Something like:
fragment float4 fragment_func(texture2d<half> colorTexture [[texture(0)]],
float2 pointCoord [[point_coord]]) {
constexpr sampler textureSampler (mag_filter::linear,
min_filter::linear);
const half4 colorSampler = colorTexture.sample(textureSampler, pointCoord);
return float4(colorSampler);
}