source/bubel/ecs/core.d

@@ -92,4 +92,20 @@ static struct ECS
 	{
 		alias ExcludedComponents = T;
 	}
+
+	/************************************************************************************************************************
+	Make list of readonly ependencies. This template get strings as arguments. Should be added inside System structure.
+	*/
+	mixin template ReadOnlyDependencies(T...)
+	{
+		alias ReadOnlyDependencies = T;
+	}
+
+	/************************************************************************************************************************
+	Make list of writable ependencies. This template get strings as arguments. Should be added inside System structure.
+	*/
+	mixin template WritableDependencies(T...)
+	{
+		alias WritableDependencies = T;
+	}
 }

source/bubel/ecs/manager.d

@@ -452,6 +452,8 @@ export struct EntityManager
             uint excluded = 1;
             uint optional = 1;
             uint req = 1;
+            uint readonly_dep = 1;
+            uint writable_dep = 1;
         }
 
         static ComponentsCounts getComponentsCounts()()
@@ -532,7 +534,22 @@ export struct EntityManager
                     {
                         components_counts.excluded++;
                     }
+                }
+            }
 
+            static if (__traits(hasMember, Sys, "ReadOnlyDependencies"))
+            {
+                foreach (str; Sys.ReadOnlyDependencies)
+                {
+                    components_counts.readonly_dep++;
+                }
+            }
+
+            static if (__traits(hasMember, Sys, "WritableDependencies"))
+            {
+                foreach (str; Sys.WritableDependencies)
+                {
+                    components_counts.writable_dep++;
                 }
             }
 
@@ -568,6 +585,16 @@ export struct EntityManager
                 return m_req[0 .. m_req_counter];
             }
 
+            CompInfo[] readonlyDeps()
+            {
+                return m_readonly_dep[0 .. m_readonly_dep_counter];
+            }
+
+            CompInfo[] writableDeps()
+            {
+                return m_writable_dep[0 .. m_writable_dep_counter];
+            }
+
             void addReadonly(CompInfo info)
             {
                 m_readonly[m_readonly_counter++] = info;
@@ -593,17 +620,31 @@ export struct EntityManager
                 m_req[m_req_counter++] = info;
             }
 
+            void addReadonlyDep(CompInfo info)
+            {
+                m_readonly_dep[m_readonly_dep_counter++] = info;
+            }
+
+            void addWritableDep(CompInfo info)
+            {
+                m_writable_dep[m_writable_dep_counter++] = info;
+            }
+
             CompInfo[counts.readonly] m_readonly;
             CompInfo[counts.mutable] m_mutable;
             CompInfo[counts.excluded] m_excluded;
             CompInfo[counts.optional] m_optional;
             CompInfo[counts.req] m_req;
+            CompInfo[counts.readonly_dep] m_readonly_dep;
+            CompInfo[counts.writable_dep] m_writable_dep;
 
             uint m_readonly_counter;
             uint m_mutable_counter;
             uint m_excluded_counter;
             uint m_optional_counter;
             uint m_req_counter;
+            uint m_readonly_dep_counter;
+            uint m_writable_dep_counter;
 
             string entites_array;
         }
@@ -616,6 +657,8 @@ export struct EntityManager
             size_t excluded = components_info.excluded.length;
             size_t read_only = components_info.readonly.length;
             size_t modified = components_info.mutable.length;
+            size_t read_only_deps = components_info.readonlyDeps.length;
+            size_t writable_deps = components_info.writableDeps.length;
 
             if (req > 0)
                 system.m_components = Mallocator.makeArray!ushort(req);
@@ -627,6 +670,10 @@ export struct EntityManager
                 system.m_read_only_components = Mallocator.makeArray!ushort(read_only);
             if (modified > 0)
                 system.m_modified_components = Mallocator.makeArray!ushort(modified);
+            if (read_only_deps > 0)
+                system.m_readonly_dependencies = Mallocator.makeArray!ushort(read_only_deps);
+            if (writable_deps > 0)
+                system.m_writable_dependencies = Mallocator.makeArray!ushort(writable_deps);
 
         }
 
@@ -714,6 +761,22 @@ export struct EntityManager
                 }
             }
 
