From 2505984b52862a4aa74af37e41d6ebdccc3c266f Mon Sep 17 00:00:00 2001
From: Sergey Sharybin <sergey.vfx@gmail.com>
Date: Thu, 25 Oct 2012 12:03:36 +0000
Subject: [PATCH] Cycles: use simplier strategy in next_tile for viewport
 rendering

No need to find tile closest to rendered center in this case, just
return first possible tile. Saves some computation power.
---
 intern/cycles/render/tile.cpp | 19 ++++++++++++++++++-
 intern/cycles/render/tile.h   |  8 +++++++-
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/intern/cycles/render/tile.cpp b/intern/cycles/render/tile.cpp
index 9928186a12f..c294239bac0 100644
--- a/intern/cycles/render/tile.cpp
+++ b/intern/cycles/render/tile.cpp
@@ -214,11 +214,28 @@ list<Tile>::iterator TileManager::next_center_tile(int device)
 	return best;
 }
 
+list<Tile>::iterator TileManager::next_simple_tile(int device)
+{
+	list<Tile>::iterator iter;
+
+	int logical_device = preserve_tile_device? device: 0;
+
+	for(iter = state.tiles.begin(); iter != state.tiles.end(); iter++) {
+		if(iter->device == logical_device && iter->rendering == false)
+			return iter;
+	}
+
+	return state.tiles.end();
+}
+
 bool TileManager::next_tile(Tile& tile, int device)
 {
 	list<Tile>::iterator tile_it;
 
-	tile_it = next_center_tile(device);
+	if(background)
+		tile_it = next_center_tile(device);
+	else
+		tile_it = next_simple_tile(device);
 
 	if(tile_it != state.tiles.end()) {
 		tile_it->rendering = true;
diff --git a/intern/cycles/render/tile.h b/intern/cycles/render/tile.h
index ad1e84cfb7b..6f7a8f20734 100644
--- a/intern/cycles/render/tile.h
+++ b/intern/cycles/render/tile.h
@@ -102,7 +102,13 @@ protected:
 	/* slices image into as much pieces as how many devices are rendering this image */
 	void gen_tiles_sliced();
 
-	list<Tile>::iterator next_center_tile(int device = 0);
+	/* returns closest tile to center of rendered tiles
+	 * mimics behavior of blender internal's tile order
+	 */
+	list<Tile>::iterator next_center_tile(int device);
+
+	/* returns first unhandled tile starting from left bottom corner of the image */
+	list<Tile>::iterator next_simple_tile(int device);
 };
 
 CCL_NAMESPACE_END