code cleanup: clarify comment about virtial-modifiers, also add comments to DNA headers when its not so obvious what their purpose is.

source/blender/blenkernel/intern/modifier.c

@@ -424,7 +424,9 @@ ModifierData *modifiers_getLastPreview(struct Scene *scene, ModifierData *md, in
 	return tmp_md;
 }
 
-/* NOTE: these aren't used anymore */
+/* NOTE: This is to support old files from before Blender supported modifiers,
+ * in some cases versioning code updates these so for new files this will
+ * return an empty list. */
 ModifierData *modifiers_getVirtualModifierList(Object *ob)
 {
 	/* Kinda hacky, but should be fine since we are never

source/blender/makesdna/DNA_action_types.h

@@ -27,6 +27,10 @@
 
 /** \file DNA_action_types.h
  *  \ingroup DNA
+ *
+ * Define actions data-block for the animation system.
+ * A collection of animation curves and drivers to be assigned to data-blocks
+ * or sequenced in the non-linear-editor (NLA).
  */
 
 #ifndef __DNA_ACTION_TYPES_H__
@@ -689,4 +693,4 @@ typedef enum ACHAN_FLAG {
 	ACHAN_MOVED     = (1 << 31)
 } ACHAN_FLAG; 
 
-#endif
+#endif  /* __DNA_ACTION_TYPES_H__ */

source/blender/makesdna/DNA_actuator_types.h

@@ -27,6 +27,8 @@
 
 /** \file DNA_actuator_types.h
  *  \ingroup DNA
+ *
+ * #bActuator type is specifically for use by Object logic-bricks in the game-engine.
  */
 
 #ifndef __DNA_ACTUATOR_TYPES_H__
@@ -535,6 +537,4 @@ typedef struct bActuator {
 #define ACT_STEERING_AUTOMATICFACING   4
 #define ACT_STEERING_NORMALUP  8
 
-#endif
-
-
+#endif  /* __DNA_ACTUATOR_TYPES_H__ */

source/blender/makesdna/DNA_controller_types.h

@@ -27,6 +27,8 @@
 
 /** \file DNA_controller_types.h
  *  \ingroup DNA
+ *
+ * #bController type is specifically for use by Object logic-bricks in the game-engine.
  */
 
 #ifndef __DNA_CONTROLLER_TYPES_H__
@@ -89,5 +91,4 @@ typedef struct bController {
 #define CONT_PY_SCRIPT	0
 #define CONT_PY_MODULE	1
 
-#endif
-
+#endif  /* __DNA_CONTROLLER_TYPES_H__ */

source/blender/makesdna/DNA_customdata_types.h

@@ -27,6 +27,8 @@
 
 /** \file DNA_customdata_types.h
  *  \ingroup DNA
+ *
+ * Used for custom mesh data types (stored per vert/edge/loop/face)
  */
 
 #ifndef __DNA_CUSTOMDATA_TYPES_H__
@@ -177,4 +179,4 @@ typedef struct CustomData {
 }
 #endif
 
-#endif
+#endif  /* __DNA_CUSTOMDATA_TYPES_H__ */

source/blender/makesdna/DNA_defs.h

@@ -22,6 +22,8 @@
 
 /** \file DNA_defs.h
  *  \ingroup DNA
+ *
+ * Group generic defines for all DNA headers may use in this file.
  */
 
 #ifndef __DNA_DEFS_H__

source/blender/makesdna/DNA_group_types.h

@@ -27,6 +27,8 @@
 
 /** \file DNA_group_types.h
  *  \ingroup DNA
+ *
+ * \brief Object groups, one object can be in many groups at once.
  */
 
 #ifndef __DNA_GROUP_TYPES_H__
@@ -58,4 +60,4 @@ typedef struct Group {
 	float dupli_ofs[3];
 } Group;
 
-#endif
+#endif  /* __DNA_GROUP_TYPES_H__ */

source/blender/makesdna/DNA_mask_types.h

@@ -30,6 +30,9 @@
  *  \ingroup DNA
  *  \since march-2012
  *  \author Sergey Sharybin
+ *
+ * Mask data-blocks are collections of 2D curves to be used
+ * for image masking in the compositor and sequencer.
  */
 
 #ifndef __DNA_MASK_TYPES_H__

source/blender/makesdna/DNA_property_types.h

@@ -31,6 +31,8 @@
  *  \author nzc
  *  \attention Renderrecipe and scene decription. The fact that there is a
  *             hierarchy here is a bit strange, and not desirable.
+ *
+ * #bProperty type is specifically for use by Objects game-logic.
  */
 
