export const vertexShader = `
    attribute float randam;
    attribute float sprite;
    attribute float centerHeight;  //add
    
    //uniform float fireHeight;  //add 
    uniform float time;
    uniform float size;
    uniform float heightOfNearPlane;
    
    
    
    
    //varying float heightRatio;
    varying float vSprite;
    varying float vOpacity; 
    float PI = 3.14;

    float quadraticIn( float t ) 
    { 
        float tt = t * t;
        return tt * tt; 
        //变化曲线  越来越快
    } 
    
    void main() {
        float progress = fract( time + ( 2.0 * randam - 1.0 ) );
        float progressNeg = 1.0 - progress;
        float ease = quadraticIn( progress );
        float influence = sin( PI * ease );
        //vec3 newPosition = position * vec3( 1.0,  1.0 , ease);
        vec3 newPosition = position;
        newPosition.z = (newPosition.z - centerHeight) * ease + centerHeight;
         
        gl_Position = projectionMatrix * modelViewMatrix * vec4( newPosition, 1.0 );
        gl_PointSize = ( heightOfNearPlane * size ) / gl_Position.w;
        vOpacity = min( influence * 4.0, 1.0 ) * progressNeg;
        vSprite = sprite;
        
        //heightRatio = (newPosition.z - centerHeight) / fireHeight ;
        
    }
` 

export const fragmentShader = `
    uniform vec3 color;
    uniform sampler2D u_sampler;

    varying float vSprite;
    varying float vOpacity;
    //varying float heightRatio;

    void main() 
    {
        
       
        vec2 texCoord = vec2(gl_PointCoord.x * 0.25 + vSprite, gl_PointCoord.y);
         
        gl_FragColor = vec4( texture2D( u_sampler, texCoord ).xyz * color * vOpacity, 1.0 );
          
         
    }
`