Codemotion Milan - November 21 2015

Pier Luca Lanzi e Michele Pirovano – Codemotion Milan November 2015

Procedural Content Generation with Unity


What is Procedural Content Generation?

Procedural Generation

with no or limited human intervention, algorithmically

of Content

of “things that affect the gameplay”, not non-player

character behavior, not the game engine


so what exactly is procedurally generated?

levels, tracks, maps, terrains, dungeons, puzzles,

buildings, trees, grass, fire, plots, descriptions,

scenarios, dialogues, quests, characters, rules,

boards, parameters, camera viewpoint, dynamics,

weapons, clothing, vehicles, personalities, etc.

Pier Luca Lanzi e Michele Pirovano – Codemotion Milan November 2015 http://en.wikipedia.org/wiki/Rogue_(video_game)#mediaviewer/File:Rogue_Screen_Shot_CAR.PNG



BBC Micro – 2 MHz MOS Technology 6502/6512

16-128 kB RAM 32-128 kB ROM

Pier Luca Lanzi e Michele Pirovano – Codemotion Milan November 2015 https://www.youtube.com/watch?v=ISR4ebdGlOk




what’s the basic principle?


f(x) = sin(x)

float y = 0f; for (float x = 0f; x<6.28f; x+=.01f) { y = Mathf.Sin(x); }


What the ingredients?

domain knowledge

structured randomness

multi-layering

filters, limits & restrictions

specialized algorithms

artificial intelligence

gameplay integration


Outline

geometry

textures

animations

dungeons


Procedural Geometry (Quads)



/// specify vertices Vector3[] vertices = new Vector3[4]; vertices[0] = new Vector3(0.0f, 0.0f, 0.0f); vertices[1] = new Vector3(0.0f, 0.0f, m_Length); vertices[2] = new Vector3(m_Width, 0.0f, m_Length); vertices[3] = new Vector3(m_Width, 0.0f, 0.0f); /// specify 2 triangles int[] indices = new int[6]; /// triangle 1 indices[0] = 0; indices[1] = 1; indices[2] = 2;

/// triangle 2 indices[3] = 0; indices[4] = 2; indices[5] = 3; /// create the mesh Mesh mesh = new Mesh(); mesh.vertices = vertices; mesh.triangles = indices; mesh.RecalculateBounds();


/// create the normals Vector3[] normals = new Vector3[4]; normals[0] = Vector3.up; normals[1] = Vector3.up; normals[2] = Vector3.up; normals[3] = Vector3.up; mesh.normals = normals; /// create the UV for the full texture Vector2[] uv = new Vector2[4]; uv[0] = new Vector2(0.0f, 0.0f); uv[1] = new Vector2(0.0f, 1.0f); uv[2] = new Vector2(1.0f, 1.0f); uv[3] = new Vector2(1.0f, 0.0f); mesh.uv = uv; /// create the UV for half texture Vector2[] uv = new Vector2[4]; uv[0] = new Vector2(0.0f, 0.0f); uv[1] = new Vector2(0.0f, 1.0f); uv[2] = new Vector2(0.5f, 1.0f); uv[3] = new Vector2(0.5f, 0.0f); mesh.uv = uv;


Procedural Geometry (Polygons)


/// specify vertices Vector3[] vertices = new Vector3[_no_sides]; float d = 2*Mathf.PI/no_sides; for(int s=0; s<_no_sides; s++) { vertices[s] = new Vector3(Mathf.Cos (-s*d), 0f, Mathf.Sin (-s*d)) * _ray; } /// compute triangles no_sides-2 triangles, 3 indices each int[] indices = new int[(_no_sides-2)*3]; for(int t=0; t<_no_sides-2; t++) { indices[t*3] = t; indices[t*3+1] = t+1; indices[t*3+2] = vertices.Length-1; } /// ...


Procedural Geometry (Surfaces)


public class MeshBuilder {

public List<Vector3> Vertices; public List<Vector3> Normals; public List<Vector2> UVs;

public void AddTriangle(int i0, int i1, int i2); public Mesh CreateMesh()

} MeshBuilder meshBuilder = new MeshBuilder(); //Set up the vertices and triangles: meshBuilder.Vertices.Add(new Vector3(0.0f, 0.0f, 0.0f)); meshBuilder.UVs.Add(new Vector2(0.0f, 0.0f)); meshBuilder.Normals.Add(Vector3.up); ... meshBuilder.AddTriangle(0, 1, 2); meshBuilder.AddTriangle(0, 2, 3); ...


