Multi-surface footsteps audio script for Unity's Viking Village

Footsteps.cs

/* ======================================================================================== */
/* FMOD Studio - Unity Integration Demo.                                                    */
/* Firelight Technologies Pty, Ltd. 2012-2016.                                              */
/* Liam de Koster-Kjaer                                                                     */
/*                                                                                          */
/* Use this script in conjunction with the Viking Village scene tutorial and Unity 5.4.     */
/* http://www.fmod.org/training/                                                            */
/*                                                                                          */
/* 1. Import Viking Village asset package                                                   */
/* 2. Import FMOD Studio Unity Integration package                                          */
/* 3. Replace Audio listener with FMOD Studio listener on player controller                 */
/*   (FlyingRigidBodyFPSController_HighQuality)                                             */
/* 4. Add footsteps script to the player controller                                         */
/* 5. Set footsteps script variable ‘Step Distance’ to a reasonable value (2.0f)            */
/* 6. Change terrain texture import settings so we can sample pixel values                  */
/*     - terrain_01_m                                                                       */
/*     - terrain_wetmud_01_sg                                                               */
/*         - Texture Type: Advanced                                                         */
/*         - Non Power of 2: N/A                                                            */
/*         - Mapping: None                                                                  */
/*         - Convolution Type: N/A                                                          */
/*         - Fixup Edge Seams: N/A                                                          */
/*         - Read/Write Enabled: Yes                                                        */
/*         - Import Type: Default                                                           */
/*         - Alpha from Greyscale: No                                                       */
/*         - Alpha is Transparency: No                                                      */
/*         - Bypass sRGB sampling: No                                                       */
/*         - Encode as RGBM: Off                                                            */
/*         - Sprite Mode: None                                                              */
/*         - Generate Mip Maps: No                                                          */
/*         - Wrap Mode: Repeat                                                              */
/*         - Filter Mode: Bilinear                                                          */
/*         - Aniso Level: 3                                                                 */
/* ======================================================================================== */


using UnityEngine;
using System.Collections;

//This script plays footstep sounds.
//It will play a footstep sound after a set amount of distance travelled.
//When playing a footstep sound, this script will cast a ray downwards. 
//If that ray hits the ground terrain mesh, it will retreive material values to determine the surface at the current position.
//If that ray does not hit the ground terrain mesh, we assume it has hit a wooden prop and set the surface values for wood.
public class Footsteps : MonoBehaviour
{
	//FMOD Studio variables
	//The FMOD Studio Event path.
	//This script is designed for use with an event that has a game parameter for each of the surface variables, but it will still compile and run if they are not present.
	[FMODUnity.EventRef]
	public string m_EventPath;

	//Surface variables
	//Range: 0.0f - 1.0f
	//These values represent the amount of each type of surface found when raycasting to the ground.
	//They are exposed to the UI (public) only to make it easy to see the values as the player moves through the scene.
	public float m_Wood;
	public float m_Water;
	public float m_Dirt;
	public float m_Sand;

	//Step variables
	//These variables are used to control when the player executes a footstep.
	//This is very basic, and simply executes a footstep based on distance travelled.
	//Ideally, in this case, footsteps would be triggered based on the headbob script. Or if there was an animated player model it could be triggered from the animation system.
	//You could also add variation based on speed travelled, and whether the player is running or walking. 
	public float m_StepDistance = 2.0f;
	float m_StepRand;
	Vector3 m_PrevPos;
	float m_DistanceTravelled;

	//Debug variables
	//If m_Debug is true, this script will:
	// - Draw a debug line to represent the ray that was cast into the ground.
	// - Draw the triangle of the mesh that was hit by the ray that was cast into the ground.
	// - Log the surface values to the console.
	// - Log to the console when an expected game parameter is not found in the FMOD Studio event.
	public bool m_Debug;
	Vector3 m_LinePos;
	Vector3 m_TrianglePoint0;
	Vector3 m_TrianglePoint1;
	Vector3 m_TrianglePoint2;

	void Start()
	{
		//Initialise random, set seed
		Random.InitState(System.DateTime.Now.Second);

		//Initialise member variables
		m_StepRand = Random.Range(0.0f, 0.5f);
		m_PrevPos = transform.position;
		m_LinePos = transform.position;
	}

	void Update()
	{
		m_DistanceTravelled += (transform.position - m_PrevPos).magnitude;
		if(m_DistanceTravelled >= m_StepDistance + m_StepRand)//TODO: Play footstep sound based on position from headbob script
		{
			PlayFootstepSound();
			m_StepRand = Random.Range(0.0f, 0.5f);//Adding subtle random variation to the distance required before a step is taken - Re-randomise after each step.
			m_DistanceTravelled = 0.0f;
		}

		m_PrevPos = transform.position;

		if(m_Debug)
		{
			Debug.DrawLine(m_LinePos, m_LinePos + Vector3.down * 1000.0f);
			Debug.DrawLine(m_TrianglePoint0, m_TrianglePoint1);
			Debug.DrawLine(m_TrianglePoint1, m_TrianglePoint2);
			Debug.DrawLine(m_TrianglePoint2, m_TrianglePoint0);
		}
	}

	void PlayFootstepSound()
	{
		//Defaults
		m_Water = 0.0f;
		m_Dirt = 1.0f;
		m_Sand = 0.0f;
		m_Wood = 0.0f;

