2.5 - Optimisations for Keyframe Drawing in DopeSheet

Keyframes are now prepared for drawing by being added to a binary-tree structure instead of using insertion-sort on a Double-Linked List. This gives rather significant improvements on a few bad cases (*).

I've implemented a basic Red-Black Tree whose nodes/data-structures can also be used as a simple Double-Linked List (ListBase) for this purpose. The implementation of this tree currently does not have support for removing individual nodes, since such capabilities aren't needed yet. 

Stats (using keyframes from an imported .bvh animation file):
* When only the keyframes are drawn (i.e. long keyframes are not identified), the time needed to draw the DopeSheet region 10 times went down from 4000ms to about 300ms.
* When long keyframes are considered as well, the same test has gone from 6000ms to 3000ms. There is still a bottleneck there that I haven't been able to remove yet (an attempt at this made the runtimes go through the roof - 32000 ms for the test done here).

Assorted Notes:
* Added missing headers for some files
* Fixed profiling flags for mingw. There was an extra space which prevented the sound-code from compiling.

1 files changed, 359 insertions, 0 deletions

diff --git a/source/blender/blenlib/intern/DLRB_tree.c b/source/blender/blenlib/intern/DLRB_tree.c
new file mode 100644
index 00000000000..debe02164fb
--- /dev/null
+++ b/source/blender/blenlib/intern/DLRB_tree.c
@@ -0,0 +1,359 @@
+/**
+ * $Id: BLI_dlrbTree.c 21514 2009-07-11 05:41:21Z aligorith $
+ *
+ * ***** BEGIN GPL LICENSE BLOCK *****
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ *
+ * The Original Code is Copyright (C) 2009 Blender Foundation, Joshua Leung
+ * All rights reserved.
+ *
+ * Contributor(s): Joshua Leung (original author)
+ *
+ * ***** END GPL LICENSE BLOCK *****
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_blenlib.h"
+#include "BLI_dlrbTree.h"
+
+#include "DNA_listBase.h"
+
+/* *********************************************** */
+/* Tree API */
+
+/* Create a new tree, and initialise as necessary */
+DLRBT_Tree *BLI_dlrbTree_new (void)
+{
+	/* just allocate for now */
+	return MEM_callocN(sizeof(DLRBT_Tree), "DLRBT_Tree");
+}
+
+/* Just zero out the pointers used */
+void BLI_dlrbTree_init (DLRBT_Tree *tree) 
+{
+	if (tree == NULL)
+		return;
+		
+	tree->first= tree->last= tree->root= NULL;
+}
+
+/* Helper for traversing tree and freeing sub-nodes */
+static void recursive_tree_free_nodes (DLRBT_Node *node)
+{
+	/* sanity check */
+	if (node == NULL)
+		return;
+	
+	/* free child nodes + subtrees */
+	recursive_tree_free_nodes(node->left);
+	recursive_tree_free_nodes(node->right);
+	
+	/* free self */
+	MEM_freeN(node);
+}
+
+/* Free the given tree's data but not the tree itself */
+void BLI_dlrbTree_free (DLRBT_Tree *tree)
+{
+	if (tree == NULL)
+		return;
+	
+	/* if the list-base stuff is set, just use that (and assume its set), 
+	 * otherwise, we'll need to traverse the tree...
+	 */
+	if (tree->first) {
+		/* free list */
+		BLI_freelistN((ListBase *)tree);
+	}
+	else {
+		/* traverse tree, freeing sub-nodes */
+		recursive_tree_free_nodes(tree->root);
+	}
+	
+	/* clear pointers */
+	tree->first= tree->last= tree->root= NULL;
+}
+
+/* ------- */
+
+/* Helper function - used for traversing down the tree from the root to add nodes in order */
+static void linkedlist_sync_add_node (DLRBT_Tree *tree, DLRBT_Node *node)
+{
+	/* sanity checks */
+	if ((tree == NULL) || (node == NULL))
+		return;
+	
+	/* add left-node (and its subtree) */
+	linkedlist_sync_add_node(tree, node->left);
+	
+	/* now add self
+	 *	- must remove detach from other links first
+	 *	  (for now, only clear own pointers)
+	 */
+	node->prev= node->next= NULL;
