Calculating dynamic light and shadows in tile based roguelike games – part 4: a first real world example

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I wanted to try a real world example of my dynamic light and shadows in tile based roguelike games, so let’s make a small recap then I am diving into the code: In first step I introduced Bresenham algorithm to draw a line between two points in a tile based environment. In step 2 with the same concept I showed you how to draw a circle in a tile based environment. In step 3 I connected all tiles along the circumference with the player using Bresenham line, stopping the line if it hits a wall. Today I am showing you a little example in a randomly generated dungeon. The code to generate the dungeon is taken from here and although it does not generate the best dungeons ever, it works so why not?
Drag the player – the green dot – inside the maze and see the light effect. To optimize a bit the code I added a visited array to keep track of tiles I already visited to avoid placing unnecessary tiles. More optimization and some performance statistics will be available next week, meanwhile have a look at the source code:
var game;
var tileSize = 12;
var sightRadius = 30;

window.onload = function() {	
	game = new Phaser.Game(768, 768, Phaser.AUTO, "");
     game.state.add("PlayGame", playGame);
     game.state.start("PlayGame");
}

var playGame = function(game){};

playGame.prototype = {
     preload: function(){
           game.load.image("tile", "tile.png");
     },
     create: function(){
          for(var i = 0; i < Dungeon.map_size; i++){
               for(var j = 0; j < Dungeon.map_size; j++){
                    var tile = Dungeon.map[j][i];
                    if(tile == 0){
                         var wall = game.add.sprite(i * tileSize, j * tileSize, "tile");   
                         wall.tint = 0x222222;       
                    }
                    if(tile == 2){
                         var wall = game.add.sprite(i * tileSize, j * tileSize, "tile");   
                         wall.tint = 0x555555;       
                    }
               }
          }
          var startCol = game.rnd.between(0, Dungeon.map_size - 1);
          var startRow = game.rnd.between(0, Dungeon.map_size - 1);
          this.lineGroup = game.add.group();
          this.playerPosition = game.add.sprite(startCol * tileSize, startRow * tileSize, "tile");
          this.playerPosition.tint = 0x00ff00;
          this.playerPosition.alpha = 0.5;
          this.playerPosition.inputEnabled = true;
          this.playerPosition.input.enableDrag();
          this.playerPosition.input.boundsRect = new Phaser.Rectangle(0, 0, game.width, game.height);
          this.playerPosition.input.enableSnap(tileSize, tileSize, true, true);
          
     },
     update: function(){
          this.visited = [];
          this.visited.length = 0;
          this.lineGroup.removeAll(true);
          this.drawCircle(this.playerPosition.x / tileSize, this.playerPosition.y / tileSize, sightRadius);
     },
     drawBresenham: function(x0, y0, x1, y1){
          var saveX0 = x0;
          var saveY0 = y0;
          var dx = Math.abs(x1 - x0);
          var sx = -1;
          if(x0 < x1){
               var sx = 1
          }
          var dy = Math.abs(y1 - y0);
          var sy = -1;
          if(y0 < y1){
               var sy = 1;
          }
          var err = -dy / 2;
          if(dx > dy){
               err = dx / 2;
          }
          do{
               var dist = this.distance(saveX0, saveY0, x0, y0);
               if(x0 < 0 || y0 < 0 || x0 >= Dungeon.map_size || y0 >= Dungeon.map_size || Dungeon.map[y0][x0] != 1 || dist > sightRadius / 2){
                    break;
               }
               if(this.visited.indexOf(x0 + "," + y0) == -1){
                    var tile = game.add.sprite(x0 * tileSize, y0 * tileSize, "tile");
                    tile.tint = 0xffff00;
                    tile.alpha = 1 - dist / (sightRadius / 2);
                    this.visited.push(x0 + "," + y0);
                    this.lineGroup.add(tile);
               }
               var e2 = err;
               if(e2 > -dx){
                    err -= dy;
                    x0 += sx;
               }
               if(e2 < dy){
                    err += dx;
                    y0 += sy;
               }
          } while(x0 != x1 || y0 != y1)        
     },
     drawCircle: function(x0, y0, radius){
          var x = -radius
          var y = 0;
          var err = 2 - 2 * radius; 
          do {
               this.drawBresenham(this.playerPosition.x / tileSize, this.playerPosition.y / tileSize, (x0 - x), (y0 + y));
               this.drawBresenham(this.playerPosition.x / tileSize, this.playerPosition.y / tileSize, (x0 - y), (y0 - x));
               this.drawBresenham(this.playerPosition.x / tileSize, this.playerPosition.y / tileSize, (x0 + x), (y0 - y));
               this.drawBresenham(this.playerPosition.x / tileSize, this.playerPosition.y / tileSize, (x0 + y), (y0 + x));
               radius = err;
               if (radius <= y){
                    y++;
                    err += y * 2 + 1;
               }          
               if (radius > x || err > y){
                    x++;
                    err += x * 2 + 1;
               } 
          } while (x < 0);    
     },
     distance: function(x0, y0, x1, y1){
          return Math.sqrt((x0-x1)*(x0-x1)+(y0-y1)*(y0-y1))     
     }
}

