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engine.js
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engine.js
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const worldMap = [
[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1],
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,3,0,3,0,0,1,1,1,2,1,1,1,1,1,2,1,1,1,2,1,0,0,0,0,0,0,0,0,1],
[1,0,0,3,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,0,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,1,1,1,1,1],
[1,0,0,3,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,3,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2],
[1,0,0,3,0,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,1,1,1,1,1],
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,0,0,0,0,0,0,3,3,3,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2],
[1,0,0,0,0,0,0,0,0,3,3,3,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,0,0,0,0,0,0,3,3,3,0,0,3,3,3,0,0,0,0,0,0,0,0,0,3,1,1,1,1,1],
[1,0,0,0,0,0,0,0,0,3,3,3,0,0,3,3,3,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,4,0,0,4,2,0,2,2,2,4,4,2,2,2,0,2,4,4,0,0,4,0,0,0,0,0,0,0,1],
[1,0,0,4,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,0,4,0,0,0,0,0,0,0,1],
[1,0,0,4,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,0,4,0,0,0,0,0,0,0,1],
[1,0,0,4,0,0,4,0,0,0,0,0,0,0,0,0,0,0,0,0,4,0,0,4,0,0,0,0,0,0,0,1],
[1,0,0,4,3,3,4,2,2,2,2,2,2,2,2,2,2,2,2,2,4,3,3,4,0,0,0,0,0,0,0,1],
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
[1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1]
];
const screenModes = [
"screen",
"minimap"
]
const floorColor = 130
const ceilingColor = 65
const stripWidth = 1;
let screenMode = screenModes[0]
let screenLines = []
let wallImages = [];
let player = {
x : 16,
y : 10,
dir : 0, // the direction that the player is turning, either -1 for left or 1 for right.
rot : 0, // the current angle of rotation
speed : 0, // is the playing moving forward (speed = 1) or backwards (speed = -1).
moveSpeed : 0.1, // how far (in map units) does the player move each step/update
rotSpeed : 3 * Math.PI / 180 // how much does the player rotate each step/update (in radians)
}
let mapWidth = worldMap[0].length;
let mapHeight = worldMap.length;
let miniMapScale = 8;
let screenWidth = 320;
let screenHeight = 200;
let fov = 60 * Math.PI / 180;
let numRays = Math.ceil(screenWidth / stripWidth);
let fovHalf = fov / 2;
let viewDist = (screenWidth/2) / Math.tan((fov / 2));
let twoPI = Math.PI * 2;
function preload() {
wallImages = [
loadImage('assets/blue_wall.png'),
loadImage('assets/blue_cell.png'),
loadImage('assets/rocks.png'),
loadImage('assets/wood.png')
]
}
function setup() {
let c = createCanvas(screenWidth, screenHeight);
c.class("gameCanvas")
let dpi = window.devicePixelRatio;
let canvas = document.getElementById('defaultCanvas0');
let ctx = canvas.getContext('2d');
ctx.webkitImageSmoothingEnabled = false;
ctx.mozImageSmoothingEnabled = false;
ctx.imageSmoothingEnabled = false; /// future
canvas.style.width = screenWidth * 2;
canvas.style.height = screenHeight * 2;
fill(255)
}
function draw() {
clear();
if (keyIsDown(TAB)) {
screenMode = screenModes[1]
} else {
screenMode = screenModes[0]
}
if (screenMode == screenModes[0]) {
resetScreenDefaults()
drawScreen()
} else if (screenMode == screenModes[1]) {
resetScreenDefaults()
drawMinimap()
}
move();
}
function drawScreen() {
noStroke()
fill(color(floorColor))
rect(0,screenHeight/2, screenWidth, (screenHeight/2))
fill(color(ceilingColor))
rect(0,0, screenWidth, (screenHeight/2))
screenLines = []
//calculate values
for (var i=0;i<numRays;i++) {
// where on the screen does ray go through?
var rayScreenPos = (-numRays/2 + i) * stripWidth;
// the distance from the viewer to the point on the screen, simply Pythagoras.
var rayViewDist = Math.sqrt(rayScreenPos*rayScreenPos + viewDist*viewDist);
// the angle of the ray, relative to the viewing direction.
