Wrapmode mirror_once is redundant

[nearnshaw]

When configuring a texture, the wrapMode has options TWM_MIRROR and TWM_MIRROR_ONCE, both look like they produce identical results.

We might want to remove Mirror_once, or make it only has one axis of symmetry

See this example, where two planes have these different modes set, but look identical:

example

See this doc for reference about what each should do:
https://learnopengl.com/Getting-started/Textures

[pravusjif]

I confirm that his looks like a problem with WebGL, since using the following test code I get the expected results in Unity Editor but not in the web build.

function setUVs(rows: number, cols: number) {
  return [
    // North side of unrortated plane
    0, //lower-left corner
    0,

    cols, //lower-right corner
    0,

    cols, //upper-right corner
    rows,

    0, //upper left-corner
    rows,

    // South side of unrortated plane
    cols, // lower-right corner
    0,

    0, // lower-left corner
    0,

    0, // upper-left corner
    rows,

    cols, // upper-right corner
    rows,
  ]
}

const meshEntity = engine.addEntity()
Transform.create(meshEntity, {
  position: Vector3.create(4, 3.5, 4),
  scale: Vector3.create(4, 4, 4) })
MeshRenderer.setPlane(meshEntity, setUVs(4, 4))
MeshCollider.setPlane(meshEntity)
const textureSource = 'images/scene-thumbnail.png'
Material.setPbrMaterial(meshEntity, {
  texture: Material.Texture.Common({
    src: textureSource,
    wrapMode: TextureWrapMode.TWM_MIRROR,
  }),
  castShadows: true,
  roughness: 1,

})

const meshEntity2 = engine.addEntity()
Transform.create(meshEntity2, {
  position: Vector3.create(9, 3.5, 4),
  scale: Vector3.create(4, 4, 4) })
MeshRenderer.setPlane(meshEntity2,setUVs(4, 4))
Material.setPbrMaterial(meshEntity2, {
  texture: Material.Texture.Common({
    src: textureSource,
    wrapMode: TextureWrapMode.TWM_MIRROR_ONCE,
  }),
  castShadows: true,
  roughness: 1,
})

I'll be removing the TWM_MIRROR_ONCE option since is the one that doesn't work in WebGL.