oilstar / minimalinstancing

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MinimalInstancing

Part01

Sample project that shows how to use the Graphics.DrawInstanced() API.

InstanceColorShader.shader

This shader has the minimum amount of code needed to allow for user defined coloring and GPU intancing support

DrawInstancedScript.cs

Monobehaviour that takes in values for number of meshes in a grid (width x height) and draws the grid in batches of 1023 instances at a time Prefab and Material need to be supplied in order to draw something

InstancedMaterial.mat

Material that uses the InstanceColorShader to draw the instances of the mesh

InstancingScene.unity

Sample scene that draws 200 x 200 prisms in white color (as shown below)

Part02

InstanceColorShader.shader

No change from Part01

DrawInstancedScript.cs

New functionality:

1. Threshold: Specifies the min. noise value to accept. This is used for randomizing when prisms show up.
2. ColorArray: Array of colors to show for the different prisms, used in the Material Property Block

Material Property Block

This controls the color setting on a per instance basis. Using this, we can have multiple colors on the same mesh, and keep them batched using Graphics.DrawMeshInstanced(). Calling

propertyBlock.SetVectorArray("_Color", batchedColorArray);
Graphics.DrawMeshInstanced(mMeshFilter.sharedMesh, 0, meshMaterial, batchedMatrices, batchCount, propertyBlock);

ensures that can pass the property block configured with an array down to the Shader so that it can extract the data per instance.

InstancedMaterial.mat

No chance from Part01

InstancingScene.unity

Sample scene that draws 200 x 200 prisms in white color (as shown below)