// right triangle: a = sin(A) * c
var rayAngle = Math.asin(rayScreenPos / rayViewDist);
castRay(
player.rot + rayAngle
)
}
//render lines
for (var i=0;i<screenWidth;i+=stripWidth) {
if (screenLines[i] != undefined) {
let lineWidth = screenLines[i][0]
let lineHeight = screenLines[i][1]
let lineTop = screenLines[i][2]
let lineWallType = screenLines[i][3]
let lineTexX = screenLines[i][4]
fill(0)
noStroke()
rect(i, lineTop, stripWidth, lineHeight)
image(wallImages[lineWallType-1], i, lineTop, stripWidth, lineHeight, (64*lineTexX)/lineWidth ,0, stripWidth, 64);
}
}
}
function castRay(rayAngle) {
// first make sure the angle is between 0 and 360 degrees
rayAngle %= twoPI;
if (rayAngle < 0) rayAngle += twoPI;
// moving right/left? up/down? Determined by which quadrant the angle is in.
var right = (rayAngle > twoPI * 0.75 || rayAngle < twoPI * 0.25);
var up = (rayAngle < 0 || rayAngle > Math.PI);
var wallType = 0;
// only do these once
var angleSin = Math.sin(rayAngle);
var angleCos = Math.cos(rayAngle);
var dist = 0; // the distance to the block we hit
var xHit = 0; // the x and y coord of where the ray hit the block
var yHit = 0;
var textureX; // the x-coord on the texture of the block, ie. what part of the texture are we going to render
var wallX; // the (x,y) map coords of the block
var wallY;
var wallIsHorizontal = false;
// first check against the vertical map/wall lines
// we do this by moving to the right or left edge of the block we're standing in
// and then moving in 1 map unit steps horizontally. The amount we have to move vertically
// is determined by the slope of the ray, which is simply defined as sin(angle) / cos(angle).
var slope = angleSin / angleCos; // the slope of the straight line made by the ray
var dXVer = right ? 1 : -1; // we move either 1 map unit to the left or right
var dYVer = dXVer * slope; // how much to move up or down
var x = right ? Math.ceil(player.x) : Math.floor(player.x); // starting horizontal position, at one of the edges of the current map block
var y = player.y + (x - player.x) * slope; // starting vertical position. We add the small horizontal step we just made, multiplied by the slope.
while (x >= 0 && x < mapWidth && y >= 0 && y < mapHeight) {
var wallX = Math.floor(x + (right ? 0 : -1));
var wallY = Math.floor(y);
// is this point inside a wall block?
if (worldMap[wallY][wallX] > 0) {
var distX = x - player.x;
var distY = y - player.y;
dist = distX*distX + distY*distY; // the distance from the player to this point, squared.
wallType = worldMap[wallY][wallX]; // we'll remember the type of wall we hit for later
textureX = y % 1; // where exactly are we on the wall? textureX is the x coordinate on the texture that we'll use later when texturing the wall.
if (!right) textureX = 1 - textureX; // if we're looking to the left side of the map, the texture should be reversed
xHit = x; // save the coordinates of the hit. We only really use these to draw the rays on minimap.
yHit = y;
wallIsHorizontal = true;
break;
}
x += dXVer;
y += dYVer;
}
// now check against horizontal lines. It's basically the same, just "turned around".
// the only difference here is that once we hit a map block,
// we check if there we also found one in the earlier, vertical run. We'll know that if dist != 0.
