libdeng2: Implemented logical state of GLUniform

Tracking the current value, notifying audiences of changes.

doomsday/libgui/include/de/gui/gluniform.h

@@ -20,20 +20,98 @@
 #define LIBGUI_GLUNIFORM_H
 
 #include <de/libdeng2.h>
+#include <de/Vector>
+#include <de/Matrix>
+#include <de/Observers>
 
 #include "libgui.h"
 
+#include <QLatin1String>
+
 namespace de {
 
 /**
- * GL uniform.
+ * Constant variable or a sampler in a shader.
+ *
+ * GLUniform's public interface allows the uniform value to be manipulated like
+ * any other native variable (assignment, arithmetic, etc.).
+ *
+ * The value of the uniform is stored locally in the GLUniform instance. When
+ * the uniform has been bound to programs and its value changes, the programs
+ * are notified and they mark the uniform as changed. When the program is then
+ * later taken into use, the updated value of the changed uniforms is sent to
+ * GL.
  *
  * @ingroup gl
  */
 class LIBGUI_PUBLIC GLUniform
 {
 public:
-    GLUniform();
+    enum Type
+    {
+        Int,
+        UInt,
+        Float,
+        Vector2,
+        Vector3,
+        Vector4,
+        Matrix3x3,
+        Matrix4x4,
+        Texture2D
+    };
+
+    /**
+     * Notified when the value of the uniform changes.
+     */
+    DENG2_DEFINE_AUDIENCE(ValueChange, void uniformValueChanged(GLUniform &))
+
+    /**
+     * Notified when the uniform instance is deleted.
+     */
+    DENG2_DEFINE_AUDIENCE(Deletion, void uniformDeleted(GLUniform &))
+
+public:
+    GLUniform(QLatin1String const &nameInShader, Type uniformType);
+
+    virtual ~GLUniform();
+
+    void setName(QLatin1String const &nameInShader);
+
+    /**
+     * Returns the name of the uniform as it appears in shaders.
+     */
+    QLatin1String name() const;
+
+    /**
+     * Returns the value type of the shader.
+     */
+    Type type() const;
+
+    GLUniform &operator = (dint value);
+    GLUniform &operator = (duint value);
+    GLUniform &operator = (dfloat value);
+    GLUniform &operator = (Vector2f const &vec);
+    GLUniform &operator = (Vector3f const &vec);
+    GLUniform &operator = (Vector4f const &vec);
+    GLUniform &operator = (Matrix3f const &vec);
+    GLUniform &operator = (Matrix4f const &vec);
+
+    operator dint() const     { return toInt(); }
+    operator duint() const    { return toUInt(); }
+    operator dfloat() const   { return toFloat(); }
+    operator ddouble() const  { return ddouble(toFloat()); }
+    operator Vector2f() const { return toVector2f(); }
+    operator Vector3f() const { return toVector3f(); }
+    operator Vector4f() const { return toVector4f(); }
+
+    dint toInt() const;
+    duint toUInt() const;
+    dfloat toFloat() const;
+    Vector2f const &toVector2f() const;
+    Vector3f const &toVector3f() const;
+    Vector4f const &toVector4f() const;
+    Matrix3f const &toMatrix3f() const;
+    Matrix4f const &toMatrix4f() const;
 
 private:
     DENG2_PRIVATE(d)