New tile based platform engine – part 9 – coins n’ spikes
You asked for coins and spikes, and here they are…
As usual I had to define some rules… in this case spikes are deadly only when the player has both feet on it… later I will make a lava (or electric) tile that will kill the player even if he only has one foot on it.
At the moment the player just restarts when he dies, later I will manage real deaths.
Coins are… well… coins… just collect them.
Fix for the fix for infamous Ladder Bug in the Platform Tutorials
In New tile based platform engine – more theory I said superdean fixed the ladder bug… that’s not completely true because with his code the player cannot climb down a ladder when he’s walking over it.
So the correct if statement to perform when the player presses DOWN is neither mine
if (over == "ladder") {
nor superdean’s one
if (top_right == 6 or bottom_right == 6 or top_left == 6 or bottom_left == 6){
but
if ((over == "ladder") or (top_right == 6 or bottom_right == 6 or top_left == 6 or bottom_left == 6)) {
Now grab the source code:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 | tile_size = 20;
ground_acceleration = 1;
ground_friction = 0.8;
air_acceleration = 0.5;
air_friction = 0.7;
ice_acceleration = 0.15;
ice_friction = 0.95;
treadmill_speed = 2;
max_speed = 3;
xspeed = 0;
yspeed = 0;
falling = false;
gravity = 0.5;
jump_speed = 6;
climbing = false;
climb_speed = 0.8;
level = new Array();
enemy = new Array();
coin = new Array();
level[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];
level[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, 1];
level[2] = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 1, 0, 0, 0, 0, 1];
level[3] = [1, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 1];
level[4] = [1, 0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 1];
level[5] = [1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 1];
level[6] = [1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 1, 0, 0, 0, 0, 0, 1];
level[7] = [1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 5, 0, 0, 0, 0, 0, 0, 6, 0, 0, 0, 0, 0, 0, 1];
level[8] = [1, 1, 1, 1, 0, 0, 0, 0, 0, 5, 5, 0, 0, 0, 7, 0, 0, 6, 0, 0, 0, 0, 7, 0, 1];
level[9] = [1, 1, 1, 1, 1, 1, 1, 2, 2, 8, 8, 8, 8, 1, 1, 3, 3, 1, 4, 4, 1, 8, 1, 8, 1];
player = [5, 8];
enemy[0] = [10, 3, -2];
enemy[1] = [3, 3, -2];
coin[0] = [2, 2];
coin[1] = [23, 4];
coin;
function create_level(l) {
_root.createEmptyMovieClip("level_container", 1);
level_height = l.length;
level_width = l[0].length;
for (y=0; y<level_height; y++) {
for (x=0; x<level_width; x++) {
if (l[y][x] != 0) {
t = level_container.attachMovie("tile", "t"+y+"_"+x, _root.level_container.getNextHighestDepth(), {_x:x*tile_size, _y:y*tile_size});
t.gotoAndStop(l[y][x]);
}
}
}
place_player();
for (x=0; x<coin.length; x++) {
coin_mc = level_container.attachMovie("coin", "coin_"+_root.level_container.getNextHighestDepth(), _root.level_container.getNextHighestDepth(), {_x:coin[x][0]*tile_size+tile_size/2, _y:coin[x][1]*tile_size+tile_size/2+1});
coin_mc.onEnterFrame = function() {
if (this.hitTest(level_container.hero._x, level_container.hero._y, true)) {
this.removeMovieClip();
}
};
}
for (x=0; x<enemy.length; x++) {
foe = level_container.attachMovie("patrol", "patrol_"+_root.level_container.getNextHighestDepth(), _root.level_container.getNextHighestDepth(), {_x:enemy[x][0]*tile_size+tile_size/2, _y:enemy[x][1]*tile_size+tile_size/2+1});
foe.speed = enemy[x][2];
foe.onEnterFrame = function() {
this.x_pos = this._x;
this.y_pos = this._y;
this.x_pos += this.speed;
this.left_foot_x = Math.floor((this.x_pos-6)/tile_size);
this.right_foot_x = Math.floor((this.x_pos+5)/tile_size);
this.foot_y = Math.floor((this.y_pos+9)/tile_size);
this.bottom = Math.floor((this.y_pos+8)/tile_size);
this.left_foot = level[this.foot_y][this.left_foot_x];
this.right_foot = level[this.foot_y][this.right_foot_x];
this.left = level[this.bottom][this.left_foot_x];
this.right = level[this.bottom][this.right_foot_x];
if (this.left_foot != 0 and this.right_foot != 0 and this.left == 0 and this.right == 0) {
this._x = this.x_pos;
} else {
this.speed *= -1;
}
};
}
}
create_level(level);
_root.onEnterFrame = function() {
ground_under_feet();
walking = false;
climbing = false;
if (Key.isDown(Key.LEFT)) {
xspeed -= speed;
walking = true;
}
if (Key.isDown(Key.RIGHT)) {
