Reorganize source files into logical subdirectories

Co-authored-by: Hirek193 <23196899+Hirek193@users.noreply.github.com>

rendering/openglcolor.h

@@ -0,0 +1,77 @@
+/*
+This Source Code Form is subject to the
+terms of the Mozilla Public License, v.
+2.0. If a copy of the MPL was not
+distributed with this file, You can
+obtain one at
+http://mozilla.org/MPL/2.0/.
+*/
+
+#pragma once
+
+#include "Globals.h"
+
+// encapsulation of the fixed pipeline opengl color
+class opengl_color {
+
+public:
+// constructors:
+    opengl_color() = default;
+
+// methods:
+    inline
+    void
+        color3( glm::vec3 const &Color ) {
+            return color4( glm::vec4{ Color, 1.f } ); }
+    inline
+    void
+        color3( float const Red, float const Green, float const Blue ) {
+            return color3( glm::vec3 { Red, Green, Blue } ); }
+    inline
+    void
+        color3( float const *Value ) {
+            return color3( glm::make_vec3( Value ) ); }
+    inline
+    void
+        color4( glm::vec4 const &Color ) {
+            if( ( Color != m_color ) || ( false == Global.bUseVBO ) ) {
+                m_color = Color;
+                ::glColor4fv( glm::value_ptr( m_color ) ); } }
+    inline
+    void
+        color4( float const Red, float const Green, float const Blue, float const Alpha ) {
+            return color4( glm::vec4{ Red, Green, Blue, Alpha } ); }
+    inline
+    void
+        color4( float const *Value ) {
+            return color4( glm::make_vec4( Value ) );
+    }
+    inline
+    glm::vec4 const &
+        data() const {
+            return m_color; }
+    inline
+    float const *
+        data_array() const {
+            return glm::value_ptr( m_color ); }
+
+private:
+// members:
+    glm::vec4 m_color { -1 };
+};
+
+extern opengl_color OpenGLColor;
+
+// NOTE: standard opengl calls re-definitions
+#undef glColor3f
+#undef glColor3fv
+#undef glColor4f
+#undef glColor4fv
+
+#define glColor3f OpenGLColor.color3
+#define glColor3fv OpenGLColor.color3
+#define glColor4f OpenGLColor.color4
+#define glColor4fv OpenGLColor.color4
+
+//---------------------------------------------------------------------------
+