phaser/src/tilemaps/dynamiclayer/DynamicTilemapLayerCanvasRenderer.js

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2018 Photon Storm Ltd.
 * @license      {@link https://github.com/photonstorm/phaser/blob/master/license.txt|MIT License}
 */

/**
 * Renders this Game Object with the Canvas Renderer to the given Camera.
 * The object will not render if any of its renderFlags are set or it is being actively filtered out by the Camera.
 * This method should not be called directly. It is a utility function of the Render module.
 *
 * @method Phaser.Tilemaps.DynamicTilemapLayer#renderCanvas
 * @since 3.0.0
 * @private
 *
 * @param {Phaser.Renderer.Canvas.CanvasRenderer} renderer - A reference to the current active Canvas renderer.
 * @param {Phaser.Tilemaps.DynamicTilemapLayer} src - The Game Object being rendered in this call.
 * @param {number} interpolationPercentage - Reserved for future use and custom pipelines.
 * @param {Phaser.Cameras.Scene2D.Camera} camera - The Camera that is rendering the Game Object.
 */
var DynamicTilemapLayerCanvasRenderer = function (renderer, src, interpolationPercentage, camera)
{
    src.cull(camera);

    var renderTiles = src.culledTiles;
    var length = renderTiles.length;
    var image = src.tileset.image.getSourceImage();
    var tileset = this.tileset;

    var tx = src.x - camera.scrollX * src.scrollFactorX;
    var ty = src.y - camera.scrollY * src.scrollFactorY;
    var ctx = renderer.currentContext;

    ctx.save();
    ctx.translate(tx, ty);
    ctx.rotate(src.rotation);
    ctx.scale(src.scaleX, src.scaleY);
    ctx.scale(src.flipX ? -1 : 1, src.flipY ? -1 : 1);

    for (var index = 0; index < length; ++index)
    {
        var tile = renderTiles[index];

        var tileTexCoords = tileset.getTileTextureCoordinates(tile.index);
        if (tileTexCoords === null) { continue; }

        var halfWidth = tile.width / 2;
        var halfHeight = tile.height / 2;

        ctx.save();
        ctx.translate(tile.pixelX + halfWidth, tile.pixelY + halfHeight);

        if (tile.rotation !== 0)
        {
            ctx.rotate(tile.rotation);
        }

        if (tile.flipX || tile.flipY)
        {
            ctx.scale(tile.flipX ? -1 : 1, tile.flipY ? -1 : 1);
        }

        ctx.globalAlpha = camera.alpha * src.alpha * tile.alpha;

        ctx.drawImage(
            image,
            tileTexCoords.x, tileTexCoords.y,
            tile.width, tile.height,
            -halfWidth, -halfHeight,
            tile.width, tile.height
        );

        ctx.restore();
    }

    ctx.restore();
};

module.exports = DynamicTilemapLayerCanvasRenderer;