Vegetation

[tournamentdan]

1. What are the polygon or vertices limit for a single instance?

 

2. Are there only two LOD for each instance? (billboard and regular model)

 

3. In this system can we add more LOD?

 

4. How are animations handled for the instanced vegetation?

 

5. If I have trees that are rigged, can I use different animations at the same time on identical instances?

[martyj]

I am pretty sure we can't animate vegetation. Just with my experience of it.

 

You may be able to find a way to animate all the vegetation at once, but probably not a specific instance. If you can run some code before and after the vegetation render sequence that would change the Model uniform maybe.

 

Are you thinking of an animation for wind?

[martyj]

Actually in C++ it looks easy to animate.

 

In class cope

VegitationAnimationFrame = 0;

 

In your update loop before rendering.

 

int searchIndex = 2; // Hard coded on the layer you wish to animate

VegitationLayer* foundLayer = NULL;

list<VegitationLayer*> layers = World->terrain->vegetationlayers

for(std::list<VegitationLayer*>::iterator it=layers.begin(), i=0; it != layers.end(); it++, i++)

{

if(i == searchIndex)

{

foundLayer = *it;

break;

}

}

 

if(foundLayer != NULL)

{

Model* model = foundLayer->model;

// Animate with the Entity SetAnimationFrame function

}

[Josh]

1. What are the polygon or vertices limit for a single instance?

Around 65,000.

 

2. Are there only two LOD for each instance? (billboard and regular model)

Yes

 

3. In this system can we add more LOD?

No.

 

4. How are animations handled for the instanced vegetation?

Animation is not supported. There is a shader for making leaves sway.

 

5. If I have trees that are rigged, can I use different animations at the same time on identical instances?

No.

[tournamentdan]

 

5. If I have trees that are rigged, can I use different animations at the same time on identical instances?

 

 

No.

 

 

How do you pick the vegetation for decals? I am looking to animate trees and others with bones. So can't I pick the closest trees around the character controller and use copies instead of instances? It shouldn't raise the entity count that much.

 

 

[Josh]

If you do a world or camera pick, it will return the vegetation layer entity. The entire layer is one entity. A new member, pickinfo.mat, returns the 4x4 matrix of the specific instance.

[Rick]

Is it a child/parent thing where the entire veg layer is an entity but it has children entities that are the trees? I'm just trying to think of possible ways where we could treat each vegetation as separate entities, even if that method is a little trickery like hiding that one in the veg system and swapping it with a real entity or something like that. Otherwise, right now the veg system doesn't handle dynamic situations like chopping down a tree, unless you have some other method in mind for that.

[Josh]

There actually isn't control for individual instances. There is a filter texture, but that does not correspond to the layout of the instances, since they might be denser than the terrain resolution. So it setting that up would be a little more difficult.

[tournamentdan]

In opengl, doesn't each instance get a invocation id in the geometry shader? With that wouldn't we have control over each individual instance?

[damvcoool]

Would it be possible to expand the LOD for vegetation to have 3 LOD instead of just 2? (Close, not so close not too far, Real Far!)

[martyj]

@tournamentdan

 

We don't have access to the geometry shader unfortunatly. It would also be hard to animate a specific tree.

 

If you're doing something that requires that much in depth work on a specific model. I'd recommend just making it an enitty.

[tournamentdan]

I have software specifically made to create and animate vegetation.

 

Depending on the distance from camera. Each individual billboard is switched out with an instance. Or vice versa. I don't see why it would be a problem switching out the closest instances with copies.