最初のHtml 5ゲームを開発(三)
(訳)最初のHtml 5ゲームを開発する(三)
この章では、画像スクロール機能を追加し、ゲームダイアログボックスを実現しました.
JSコード:(完全なコードは文章の末尾のリンクを参照してください)
テキストアドレスhttp://www.script-tutorials.com/html5-game-development-navigating-your-spaceship-lesson-3/
Demoアドレスhttp://www.script-tutorials.com/demos/166/index.html
ソースのダウンロードhttp://www.script-tutorials.com/demos/166/source.zip
この章では、画像スクロール機能を追加し、ゲームダイアログボックスを実現しました.
JSコード:(完全なコードは文章の末尾のリンクを参照してください)
// inner variables
var canvas, ctx;
var button;
var backgroundImage;
var spaceShip;
var iBgShiftX = 1024;
var bDrawDialog = true;
var iDialogPage = 1;
// -------------------------------------------------------------
// objects :
function Button(x, y, w, h, state, image) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.state = state;
this.imageShift = 0;
this.image = image;
}
function SpaceShip(x, y, w, h, image) {
this.x = x;
this.y = y;
this.w = w;
this.h = h;
this.image = image;
this.bDrag = false;
}
// -------------------------------------------------------------
// draw functions :
function clear() { // clear canvas function
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
}
function drawDialog() { // draw dialog function
if (bDrawDialog) {
var bg_gradient = ctx.createLinearGradient(0, 200, 0, 400);
bg_gradient.addColorStop(0.0, 'rgba(160, 160, 160, 0.8)');
bg_gradient.addColorStop(1.0, 'rgba(250, 250, 250, 0.8)');
ctx.beginPath(); // custom shape begin
ctx.fillStyle = bg_gradient;
ctx.moveTo(100, 100);
ctx.lineTo(700, 100);
ctx.lineTo(700, 500);
ctx.lineTo(100, 500);
ctx.lineTo(100, 100);
ctx.closePath(); // custom shape end
ctx.fill(); // fill custom shape
ctx.lineWidth = 2;
ctx.strokeStyle = 'rgba(128, 128, 128, 0.5)';
ctx.stroke(); // draw border
// draw the title text
ctx.font = '42px DS-Digital';
ctx.textAlign = 'center';
ctx.textBaseline = 'top';
ctx.shadowColor = '#000';
ctx.shadowOffsetX = 2;
ctx.shadowOffsetY = 2;
ctx.shadowBlur = 2;
ctx.fillStyle = '#fff';
if (iDialogPage == 1) {
ctx.fillText('Welcome to lesson #3', ctx.canvas.width/2, 150);
ctx.font = '24px DS-Digital';
ctx.fillText('After closing dialog you will able', ctx.canvas.width/2, 250);
ctx.fillText('to handle with spaceship with your mouse', ctx.canvas.width/2, 280);
} else if (iDialogPage == 2) {
ctx.fillText('Second page of dialog', ctx.canvas.width/2, 150);
ctx.font = '24px DS-Digital';
ctx.fillText('Any another text', ctx.canvas.width/2, 250);
}
}
}
function drawScene() { // main drawScene function
clear(); // clear canvas
// draw background
iBgShiftX -= 10;
if (iBgShiftX <= 0) {
iBgShiftX = 1024;
}
ctx.drawImage(backgroundImage, 0 + iBgShiftX, 0, 1024, 768, 0, 0, 800, 600);
// draw space ship
ctx.drawImage(spaceShip.image, 0, 0, spaceShip.w, spaceShip.h, spaceShip.x-128, spaceShip.y-128, spaceShip.w, spaceShip.h);
// draw dialog
drawDialog();
// draw button
ctx.drawImage(button.image, 0, button.imageShift, button.w, button.h, button.x, button.y, button.w, button.h);
// draw button's text
ctx.font = '22px DS-Digital';
ctx.fillStyle = '#ffffff';
ctx.fillText('next/hide/show', 400, 465);
ctx.fillText('dialog', 400, 500);
}
// -------------------------------------------------------------
// initialization
$(function(){
canvas = document.getElementById('scene');
ctx = canvas.getContext('2d');
var width = canvas.width;
var height = canvas.height;
// load background image
backgroundImage = new Image();
backgroundImage.src = 'images/stars.jpg';
backgroundImage.onload = function() {
}
backgroundImage.onerror = function() {
console.log('Error loading the background image.');
}
// initialization of space ship
var oSpShipImage = new Image();
oSpShipImage.src = 'images/space_ship.png';
oSpShipImage.onload = function() {
}
spaceShip = new SpaceShip(400, 300, 256, 256, oSpShipImage);
// load the button sprite image
var buttonImage = new Image();
buttonImage.src = 'images/button.png';
buttonImage.onload = function() {
}
button = new Button(310, 450, 180, 120, 'normal', buttonImage);
$('#scene').mousedown(function(e) { // binding mousedown event (for dragging)
var mouseX = e.layerX || 0;
var mouseY = e.layerY || 0;
if (!bDrawDialog &&
mouseX > spaceShip.x-128 && mouseX < spaceShip.x-128+spaceShip.w &&
mouseY > spaceShip.y-128 && mouseY < spaceShip.y-128+spaceShip.h) {
spaceShip.bDrag = true;
spaceShip.x = mouseX;
spaceShip.y = mouseY;
}
// button behavior
if (mouseX > button.x && mouseX < button.x+button.w && mouseY > button.y && mouseY < button.y+button.h) {
button.state = 'pressed';
button.imageShift = 262;
}
});
$('#scene').mousemove(function(e) { // binding mousemove event
var mouseX = e.layerX || 0;
var mouseY = e.layerY || 0;
if (!bDrawDialog && spaceShip.bDrag) {
spaceShip.x = mouseX;
spaceShip.y = mouseY;
}
// button behavior
if (button.state != 'pressed') {
button.state = 'normal';
button.imageShift = 0;
if (mouseX > button.x && mouseX < button.x+button.w && mouseY > button.y && mouseY < button.y+button.h) {
button.state = 'hover';
button.imageShift = 131;
}
}
});
$('#scene').mouseup(function(e) { // binding mouseup event
spaceShip.bDrag = false;
// button behavior
if (button.state == 'pressed') {
if (iDialogPage == 0) {
iDialogPage++;
bDrawDialog = !bDrawDialog;
} else if (iDialogPage == 2) {
iDialogPage = 0;
bDrawDialog = !bDrawDialog;
} else {
iDialogPage++;
}
}
button.state = 'normal';
button.imageShift = 0;
});
setInterval(drawScene, 30); // loop drawScene
});
テキストアドレスhttp://www.script-tutorials.com/html5-game-development-navigating-your-spaceship-lesson-3/
Demoアドレスhttp://www.script-tutorials.com/demos/166/index.html
ソースのダウンロードhttp://www.script-tutorials.com/demos/166/source.zip