Animate Sprite transparency

🌵 Needle Engine
1

I’m trying to create a smooth dimming effect by animating a sprite’s transparency. I’ve tried animating the main color alpha channel as well as the material tint, with no luck. I’m animating via a timeline, if that matters. Is there a way to achieve this?

Original Post on Discord

by user 300386587278049291

2

Hello there – I’m an AI powered assistant :robot: that might be able to help you with your question. Would you like me to try helping you?

How it works:
Reply to the messages of the bot that end with a thread_id to interact with it and ask follow-up questions. You can also mention the bot directly in this channel to get help.

Help requested: please wait a moment…

3

Here is what I found for you :brain: Discord

4

To achieve a smooth dimming effect for a sprite’s transparency in Needle Engine, you can animate the color property’s alpha channel of the SpriteRenderer component. The SpriteRenderer has a color field of type RGBAColor, which includes an alpha value for transparency. Here’s an example of how you could implement this by gradually decreasing the alpha value over time in the update method:

import { SpriteRenderer, RGBAColor, Vec2 } from "@needle-tools/engine"; // Import necessary components

export class DimmingSprite extends SpriteRenderer {
    startFadeDuration: number = 1; // Duration for the fade in seconds
    private elapsedTime: number = 0; // Time elapsed since the start of the fade
    private startColor: RGBAColor; // The initial color of the sprite

    awake() {
        this.startColor = this.color ? new RGBAColor(this.color.r, this.color.g, this.color.b, this.color.a) : new RGBAColor(1, 1, 1, 1);
    }

    update() {
        if (this.elapsedTime < this.startFadeDuration) {
            this.elapsedTime += this.context.time.deltaTime;
            const alpha = 1 - (this.elapsedTime / this.startFadeDuration);
            this.color.a = this.startColor.a * alpha;
            this.transparent = this.color.a < 1;
            this.updateSprite();
        }
    }
}

Ensure you have initialized the SpriteRenderer with the color field set, and then gradually change the alpha channel (a) over time based on the startFadeDuration property. Remember to set the transparent flag to true for transparency to have an effect (see the documentation).

1 messages left GPT 4
thread_DgS2AuRQkddwiTSfd4H7AbP6
Thanks for your feedback!

5

I want to use the timeline or an animator as there are several other components to the animation

by user 300386587278049291