		RaycastHit hit;
		if(Physics.Raycast(transform.position, Vector3.down, out hit, 1000.0f))
		{
			if(m_Debug)
				m_LinePos = transform.position;

			if(hit.collider.gameObject.layer == LayerMask.NameToLayer("Ground"))//The Viking Village terrain mesh (terrain_near_01) is set to the Ground layer.
			{
				int materialIndex = GetMaterialIndex(hit);
				if(materialIndex != -1)
				{
					Material material = hit.collider.gameObject.GetComponent<Renderer>().materials[materialIndex];
					if(material.name == "mat_terrain_near_01 (Instance)")//This texture name is specific to the terrain mesh in the Viking Village scene.
					{
						if(m_Debug)
						{//Calculate the points for the triangle in the mesh that we have hit with our raycast.
							MeshFilter mesh = hit.collider.gameObject.GetComponent<MeshFilter>();
							if(mesh)
							{
								Mesh m = hit.collider.gameObject.GetComponent<MeshFilter>().mesh;
								m_TrianglePoint0 = hit.collider.transform.TransformPoint(m.vertices[m.triangles[hit.triangleIndex * 3 + 0]]);
								m_TrianglePoint1 = hit.collider.transform.TransformPoint(m.vertices[m.triangles[hit.triangleIndex * 3 + 1]]);
								m_TrianglePoint2 = hit.collider.transform.TransformPoint(m.vertices[m.triangles[hit.triangleIndex * 3 + 2]]);
							}
						}

						//The mask texture determines how the material's main two textures are blended.
						//Colour values from each texture are blended based on the mask texture's alpha channel value.
							//0.0f is full dirt texture, 1.0f is full sand texture, 0.5f is half of each. 
						Texture2D maskTexture = material.GetTexture("_Mask") as Texture2D;
						Color maskPixel = maskTexture.GetPixelBilinear(hit.textureCoord.x, hit.textureCoord.y);

						//The specular texture maps shininess / gloss / reflection to the terrain mesh.
						//We are using it to determine how much water is shown at the cast ray's point of intersection.
						Texture2D specTexture2 = material.GetTexture("_SpecGlossMap2") as Texture2D;
						//We apply tiling assuming it is not already applied to hit.textureCoord2
						float tiling = 40.0f;//This is a public variable set on the material, we could reference the actual variable but I ran out of time.
						float u = hit.textureCoord.x % (1.0f / tiling);
						float v = hit.textureCoord.y % (1.0f / tiling);
						Color spec2Pixel = specTexture2.GetPixelBilinear(u, v);

						float specMultiplier = 6.0f;//We use a multiplier to better represent the amount of water.
						m_Water = maskPixel.a * Mathf.Min(spec2Pixel.a * specMultiplier, 0.9f);//Only the sand texture has water, so we multiply by the mask pixel alpha value.
						m_Dirt = (1.0f - maskPixel.a);
						m_Sand = maskPixel.a - m_Water * 0.1f;//Ducking the sand a little for the water
						m_Wood = 0.0f;
					}
				}
			}
			else//If the ray hits somethign other than the ground, we assume it hit a wooden prop (This is specific to the Viking Village scene) - and set the parameter values for wood.
			{
				m_Water = 0.0f;
				m_Dirt = 0.0f;
				m_Sand = 0.0f;
				m_Wood = 1.0f;
			}
		}

		if(m_Debug)
			Debug.Log("Wood: " + m_Wood + " Dirt: " + m_Dirt + " Sand: " + m_Sand + " Water: " + m_Water);

		if(m_EventPath != null)
		{
			FMOD.Studio.EventInstance e = FMODUnity.RuntimeManager.CreateInstance(m_EventPath);
			e.set3DAttributes(FMODUnity.RuntimeUtils.To3DAttributes(transform.position));

			e.setParameterByName("Wood", m_Wood);
			e.setParameterByName("Dirt", m_Wood);
			e.setParameterByName("Sand", m_Wood);
			e.setParameterByName("Water", m_Wood);

			e.start();
			e.release();//Release each event instance immediately, there are fire and forget, one-shot instances. 
		}
	}

	
	int GetMaterialIndex(RaycastHit hit)
	{
		Mesh m = hit.collider.gameObject.GetComponent<MeshFilter>().mesh;
		int[] triangle = new int[]
		{
			m.triangles[hit.triangleIndex * 3 + 0],
			m.triangles[hit.triangleIndex * 3 + 1],
			m.triangles[hit.triangleIndex * 3 + 2]
		};
		for(int i = 0; i < m.subMeshCount; ++i)
		{
			int[] triangles = m.GetTriangles(i);
			for(int j = 0; j < triangles.Length; j += 3)
			{
				if(triangles[j + 0] == triangle[0] &&
					triangles[j + 1] == triangle[1] &&
					triangles[j + 2] == triangle[2])
					return i;
			}
		}
		return -1;
	}
}

Does anybody have an updated version of this? I cannot for the life of me get it to work...