MeshInstance

Remarks

A hundred and ninety-two bytes per entity per frame, and that number is the whole point. The path this replaces cost one MeshVertex per vertex per frame — forty bytes times a shape's vertex count, times every entity, with a cube's four hundred bytes and a sphere's twenty-odd kilobytes rebuilt whether or not anything moved. What crosses the bus now is linear in entities.

⚠ and are the material, and they are per instance because a material is per entity. Two entities sharing a shape and differing only in what they are made of stay one draw, which is what would have been lost by putting them anywhere else — a uniform block would be one material per draw, and a descriptor set would be one per material, which is the compositor's arrangement and needs a compositor. Thirty-two more bytes an entity buys a block-out that reads as brick and metal rather than as grey and grey.

⚠ The normal matrix is stored rather than derived, and it is per entity rather than per vertex. A cube scaled 2 1 1 transformed by its own matrix comes out with normals that are no longer perpendicular to their faces, and the shading then slides across the object as it is scaled — which reads as the light moving. The inverse is one matrix inverse per entity here; asking the vertex stage for it would be one per vertex, and the shader language has no inverse to ask with.

The fourth row of is never read — a direction has no translation — and is kept because a Matrix4x4 is what Transpose hands back. Sixteen bytes to avoid a hand-packed three-row layout that only the shader and this struct would agree about.

Fields and properties (6)

• public Matrix4x4 Transform

  Where the entity is, as WorldTransform holds it.

• public Matrix4x4 Normals

  The matrix normals go through, which is 's inverse transpose. See Of, which is the only reason a caller would build one by hand.

• public Color4 Colour

  What colour the surface is, linear and straight-alpha.

• public Vector4 Style

  Four independent decisions about how this instance is drawn, described by the shader that reads them: an outline width in pixels, an outline depth bias in pixels, whether to light it flat, and whether to take its colour from the world normal instead of from .

• public Vector4 Surface

  How the light behaves on it: metalness in x, perceptual roughness in y. The remaining two lanes are reserved — see DielectricF0 for what goes in them when something authors it.

• public Color4 Emissive

  What it emits on its own, linear, with the material's intensity already folded into the components. Alpha is unused. Black for a surface that emits nothing, which is nearly all of them.

Methods (4)

• public MeshInstance(Matrix4x4 Transform, Matrix4x4 Normals, Color4 Colour, Vector4 Style, Vector4 Surface, Color4 Emissive)

  One entity's copy of a shape: where it is, and what it looks like.

• public static MeshInstance Of(in Matrix4x4 transform, Color4 colour, Vector4 style = default(Vector4), MaterialSurface? surface = null, float checker = 0, float tint = 0)

  An instance of a shape at a transform, with its normal matrix worked out.

• public static Vector4 Packed(MaterialSurface surface, float checker = 0, float tint = 0)

  The lanes the shader reads a surface's shading from.

• public static Matrix4x4 NormalMatrix(in Matrix4x4 transform)

  The matrix a normal goes through under a transform.

Used by (8)

• MaterialSurfaceTestsVixen.Rendering.Tests
• MeshInstanceRendererVixen.Rendering
• MeshInstanceRendererTestsVixen.Rendering.Tests
• PrimitiveShapeTestsVixen.Editor.SceneView.Tests
• SceneMaterialTestsVixen.Editor.SceneView.Tests
• SceneMeshAssetTestsVixen.Editor.SceneView.Tests
• SceneMeshesVixen.Editor.SceneView
• ViewportStateTestsVixen.Editor.SceneView.Tests