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, 43 insertions, 1 deletions

diff --git a/intern/cycles/device/device_memory.h b/intern/cycles/device/device_memory.h
index 4b10514a9d2..b63dd00068b 100644
--- a/intern/cycles/device/device_memory.h
+++ b/intern/cycles/device/device_memory.h
@@ -35,6 +35,8 @@
 
 CCL_NAMESPACE_BEGIN
 
+class Device;
+
 enum MemoryType {
 	MEM_READ_ONLY,
 	MEM_WRITE_ONLY,
@@ -144,7 +146,7 @@ template<> struct device_type_traits<float2> {
 
 template<> struct device_type_traits<float3> {
 	static const DataType data_type = TYPE_FLOAT;
-	static const int num_elements = 3;
+	static const int num_elements = 4;
 };
 
 template<> struct device_type_traits<float4> {
@@ -173,6 +175,9 @@ class device_memory
 {
 public:
 	size_t memory_size() { return data_size*data_elements*datatype_size(data_type); }
+	size_t memory_elements_size(int elements) {
+		return elements*data_elements*datatype_size(data_type);
+	}
 
 	/* data information */
 	DataType data_type;
@@ -213,6 +218,22 @@ protected:
 	device_memory& operator = (const device_memory&);
 };
 
+template<typename T>
+class device_only_memory : public device_memory
+{
+public:
+	device_only_memory()
+	{
+		data_type = device_type_traits<T>::data_type;
+		data_elements = max(device_type_traits<T>::num_elements, 1);
+	}
+
+	void resize(size_t num)
+	{
+		device_memory::resize(num*sizeof(T));
+	}
+};
+
 /* Device Vector */
 
 template<typename T> class device_vector : public device_memory
@@ -299,6 +320,27 @@ private:
 	array<T> data;
 };
 
+/* A device_sub_ptr is a pointer into another existing memory.
+ * Therefore, it is not allocated separately, but just created from the already allocated base memory.
+ * It is freed automatically when it goes out of scope, which should happen before the base memory is freed.
+ * Note that some devices require the offset and size of the sub_ptr to be properly aligned. */
+class device_sub_ptr
+{
+public:
+	device_sub_ptr(Device *device, device_memory& mem, int offset, int size, MemoryType type);
+	~device_sub_ptr();
+	/* No copying. */
+	device_sub_ptr& operator = (const device_sub_ptr&);
+
+	device_ptr operator*() const
+	{
+		return ptr;
+	}
+protected:
+	Device *device;
+	device_ptr ptr;
+};
+
 CCL_NAMESPACE_END
 
 #endif /* __DEVICE_MEMORY_H__ */