+	BLI_addtail((ListBase *)tree, (Link *)node);
+	
+	/* finally, add right node (and its subtree) */
+	linkedlist_sync_add_node(tree, node->right);
+}
+
+/* Make sure the tree's Double-Linked list representation is valid */
+void BLI_dlrbTree_linkedlist_sync (DLRBT_Tree *tree)
+{
+	/* sanity checks */
+	if (tree == NULL)
+		return;
+		
+	/* clear list-base pointers so that the new list can be added properly */
+	tree->first= tree->last= NULL;
+	
+	/* start adding items from the root */
+	linkedlist_sync_add_node(tree, tree->root);
+}
+
+/* *********************************************** */
+/* Tree Relationships Utilities */
+
+/* get the 'grandparent' - the parent of the parent - of the given node */
+static DLRBT_Node *get_grandparent (DLRBT_Node *node)
+{
+	if (node && node->parent)
+		return node->parent->parent;
+	else
+		return NULL;
+}
+
+/* get the 'uncle' - the sibling of the parent - of the given node */
+static DLRBT_Node *get_uncle (DLRBT_Node *node)
+{
+	DLRBT_Node *gpn= get_grandparent(node);
+	
+	/* return the child of the grandparent which isn't the node's parent */
+	if (gpn) {
+		if (gpn->left == node->parent)
+			return gpn->right;
+		else
+			return gpn->left;
+	}
+	
+	/* not found */
+	return NULL;
+}
+
+/* *********************************************** */
+/* Tree Rotation Utilities */
+
+/* Left Rotation is only done for Right-Right Case, and Left-Right Case */
+static void rotate_left (DLRBT_Tree *tree, DLRBT_Node *root)
+{
+	DLRBT_Node **root_slot, *pivot;
+	
+	/* pivot is simply the root's right child, to become the root's parent */
+	pivot= root->right;
+	if (pivot == NULL)
+		return;
+	
+	if (root->parent) {
+		if (root == root->parent->left)
+			root_slot= &root->parent->left;
+		else
+			root_slot= &root->parent->right;
+	}
+	else
+		root_slot= ((DLRBT_Node**)&tree->root);//&((DLRBT_Node*)tree->root);
+		
+	/* - pivot's left child becomes root's right child
+	 * - root now becomes pivot's left child  
+	 */
+	root->right= pivot->left;	
+	if (pivot->left) pivot->left->parent= root;
+	
+	pivot->left= root;
+	pivot->parent= root->parent;
+	root->parent= pivot;
+	
+	/* make the pivot the new root */
+	if (root_slot)
+		*root_slot= pivot;
+}
+
+static void rotate_right (DLRBT_Tree *tree, DLRBT_Node *root)
+{
+	DLRBT_Node **root_slot, *pivot;
+	
+	/* pivot is simply the root's left child, to become the root's parent */
+	pivot= root->left;
+	if (pivot == NULL)
+		return;
+	
+	if (root->parent) {
+		if (root == root->parent->left)
+			root_slot= &root->parent->left;
+		else
+			root_slot= &root->parent->right;
+	}
+	else
+		root_slot= ((DLRBT_Node**)&tree->root);//&((DLRBT_Node*)tree->root);
+		
+	/* - pivot's right child becomes root's left child
+	 * - root now becomes pivot's right child  
+	 */
+	root->left= pivot->right;	
+	if (pivot->right) pivot->right->parent= root;
+	
+	pivot->right= root;
+	pivot->parent= root->parent;
+	root->parent= pivot;
+	
+	/* make the pivot the new root */
+	if (root_slot)
+		*root_slot= pivot;
+}
+
+/* *********************************************** */
+/* Post-Insertion Balancing  */
+
+/* forward defines for insertion checks */
+static void insert_check_1(DLRBT_Tree *tree, DLRBT_Node *node);
+static void insert_check_2(DLRBT_Tree *tree, DLRBT_Node *node);
+static void insert_check_3(DLRBT_Tree *tree, DLRBT_Node *node);
+static void insert_check_4(DLRBT_Tree *tree, DLRBT_Node *node);
+
+/* ----- */
+
+/* W. 1) Root must be black (so that the 2nd-generation can have a black parent) */
+static void insert_check_1 (DLRBT_Tree *tree, DLRBT_Node *node)
+{
+	if (node) {
+		/* if this is the root, just ensure that it is black */
+		if (node->parent == NULL)
+			node->tree_col= DLRBT_BLACK;
+		else
+			insert_check_2(tree, node);
