Merge pull request #47 from Alpha-Blend-Interactive/add-runtime-mesh-…

…gen-example

Added example for runtime mesh generation using Lua

docs/cck/lua/examples/.pages

@@ -6,5 +6,6 @@ nav:
     - player-profile-picture.md
     - player-thumbs-up-launch.md
     - player-teleport-away-from-water.md
+    - runtime-mesh-gen.md
     - viewpoint-raycast.md
-    - persistence.md
+    - persistence.md

docs/cck/lua/examples/index.md

@@ -8,4 +8,5 @@ Here are some example scripts that can be used as an example to learn about Lua.
 * [Thumbs Up Player Launcher](player-thumbs-up-launch.md) - Launch upward when doing 2x thumbs up gesture.
 * [Viewpoint Raycast](viewpoint-raycast.md) - Perform a raycast from the player's viewpoint.
 * [Player Profile / Avatar Picture](player-profile-picture.md) - Get Player Profile and Avatar pictures.
-* [Persistence](persistence.md) - Store all kinds of data on the user's PC.
+* [Persistence](persistence.md) - Store all kinds of data on the user's PC.
+* [Runtime Mesh Generation (Wobbly Cube)](runtime-mesh-gen.md) - Generate a wobbly cube in runtime.

docs/cck/lua/examples/runtime-mesh-gen.md

@@ -0,0 +1,193 @@
+# Runtime Mesh Generation (Wobbly Cube)
+
+This shows how to create a Cube mesh, and assign it to a mesh renderer and a collider, just from code. It also moves
+the vertices around every frame in a wobbly movement.
+
+Mesh generation can only run on world scripts.
+
+This example is a bit silly because we're updating a mesh in the update loop (which is performance heavy). You should
+not update meshes every frame, instead you should focus on generating things and then keeping them static.
+
+We're also doing a bit of a hack enabling and disabling the mesh collider component, so it forces an update. Otherwise
+the new collision shape won't register.
+
+For this example we require to assign a MeshFilter as `meshFilter` and a MeshCollider component as `meshCollider` to the
+Bound Objects. Note these are components, not gameObjects. If you want to use gameObjects, edit the code to perform a 
+GetComponent.
+
+
+```lua
+
+UnityEngine = require "UnityEngine"
+
+-- Variables to store mesh data
+local mesh = nil
+local meshCollider = nil
+local vertices = nil
+local originalVertices = nil
+
+-- Configurable parameters
+local wobbleStrength = 0.5
+local wobbleSpeed = 2.0
+
+function Start()
+
+    -- Save a reference of our mesh collider, so we can force it to update
+    meshCollider = BoundObjects.meshCollider
+
+    if not meshCollider then
+        Script.Destroy("No MeshCollider component found!")
+        return
+    end
+
+    local meshFilter = BoundObjects.meshFilter
+
+    if not meshFilter then
+        Script.Destroy("No MeshFilter component found!")
+        return
+    end
+
+    -- Create an empty mesh
+    mesh = UnityEngine.Mesh()
+
+    -- Create cube vertices (24 vertices, 4 for each face)
+    vertices = {
+        -- Front face
+        UnityEngine.NewVector3(-0.5, -0.5,  0.5),  -- Bottom Left
+        UnityEngine.NewVector3( 0.5, -0.5,  0.5),  -- Bottom Right
+        UnityEngine.NewVector3( 0.5,  0.5,  0.5),  -- Top Right
+        UnityEngine.NewVector3(-0.5,  0.5,  0.5),  -- Top Left
+
+        -- Right face
+        UnityEngine.NewVector3( 0.5, -0.5,  0.5),  -- Bottom Left
+        UnityEngine.NewVector3( 0.5, -0.5, -0.5),  -- Bottom Right
+        UnityEngine.NewVector3( 0.5,  0.5, -0.5),  -- Top Right
+        UnityEngine.NewVector3( 0.5,  0.5,  0.5),  -- Top Left
+
+        -- Back face
+        UnityEngine.NewVector3( 0.5, -0.5, -0.5),  -- Bottom Left
+        UnityEngine.NewVector3(-0.5, -0.5, -0.5),  -- Bottom Right
+        UnityEngine.NewVector3(-0.5,  0.5, -0.5),  -- Top Right
+        UnityEngine.NewVector3( 0.5,  0.5, -0.5),  -- Top Left
+
+        -- Left face
+        UnityEngine.NewVector3(-0.5, -0.5, -0.5),  -- Bottom Left
+        UnityEngine.NewVector3(-0.5, -0.5,  0.5),  -- Bottom Right
