From d251a96929b4948042097c4a5fea114eb5f2d06c Mon Sep 17 00:00:00 2001
From: Zykatious <30608121+Zykatious@users.noreply.github.com>
Date: Mon, 18 Dec 2017 18:48:32 +0000
Subject: [PATCH] Updated neighbor count code

Also added the ability to click toggle cells and all edges wrap.
---
 examples/games/life/main.go | 200 ++++++++++++++++++++++++++++++++++++
 1 file changed, 200 insertions(+)
 create mode 100644 examples/games/life/main.go

diff --git a/examples/games/life/main.go b/examples/games/life/main.go
new file mode 100644
index 0000000..91e35c1
--- /dev/null
+++ b/examples/games/life/main.go
@@ -0,0 +1,200 @@
+package main
+
+import (
+	"math/rand"
+	"time"
+
+	"github.com/gen2brain/raylib-go/raylib"
+)
+
+const (
+	squareSize = 8
+)
+
+// Cell type
+type Cell struct {
+	Position raylib.Vector2
+	Size     raylib.Vector2
+	Alive    bool
+	Next     bool
+	Visited  bool
+}
+
+// Game type
+type Game struct {
+	ScreenWidth   int32
+	ScreenHeight  int32
+	Cols          int32
+	Rows          int32
+	FramesCounter int32
+	Playing       bool
+	Cells         [][]*Cell
+}
+
+func main() {
+	rand.Seed(time.Now().UnixNano())
+
+	game := Game{}
+	game.Init(false)
+
+	raylib.InitWindow(game.ScreenWidth, game.ScreenHeight, "Conway's Game of Life")
+	raylib.SetTargetFPS(20)
+
+	for !raylib.WindowShouldClose() {
+		if game.Playing {
+			game.Update()
+		}
+
+		game.Input()
+
+		game.Draw()
+	}
+
+	raylib.CloseWindow()
+}
+
+// Init - Initialize game
+func (g *Game) Init(clear bool) {
+	g.ScreenWidth = 1920
+	g.ScreenHeight = 1100
+	g.FramesCounter = 0
+
+	g.Cols = g.ScreenWidth / squareSize
+	g.Rows = g.ScreenHeight / squareSize
+
+	g.Cells = make([][]*Cell, g.Cols+1)
+	for i := int32(0); i <= g.Cols; i++ {
+		g.Cells[i] = make([]*Cell, g.Rows+1)
+	}
+
+	for x := int32(0); x <= g.Cols; x++ {
+		for y := int32(0); y <= g.Rows; y++ {
+			g.Cells[x][y] = &Cell{}
+			g.Cells[x][y].Position = raylib.NewVector2((float32(x) * squareSize), (float32(y)*squareSize)+1)
+			g.Cells[x][y].Size = raylib.NewVector2(squareSize-1, squareSize-1)
+			if rand.Float64() < 0.1 && clear == false {
+				g.Cells[x][y].Alive = true
+			}
+		}
+	}
+}
+
+// Input - Game input
+func (g *Game) Input() {
+	// control
+	if raylib.IsKeyPressed(raylib.KeyR) {
+		g.Init(false)
+	}
+	if raylib.IsKeyPressed(raylib.KeyC) {
+		g.Init(true)
+	}
+	if raylib.IsKeyDown(raylib.KeyRight) && !g.Playing {
+		g.Update()
+	}
+	if raylib.IsMouseButtonPressed(raylib.MouseLeftButton) {
+		g.Click(raylib.GetMouseX(), raylib.GetMouseY())
+	}
+	if raylib.IsKeyPressed(raylib.KeySpace) {
+		g.Playing = !g.Playing
+	}
+
+	g.FramesCounter++
+}
+
+// Click - Toggle if a cell is alive or dead on click
+func (g *Game) Click(x, y int32) {
+	for i := int32(0); i <= g.Cols; i++ {
+		for j := int32(0); j <= g.Rows; j++ {
+			cell := g.Cells[i][j].Position
+			if int32(cell.X) < x && int32(cell.X)+squareSize > x && int32(cell.Y) < y && int32(cell.Y)+squareSize > y {
+				g.Cells[i][j].Alive = !g.Cells[i][j].Alive
+				g.Cells[i][j].Next = g.Cells[i][j].Alive
+			}
+		}
+	}
+}
+
+// Update - Update game
+func (g *Game) Update() {
+	for i := int32(0); i <= g.Cols; i++ {
+		for j := int32(0); j <= g.Rows; j++ {
+			NeighborCount := g.CountNeighbors(i, j)
+			if g.Cells[i][j].Alive {
+				if NeighborCount < 2 {
+					g.Cells[i][j].Next = false
+				} else if NeighborCount > 3 {
+					g.Cells[i][j].Next = false
+				} else {
+					g.Cells[i][j].Next = true
+				}
+			} else {
+				if NeighborCount == 3 {
+					g.Cells[i][j].Next = true
+					g.Cells[i][j].Visited = true
+				}
+			}
+		}
+	}
+	for i := int32(0); i <= g.Cols; i++ {
+		for j := int32(0); j < g.Rows; j++ {
+			g.Cells[i][j].Alive = g.Cells[i][j].Next
+		}
+	}
+}
+
+// CountNeighbors - Counts how many neighbous a cell has
+func (g *Game) CountNeighbors(x, y int32) int {
+	count := 0
+
+	for i := int32(-1); i < 2; i++ {
+		for j := int32(-1); j < 2; j++ {
+			col := (x + i + (g.Cols)) % (g.Cols)
+			row := (y + j + (g.Rows)) % (g.Rows)
+			if g.Cells[col][row].Alive {
+				count++
+			}
+		}
+	}
+
+	if g.Cells[x][y].Alive {
+		count--
+	}
+
+	return count
+}
+
+// Draw - Draw game
+func (g *Game) Draw() {
+	raylib.BeginDrawing()
+	raylib.ClearBackground(raylib.RayWhite)
+
+	// Draw cells
+	for x := int32(0); x <= g.Cols; x++ {
+		for y := int32(0); y <= g.Rows; y++ {
+			if g.Cells[x][y].Alive {
+				raylib.DrawRectangleV(g.Cells[x][y].Position, g.Cells[x][y].Size, raylib.Blue)
+			} else if g.Cells[x][y].Visited {
+				raylib.DrawRectangleV(g.Cells[x][y].Position, g.Cells[x][y].Size, raylib.Color{R: 128, G: 177, B: 136, A: 255})
+			}
+		}
+	}
+
+	// Draw grid lines
+	for i := int32(0); i < g.Cols+1; i++ {
+		raylib.DrawLineV(
+			raylib.NewVector2(float32(squareSize*i), 0),
+			raylib.NewVector2(float32(squareSize*i), float32(g.ScreenHeight)),
+			raylib.LightGray,
+		)
+	}
+
+	for i := int32(0); i < g.Rows+1; i++ {
+		raylib.DrawLineV(
+			raylib.NewVector2(0, float32(squareSize*i)),
+			raylib.NewVector2(float32(g.ScreenWidth), float32(squareSize*i)),
+			raylib.LightGray,
+		)
+	}
+
+	raylib.EndDrawing()
+}