Tile Experiment

A simple javascript experiment with both static and scrolling tiles.

The Game Object

Everything is accessible through the game object, which you mess around with from the Web Console in your browser.

Explore the game object below!

Json Tile maps

The Game Maps are stored in JSON format, for simplicity. The default map is fetched when the page is loaded, but they can be loaded interactively through the Browser Console with game.FetchMap(URL), where URL is the location of the .json file.

Example

{
    "Map": 
    {
        "Width": 4,
        "Height": 4,
        "Data":
        [
            [
                [1,2,3,4],
                [1,2,3,4],
                [1,2,3,4],
                [1,2,3,4]
            ],
            [
                [0,0,0,5],
                [0,0,0,5],
                [0,0,0,5],
                [0,0,0,5]
            ]
        ]
    },
    "Atlas": 
    {
        "ImagePath": "https://example.com/tiles.png",
        "ImageCols": 5,
        "TileWidth": 64,
        "TileHeight": 64,
    },
}

Field Definitions

Map Definitions

Atlas Field Definitions

The Atlas field contains information about the image file that is used by the logical map. It gives meaning the numbers in the Data field. The "Atlas image" can also be referred to as the "source image".

Notes

Notes about Data Field

If the data field were written using array[index] notation, then it would look like: data[layer][row][column]. Note that this implies data[layer][y][x], which will probably cause confusion at some point, but makes much more sense than the alternative looking at the map data.

Each Layer is an array of "Rows": each "Row" is an array of numbers. Each number corresponds to the type of Tile. 0 always means empty. The order of the layers in the json is the order that they will be drawn onto the Canvas. Each layer will be drawn on top of the previous layer.

Note about ImageCols

The ImageCols (image columns) field is used to convert the MapData numbers into their corresponding image in the Atlas. For example, if ImageCols = 3, then MapData number 4 would reference the 1st column of the 2nd row in the source image.

Source Image Example with ImageCols = 3, and their corresponding MapData numbers.

123
456
789

Just so the pattern is obvious, here are the first few conversions:

n   y   x

1   0   0
2   0   1
3   0   2
4   1   0
5   1   1
6   1   2
7   2   0
8   2   1
9   2   2

Python code:

y, x = divmod(DataNum-1, ImageCols)

Javascript code for the conversion (assumes positive numbers):

function DataNumberToLocation(DataNum, ImageCols) {
    return {
        "y": ~~((DataNum-1) / ImageCols)
        "x": (DataNum-1) % ImageCols
    }
}

See json/example.json for a current working json example.

Credits

Thank you Mozilla Developer Network for the web documentation and tutorials!

Specifically:

• https://developer.mozilla.org/en-US/docs/Games/Techniques/Tilemaps
• https://github.com/mozdevs/gamedev-js-tiles