leaflet 雷达探测的shader

0.效果：

1.定点着色器：

attribute vec2 aCRSCoords;        
        attribute vec2 aExtrudeCoords;
        uniform mat4 uTransformMatrix;     
        uniform vec2 uPixelSize;
        uniform float uNow;
        
        attribute float adm0cap;

        varying vec2 vExtrudeCoords;
        
        varying float vTimeNow ;

        varying vec2 vCRSCoords;

        void main(void) {
            vExtrudeCoords = aExtrudeCoords;
            vTimeNow = uNow;

            gl_Position = uTransformMatrix * vec4(aCRSCoords, 1.0, 1.0);
    
            // If not, just place a smaller kitten.
            gl_Position += vec4(aExtrudeCoords * uPixelSize * 100.0, 0.0, 0.0);   //这里设置像素大小。
            
        }

2.片元着色器

uniform sampler2D uTexture0;
        precision highp float;
        varying float vTimeNow ;
        varying vec2 vExtrudeCoords;

        void main(void) {
            // Our extrude coordinates go from [-1,-1] to [1,1],
            // but the texture lookup needs coords in the [0,0]-[1,1]
            // range.
            vec2 texelCoords;
            texelCoords.x = (vExtrudeCoords.x + 1.0) / 2.0;
            texelCoords.y = (1.0 - vExtrudeCoords.y) / 2.0;
            
            // Perform a texture lookup
            vec4 texelColour = texture2D(uTexture0, texelCoords);
            texelColour.a = texelColour.a * abs( 
                    sin(
                        -vTimeNow/500.0 + length(texelCoords.xy)*10.0
                        ) 
                    );
            
            // Use the colour from the texture as the colour for this pixel
            gl_FragColor = texelColour;
        }