Efficient mesh instantiation

You can place them out over the span of several frames ins$$anonymous$$d of trying to create them all in the same frame.

For example, with a coroutine you can use a while loop with a yield return null; inside it so it will skip a frame for each iteration

This way you could instantiate maybe a couple of hundred to a thousand per frame ins$$anonymous$$d of waiting for everything.

I have a problem, my yield return null line says that it needs a semicolon which it has.

 function Grass() {
     var chunkGrass = 0;
     while (chunkGrass < grassPerChunk) {
             chunkGrass++;
             if (chunkGrass == grassPerChunk / 20) {
                 yield return null; //UCE0001: ';' expected. Insert a semicolon at the end.
             }
     }
 }

In JS you do not need to specify 'yield return null', It is used in C#. In JS just use:

 yield;

Hi, I don't know exactly what are your needs but 10k meshes or objects is a lot to manage for an engine. Why don't you create 1 mesh composed of 10k quads, each representing 1 grass leaf ?

@Harshad$$anonymous$$ Thx :)

@dns How would I do that? :)

Well, you need to create vertices and triangles like in some procedural geometry example (http://u3d.as/content/unity-technologies/procedural-examples/3zu), you may need to raycast on your terrain mesh so you can position those vertices/triangles on it with random rotations. You'll also have to choose a shader that renders both sides of the geometry. Note that doing so will produce a mesh that should be quite quick to draw but won't have "billboards" leaves. This is not such a simple script, maybe there are solutions in the asset store that can do what you want.

AFAI$$anonymous$$ you can't make a shader render both sides of the face, since 1 face only have 1 normal... Would i really have to create two quads facing different directions then?

That's right, lighting may be a problem. It depends how you want to do the grass lighting, with dynamic or static/precomputed lighting. $$anonymous$$aybe you can get a color from a point on the ground/terrain mesh after baking lights & shadows and use this value in vertex color of each grass leaf. If you want real time light & shadow on the grass, then it may be better to have 2 quads or a 2 pass shader (it look like it's possible: http://forum.unity3d.com/threads/double-sided-material.21778/). This depends on your needs, target platform & performance concerns. Having to double the geometry will not be a problem on PC/$$anonymous$$ac but may slow down a phone, you may want to make some tests or search about this (I don't know a lot about current mobile platforms, only read some stuff).

Another solution could be to spawn 10k billboard particles with zero speed&gravity & long/infinite life so they don't move at all. Then you position them on the terrain using raycast & http://docs.unity3d.com/ScriptReference/ParticleSystem.GetParticles.html and SetParticle (and no need to do this each frame as the particles won't move). Expect some complications as particle systems are not made to do that, but it could work.

@dns The thing with the particles sounds interesting, but the problem is that I have found a shader which allows shadows on particles since I don't want my grass to be lit all the time, the problem is that it is affected by the direction the light is co$$anonymous$$g from, which makes sense of course. but this make the grass billboard change color as I rotate my camera. Do you have an idea how I could fix this :)

The shader must use the normal to compute lighting on the particles. As you rotate the camera, the particle billboards rotate too to continually face it, then the light computation changes because the billboard & normal are rotated. $$anonymous$$aybe some "unlit" shaders are better, with alpha/transparency cutout or you'll also have sorting problems. I think you can still get shadows with it, or you'll have to customize your own shader.

Grass rendering is not an easy task, there are lots of different techniques that evolved with hardware capabilities. Re-doing it yourself will take lots of time doing research, tests, debugging before it "looks good"... This can be very interesting to do but if what you want to make is a game, I would recommend to use the maximum of what Unity can provide so you can focus on the game itself. I don't know what features your terrain is using that makes it different than the one Unity provides, maybe you can convert this terrain into Unity's one using heightmap import or by a script. You could then have "free" grass, trees, optimizations, documentation, examples... There are also more advanced terrain packages in the asset store that could be time saving for not so much money. Well, that's a "best practice" I'm following myself :-)

The problem is that unlit grass gets too bright at night.. And the reason I use a mesh ins$$anonymous$$d of a terrain is because it can have non-shared vertices.

$$anonymous$$aybe you can modify the default Unlit shader to add a simple color modulation with your current time-of-day color.

About the terrain, you can also modify Unity's terrain shader. I guess you need non-shared vertices to have different textures or UV for each triangle. You could generate a texture containing information to modify UV or index to sub-texture in an atlas. The pixel shader could read this texture and do different things than the default shader does. I do this for my actual project (on PC though, it may be expensive on mobile), it is a little complicated but I get all the other benefits of the built in terrain. Just in case, Unity's shaders are here: http://unity3d.com/unity/download/archive