jtBaseApp/node_modules/cesium/Source/Shaders/Materials/PolylineOutlineMaterial.glsl

uniform vec4 color;
uniform vec4 outlineColor;
uniform float outlineWidth;

varying float v_width;

czm_material czm_getMaterial(czm_materialInput materialInput)
{
    czm_material material = czm_getDefaultMaterial(materialInput);

    vec2 st = materialInput.st;
    float halfInteriorWidth =  0.5 * (v_width - outlineWidth) / v_width;
    float b = step(0.5 - halfInteriorWidth, st.t);
    b *= 1.0 - step(0.5 + halfInteriorWidth, st.t);

    // Find the distance from the closest separator (region between two colors)
    float d1 = abs(st.t - (0.5 - halfInteriorWidth));
    float d2 = abs(st.t - (0.5 + halfInteriorWidth));
    float dist = min(d1, d2);

    vec4 currentColor = mix(outlineColor, color, b);
    vec4 outColor = czm_antialias(outlineColor, color, currentColor, dist);
    outColor = czm_gammaCorrect(outColor);

    material.diffuse = outColor.rgb;
    material.alpha = outColor.a;

    return material;
}