store GL programs as GLProgram pointers instead of GLuints

src/GLProgram.cc

@@ -134,10 +134,3 @@ void GLProgram_Init()
     rb_define_method(ruby_class, "link", (VALUE(*)(...))GLProgram_link, 0);
     rb_define_method(ruby_class, "load_uniform_location", (VALUE(*)(...))GLProgram_load_uniform_location, 1);
 }
-
-GLuint GLProgram_GetID(VALUE program)
-{
-    GLProgram * glprogram;
-    Data_Get_Struct(program, GLProgram, glprogram);
-    return glprogram->id;
-}

src/GLProgram.h

@@ -21,6 +21,12 @@ struct GLProgram
 };
 
 void GLProgram_Init();
-GLuint GLProgram_GetID(VALUE program);
+
+static inline GLProgram * GLProgram_FromRuby(VALUE glprogram_obj)
+{
+    GLProgram * glprogram;
+    Data_Get_Struct(glprogram_obj, GLProgram, glprogram);
+    return glprogram;
+}
 
 #endif

src/Window.cc

@@ -26,7 +26,7 @@ typedef struct
 {
     SDL_Window * sdl_window;
     GLBufferRef rect_buffer;
-    GLuint programs[PROGRAM_COUNT];
+    GLProgram * programs[PROGRAM_COUNT];
 } Window;
 
 static VALUE ruby_class;
@@ -159,7 +159,7 @@ static VALUE Window_new(VALUE klass)
                                    ID2SYM(rb_intern(program_names[i])));
         if (RTEST(program))
         {
-            window->programs[i] = GLProgram_GetID(program);
+            window->programs[i] = GLProgram_FromRuby(program);
         }
         else
         {