Add MeshPrimitiveModes

2.0/MeshPrimitiveModes/README.md

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+# MeshPrimitiveModes
+
+An example that shows rendering modes that are supported for mesh primitives in glTF.
+
+## Screenshot
+
+![screenshot](screenshot/screenshot.png)
+
+## Structure
+
+The example contains seven meshes, each with one mesh primitive. All mesh primitives have the same vertex positions, forming a regular hexagon:
+```
+       3
+   4       2
+       0   
+   5       1
+       6
+```
+
+Each mesh primitive has a different `mode`, corresponding to the glTF [mesh topology types](https://registry.khronos.org/glTF/specs/2.0/glTF-2.0.html#meshes-overview). The `indices` of each mesh primitive for the respective modes are as follows:
+
+- indices for `mode=0` (`POINTS`): `[0, 1, 2, 3, 4, 5, 6]`
+- indices for `mode=1` (`LINES`): `[0, 1, 0, 2, 0, 3, 0, 4, 0, 5, 0, 6]`
+- indices for `mode=2` (`LINE_LOOP`): `[0, 1, 2, 3, 4, 5, 6]`
+- indices for `mode=3` (`LINE_STRIP`): `[0, 1, 2, 3, 4, 5, 6]`
+- indices for `mode=4` (`TRIANGLES`): `[0, 1, 2, 0, 2, 3, 0, 3, 4, 0, 4, 5, 0, 5, 6, 0, 6, 1]`
+- indices for `mode=5` (`TRIANGLE_STRIP`): `[2, 3, 1, 4, 6, 5]` (vertex `0` is unused here)
+- indices for `mode=6` (`TRIANGLE_FAN`): `[0, 1, 2, 3, 4, 5, 6, 1]`
+
+## License Information
+
+Public domain ([CC0](https://creativecommons.org/publicdomain/zero/1.0/))

2.0/MeshPrimitiveModes/glTF-Embedded/MeshPrimitiveModes.gltf

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+{
+  "asset": {
+    "version": "2.0"
+  },
+
+  "scene": 0,
+  "scenes": [
+    {
+      "nodes": [0, 1, 2, 3, 4, 5, 6]
+    }
+  ],
+
+  "nodes": [
+    {
+      "translation": [-0, 3, 0],
+      "mesh": 0
+    },
+    {
+      "translation": [-2, 0, 0],
+      "mesh": 1
+    },
+    {
+      "translation": [0, 0, 0],
+      "mesh": 2
+    },
+    {
+      "translation": [2, 0, 0],
+      "mesh": 3
+    },
+    {
+      "translation": [-2, -3, 0],
+      "mesh": 4
+    },
+    {
+      "translation": [0, -3, 0],
+      "mesh": 5
+    },
+    {
+      "translation": [2, -3, 0],
+      "mesh": 6
+    }
+  ],
+
+  "meshes": [
+    {
+      "name": "mesh with POINTS",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 7
+          },
+          "indices": 0,
+          "mode": 0
+        }
+      ]
+    },
+    {
+      "name": "mesh with LINES",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 7
+          },
+          "indices": 1,
+          "mode": 1
+        }
+      ]
+    },
+    {
+      "name": "mesh with LINE_LOOP",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 7
+          },
+          "indices": 2,
+          "mode": 2
+        }
+      ]
+    },
+    {
+      "name": "mesh with LINE_STRIP",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 7
+          },
+          "indices": 3,
+          "mode": 3
+        }
+      ]
+    },
+    {
+      "name": "mesh with TRIANGLES",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 7
+          },
+          "indices": 4,
+          "mode": 4
+        }
+      ]
+    },
+    {
+      "name": "mesh with GL_TRIANGLE_STRIP",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 7
+          },
+          "indices": 5,
+          "mode": 5
+        }
+      ]
+    },
+    {
+      "name": "mesh with GL_TRIANGLE_FAN",
+      "primitives": [
+        {
+          "attributes": {
+            "POSITION": 7
+          },
+          "indices": 6,
+          "mode": 6
+        }
+      ]
+    }
+  ],
+
+  "buffers": [
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+      "type": "SCALAR",
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+    },
+    {
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+      "type": "VEC3",
+      "max": [0.866, 1.0, 0.0],
+      "min": [-0.866, -1.0, 0.0]
+    }
+  ]
+}