definition:
| "uchar2"
| "uchar4"
| "char2"
| "char4"
| "uchar2norm"
| "uchar4norm"
| "char2norm"
| "char4norm"
| "ushort2"
| "ushort4"
| "short2"
| "short4"
| "ushort2norm"
| "ushort4norm"
| "short2norm"
| "short4norm"
| "half2"
| "half4"
| "float"
| "float2"
| "float3"
| "float4"
| "uint"
| "uint2"
| "uint3"
| "uint4"
| "int"
| "int2"
| "int3"
| "int4"