bgfx/examples/37-gpudrivenrendering/varying.def.sc

vec3 a_position  : POSITION;
vec2 a_texcoord0 : TEXCOORD0;
vec4 i_data0     : TEXCOORD7;
vec4 i_data1     : TEXCOORD6;
vec4 i_data2     : TEXCOORD5;
vec4 i_data3     : TEXCOORD4;

vec2  v_texcoord0 : TEXCOORD0;
flat float v_materialID : TEXCOORD0;