var Dungeon = {
    map: null,
    map_size: 64,
    rooms: [],
    Generate: function () {
        this.map = [];
        for (var x = 0; x < this.map_size; x++) {
            this.map[x] = [];
            for (var y = 0; y < this.map_size; y++) {
                this.map[x][y] = 0;
            }
        }

        var room_count = Helpers.GetRandom(10, 20);
        var min_size = 5;
        var max_size = 15;

        for (var i = 0; i < room_count; i++) {
            var room = {};

            room.x = Helpers.GetRandom(1, this.map_size - max_size - 1);
            room.y = Helpers.GetRandom(1, this.map_size - max_size - 1);
            room.w = Helpers.GetRandom(min_size, max_size);
            room.h = Helpers.GetRandom(min_size, max_size);

            if (this.DoesCollide(room)) {
                i--;
                continue;
            }
            room.w--;
            room.h--;

            this.rooms.push(room);
        }

        this.SquashRooms();

        for (i = 0; i < room_count; i++) {
            var roomA = this.rooms[i];
            var roomB = this.FindClosestRoom(roomA);

            pointA = {
                x: Helpers.GetRandom(roomA.x, roomA.x + roomA.w),
                y: Helpers.GetRandom(roomA.y, roomA.y + roomA.h)
            };
            pointB = {
                x: Helpers.GetRandom(roomB.x, roomB.x + roomB.w),
                y: Helpers.GetRandom(roomB.y, roomB.y + roomB.h)
            };

            while ((pointB.x != pointA.x) || (pointB.y != pointA.y)) {
                if (pointB.x != pointA.x) {
                    if (pointB.x > pointA.x) pointB.x--;
                    else pointB.x++;
                } else if (pointB.y != pointA.y) {
                    if (pointB.y > pointA.y) pointB.y--;
                    else pointB.y++;
                }

                this.map[pointB.x][pointB.y] = 1;
            }
        }

        for (i = 0; i < room_count; i++) {
            var room = this.rooms[i];
            for (var x = room.x; x < room.x + room.w; x++) {
                for (var y = room.y; y < room.y + room.h; y++) {
                    this.map[x][y] = 1;
                }
            }
        }

        for (var x = 0; x < this.map_size; x++) {
            for (var y = 0; y < this.map_size; y++) {
                if (this.map[x][y] == 1) {
                    for (var xx = x - 1; xx <= x + 1; xx++) {
                        for (var yy = y - 1; yy <= y + 1; yy++) {
                            if (this.map[xx][yy] == 0) this.map[xx][yy] = 2;
                        }
                    }
                }
            }
        }
    },
    FindClosestRoom: function (room) {
        var mid = {
            x: room.x + (room.w / 2),
            y: room.y + (room.h / 2)
        };
        var closest = null;
        var closest_distance = 1000;
        for (var i = 0; i < this.rooms.length; i++) {
            var check = this.rooms[i];
            if (check == room) continue;
            var check_mid = {
                x: check.x + (check.w / 2),
                y: check.y + (check.h / 2)
            };
            var distance = Math.min(Math.abs(mid.x - check_mid.x) - (room.w / 2) - (check.w / 2), Math.abs(mid.y - check_mid.y) - (room.h / 2) - (check.h / 2));
            if (distance < closest_distance) {
                closest_distance = distance;
                closest = check;
            }
        }
        return closest;
    },
    SquashRooms: function () {
        for (var i = 0; i < 10; i++) {
            for (var j = 0; j < this.rooms.length; j++) {
                var room = this.rooms[j];
                while (true) {
                    var old_position = {
                        x: room.x,
                        y: room.y
                    };
                    if (room.x > 1) room.x--;
                    if (room.y > 1) room.y--;
                    if ((room.x == 1) && (room.y == 1)) break;
                    if (this.DoesCollide(room, j)) {
                        room.x = old_position.x;
                        room.y = old_position.y;
                        break;
                    }
                }
            }
        }
    },
    DoesCollide: function (room, ignore) {
        for (var i = 0; i < this.rooms.length; i++) {
            if (i == ignore) continue;
            var check = this.rooms[i];
            if (!((room.x + room.w < check.x) || (room.x > check.x + check.w) || (room.y + room.h < check.y) || (room.y > check.y + check.h))) return true;
        }

        return false;
    }
}

var Helpers = {
    GetRandom: function (low, high) {
        return~~ (Math.random() * (high - low)) + low;
    }
};

Dungeon.Generate();
Remember roguelike games are turn based games so performance is not a top feature, anyway I will show you some full stats next week, meanwhile download the source code of this experiment.

