Mesh Melt shader test

An article by mgear

8 Comments

mesh_melt_shader

Quick test for melting mesh effect using vertex extrusion shader

Gif anim preview:
http://pasteboard.co/1QARh81p.gif

Forum topic: http://forum.unity3d.com/threads/has-anyone-ever-written-a-mesh-melter.311135/

Info:
– C# Script adjusts mesh vertex colors, based on the distance to heat point gameobject
– Then shader pushes(extrudes) vertices based on that vertex color (alpha)
– Would be probably better to do everything from script (to allow splitting the object, avoid intersecting faces etc..)

Instructions:
– Download sources below
– Add sphere to scene
– Add Melter.cs script to that sphere
– Create new material “meltmat” and assign it to that sphere
– Assign Custom/MeshMelt2 shader to that material
– Add empty gameobject to scene (this is the heat source)
– Assign heatsource gameobject into Melter.cs “HeatPoint” field in inspector
– Hit play, then inside scene view move heat source near to sphere to see effect

Customizations:
– Melter.cs has public bool, [x] Restore Color, this slowly restores vertex colors
– MeshMelt2.shader, see line 23 & 24 for different effects (melt in normal direction or melt downwards)
– Adjust Extrusion amount in shader material

Shader source: MeshMelt2.shader

	Shader "Custom/MeshMelt2" {
	Properties {
	_MainTex ("Texture", 2D) = "white" {}
	_LavaTex ("LavaTexture", 2D) = "white" {}
	_Amount ("Extrusion Amount", Range(-1,1)) = 0.5
	}

	SubShader {
	Tags { "RenderType" = "Opaque" }
	CGPROGRAM
	#pragma surface surf Lambert vertex:vert

	struct Input {
	float2 uv_MainTex;
	float4 customColor;
	};

	float _Amount;

	void vert (inout appdata_full v,out Input o)
	{
	UNITY_INITIALIZE_OUTPUT(Input,o);
	v.vertex.xyz += v.normal * v.color.a * _Amount; // move in normal direction
	// v.vertex.xyz += float3(0,1,0) * v.color.a * _Amount; // move down
	o.customColor = v.color;
	}

	sampler2D _MainTex;
	sampler2D _LavaTex;

	void surf (Input IN, inout SurfaceOutput o)
	{
	float3 main = tex2D(_MainTex, IN.uv_MainTex).rgb;

	float2 scroll = float2(_Time.x0.032f(1-IN.customColor.a),_Time.y0.02f(1-IN.customColor.a));
	float3 lava = tex2D(_LavaTex, IN.uv_MainTex+scroll).rgb;

	float3 c = lerp(lava,main, IN.customColor.a);

	o.Albedo = c;
	o.Emission = c*(1-IN.customColor.a);
	}
	ENDCG
	}
	Fallback "Diffuse"
	}

view raw

MeshMelt.shader

hosted with ❤ by GitHub

Script source: Melter.cs

	using UnityEngine;
	using System.Collections;

	public class Melter : MonoBehaviour {

	public Transform heatPoint;
	public bool restoreColor=false;

	void Start () {
	var mesh = GetComponent<MeshFilter>().mesh;
	var cols = new Color[mesh.vertexCount];
	for (int i = 0; i < mesh.vertexCount; i++)
	{
	cols[i] = Color.white;
	}
	mesh.colors = cols;
	UpdateColor();
	}

	void Update () {
	UpdateColor();
	}


	void UpdateColor()
	{
	float viewDistance = 1f;
	float fadeSpeed = 1f;

	var mesh = GetComponent<MeshFilter>().mesh;
	var verts = mesh.vertices;
	var cols = mesh.colors;

	for (int i = 0; i < mesh.vertexCount; i++)
	{
	//float distance = Vector3.Distance(heatPoint.position.normalized, verts[i].normalized);
	float dist = Mathf.Exp(Vector3.Distance(heatPoint.position, verts[i])); // broken
	float distance = Remap (dist,0f,3f,0f,1f);

	if (restoreColor)
	{
	cols[i].a = Mathf.Clamp01(cols[i].a-(viewDistance-distance)Time.deltaTimefadeSpeed);
	}else{
	cols[i].a = Mathf.Min(cols[i].a,Mathf.Clamp01(cols[i].a-(viewDistance-distance)Time.deltaTimefadeSpeed));
	}
	}
	mesh.colors = cols;
	}

	float Remap(float val, float low1, float high1, float low2, float high2)
	{
	return low2 + (val-low1)*(high2-low2)/(high1-low1);
	}
	}

view raw

Melter.cs

hosted with ❤ by GitHub

—

Tags: effect, melt, mesh, shader, vertex

About the Author:

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8 Comments + Add Comment

chiuan 29/03/2015 at 15:58

wa~sounds cool!

Reply
Unity – Realtime Mesh Deformation – Package | Labertorium 31/03/2015 at 22:20

[…] across a deformation shader which was easy and fun to use on a bunch of objects lying around (original inspiration). We discussed a bit about what can be done with it and what features were missing before we could […]

Reply
Codez 08/04/2015 at 21:30

I am getting Array errors at 46 if Restore Color is enabled, and 50 if it is not.
I have checked these lines and cannot find anything wrong with either.

I am using Unity 5.

Reply
- Andrew 11/04/2015 at 19:46
  
  Yeah getting the same thing, any idea how to fix this?
  
  Reply
- mgear 12/04/2015 at 00:46
  
  Does it work if you try with default unity sphere? (works here atleast)
  
  Reply
  - Andrew 12/04/2015 at 04:55
    
    No, using a default sphere here is an image of the errors I’m getting:
    
    http://i.imgur.com/j8iENP8.png
    
    Reply
    - mgear 13/04/2015 at 01:36
      
      Script updated, for some reason it didnt get the vertex colors from mesh, even though it worked before.
      (maybe I had modified the builtin sphere vertex colors during that unity session, so it had them, while in default there are no colors).
      
      Reply
SIRIUS 29/06/2017 at 23:11

GAME DEVELOPER

Reply