Fix NaNs when no lights exist in scene

Author: JMS55

crates/bevy_solari/src/realtime/specular_gi.wgsl

@@ -145,8 +145,8 @@ fn nee_mis_weight(inverse_p_light: f32, brdf_rays_can_hit: bool, wo_tangent: vec
     let wi_tangent = vec3(dot(wi, T), dot(wi, B), dot(wi, N));
 
     let p_light = 1.0 / inverse_p_light;
-    let p_bounce = max(0.0, ggx_vndf_pdf(wo_tangent, wi_tangent, ray_hit.material.roughness));
-    return power_heuristic(p_light, p_bounce);
+    let p_bounce = ggx_vndf_pdf(wo_tangent, wi_tangent, ray_hit.material.roughness);
+    return max(0.0, power_heuristic(p_light, p_bounce));
 }
 
 // Don't adjust the size of this struct without also adjusting GI_RESERVOIR_STRUCT_SIZE.