("abstract::flare1.mat"));

 

Also, this example also show me nothing

http://leadwerks.com/werkspace/index.php/topic/1158-billboards/page__view__findpost__p__10683

 

log:

Loading material "d:/ik/ikdemo/assets/models/environment/corona/flare1.mat"...
Loading texture "d:/ik/ikdemo/assets/models/environment/corona/flare1.dds"...
Loading shader "zip::/ik/ikdemo/shaders.pak//corona.vert", "zip::/ik/ikdemo/shaders.pak//corona.frag"...
Loading shader "zip::/ik/ikdemo/shaders.pak//guide.vert", "zip::/ik/ikdemo/shaders.pak//editor/guide.frag"...
Loading shader "zip::/ik/ikdemo/shaders.pak//terrain/terrain.vert", "zip::/ik/ikdemo/shaders.pak//terrain/terrain.frag"...
Loading texture "incbin::noise.dds"...

[Marleys Ghost]

Before the data loss, I think Flexman and Paul had voiced concerns over a possible bug with coronas.

[Canardia]

You need a light for the corona, and you need to position the corona where the light is:

TLight lamp = CreatePointLight();
TCorona corona = CreateCorona(lamp);
MoveEntity(lamp, Vec3(0,2,2));
PositionEntity(corona, EntityPosition(lamp));
SetCoronaRadius(corona, 10, 20);
PaintEntity(corona, LoadMaterial("l:/lesdk541/sdk/models/entities/environment/corona/flare1.mat"));

[Flexman]

Coronas stopped appearing in the background world. The shaders they use haven't changed so it's likely a change in the engine. And culling can be an issue too. I only just noticed that one last night.

 

Avoid parenting them to objects in different worlds (or at all if you can avoid it).

 

Why is it needed to parent them to light sources now? They are handy for other uses.

[VeTaL]

I just wanted to see if i can use coronas to debug vertex/bones positions in a model.

 

TLight lamp = CreatePointLight();
TCorona corona = CreateCorona(lamp);
MoveEntity(lamp, EntityPosition(rightToe));
PositionEntity(corona, EntityPosition(lamp));
SetCoronaRadius(corona, 1, 5);
PaintEntity(corona, LoadMaterial("abstract::flare1.mat"));

Now i can see light, but i cant see corona... strange things are happen

[Canardia]

Coronas don't show when they are behind or inside a mesh.

[VeTaL]

Ah, ok.. bad idea to use them for debug

[Flexman]

Is it possible to disable culling for coronas?

 

I used to have coronas position at or near lights that are often near other entities. For explosions I can't position them at the point of the explosion as the vehicle I'm destroying occludes it, same goes for the emitter in the transparency world. A workaround is to 'lift' the flash over the vehicle, since it only lasts a few frames you don't notice.

[Josh]

That would mean if you were behind a building or something, you would see the corona right through it.

[Flexman]

That would mean if you were behind a building or something, you would see the corona right through it.

 

Would it? I thought geometry of the building would mask it if it was? Are they not depth tested if you specify that in the material, it must be because I have a huge corona that acts as a short flash and is correctly masked in the scene by trees, objects etc. unless the exact centre is behind something. As it is, it almost works perfectly for what I needed.

 

Maybe I don't quite fully appreciate how they work, they do have a neat auto-fade so they don't blink, nice touch that. Perhaps what I really need is just a straight billboard with alpha.

 

As a programmer I would like the option of having it show through a house or not via EntityOcclusionMode() but technically Coronas are not true entities.

 

Is it just a bounding box test?

[Josh]

Coronas work by performing an occlusion query to see whether they are visible or not. This allows them to shine through a masked texture, like a chain link fence, with per-pixel occlusion. No geometry tests are performed.

[Flexman]

Ahhh, ok interesting. Cheers.