// If so, we only register this hit if this distance is smaller.
var slope = angleCos / angleSin;
var dYHor = up ? -1 : 1;
var dXHor = dYHor * slope;
var y = up ? Math.floor(player.y) : Math.ceil(player.y);
var x = player.x + (y - player.y) * slope;
while (x >= 0 && x < mapWidth && y >= 0 && y < mapHeight) {
var wallY = Math.floor(y + (up ? -1 : 0));
var wallX = Math.floor(x);
if (worldMap[wallY][wallX] > 0) {
var distX = x - player.x;
var distY = y - player.y;
var blockDist = distX*distX + distY*distY;
if (!dist || blockDist < dist) {
dist = blockDist;
xHit = x;
yHit = y;
wallType = worldMap[wallY][wallX];
textureX = x % 1;
if (up) textureX = 1 - textureX;
}
break;
}
x += dXHor;
y += dYHor;
}
if (dist) {
//drawRay(xHit, yHit);
dist = Math.sqrt(dist);
// use perpendicular distance to adjust for fish eye
// distorted_dist = correct_dist / cos(relative_angle_of_ray)
dist = dist * Math.cos(player.rot - rayAngle);
// now calc the position, height and width of the wall strip
// "real" wall height in the game world is 1 unit, the distance from the player to the screen is viewDist,
// thus the height on the screen is equal to wall_height_real * viewDist / dist
var height = Math.round(viewDist / dist);
// width is the same, but we have to stretch the texture to a factor of stripWidth to make it fill the strip correctly
var width = height * stripWidth;
// top placement is easy since everything is centered on the x-axis, so we simply move
// it half way down the screen and then half the wall height back up.
var top = Math.round((screenHeight - height) / 2);
var texX = Math.round(textureX*width);
if (texX > width - stripWidth)
texX = width - stripWidth;
screenLines.push([width, height, top, wallType, texX]);
}
}
function resetScreenDefaults() {
fill(255)
stroke(0)
strokeWeight(1)
}
function drawMinimap(){
//MINIMAP BLOCKS
fill(200)
noStroke()
for (var y=0;y<mapHeight;y++) {
for (var x=0;x<mapWidth;x++) {
var wall = worldMap[y][x];
if (wall > 0) {
rect(x * miniMapScale, y * miniMapScale, miniMapScale, miniMapScale)
}
}
}
//MINIMAP PLAYER
fill(color("red"))
rect(player.x * miniMapScale - 2, player.y * miniMapScale - 2, miniMapScale / 2, miniMapScale / 2)
strokeWeight(2)
stroke(color("red"));
line(player.x * miniMapScale, player.y * miniMapScale, (player.x + Math.cos(player.rot) * 2) * miniMapScale, (player.y + Math.sin(player.rot) * 2) * miniMapScale);
}
function keyPressed() {
if (keyCode === LEFT_ARROW) {
player.dir = -1;
} else if (keyCode === RIGHT_ARROW) {
player.dir = 1;
}
if (keyCode === UP_ARROW) {
player.speed = 1;
} else if (keyCode === DOWN_ARROW) {
player.speed = -1;
}
//Refresh Page Override
if (keyCode === 116) {
location.reload();
}
return false
}
function keyReleased() {
if (keyCode === LEFT_ARROW || keyCode === RIGHT_ARROW) {
player.dir = 0;
}
if (keyCode === UP_ARROW || keyCode === DOWN_ARROW) {
player.speed = 0;
}
return false
}
function move() {
var moveStep = player.speed * player.moveSpeed; // player will move this far along the current direction vector
player.rot += player.dir * player.rotSpeed; // add rotation if player is rotating (player.dir != 0)
// make sure the angle is between 0 and 360 degrees
//while (player.rot < 0) player.rot += twoPI;
//while (player.rot >= twoPI) player.rot -= twoPI;
var newX = player.x + Math.cos(player.rot) * moveStep; // calculate new player position with simple trigonometry
var newY = player.y + Math.sin(player.rot) * moveStep;
if (isBlocking(newX, newY)) { // are we allowed to move to the new position?
return; // no, bail out.
}
player.x = newX; // set new position
player.y = newY;
}
function isBlocking(x,y) {
// first make sure that we cannot move outside the boundaries of the level
if (y < 0 || y >= mapHeight || x < 0 || x >= mapWidth)
return true;
// return true if the map block is not 0, ie. if there is a blocking wall.
return (worldMap[Math.floor(y)][Math.floor(x)] != 0);
}
// Prevent Default TAB
document.addEventListener("keydown", function(e) {
if (e.keyCode == 9) {
e.preventDefault();
}
}, false);