External cache

Particle point cache can now be loaded from external files.
- Activated by "external" checkbox in cache panel and giving proper folder path and file name identifier.
- External cache panel has controls for particle emission start, end, lifetime and random lifetime. These should be set according to the external data for correct playback.
- External files should be named "identifier_frame_index.bphys" or "identifier_frame.bphys" where:
	* "identifier" is a freely choseable name.
	* "frame" is the cached frame number.
		** Six digits padded with zeros!, for example "000024".
	* "index" can be used to tell caches with the same identifier apart.
		** Two digits starting from zero.
		** The index and the underscore before are optional. If no index is present the index number in ui should be set to -1.
- Cache file format is pure floating point numbers (in binary, not text!) with each particle's data one after the other with the following data members:
	* 3 floats: particle's location vector
	* 3 floats: particle's velocity vector (per second)
	* 4 floats: particle's rotation quaternion
	* 3 floats: particle's angular velocity vector (per second)
	* 1 float: frame of the actual data (this can be non-integer for particles that are born or die between two integer frames, but otherwise should be the same as the "frame" in the file name)
- Cache files don't have to exist for each frame.
	* Frames without actual data are interpolated from surrounding frames that have data (extrapolation is not supported).
- Cache file formats with extended (or reduced even) data members are in future plans for easier usage.
- Current code only does particles, don't yet know if it's applicable to cloth or sb.
- Known issue: endianness can't yet be handled in any way.

Other changes:

New hard limits for many particle parameters. Some examples:
- Maximum amount of particles: 10M particles :) And before you all go and crash your Blender trying this out remember that this limit is only for those freaks who really have the machine power to handle it. 10M particles alone take around 2.2 Gb of memory / disk space in saved file and each cached frame takes around 0.5 Gb of memory / disk space depending on cache mode.
	* Known issue: To actually use this many particles they most likely need to be allocated in parts as taking hold of a 2.2Gb chunk of memory at once is probably not ok with any operating system.
- Maximum amount of children: 100k children/particle (1T childparticles here we come :D)
- Kink frequency: -100k to 100k half-rotations (really strange the previous limit was only from zero upwards)
- Path draw steps: 10 (power of 2 remember)
- Path render steps: 20 (power of 2 also!! If over 1M segments doesn't get you smooth paths then I think nothing will!)

1 files changed, 7 insertions, 1 deletions

diff --git a/source/blender/makesdna/DNA_object_force.h b/source/blender/makesdna/DNA_object_force.h
index 6cf20cc25a2..d640e37f48d 100644
--- a/source/blender/makesdna/DNA_object_force.h
+++ b/source/blender/makesdna/DNA_object_force.h
@@ -89,10 +89,15 @@ typedef struct PointCache {
 	int endframe;	/* simulation end frame */
 	int editframe;	/* frame being edited (runtime only) */
 	int last_exact; /* last exact frame that's cached */
-	int xdata_type;	/* type of extra data */
+
+	/* for external cache files */
+	int totpoint;   /* number of cached points */
+	int index, rt;	/* modifier stack index */
+	
 	char name[64];
 	char prev_name[64];
 	char info[64];
+	char path[240]; /* file path */
 	struct ListBase mem_cache;
 } PointCache;
 
@@ -267,6 +272,7 @@ typedef struct SoftBody {
 #define PTCACHE_DISK_CACHE			64
 #define PTCACHE_QUICK_CACHE			128
 #define PTCACHE_FRAMES_SKIPPED		256
+#define PTCACHE_EXTERNAL			512
 
 /* PTCACHE_OUTDATED + PTCACHE_FRAMES_SKIPPED */
 #define PTCACHE_REDO_NEEDED			258