Use proper space for forward GI reflections

servers/rendering/renderer_rd/shaders/forward_clustered/scene_forward_clustered.glsl

@@ -1305,24 +1305,26 @@ void fragment_shader(in SceneData scene_data) {
 	}
 
 	if (sc_use_forward_gi && bool(instances.data[instance_index].flags & INSTANCE_FLAGS_USE_VOXEL_GI)) { // process voxel_gi_instances
-
 		uint index1 = instances.data[instance_index].gi_offset & 0xFFFF;
-		vec3 ref_vec = normalize(reflect(-view, normal));
-		ref_vec = mix(ref_vec, normal, roughness * roughness);
+		// Make vertex orientation the world one, but still align to camera.
+		vec3 cam_pos = mat3(scene_data.inv_view_matrix) * vertex;
+		vec3 cam_normal = mat3(scene_data.inv_view_matrix) * normal;
+		vec3 ref_vec = mat3(scene_data.inv_view_matrix) * normalize(reflect(-view, normal));
+
 		//find arbitrary tangent and bitangent, then build a matrix
-		vec3 v0 = abs(normal.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(0.0, 1.0, 0.0);
-		vec3 tangent = normalize(cross(v0, normal));
-		vec3 bitangent = normalize(cross(tangent, normal));
-		mat3 normal_mat = mat3(tangent, bitangent, normal);
+		vec3 v0 = abs(cam_normal.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(0.0, 1.0, 0.0);
+		vec3 tangent = normalize(cross(v0, cam_normal));
+		vec3 bitangent = normalize(cross(tangent, cam_normal));
+		mat3 normal_mat = mat3(tangent, bitangent, cam_normal);
 
 		vec4 amb_accum = vec4(0.0);
 		vec4 spec_accum = vec4(0.0);
-		voxel_gi_compute(index1, vertex, normal, ref_vec, normal_mat, roughness * roughness, ambient_light, specular_light, spec_accum, amb_accum);
+		voxel_gi_compute(index1, cam_pos, cam_normal, ref_vec, normal_mat, roughness * roughness, ambient_light, specular_light, spec_accum, amb_accum);
 
 		uint index2 = instances.data[instance_index].gi_offset >> 16;
 
 		if (index2 != 0xFFFF) {
-			voxel_gi_compute(index2, vertex, normal, ref_vec, normal_mat, roughness * roughness, ambient_light, specular_light, spec_accum, amb_accum);
+			voxel_gi_compute(index2, cam_pos, cam_normal, ref_vec, normal_mat, roughness * roughness, ambient_light, specular_light, spec_accum, amb_accum);
 		}
 
 		if (amb_accum.a > 0.0) {