add emission gbuffer attachment

res/shaders/main.glslv

@@ -15,6 +15,7 @@ out vec3 a_realnormal;
 out vec4 a_torchLight;
 out vec3 a_skyLight;
 out vec4 a_modelpos;
+out float a_emission;
 
 uniform mat4 u_model;
 uniform mat4 u_proj;
@@ -51,6 +52,7 @@ void main() {
     mat4 viewmodel = u_view * u_model;
     a_distance = length(viewmodel * vec4(pos3d, 0.0));
     a_fog = calc_fog(length(viewmodel * vec4(pos3d * FOG_POS_SCALE, 0.0)) / 256.0);
+    a_emission = v_normal.w;
 
     vec4 viewmodelpos = u_view * a_modelpos;
     a_position = viewmodelpos.xyz;