sfatihk / React World

Few layers, scroll event manipulations and of course famous movie and game characters. Live Demo

This document aims to explain how React World works.

There are 4 topics: withScroll, SceneObject, MainLayer and Player

withScroll

• Scroll event handling and computing processes takes place within this component.
• And re-adjust page height for scroll manipulation. (or fake scroll page)
• withScroll is High Order Component(HOC) and provides onScrolling, scroll and scrollDirection datas to wrapped component. Also it covered whole App.

usage :

import withScroll from "./withScroll";

class wrappedComp ...{
    ...

    const {scroll,onScrolling,scrollDirection} = this.props

    ...
}

export default withScroll(wrappedComp);

withScroll props :

SceneObject

• I created a standard for inter-component compatibility. Then i called it SceneObject, like GameObject in Unity Game Engine.
• Every components are derived from the SceneObject.
• You can set component position, scale and rotation easily.

usage :

import SceneObject from "./SceneObject";

const Enemy = props => {
  return (
    <SceneObject
      name="Enemy"
      transform={{
        position: props.transform.position, //or {x:100,y:"50%"}
        scale: { x: 200, y: 203 }, //or {x:"100%,y:"100%"}
        rotation: 180,
        opacity: 1
      }}
      bgRepeat={false}
      color={"none"}
      imgUrl={enemyPicture}
      animation={props.canAnimate ? animateNow : ""}
    />
  );
};

export default Enemy;

SceneObject options :

Main Layers

• There are 3 main layers. Sky,Environment and Ground.
• Scenes are defined in the main layers, so if main layer move whole scene will move.
• Every main layer has a animations structure, like movement instructions.
• The behavior related to scroll movement is defined in this structure.
• Animations, includes start-finish scroll ranges and start-finish layer position.
• Animation Calculation function calculates every scroll movement steps and returns the new position.

example of animation structure :

//...
this.animations = {
      //it will swipe ground layer -10000px on x axis at 0-5050 scroll range
      //wont move on y axis
      "0-5050": { position: { x: [0, -10000], y: [0, 0] } },

      //it will swipe ground layer -10000px to -15000 on x axis and
      //it will swipe ground layer 700px on x yxis at at 5050-7050 scroll range and,
      "5050-7050": { position: { x: [-10000, -15000], y: [0, 700] } },
    };
  }

  //will calculate when scroll change
  shouldComponentUpdate(nextProps, nextState) {
    if (this.props.scroll !== nextProps.scroll) {
      this.transform = AnimateCalculation(this.animations, nextProps.scroll);
      return true;
    }

    return false;
  }

Player

• Player is actually a main layer. But didn't move x or y axis.
• Player includes 2 animations: hero/skin changing and jumping, and they defined in animation structure.

animations example in for jump

const animations = {
  //vader jumps
  "8000-8650": { startHeight: 200, endHeight: 100, type: "fall" },
  "8700-9320": { startHeight: 100, endHeight: 200, type: "jump" },
  "9370-9800": { startHeight: 200, endHeight: 100, type: "fall" },
...
}

animations example in hero/skin changing and walking

const heroes = {
  gandalf: {
    speed: 30,
    delimiter: 10, // speed / step
    frames: [
      [gandalf_01, gandalf_02, gandalf_03],
      [gandalf_11, gandalf_12, gandalf_13]
    ] //left - right
  }
  ...
}
...
const heroesShowUp = {
  "0-7050": { hero: "gandalf" },
  "7050-12100": { hero: "vader" },

I hope you enjoyed it

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