bgfx/examples/19-oit/varying.def.sc

vec2 v_texcoord0 : TEXCOORD0 = vec2(0.0, 0.0);
vec4 v_pos       : TEXCOORD4 = vec4(0.0, 0.0, 0.0, 0.0);

vec3 a_position  : POSITION;
vec2 a_texcoord0 : TEXCOORD0;