+            static if (__traits(hasMember, Sys, "ReadOnlyDependencies"))
+            {
+                foreach (str; Sys.ReadOnlyDependencies)
+                {
+                    components_info.addReadonlyDep(CompInfo(str, str));
+                }
+            }
+
+            static if (__traits(hasMember, Sys, "WritableDependencies"))
+            {
+                foreach (str; Sys.WritableDependencies)
+                {
+                    components_info.addWritableDep(CompInfo(str, str));
+                }
+            }
+
             return components_info;
         }
 
@@ -809,7 +872,6 @@ export struct EntityManager
                             ~ "\" due to non existing component \"" ~ comp_info.type ~ "\".");
                 system.m_modified_components[iii] = comp;
             }
-
         }
 
         static void fillInputData(ref Sys.EntitiesData input_data, EntityInfo* info,
@@ -1059,6 +1121,32 @@ export struct EntityManager
 
         genCompList(system, components_map);
 
+        foreach (iii, comp_info; components_info.readonlyDeps)
+        {
+            ushort comp = external_dependencies_map.get(cast(const (char)[]) comp_info.type, ushort.max);
+            version (D_BetterC)
+                assert(comp != ushort.max,
+                        "Can't register system \"" ~ Sys.stringof
+                        ~ "\" due to non existing dependency.");
+            else
+                assert(comp != ushort.max, "Can't register system \"" ~ Sys.stringof
+                        ~ "\" due to non existing dependency \"" ~ comp_info.type ~ "\".");
+            system.m_readonly_dependencies[iii] = comp;
+        }
+        
+        foreach (iii, comp_info; components_info.writableDeps)
+        {
+            ushort comp = external_dependencies_map.get(cast(char[]) comp_info.type, ushort.max);
+            version (D_BetterC)
+                assert(comp != ushort.max,
+                        "Can't register system \"" ~ Sys.stringof
+                        ~ "\" due to non existing dependency.");
+            else
+                assert(comp != ushort.max, "Can't register system \"" ~ Sys.stringof
+                        ~ "\" due to non existing dependency \"" ~ comp_info.type ~ "\".");
+            system.m_writable_dependencies[iii] = comp;
+        }
+
         ushort sys_id = systems_map.get(cast(char[]) Sys.stringof, ushort.max);
         if (sys_id < systems.length)
         {
@@ -1118,6 +1206,11 @@ export struct EntityManager
         return cast(ushort)(passes.length - 1);
     }
 
+    export void registerDependency(const(char)[] name)
+    {
+        return external_dependencies_map.add(name, cast(ushort)external_dependencies_map.length);
+    }
+
     /************************************************************************************************************************
     Register component into EntityManager.
     */
@@ -2820,10 +2913,45 @@ export struct EntityManager
             foreach (caller; pass.system_callers)
             {
                 index = 0;
+                ///gets systems which are excluding each other
                 out_for: foreach (caller2; pass.system_callers)
                 {
                     if (caller is caller2)
                         continue;
+
+                    ///check for external dependencies
+                    foreach (cmp; caller.system.m_readonly_dependencies)
+                    {
+                        foreach (cmp2; caller2.system.m_writable_dependencies)
+                        {
+                            if (cmp == cmp2)
+                            {
+                                exclusion[index++] = caller2;
+                                continue out_for;
+                            }
+                        }
+                    }
+                    foreach (cmp; caller.system.m_writable_dependencies)
+                    {
+                        foreach (cmp2; caller2.system.m_readonly_dependencies)
+                        {
+                            if (cmp == cmp2)
+                            {
+                                exclusion[index++] = caller2;
+                                continue out_for;
+                            }
+                        }
+                        foreach (cmp2; caller2.system.m_writable_dependencies)
+                        {
+                            if (cmp == cmp2)
+                            {
+                                exclusion[index++] = caller2;
+                                continue out_for;
+                            }
+                        }
+                    }
+
+                    ///check for component dependencies
                     foreach (cmp; caller.system.m_read_only_components)
                     {
                         foreach (cmp2; caller2.system.m_modified_components)
@@ -2923,6 +3051,18 @@ export struct EntityManager
         }
     }
 
