Demos update (SpaceInvaders demo)

-added new sprites
-added new functions to vectors
-fixed rendering rotated sprites
-small performance improvement and some bug fixes
-added animations support
-bullets get initial velocity from parent
-added partiles for fire from gun and explosion of enemies

demos/utils/source/ecs_utils/math/vector.d

@@ -2,6 +2,18 @@ module ecs_utils.math.vector;
 
 struct vec2
 {
+    this(float v) @nogc nothrow
+    {
+        x = v;
+        y = v;
+    }
+    
+    this(float x, float y) @nogc nothrow
+    {
+        this.x = x;
+        this.y = y;
+    }
+
     union
     {
         struct
@@ -75,6 +87,22 @@ struct vec4
         float[4] data;
     }
 
+    this(float v) @nogc nothrow
+    {
+        x = v;
+        y = v;
+        z = v;
+        w = v;
+    }
+
+    this(float x, float y, float z, float w) @nogc nothrow
+    {
+        this.x = x;
+        this.y = y;
+        this.z = z;
+        this.w = w;
+    }
+
     vec4 opBinary(string op)(float v)
     {
         static if (op == "+") return vec4(x + v, y + v, z + v, w + v);
@@ -96,6 +124,18 @@ struct ivec2
         }
         int[2] data;
     }
+    
+    this(int v) @nogc nothrow
+    {
+        x = v;
+        y = v;
+    }
+
+    this(int x, int y) @nogc nothrow
+    {
+        this.x = x;
+        this.y = y;
+    }
 
     ivec2 opBinary(string op, T)(T v)
     {
@@ -125,4 +165,20 @@ struct ivec4
         }
         int[4] data;
     }
+
+    this(int v) @nogc nothrow
+    {
+        x = v;
+        y = v;
+        z = v;
+        w = v;
+    }
+    
+    this(int x, int y, int z, int w) @nogc nothrow
+    {
+        this.x = x;
+        this.y = y;
+        this.z = z;
+        this.w = w;
+    }
 }