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215 GAME PROTOTYPES EXPLAINED WITH SOURCE CODE
// 1+2=3
// 100 rounds
// 10000000
// 2 Cars
// 2048
// A Blocky Christmas
// A Jumping Block
// A Life of Logic
// Angry Birds
// Angry Birds Space
// Artillery
// Astro-PANIC!
// Avoider
// Back to Square One
// Ball Game
// Ball vs Ball
// Ball: Revamped
// Balloon Invasion
// BallPusher
// Ballz
// Bar Balance
// Bejeweled
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// Blockage
// Bloons
// Boids
// Bombuzal
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// Bouncing Ball 2
// Bouncy Light
// BoxHead
// Breakout
// Bricks
// Bubble Chaos
// Bubbles 2
// Card Game
// Castle Ramble
// Chronotron
// Circle Chain
// Circle Path
// Circle Race
// Circular endless runner
// Cirplosion
// CLOCKS - The Game
// Color Hit
// Color Jump
// ColorFill
// Columns
// Concentration
// Crossy Road
// Crush the Castle
// Cube Jump
// CubesOut
// Dash N Blast
// Dashy Panda
// Deflection
// Diamond Digger Saga
// Don't touch the spikes
// Dots
// Down The Mountain
// Drag and Match
// Draw Game
// Drop Wizard
// DROP'd
// Dudeski
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// Filler
// Flappy Bird
// Fling
// Flipping Legend
// Floaty Light
// Fuse Ballz
// GearTaker
// Gem Sweeper
// Globe
// Goat Rider
// Gold Miner
// Grindstone
// GuessNext
// Helicopter
// Hero Emblems
// Hero Slide
// Hexagonal Tiles
// HookPod
// Hop Hop Hop Underwater
// Horizontal Endless Runner
// Hundreds
// Hungry Hero
// Hurry it's Christmas
// InkTd
// Iromeku
// Jet Set Willy
// Jigsaw Game
// Knife Hit
// Knightfall
// Legends of Runeterra
// Lep's World
// Line Rider
// Lumines
// Magick
// MagOrMin
// Mass Attack
// Math Game
// Maze
// Meeblings
// Memdot
// Metro Siberia Underground
// Mike Dangers
// Mikey Hooks
// Nano War
// Nodes
// o:anquan
// One Button Game
// One Tap RPG
// Ononmin
// Pacco
// Perfect Square!
// Perfectionism
// Phyballs
// Pixel Purge
// PixelField
// Planet Revenge
// Plants Vs Zombies
// Platform
// Platform game
// Plus+Plus
// Pocket Snap
// Poker
// Pool
// Pop the Lock
// Pop to Save
// Poux
// Pudi
// Pumpkin Story
// Puppet Bird
// Pyramids of Ra
// qomp
// Quick Switch
// Racing
// Radical
// Rebuild Chile
// Renju
// Rise Above
// Risky Road
// Roguelike
// Roly Poly
// Run Around
// Rush Hour
// SameGame
// SamePhysics
// Save the Totem
// Security
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// Shrink it
// Sling
// Slingy
// Snowflakes
// Sokoban
// Space Checkers
// Space is Key
// Spellfall
// Spinny Gun
// Splitter
// Spring Ninja
// Sproing
// Stabilize!
// Stack
// Stairs
// Stick Hero
// String Avoider
// Stringy
// Sudoku
// Super Mario Bros
// Surfingers
// Survival Horror
// Talesworth Adventure
// Tetris
// The Impossible Line
// The Moops - Combos of Joy
// The Next Arrow
// Threes
// Tic Tac Toe
// Timberman
// Tiny Wings
// Tipsy Tower
// Toony
// Totem Destroyer
// Tower Defense
// Trick Shot
// Tunnelball
// Turn
// Turnellio
// TwinSpin
// vvvvvv
// Warp Shift
// Way of an Idea
// Whack a Creep
// Wheel of Fortune
// Where's my Water
// Wish Upon a Star
// Word Game
// Wordle
// Worms
// Yanga
// Yeah Bunny
// Zhed
// zNumbers