+    const (UpdatePass)* getPass(const (char)[] name)
+    {
+        ushort id = getPassID(name);
+        if(id == ushort.max)return null;
+        return passes[id];
+    }
+
+    ushort getPassID(const (char)[] name)
+    {
+        return passes_map.get(name, ushort.max);
+    }
+
     /************************************************************************************************************************
     Component info;
     */
@@ -3350,6 +3490,7 @@ export struct EntityManager
     HashMap!(char[], ushort) components_map;
     HashMap!(const(char)[], ushort) events_map;
     HashMap!(const(char)[], ushort) passes_map;
+    HashMap!(const(char)[], ushort) external_dependencies_map;
     Vector!System systems;
     Vector!ComponentInfo components;
     Vector!EventInfo events;

source/bubel/ecs/system.d

@@ -129,6 +129,9 @@ package:
     ushort[] m_read_only_components;
     ushort[] m_modified_components;
 
+    ushort[] m_readonly_dependencies;
+    ushort[] m_writable_dependencies;
+
     EntityManager.SystemCaller* m_any_system_caller;
 
     EventCaller[] m_event_callers;

source/bubel/ecs/vector.d

@@ -62,11 +62,11 @@ public:
 		used = 0;
 	}
 
-	export bool empty() {
+	export bool empty() const {
 		return (used == 0);
 	}
 
-	export size_t length() {
+	export size_t length() const {
 		return used;
 	}
 
@@ -197,9 +197,9 @@ public:
 		assert(ok, "There is no such an element in vector");
 	}
 
-	export ref T opIndex(size_t elemNum) {
+	export ref T opIndex(size_t elemNum) const {
 		//debug assert(elemNum < used, "Range violation [index]");
-		return array.ptr[elemNum];
+		return *cast(T*)&array.ptr[elemNum];
 	}
 
