Cycles: Implement denoising option for reducing noise in the rendered image

This commit contains the first part of the new Cycles denoising option,
which filters the resulting image using information gathered during rendering
to get rid of noise while preserving visual features as well as possible.

To use the option, enable it in the render layer options. The default settings
fit a wide range of scenes, but the user can tweak individual settings to
control the tradeoff between a noise-free image, image details, and calculation
time.

Note that the denoiser may still change in the future and that some features
are not implemented yet. The most important missing feature is animation
denoising, which uses information from multiple frames at once to produce a
flicker-free and smoother result. These features will be added in the future.

Finally, thanks to all the people who supported this project:

- Google (through the GSoC) and Theory Studios for sponsoring the development
- The authors of the papers I used for implementing the denoiser (more details
  on them will be included in the technical docs)
- The other Cycles devs for feedback on the code, especially Sergey for
  mentoring the GSoC project and Brecht for the code review!
- And of course the users who helped with testing, reported bugs and things
  that could and/or should work better!

1 files changed, 23 insertions, 3 deletions

diff --git a/intern/cycles/render/session.h b/intern/cycles/render/session.h
index a7e5f78a64d..a7ca90abbce 100644
--- a/intern/cycles/render/session.h
+++ b/intern/cycles/render/session.h
@@ -57,6 +57,12 @@ public:
 
 	bool display_buffer_linear;
 
+	bool use_denoising;
+	int denoising_radius;
+	float denoising_strength;
+	float denoising_feature_strength;
+	bool denoising_relative_pca;
+
 	double cancel_timeout;
 	double reset_timeout;
 	double text_timeout;
@@ -77,6 +83,12 @@ public:
 		start_resolution = INT_MAX;
 		threads = 0;
 
+		use_denoising = false;
+		denoising_radius = 8;
+		denoising_strength = 0.0f;
+		denoising_feature_strength = 0.0f;
+		denoising_relative_pca = false;
+
 		display_buffer_linear = false;
 
 		cancel_timeout = 0.1;
@@ -99,6 +111,11 @@ public:
 		&& tile_size == params.tile_size
 		&& start_resolution == params.start_resolution
 		&& threads == params.threads
+		&& use_denoising == params.use_denoising
+		&& denoising_radius == params.denoising_radius
+		&& denoising_strength == params.denoising_strength
+		&& denoising_feature_strength == params.denoising_feature_strength
+		&& denoising_relative_pca == params.denoising_relative_pca
 		&& display_buffer_linear == params.display_buffer_linear
 		&& cancel_timeout == params.cancel_timeout
 		&& reset_timeout == params.reset_timeout
@@ -126,7 +143,7 @@ public:
 	Stats stats;
 
 	function<void(RenderTile&)> write_render_tile_cb;
-	function<void(RenderTile&)> update_render_tile_cb;
+	function<void(RenderTile&, bool)> update_render_tile_cb;
 
 	explicit Session(const SessionParams& params);
 	~Session();
@@ -162,7 +179,7 @@ protected:
 	void update_status_time(bool show_pause = false, bool show_done = false);
 
 	void tonemap(int sample);
-	void path_trace();
+	void render();
 	void reset_(BufferParams& params, int samples);
 
 	void run_cpu();
@@ -177,6 +194,9 @@ protected:
 	void update_tile_sample(RenderTile& tile);
 	void release_tile(RenderTile& tile);
 
+	void map_neighbor_tiles(RenderTile *tiles, Device *tile_device);
+	void unmap_neighbor_tiles(RenderTile *tiles, Device *tile_device);
+
 	bool device_use_gl;
 
 	thread *session_thread;
@@ -202,7 +222,7 @@ protected:
 	double last_update_time;
 	bool update_progressive_refine(bool cancel);
 
-	vector<RenderBuffers *> tile_buffers;
+	vector<RenderTile> render_tiles;
 
 	DeviceRequestedFeatures get_requested_device_features();