DBM Game Engine

Members

This engine was made by David Lee and Brickson Cain.

Notable Features

We designed the engine with the main goals being the simulation of 3d in a 2d engine, and joypad input. We thought that these would be fun to apply to different genres, with David wanting to make a platformer and Brickson wanting to make a Pole Position-style racing game.

Current State

The engine can draw circles, squares and lines, all taking their typical 2-dimensional inputs as well as depth inputs. As the depth value gets larger, the object is drawn smaller and smaller, and is positioned closer and closer to the center of the screen, mimicing a one-point perspective drawing. B_Racer (by Brickson Cain) currently demonstrates these features of the engine by drawing a background that mimics a road with lines moving toward the camera and a simple car, making it seem like the camera is following a car as it drives down the tunnel. There are now opponent cars as well, which move towards the horizon at different speeds depending on the speed of the player's car.

The engine supports input from keyboard and joystick. Keyboard can detect keys. Joystick can detect if a joystick is connected, if a button is pressed, and what the current axis position is.

Key 2D platformer features such as importing tile map, sprite sheet, animation, collision, detect area enter and text pringing is supported.

In game photos

These are the games built using DBM Game Engine

Documentation

Engine

draw_circle(long x, long y, lons z, long r, long R, long G, long B, long A)
Draw a circle centered at (x,y) at depth z with radius r in the window. It will have a color with RGB value, and its transparency will be decided by A.
Parameters
long x position
long y position
long z depth
long r radius
long R red
long G green
long B blue
long A alpha
Returns
Nothing

draw_rect(long x, long y, lons z, long w, long h, long R, long G, long B, long A)
Draw a rectangle centered at (x,y) at depth z with width w and height h in the window. It will have a color with RGB value, and its transparency will be decided by A.
Parameters
long x position
long y position
long z depth
long w width long h height
long R red
long G green
long B blue
long A alpha
Returns
Nothing

draw_line(long x1, long y1, lons z1, long x2, long y2, long z2, long R, long G, long B)
Draw a line from (x1,y1,z1) to (x2,y2,z2) in the window. It will have a color with RGB value.
Parameters
long x1 position
long y1 position
long z1 position
long x2 position
long y2 position
long z2 position
long R red
long G green
long B blue
Returns
Nothing

print(string font, string string, int x, int y, int size)
Print text at (x, y)
Parameters
font path to the font file
string string to print
x x coordinate to print
y y coordinate to print
size size of the text
Returns
Nothing

load_tilemap(string filename, string spriteName, int offsetX, int offsetY)
Import tilemap json file and spritesheet image from the path filenam and spriteName respectively. Apply offset of offsetX and offsetY.
Parameters
filename path to the tilemap json file
spriteName path to the sprite sheet image file
offsetX offset x
offsetY offset y
Returns
Nothing

draw_map()
Draw loaded map and spritesheet.
Parameters
None
Returns
Nothing

is_colliding(int x, int y, int w, int h)
Check if the w width, h height rectangular area with (x,y) top-left collides with any collidable tile of the map.
Parameters
x top left x coordinate of the rectangular area to check (e.g, player.x)
y top left y coordinate of the rectangular area to check (e.g, player.y)
w width of the rectangular area to check (e.g, player.w)
h heigh of the rectangular area to check (e.g, player.h)
Returns
Nothing

add_area2d(string name, int x, int y, int w, int h)
Create a 2D area with the given name. It is created to call is_in_area() Parameters
name Name of the area
x top left x coordinate of the rectangular area
y top left y coordinate of the rectangular area
w width of the area
h heigh of the area
Returns
Nothing

is_in_area(string name, int x, int y, int w, int h)
Return true if the rectangle that has x and y as the top-left and wwidth hheight is in the name2d area.
Parameters
name Name of the area to check
x top left x coordinate of the rectangle area to check. (e.g, player.x)
y top left y coordinate of the rectangle area to check. (e.g, player.y)
w width of the area to check (e.g, player.h)
h heigh of the area to check (e.g, player.x)
Returns
True if is area, False if not.

draw_tile(int tile_id, int x, int y, int tileSize)
Draw a tile with index number of tile_id from the loaded sprite sheet at (x,y). This tile must have width and height of tileSize.
Parameters
tile_id Index number of the tile to draw
x x coordinate to draw at
y y coordinate to draw at
tileSize width and height of the tile
Returns
Nothing.

draw_sprite_frame(string filename, string frame_index, int x, int y, int frame_w, int frame_h, int scale, int faceRight)
Draw a sprite with index number of frame_index from spritesheet filename at (x, y). The sprite must have width of frame_w and height of frame_h. The sprite is scaled by scale times and flips vertically if faceRight is False.
Parameters
filename Path of the spritesheet to use
frame_index index number of the sprite to draw
x x coordinate to draw at (E.g, player.x)
y y coordinate to draw at (E.g, player.y)
frame_w width of the sprite
frame_h height of the sprite
scale sprite is drawn this times bigger
faceRight flips if false
Returns
Nothing.

tilemap

Tilemap is a json file that contains the information of the map with following structure:

{
  "tileSize": 16,
  "mapWidth": 38,
  "mapHeight": 14,
  "layers": [
    {
      "name": "Background",
      "tiles": [
        {
          "id": "26",
          "x": 0,
          "y": 6
        },
      ],
      "collider": false
    },
    {
     // more layers
    }
  ]
}

Engine.keyboard

isKeyPressed(string)
Check if a key is pressed.
Parameters
string key to check
Returns
true if the key is pressed, false otherwise

Keys

Key	Description
unknown	Unhandled key.
a ~ z	The lowercase alphabet keys.
num0 ~ num9	Number keys at the top of the keyboard.
escape	Escape key.
lcontrol	Left Control key.
lshift	Left Shift key.
lalt	Left Alt key.
lsystem	Left system key (e.g., Windows key).
rcontrol	Right Control key.
rshift	Right Shift key.
ralt	Right Alt key.
rsystem	Right system key.
menu	Menu key.
lbracket	Left square bracket [.
rbracket	Right square bracket ].
semicolon	Semicolon ;.
comma	Comma ,.
period	Period ..
quote	Quote '.
slash	Slash /.
backslash	Backslash \.
tilde	Tilde ~.
equal	Equal sign =.
hyphen	Hyphen -.
space	Space bar.
enter	Enter/Return key.
backspace	Backspace key.
tab	Tab key.
pageup	Page Up key.
pagedown	Page Down key.
end	End key.
home	Home key.
insert	Insert key.
delete	Delete key.
add	Numpad +.
subtract	Numpad -.
multiply	Numpad *.
divide	Numpad /.
left	Left arrow key.
right	Right arrow key.
up	Up arrow key.
down	Down arrow key.
numpad0 ~ numpad9	Number pad keys 0–9.
f1 ~ f15	Function keys F1 to F15.
pause	Pause/Break key.

Engine.joystick

isConnected(int)
Return if joystick is connected
Parameters
int Index of the joystick to check
Returns
true if the joystick is connected, false otherwise

isButtonPressed(int, int)
Check if a joystick button is pressed.
If the joystick is not connected, this function returns false.
Parameters
int Index of the joystick
int Button to check
Returns
true if the button is pressed, false otherwise

getAxisPosition(int, int)
Get the current position of a joystick axis.
If the joystick is not connected, this function returns 0.
Parameters
int Index of the joystick
int Axis to check
Returns
urrent position of the axis, in range [-100 .. 100]