MeshBuilder meshBuilder = new MeshBuilder(); for (int i = 0; i < m_SegmentCount; i++) { float z = m_Length * i; for (int j = 0; j < m_SegmentCount; j++) { float x = m_Width * j; Vector3 offset = new Vector3(x, Random.Range(0.0f, m_Height), z); BuildQuad(meshBuilder, offset); } }



Procedural Geometry (Cubes, Cylinders, Flowers)





Procedural Generation of Textures


structured noise



// Create the new texture texture = new Texture2D(width, height, TextureFormat.RGBA32, false); // Assign it to the material GetComponent<MeshRenderer>().material.mainTexture = texture; // Generate the pixels for (int y = 0; y < height; y++){ for (int x = 0; x < width; x++){ R = … G = … B = … A = … texture.SetPixel(x, y, new Color (R, G, B, A)); } } // Apply the texture texture.Apply();


// Noise pattern noiseR = SimplexNoise.noiseOctaves(nOctaves,xx*betaWR,yy,seed,frequency); // Alpha blending valueR = (1-alphaR)+alphaR*noiseR; // Sine pattern valueR *= Mathf.Sin(noiseR*(sineX*x+sineY*y)*sineFrequency);


Procedural Animations


Procedural Animation


Animation in Unity

Skinned mesh renderer

Transforms = Bones


// Get all children transforms var bones = gameObject.GetComponentsInChildren<Transform>(); // Rotate them using a sine wave foreach(var bone in bones) { // Create a sine wave float angle = Mathf.Sin(t + phase)*amplitude; // Assign rotation Vector3 tmpRot = bone.localEulerAngles; tmpRot.z = angle; bone.localEulerAngles = tmpRot; }


Dungeon Generation


Dungeon Generation


The Grid Map


// Mark the starting location CellLocation currentLocation = starting_location; map.MarkAsVisited(currentLocation); // Pick a starting direction Direction previousDirection = Direction.North; // Repeat until all cells have been visited while (!map.AllCellsVisited) { // Choose a direction DirectionPicker directionPicker = new DirectionPicker(map, currentLocation, directionChangeModifier, previousDirection); Direction direction = directionPicker.GetNextDirection(map, currentLocation); // Check if we can go in that direction if (direction != Direction.None) { // Create a corridor to the next cell and flag this cell as visited previousLocations.Add(currentLocation); previousDirection = direction; currentLocation = map.CreateCorridor(currentLocation, direction); map.FlagCellAsVisited(currentLocation); } else { // Backtrack currentLocation = previousLocations[previousLocations.Count - 1]; previousLocations.RemoveAt(previousLocations.Count - 1); } }

Recursive Backtracking algorithm


Virtual Map -> Physical Map

// Choose a prefab based on the cell type GameObject prefab = behaviour.GetPrefab(cell_type); // Instantiate the prefab at the given position GameObject go = (GameObject)GameObject.Instantiate(prefab, new Vector3(l.x*behaviour.tileSize,l.storey*(behaviour.wallHeight+behaviour.storeySeparationHeight),l.y*behaviour.tileSize), Quaternion.identity); go.name = cell_type.ToString();


we can do it, so can you!


http://www.youtube.com/watch?v=uIUYWzdMXog

Pier Luca Lanzi e Michele Pirovano – Codemotion Milan November 2015 http://www.michelepirovano.com/portfolio_swordgenerator.php

Pier Luca Lanzi e Michele Pirovano – Codemotion Milan November 2015 http://www.michelepirovano.com/portfolio_swordgenerator.php


http://www.polimigamecollective.orghttp://www.facebook.com/polimigamecollective

http://www.youtube.com/PierLucaLanzi


47


Ingredients #1 & #2 Domain Knowledge & Artificial Intelligence

•  Domain Knowledge § To generate something you need to know it

§ PCG typically aims at building an artificial level designer, usually needs domain knowledge about level design

•  Artificial Intelligence

§ Need algorithms that can work on complex knowledge and generate plausible content

§ Search-based methods, L-systems, evolutionary computation, fractals, cellular automata, agent-based methods, planning, etc.

48



ingredient #3

structured randomness

things look like they have been randomly

generated but it is not completely at random!


f(x) = sin(x)



they both look like “noise”

but one of them feels like it has structure…

it is structured randomness



ingredient #4

multi-layering

typically more layers of procedural

content generation are applied in sequence


• Warzone 2100

§ Heights & Cliffs

§ Roads

§ Textures

§ Player Bases

§ Local Features

•  Civilization 4

§ Fractal Heightfield

§ Plate Tectonics

§ Tile Types

§ Rivers and Lakes

§ Map Bonuses


ingredient #5

Filters, Limits & Restrictions

“In Civ3 I would say we even shipped with a sub-standard resource

placement algorithm where all the iron could be concentrated in just

a few small locations on the map, and for one player there may be literally no way for them to build swordsmen.” – Soren Johnson

"With Civ4 we instituted randomness with limitations. There

always has to be a minimum distance between each element of

iron, or each element of horses, and that completely solved the

problem.” – Soren Johnson


ingredient #6

specialized algorithms

placing special items, requires special tricks

this tricks must be encoded in the PCG


1.  Connect all bases, the resources, pick three random points and connect them

2.  Apply a customize A* heuristic and reuse roads!

3.  Customize A* heuristic with randomize cost of non-road grid cells.


ingredient #7

gameplay integration

Is it fun to play? Is the progression adequate?


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Codemotion Milan - November 21 2015

Education