Cycles: Refactor Progress system to provide better estimates

The Progress system in Cycles had two limitations so far:
 - It just counted tiles, but ignored their size. For example, when rendering a 600x500 image with 512x512 tiles, the right 88x500 tile would count for 50% of the progress, although it only covers 15% of the image.
 - Scene update time was incorrectly counted as rendering time - therefore, the remaining time started very long and gradually decreased.

This patch fixes both problems:
First of all, the Progress now has a function to ignore time spans, and that is used to ignore scene update time.
The larger change is the tile size: Instead of counting samples per tile, so that the final value is num_samples*num_tiles, the code now counts every sample for every pixel, so that the final value is num_samples*num_pixels.

Along with that, some unused variables were removed from the Progress and Session classes.

Reviewers: brecht, sergey, #cycles

Subscribers: brecht, candreacchio, sergey

Differential Revision: https://developer.blender.org/D2214

1 files changed, 4 insertions, 5 deletions

diff --git a/intern/cycles/render/session.h b/intern/cycles/render/session.h
index 1db4692e171..c7ff1446171 100644
--- a/intern/cycles/render/session.h
+++ b/intern/cycles/render/session.h
@@ -145,6 +145,10 @@ public:
 
 	void device_free();
 
+	/* Returns the rendering progress or 0 if no progress can be determined
+	 * (for example, when rendering with unlimited samples). */
+	float get_progress();
+
 protected:
 	struct DelayedReset {
 		thread_mutex mutex;
@@ -173,8 +177,6 @@ protected:
 	void update_tile_sample(RenderTile& tile);
 	void release_tile(RenderTile& tile);
 
-	void update_progress_sample();
-
 	bool device_use_gl;
 
 	thread *session_thread;
@@ -194,10 +196,7 @@ protected:
 
 	bool kernels_loaded;
 
-	double start_time;
 	double reset_time;
-	double preview_time;
-	double paused_time;
 
 	/* progressive refine */
 	double last_update_time;