 #ifndef __DNA_PROPERTY_TYPES_H__
@@ -60,5 +62,4 @@ typedef struct bProperty {
 
 #define MAX_PROPSTRING	128
 
-#endif
-
+#endif  /* __DNA_PROPERTY_TYPES_H__ */

source/blender/makesdna/DNA_sensor_types.h

@@ -29,6 +29,8 @@
  *  \ingroup DNA
  *  \since mar-2001
  *  \author nzc
+ *
+ * #bSensor type is specifically for use by Object logic-bricks in the game-engine.
  */
 
 #ifndef __DNA_SENSOR_TYPES_H__
@@ -324,5 +326,5 @@ typedef struct bJoystickSensor {
 #define SENS_DELAY_REPEAT		1
 // should match JOYINDEX_MAX in SCA_JoystickDefines.h */
 #define SENS_JOY_MAXINDEX		8
-#endif
 
+#endif  /* __DNA_SENSOR_TYPES_H__ */

source/blender/makesdna/DNA_sequence_types.h

@@ -28,6 +28,14 @@
  *  \ingroup DNA
  *  \since mar-2001
  *  \author nzc
+ *
+ * Structs for use by the 'Sequencer' (Video Editor)
+ *
+ * Note on terminology
+ * - #Sequence: video/effect/audio data you can select and manipulate in the sequencer.
+ * - #Sequence.machine: Strange name for the channel.
+ * - #Strip: The data referenced by the #Sequence
+ * - Meta Strip (SEQ_TYPE_META): Support for nesting Sequences.
  */
 
 #ifndef __DNA_SEQUENCE_TYPES_H__
@@ -441,4 +449,4 @@ enum {
 	SEQUENCE_MASK_INPUT_ID      = 1
 };
 
-#endif
+#endif  /* __DNA_SEQUENCE_TYPES_H__ */

source/blender/makesdna/DNA_space_types.h

@@ -28,6 +28,8 @@
  *  \ingroup DNA
  *  \since mar-2001
  *  \author nzc
+ *
+ * Structs for each of space type in the user interface.
  */
 
 #ifndef __DNA_SPACE_TYPES_H__
@@ -1133,4 +1135,4 @@ typedef enum eSpace_Type {
 
 #define IMG_SIZE_FALLBACK 256
 
-#endif
+#endif  /* __DNA_SPACE_TYPES_H__ */

source/blender/makesdna/DNA_text_types.h

@@ -28,6 +28,9 @@
  *  \ingroup DNA
  *  \since mar-2001
  *  \author nzc
+ *
+ * Text blocks used for Python-Scripts, OpenShadingLanguage
+ * and arbitrary text data to store in blend files.
  */
 
 #ifndef __DNA_TEXT_TYPES_H__
@@ -75,4 +78,4 @@ typedef struct Text {
 #define TXT_FOLLOW              0x0200 /* always follow cursor (console) */
 #define TXT_TABSTOSPACES        0x0400 /* use space instead of tabs */
 
-#endif
+#endif  /* __DNA_TEXT_TYPES_H__ */

source/blender/makesdna/DNA_tracking_types.h

@@ -30,6 +30,8 @@
  *  \ingroup DNA
  *  \since may-2011
  *  \author Sergey Sharybin
+ *
+ * Structs used for camera tracking and the movie-clip editor.
  */
 
 #ifndef __DNA_TRACKING_TYPES_H__
@@ -431,4 +433,4 @@ enum {
 	TRACKING_COVERAGE_OK         = 2
 };
 
-#endif
+#endif  /* __DNA_TRACKING_TYPES_H__ */

source/blender/makesdna/DNA_vfont_types.h

@@ -29,6 +29,9 @@
  *  \ingroup DNA
  *  \since mar-2001
  *  \author nzc
+ *
+ * Vector Fonts used for text in the 3D view-port
+ * (unrelated to text used to render the GUI).
  */
 
 #ifndef __DNA_VFONT_TYPES_H__
@@ -63,5 +66,5 @@ typedef struct VFont {
 #define FO_SELCHANGE	10
 
 #define FO_BUILTIN_NAME "<builtin>"
-#endif
 
+#endif  /* __DNA_VFONT_TYPES_H__ */