What is the difference between polyline and polylinevolume，In terms of image texture settings？
I want to custom material by glsl，but why the image is not displayed？
for example
`czm_material czm_getMaterial(czm_materialInput materialInput)
{
czm_material material = czm_getDefaultMaterial(materialInput);
vec2 st = materialInput.st;
vec4 colorImage = texture2D(image, vec2(fract(st.s*repeat.x - time),fract(st.t*repeat.y)* czm_pi));
material.alpha = colorImage.a * color.a;
material.diffuse = color.rgb;
return material;
}`;