+        UnityEngine.NewVector3(-0.5,  0.5,  0.5),  -- Top Right
+        UnityEngine.NewVector3(-0.5,  0.5, -0.5),  -- Top Left
+
+        -- Top face
+        UnityEngine.NewVector3(-0.5,  0.5,  0.5),  -- Bottom Left
+        UnityEngine.NewVector3( 0.5,  0.5,  0.5),  -- Bottom Right
+        UnityEngine.NewVector3( 0.5,  0.5, -0.5),  -- Top Right
+        UnityEngine.NewVector3(-0.5,  0.5, -0.5),  -- Top Left
+
+        -- Bottom face
+        UnityEngine.NewVector3(-0.5, -0.5, -0.5),  -- Bottom Left
+        UnityEngine.NewVector3( 0.5, -0.5, -0.5),  -- Bottom Right
+        UnityEngine.NewVector3( 0.5, -0.5,  0.5),  -- Top Right
+        UnityEngine.NewVector3(-0.5, -0.5,  0.5)   -- Top Left
+    }
+
+    -- Create triangles (faces)
+    local triangles = {
+        -- Front face
+        0, 1, 2,  0, 2, 3,
+        -- Right face
+        4, 5, 6,  4, 6, 7,
+        -- Back face
+        8, 9, 10, 8, 10, 11,
+        -- Left face
+        12, 13, 14, 12, 14, 15,
+        -- Top face
+        16, 17, 18, 16, 18, 19,
+        -- Bottom face
+        20, 21, 22, 20, 22, 23
+    }
+
+    -- Create normals (pointing outward)
+    local normals = {
+        -- Front face normals (pointing forward)
+        UnityEngine.NewVector3(0, 0, 1),
+        UnityEngine.NewVector3(0, 0, 1),
+        UnityEngine.NewVector3(0, 0, 1),
+        UnityEngine.NewVector3(0, 0, 1),
+
+        -- Right face normals (pointing right)
+        UnityEngine.NewVector3(1, 0, 0),
+        UnityEngine.NewVector3(1, 0, 0),
+        UnityEngine.NewVector3(1, 0, 0),
+        UnityEngine.NewVector3(1, 0, 0),
+
+        -- Back face normals (pointing back)
+        UnityEngine.NewVector3(0, 0, -1),
+        UnityEngine.NewVector3(0, 0, -1),
+        UnityEngine.NewVector3(0, 0, -1),
+        UnityEngine.NewVector3(0, 0, -1),
+
+        -- Left face normals (pointing left)
+        UnityEngine.NewVector3(-1, 0, 0),
+        UnityEngine.NewVector3(-1, 0, 0),
+        UnityEngine.NewVector3(-1, 0, 0),
+        UnityEngine.NewVector3(-1, 0, 0),
+
+        -- Top face normals (pointing up)
+        UnityEngine.NewVector3(0, 1, 0),
+        UnityEngine.NewVector3(0, 1, 0),
+        UnityEngine.NewVector3(0, 1, 0),
+        UnityEngine.NewVector3(0, 1, 0),
+
+        -- Bottom face normals (pointing down)
+        UnityEngine.NewVector3(0, -1, 0),
+        UnityEngine.NewVector3(0, -1, 0),
+        UnityEngine.NewVector3(0, -1, 0),
+        UnityEngine.NewVector3(0, -1, 0)
+    }
+
+    -- Store original vertices positions
+    originalVertices = {}
+    for i = 1, #vertices do
+        originalVertices[i] = UnityEngine.NewVector3(vertices[i].x, vertices[i].y, vertices[i].z)
+    end
+
+    -- Set the mesh data
+    mesh.vertices = vertices
+    mesh.triangles = triangles
+    mesh.normals = normals
+
+    -- Assign the created mesh instance, to both the mesh filter and mesh collider
+    meshFilter.mesh = mesh
+    meshCollider.sharedMesh = mesh
+
+    print("Cube Mesh created and Wobble initialized successfully! Vertice Count: " .. tostring(#vertices))
+
+end
+
+function Update()
+    if not mesh or not originalVertices then return end
+
+    -- Update vertices using original positions
+    for i = 1, #vertices do
+        local originalVertex = originalVertices[i]
+
+        -- Calculate wobble based on original position
+        local wobble = math.sin(UnityEngine.Time.time * wobbleSpeed + originalVertex.x) * wobbleStrength
+
+        -- Create new vertex position based on original position
+        vertices[i] = UnityEngine.NewVector3(
+            originalVertex.x,
+            originalVertex.y + wobble,
+            originalVertex.z
+        )
+    end
+
+    -- Apply vertices to mesh
+    mesh.vertices = vertices
+
+    -- Force mesh collider to update
+    -- We need to do this to force the collider to update with the mesh changes
+    meshCollider.enabled = false
+    meshCollider.enabled = true
+end
+
+```