Refactor object engine data storage

Main idea is to make specific engine types be a subclass of generic
ObjectEngineData structure.

This required following changes:

- Have extra size argument to engine data allocation function.

  Not sure whether there is less error-prone way of doing this.

- Add init() callback to engine data allocation function.

Additionally, added some extra checks to Eevee's engine data getters, so we do
not silently cast lamp data to lightprobe data.

Reviewers: dfelinto, fclem

Differential Revision: https://developer.blender.org/D3027

1 files changed, 8 insertions, 2 deletions

diff --git a/source/blender/makesdna/DNA_object_types.h b/source/blender/makesdna/DNA_object_types.h
index 7364dcbc167..d62ec746309 100644
--- a/source/blender/makesdna/DNA_object_types.h
+++ b/source/blender/makesdna/DNA_object_types.h
@@ -75,11 +75,17 @@ typedef struct bFaceMap {
 } bFaceMap;
 
 /* Object Runtime display data */
+struct ObjectEngineData;
+typedef void (*ObjectEngineDataInitCb)(struct ObjectEngineData *engine_data);
+typedef void (*ObjectEngineDataFreeCb)(struct ObjectEngineData *engine_data);
+
+#
+#
 typedef struct ObjectEngineData {
 	struct ObjectEngineData *next, *prev;
 	struct DrawEngineType *engine_type;
-	void *storage;
-	void (*free)(void *storage);
+	/* Only nested data, NOT the engine data itself. */
+	ObjectEngineDataFreeCb free;
 } ObjectEngineData;
 
 #define MAX_VGROUP_NAME 64