xspeed += speed;
walking = true;
}
if (Key.isDown(Key.UP)) {
get_edges();
if (top_right == 6 or bottom_right == 6 or top_left == 6 or bottom_left == 6) {
jumping = false;
falling = false;
climbing = true;
climbdir = -1;
}
}
if (Key.isDown(Key.DOWN)) {
get_edges();
if ((over == "ladder") or (top_right == 6 or bottom_right == 6 or top_left == 6 or bottom_left == 6)) {
jumping = false;
falling = false;
climbing = true;
climbdir = 1;
}
}
if (Key.isDown(Key.SPACE)) {
get_edges();
if (!falling and !jumping) {
jumping = true;
yspeed = -jump_speed;
}
}
if (!walking) {
xspeed *= friction;
if (Math.abs(xspeed)<0.5) {
xspeed = 0;
}
}
if (xspeed>max_speed) {
xspeed = max_speed;
}
if (xspeed<max_speed*-1) {
xspeed = max_speed*-1;
}
if (falling or jumping) {
yspeed += gravity;
}
if (climbing) {
yspeed = climb_speed*climbdir;
}
if (!falling and !jumping and !climbing) {
yspeed = 0;
}
xspeed += bonus_speed;
check_collisions();
level_container.hero._x = x_pos;
level_container.hero._y = y_pos;
xspeed -= bonus_speed;
};
function ground_under_feet() {
bonus_speed = 0;
left_foot_x = Math.floor((x_pos-6)/tile_size);
right_foot_x = Math.floor((x_pos+5)/tile_size);
foot_y = Math.floor((y_pos+9)/tile_size);
left_foot = level[foot_y][left_foot_x];
right_foot = level[foot_y][right_foot_x];
if (left_foot != 0) {
current_tile = left_foot;
} else {
current_tile = right_foot;
}
switch (current_tile) {
case 0 :
over = "air";
speed = air_acceleration;
friction = air_friction;
falling = true;
break;
case 1 :
over = "ground";
speed = ground_acceleration;
friction = ground_friction;
break;
case 2 :
over = "ice";
speed = ice_acceleration;
friction = ice_friction;
break;
case 3 :
over = "treadmill";
speed = ground_acceleration;
friction = ground_friction;
bonus_speed = -treadmill_speed;
break;
case 4 :
over = "treadmill";
speed = ground_acceleration;
friction = ground_friction;
bonus_speed = treadmill_speed;
break;
case 5 :
over = "cloud";
speed = ground_acceleration;
friction = ground_friction;
break;
case 6 :
over = "ladder";
speed = ground_acceleration;
friction = ground_friction;
break;
case 7 :
over = "trampoline";
speed = ground_acceleration;
friction = ground_friction;
break;
case 8 :
over = "spikes";
if (left_foot == 8 and right_foot == 8) {
place_player();
}
}
}
function check_collisions() {
y_pos += yspeed;
get_edges();
// collision to the bottom
if (yspeed>0) {
if ((bottom_right != 0 and bottom_right != 6) or (bottom_left != 0 and bottom_left != 6)) {
// not a cloud...
if (bottom_right != 5 and bottom_left != 5) {
// a trampoline
if ((bottom_right == 7 or bottom_left == 7) and (Math.abs(yspeed)>1)) {
yspeed = yspeed*-1;
jumping = true;
falling = true;
} else {
y_pos = bottom*tile_size-9;
yspeed = 0;
falling = false;
jumping = false;
}
} else {
//cloud
if (prev_bottom<bottom) {
y_pos = bottom*tile_size-9;
yspeed = 0;
falling = false;
jumping = false;
}
}
}
}
// collision to the top
if (yspeed<0) {
if ((top_right != 0 and top_right != 5 and top_right != 6) or (top_left != 0 and top_left != 5 and top_left != 6)) {
y_pos = bottom*tile_size+1+8;
yspeed = 0;
falling = false;
jumping = false;
}
}
x_pos += xspeed;
get_edges();
// collision to the left
if (xspeed<0) {
if ((top_left != 0 and top_left != 5 and top_left != 6 and top_left != 7) or (bottom_left != 0 and bottom_left != 5 and bottom_left != 6 and bottom_left != 7)) {
x_pos = (left+1)*tile_size+6;
xspeed = 0;
}
}
// collision to the right
if (xspeed>0) {
if ((top_right != 0 and top_right != 5 and top_right != 6 and top_right != 7) or (bottom_right != 0 and bottom_right != 5 and bottom_right != 6 and bottom_right != 7)) {
x_pos = right*tile_size-6;
xspeed = 0;
}
}
prev_bottom = bottom;
}
function get_edges() {
// right edge
right = Math.floor((x_pos+5)/tile_size);
// left edge
left = Math.floor((x_pos-6)/tile_size);
// bottom edge
bottom = Math.floor((y_pos+8)/tile_size);
// top edge
top = Math.floor((y_pos-9)/tile_size);
// adjacent tiles
top_right = level[top][right];
top_left = level[top][left];
bottom_left = level[bottom][left];
bottom_right = level[bottom][right];
}
function place_player() {
level_container.hero.removeMovieClip();
x_pos = player[0]*tile_size+tile_size/2;
y_pos = player[1]*tile_size+tile_size/2+1;
level_container.attachMovie("hero", "hero", _root.level_container.getNextHighestDepth(), {_x:x_pos, _y:y_pos});
} |
and play the game.
