SPIRV-Cross/reference/shaders/geom/basic.geom

#version 310 es
#extension GL_EXT_geometry_shader : require
layout(invocations = 4, triangles) in;
layout(max_vertices = 3, triangle_strip) out;

out vec3 vNormal;
in VertexData
{
    vec3 normal;
} vin[3];


void main()
{
    gl_Position = gl_in[0].gl_Position;
    vNormal = (vin[0].normal + vec3(float(gl_InvocationID)));
    EmitVertex();
    gl_Position = gl_in[1].gl_Position;
    vNormal = (vin[1].normal + vec3((4.0 * float(gl_InvocationID))));
    EmitVertex();
    gl_Position = gl_in[2].gl_Position;
    vNormal = (vin[2].normal + vec3((2.0 * float(gl_InvocationID))));
    EmitVertex();
    EndPrimitive();
}