Method preDraw

packages/melonjs/src/renderable/renderable.js:845–906

* Prepare the rendering context before drawing (automatically called by melonJS). * This will apply any defined transforms, anchor point, tint or blend mode and translate the context accordingly to this renderable position. * @see Renderable#draw * @see Renderable#postDraw * @param {CanvasRe

(renderer)

	 * @param {CanvasRenderer|WebGLRenderer} renderer - a renderer object
	 */
	preDraw(renderer) {
		const ax = this.width * this.anchorPoint.x;
		const ay = this.height * this.anchorPoint.y;

		// save renderer context
		renderer.save();

		// apply the defined alpha value
		renderer.setGlobalAlpha(renderer.globalAlpha() * this.getOpacity());

		// apply flip
		if (this._flip.x || this._flip.y) {
			const dx = this._flip.x ? this.centerX - ax : 0;
			const dy = this._flip.y ? this.centerY - ay : 0;

			renderer.translate(dx, dy);
			renderer.scale(this._flip.x ? -1 : 1, this._flip.y ? -1 : 1);
			renderer.translate(-dx, -dy);
		}

		// apply stencil mask if defined
		if (this.mask) {
			renderer.translate(this.pos.x, this.pos.y);
			renderer.setMask(this.mask);
			renderer.translate(-this.pos.x, -this.pos.y);
		}

		// delegate post-effect setup to the renderer.
		// Camera manages its own FBO lifecycle in draw().
		if (!this._postEffectManaged) {
			renderer.beginPostEffect(this);
		}

		if (this.autoTransform === true && !this.currentTransform.isIdentity()) {
			// apply the renderable transformation matrix
			renderer.translate(this.pos.x, this.pos.y);
			renderer.transform(this.currentTransform);
			renderer.translate(-this.pos.x, -this.pos.y);
		}

		// offset by the anchor point — unless this renderable manages its own
		// world placement (see Renderable#applyAnchorTransform), in which case
		// the normalized anchor offset must not leak into the renderer/view
		// transform.
		if (this.applyAnchorTransform !== false) {
			renderer.translate(-ax, -ay);
		}

		// apply the current tint and opacity
		renderer.setTint(this.tint, this.getOpacity());

		// forward depth to the renderer — pushed into the WebGL vertex
		// stream as the `z` component by the batchers. No visible effect
		// under the default ortho projection; required for perspective
		// (Camera3d) to scale and parallax this renderable by distance.
		renderer.setDepth(this.depth);

		// apply blending if different from "normal"