+	}
+}
+
+/* W. 2+3) Parent of node must be black, otherwise recolor and flush */
+static void insert_check_2 (DLRBT_Tree *tree, DLRBT_Node *node)
+{
+	/* if the parent is not black, we need to change that... */
+	if (node && node->parent && node->parent->tree_col) {
+		DLRBT_Node *unc= get_uncle(node);
+		
+		/* if uncle and parent are both red, need to change them to black and make 
+		 * the parent black in order to satisfy the criteria of each node having the
+		 * same number of black nodes to its leaves
+		 */
+		if (unc && unc->tree_col) {
+			DLRBT_Node *gp= get_grandparent(node);
+			
+			/* make the n-1 generation nodes black */
+			node->parent->tree_col= unc->tree_col= DLRBT_BLACK;
+			
+			/* - make the grandparent red, so that we maintain alternating red/black property 
+			 *  (it must exist, so no need to check for NULL here),
+			 * - as the grandparent may now cause inconsistencies with the rest of the tree, 
+			 *   we must flush up the tree and perform checks/rebalancing/repainting, using the 
+			 * 	grandparent as the node of interest
+			 */
+			gp->tree_col= DLRBT_RED;
+			insert_check_1(tree, gp);
+		}
+		else {
+			/* we've got an unbalanced branch going down the grandparent to the parent,
+			 * so need to perform some rotations to re-balance the tree
+			 */
+			insert_check_3(tree, node);
+		}
+	}
+}
+
+/* W. 4) Perform rotation on sub-tree containing the 'new' node */
+static void insert_check_3 (DLRBT_Tree *tree, DLRBT_Node *node)
+{
+	DLRBT_Node *gp= get_grandparent(node);
+	
+	/* check that grandparent and node->parent exist (jut in case... really shouldn't happen on a good tree) */
+	if (node && node->parent && gp) {
+		/* a left rotation will switch the roles of node and its parent, assuming that
+		 * the parent is the left child of the grandparent... otherwise, rotation direction
+		 * should be swapped
+		 */
+		if ((node == node->parent->right) && (node->parent == gp->left)) {
+			rotate_left(tree, node);
+			node= node->left;
+		}
+		else if ((node == node->parent->left) && (node->parent == gp->right)) {
+			rotate_right(tree, node); 
+			node= node->right;
+		}
+		// TODO: what about other cases?
+		
+		/* fix old parent's color-tagging */
+		insert_check_4(tree, node);
+	}
+}
+
+/* W. 5) Perform rotation in the opposite direction on the parent of the given node */
+static void insert_check_4 (DLRBT_Tree *tree, DLRBT_Node *node)
+{
+	DLRBT_Node *gp= get_grandparent(node);
+	
+	if (node == NULL)
+		return;
+	
+	/* modify the coloring of the grandparent and parent so that they still satisfy the constraints */
+	node->parent->tree_col= DLRBT_BLACK;
+	gp->tree_col= DLRBT_RED;
+	
+	/* if there are several nodes that all form a left chain, do a right rotation to correct this
+	 * (or a rotation in the opposite direction if they all form a right chain)
+	 */
+	if ((node == node->parent->left) && (node->parent == gp->left))
+		rotate_right(tree, gp);
+	else /* ((node == node->parent->right) && (node->parent == gp->right)) */
+		rotate_left(tree, gp);
+}
+
+/* ----- */
+
+/* Balance the tree after the given element has been added to it 
+ * (using custom code, in the Binary Tree way).
+ */
+void BLI_dlrbTree_insert(DLRBT_Tree *tree, DLRBT_Node *node)
+{
+	/* sanity checks */
+	if ((tree == NULL) || (node == NULL))
+		return;
+		
+	/* firstly, the node we just added should be red by default */
+	node->tree_col= DLRBT_RED;
+		
+	/* start from case 1, an trek through the tail-recursive insertion checks */
+	insert_check_1(tree, node);
+}
+
+/* *********************************************** */
+/* Remove */
+
+// TODO: this hasn't been coded yet, since this functionality was not needed by the author
+
+/* *********************************************** */