ShaderMaterial

[monkeyface]

I'm trying to construct a custom mesh using ShaderMaterial porting some code from three.js.

In the example I'm copying though, since the shape is only 2d, they save performance by making the vertex positions in a vec2 buffer instead of vec3 and they don't use any indices at all (it just uses gl.TRIANGLE calls to make each set of 3 verts into a triangle.

The problem I am having is that if I don't do setVerticesData with the full vec3 vertices and then setIndices with a list of indices, Babylon doesn't seem to draw anything.

 

Is there some way to do these kind of tricks without having to fill in all the vertices and generate the indices manually?

 

Thanks!

[GameMonetize]

Unfortunately, we do not have "direct" support for unindexed vertices.

But you can inherit from AbstractMesh like the LineMesh for instance: https://github.com/BabylonJS/Babylon.js/blob/master/src/Mesh/babylon.linesMesh.ts

 

But are you sure there is no vertex redundancy with your model? I'm surprised that, even to draw a 2d mesh, you do not have reusable vertices.

[monkeyface]

Thanks! I will take a look at that.

I think its a tradeoff... you do get some redundancy on the gpu side, but you save javascript cpu time constructing the indices and less I/O by using vec2 positions with no indices...  

[monkeyface]

But you can inherit from AbstractMesh like the LineMesh for instance: https://github.com/BabylonJS/Babylon.js/blob/master/src/Mesh/babylon.linesMesh.ts

 

 

HI DK, 

 

I've got my class inheriting in this way, but I'm still not sure how it helps...

With  engine.bindBuffers I still need to pass in an index buffer as parameter and it doesn't work if I don't set the indices...

 

Also, with the vertexDeclaration = [3] and vertexStrideSize = 3 * 4, I understand we're telling it each vertex is made of 3 values, each of size 4 bytes (3*4), but what is the [3] part for?

[GameMonetize]

About performance: I think this is unwise to save some CPU cycles just at the beginning against saving GPU cycles on EVERY frame

 

for my suggestion, you are completey right and I'm just stupid . I thought I added an API for VB only but I removed it sometimes ago (To favor indexed content)