phaser/src/gameobjects/layer/LayerCanvasRenderer.js

/**
 * @author       Richard Davey <rich@photonstorm.com>
 * @copyright    2022 Photon Storm Ltd.
 * @license      {@link https://opensource.org/licenses/MIT|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.GameObjects.Layer#renderCanvas
 * @since 3.50.0
 * @private
 *
 * @param {Phaser.Renderer.Canvas.CanvasRenderer} renderer - A reference to the current active Canvas renderer.
 * @param {Phaser.GameObjects.Layer} layer - The Game Object being rendered in this call.
 * @param {Phaser.Cameras.Scene2D.Camera} camera - The Camera that is rendering the Game Object.
 */
var LayerCanvasRenderer = function (renderer, layer, camera)
{
    var children = layer.list;

    if (children.length === 0)
    {
        return;
    }

    layer.depthSort();

    var layerHasBlendMode = (layer.blendMode !== -1);

    if (!layerHasBlendMode)
    {
        //  If Layer is SKIP_TEST then set blend mode to be Normal
        renderer.setBlendMode(0);
    }

    var alpha = layer._alpha;

    if (layer.mask)
    {
        layer.mask.preRenderCanvas(renderer, null, camera);
    }

    for (var i = 0; i < children.length; i++)
    {
        var child = children[i];

        if (!child.willRender(camera))
        {
            continue;
        }

        var childAlpha = child.alpha;

        if (!layerHasBlendMode && child.blendMode !== renderer.currentBlendMode)
        {
            //  If Layer doesn't have its own blend mode, then a child can have one
            renderer.setBlendMode(child.blendMode);
        }

        //  Set parent values
        child.setAlpha(childAlpha * alpha);

        //  Render
        child.renderCanvas(renderer, child, camera);

        //  Restore original values
        child.setAlpha(childAlpha);
    }

    if (layer.mask)
    {
        layer.mask.postRenderCanvas(renderer);
    }
};

module.exports = LayerCanvasRenderer;