Can you grab the rightmost coin? (the other is too easy because patrols can’t kill the player)
Download the source code and enjoy.
Nest step… code optimization.
Rate this post: 
(15 votes, average: 5.00 out of 5)
(15 votes, average: 5.00 out of 5)
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This post has 23 comments
Andrius
Awesome. I allredy made spikes but these are good too. And after all stuff, can you make level editor/loader? Thanks!
dix huit
This is great and all but what’s happening with the WordPress arcade plugin?
Gabriel Bianconi
Nice tut… But where’s the WP Arcade?
And BoxHead Tutorial?
And AS3 Versions?
Ok… I know I’m asking too much…
MalQue
Yeah, I think the Boxhead tutorial became vaporware. I was waiting on that one too.
Christo
How can I contact you, I dont think me email is going through ?
Josh
Tower defense tuts lol pls that would make my month
and gh4 is gonna be awesome but tower defense tuts good i guess
EagleVision
Very nice.
I might actually use this! =)
Thank you!
Boxhead tutorial became vaporware I suppose.
But anyhow, keep it up, you’ve improved with the blog. =) …And me = Bad
Javier Lázaro
Code optimization! Cool! I always want to make my code as efficient as possible.
BTW, I hope the Boxhead tutorial will not become vaporware…
Andrius
Not boxhead tut. Nano wars :)
Superdean
aww…so i was WRONG???
i knew i forgot something…
Brad
Its okay superdean, who needs to climb down a ladder when they can jump down right. :)
Emanuele Feronato
christo: info[at]emanueleferonato.com
Basic level editor for a tile based game : Emanuele Feronato
[...] am sharing with you a basic level editor made for the platform engine but easily adaptable to any tile based game made by Daniel Felipe Rodriguez Your recent set of [...]
JDog053
Awesome stuff here Emanuele, I still check daily even if I don’t post a response. I’ve also got a good game idea that uses a tile engine I made before. It should be good, it also hlps that I love Pixel art too. I’d love to get as much money as Nitrome per game, they must get 5k per game atleast, they’re fantastic !
Christo
Ok I try again, allready sent you 3 or 4 emails, perhaps they are not going through, I really dont want too spam you, I’ll try again now.
Thanks
BTW awesome tutorials on your site :)
Jerry
Great work as always.
FrozenHaddock
Excellent engine, definitely going to look into developing it further.
Also, optimisation? What is this ‘optimisation’ you speak of?
/Recently got shouted at for poor optimisation
http://frozenhaddock.co.uk/2008/10/avoiding-game-pt-5b/
Daniel Rodriguez
One interesting tile will be slopes, really dont have any idea to do it.
Michael Brandse
Just found your blog through google, as I am interested in getting some actionscript experience and want to do so while making a side scrolling action adventure. So, there are two particular things that have been on my mind as a completely inexperienced programmer:
-How to implement doors? So that you can switch from the one levelsheet to the other? I have seen some tutorials with doors implemented, but the problem with those were that they relied on going to a different frame. What I am searching for is to replace the level while staying in the same frame; cleaning up one level and loading the other.
-How to implement a scrolling feature, where the player walks to the middle of the screen and as long as the level is long enough the level starts scrolling at that point?
Sorry for the questions already…
oventoaster
Ahm may i ask something sir? this question might have been ask by others on the comment but,
is there a way where the players jump height can be determine on how long the player presses the jump key?
i mean just like how super mario does but of course theres a limit to how high he jumps. i already got the idea but dont really know how to apply it, im thinking of a loop where it checks if the max height of a jump is reached.
New tile based platform engine - part 10 - optimization, doors n’ keys : Emanuele Feronato
[...] how does the script at step 9 determine if a tile is walkable (player can pass through [...]
Gatzä02
hi,
i have a question. Can you write me an e-mail? I wanna send you a try of my platform game…. but I still have two problems.
DannyDaNinja
Cool.