 	export auto opSlice() {

tests/basic.d

@@ -1221,3 +1221,278 @@ unittest
 
     gEM.end();
 }
+
+@("SystemDependencies")
+unittest
+{
+    struct TestSystem
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            uint length;
+            @readonly CInt[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem2
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            uint length;
+            CInt[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem3
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            uint length;
+            @readonly CInt[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem4
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            uint length;
+            CInt[] int_;
+            CLong[] long_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem5
+    {
+        mixin ECS.System;
+
+        struct EntitiesData
+        {
+            uint length;
+            @readonly CLong[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    void func1(TestSystem.EntitiesData entities)
+    {
+        foreach(i;0 .. entities.length)
+        {
+            entities.int_[i] += entities.int_[i] / 2;
+        }
+    }
+
+    void func2(TestSystem.EntitiesData entities)
+    {
+        foreach(i;0 .. entities.length)
+        {
+            entities.int_[i] += 8;
+        }
+    }
+
+    gEM.beginRegister();
+
+    gEM.registerSystem!TestSystem(0);
+    gEM.registerSystem!TestSystem2(1);
+    gEM.registerSystem!TestSystem3(2);
+    gEM.registerSystem!TestSystem4(3);
+    gEM.registerSystem!TestSystem5(4);
+
+    gEM.endRegister();
+
+    const (EntityManager.UpdatePass)* pass = gEM.getPass("update");
+    assert(pass != null);
+    assert(pass.system_callers.length == 5);
+    assert(pass.system_callers[0].system_id == TestSystem.system_id);
+    assert(pass.system_callers[1].system_id == TestSystem2.system_id);
+    assert(pass.system_callers[2].system_id == TestSystem3.system_id);
+    assert(pass.system_callers[3].system_id == TestSystem4.system_id);
+    assert(pass.system_callers[4].system_id == TestSystem5.system_id);
+    assert(pass.system_callers[0].dependencies.length == 0);
+    assert(pass.system_callers[1].dependencies.length == 1);
+    assert(pass.system_callers[2].dependencies.length == 1);
+    assert(pass.system_callers[3].dependencies.length == 3);
+    assert(pass.system_callers[4].dependencies.length == 1);
+    assert(pass.system_callers[1].dependencies[0].system_id == TestSystem.system_id);
+    assert(pass.system_callers[2].dependencies[0].system_id == TestSystem2.system_id);
+    assert(pass.system_callers[3].dependencies[0].system_id == TestSystem.system_id);
+    assert(pass.system_callers[3].dependencies[1].system_id == TestSystem2.system_id);
+    assert(pass.system_callers[3].dependencies[2].system_id == TestSystem3.system_id);
+    assert(pass.system_callers[4].dependencies[0].system_id == TestSystem4.system_id);
+}
+
+@("ExternalSystemDependencies")
+unittest
+{
+    enum TestDependency = "TestDepencency";
+    
+    struct TestSystem
+    {
+        mixin ECS.System;
+
+        mixin ECS.ReadOnlyDependencies!(TestDependency);
+
+        struct EntitiesData
+        {
+            uint length;
+            @readonly CInt[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem2
+    {
+        mixin ECS.System;
+
+        mixin ECS.WritableDependencies!(TestDependency);
+
+        struct EntitiesData
+        {
+            uint length;
+            @readonly CInt[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem3
+    {
+        mixin ECS.System;
+        
+        mixin ECS.ReadOnlyDependencies!(TestDependency);
+
+        struct EntitiesData
+        {
+            uint thread_id;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem4
+    {
+        mixin ECS.System;
+
+        mixin ECS.WritableDependencies!(TestDependency);
+
+        struct EntitiesData
+        {
+            uint length;
+            @readonly CInt[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    struct TestSystem5
+    {
+        mixin ECS.System;
+
+        mixin ECS.ReadOnlyDependencies!(TestDependency);
+
+        struct EntitiesData
+        {
+            uint length;
+            @readonly CLong[] int_;
+        }
+
+        void onUpdate(EntitiesData entities)
+        {
+            
+        }
+    }
+
+    void func1(TestSystem.EntitiesData entities)
+    {
+        foreach(i;0 .. entities.length)
+        {
+            entities.int_[i] += entities.int_[i] / 2;
+        }
+    }
+
+    void func2(TestSystem.EntitiesData entities)
+    {
+        foreach(i;0 .. entities.length)
+        {
+            entities.int_[i] += 8;
+        }
+    }
+
+    gEM.beginRegister();
+
+    gEM.registerDependency(TestDependency);
+
+    gEM.registerSystem!TestSystem(0);
+    gEM.registerSystem!TestSystem2(1);
+    gEM.registerSystem!TestSystem3(2);
+    gEM.registerSystem!TestSystem4(3);
+    gEM.registerSystem!TestSystem5(4);
+
+    gEM.endRegister();
+
+    const (EntityManager.UpdatePass)* pass = gEM.getPass("update");
+    assert(pass != null);
+    assert(pass.system_callers.length == 5);
+    assert(pass.system_callers[0].system_id == TestSystem.system_id);
+    assert(pass.system_callers[1].system_id == TestSystem2.system_id);
+    assert(pass.system_callers[2].system_id == TestSystem3.system_id);
+    assert(pass.system_callers[3].system_id == TestSystem4.system_id);
+    assert(pass.system_callers[4].system_id == TestSystem5.system_id);
+    assert(pass.system_callers[0].dependencies.length == 0);
+    assert(pass.system_callers[1].dependencies.length == 1);
+    assert(pass.system_callers[2].dependencies.length == 1);
+    assert(pass.system_callers[3].dependencies.length == 3);
+    assert(pass.system_callers[4].dependencies.length == 2);
+    assert(pass.system_callers[1].dependencies[0].system_id == TestSystem.system_id);
+    assert(pass.system_callers[2].dependencies[0].system_id == TestSystem2.system_id);
+    assert(pass.system_callers[3].dependencies[0].system_id == TestSystem.system_id);
+    assert(pass.system_callers[3].dependencies[1].system_id == TestSystem2.system_id);
+    assert(pass.system_callers[3].dependencies[2].system_id == TestSystem3.system_id);
+    assert(pass.system_callers[4].dependencies[0].system_id == TestSystem2.system_id);
+    assert(pass.system_callers[4].dependencies[1].system_id == TestSystem4.system_id);
+}