025 : Node 025

Since we're going to add a second player, rename _player to _player1.

If your text editor supports global search and replace, change all occurrences "_player" to "_player1".

script.js:

// Global variables. var _game = {}; var _player = {}; var _player1 = {};

If you run your code now, you'll see an error because all the references to _player are now invalid.

script.js:

// Initialize the game state. function init() { init_game(); init_player(); init_player1(); }

If you run your code now, you'll see an error because init_player1() hasn't been renamed yet.

script.js:

// Initialize player data. // Initialize Player 1 data. function init_player() { function init_player1() { _player.x = 0; _player1.x = 0; _player.y = 0; _player1.y = 0; _player.width = 20; _player1.width = 20; _player.height = 20; _player1.height = 20; _player.velocity_x = 0; _player1.velocity_x = 0; _player.velocity_y = 0; _player1.velocity_y = 0; }

If you run your code now, you'll see an error because there are still more places to fix up.

script.js:

// Erase the canvas and draw all the objects. function draw() { var canvas = document.getElementById("stage"); var ctx = canvas.getContext("2d"); erase(ctx); draw_player(ctx); draw_player1(ctx); }

If you run your code now, you'll see an error because draw_player1() hasn't been renamed yet.

script.js:

// Draw the player. // Draw player 1. function draw_player(ctx) { function draw_player1(ctx) { ctx.fillStyle = "blue"; ctx.fillRect(_player.x, _player.y, _player.width, _player.height); ctx.fillRect(_player1.x, _player1.y, _player1.width, _player1.height); }

If you run your code now, you'll see an error because there are still a few more to fix.

script.js:

// Handle input and move the player. // Handle input and move player 1. function update_player() { function update_player1() { check_input(); // Move the player to the new location. _player.x += _player.velocity_x; _player.y += _player.velocity_y; _player1.x += _player1.velocity_x; _player1.y += _player1.velocity_y; }

If you run your code now, you'll see an error because there are still a few more to fix.

script.js:

function check_input() { _player.velocity_x = 0; _player.velocity_y = 0; _player1.velocity_x = 0; _player1.velocity_y = 0; // Left arrow or 'a' to move left. if (_game.keymap[37] || _game.keymap[65]) { _player.velocity_x = -1; _player1.velocity_x = -1; } // Right arrow or 'd' to move right. if (_game.keymap[39] || _game.keymap[68]) { _player.velocity_x = 1; _player1.velocity_x = 1; } // Up arrow or 'w' to move up. if (_game.keymap[38] || _game.keymap[87]) { _player.velocity_y = -1; _player1.velocity_y = -1; } // Down arrow or 's' to move up. if (_game.keymap[40] || _game.keymap[83]) { _player.velocity_y = 1; _player1.velocity_y = 1; } }

If you run your code now, you'll see an error because there is still one last thing to fix.

script.js:

// This is called ~60 times per second to update the world. function update_world() { update_player(); update_player1(); draw(); requestAnimationFrame(update_world); }

Run your code in a browser and verify that there are no errors.

GOTO 030