Cycles: Added Cryptomatte output.

This allows for extra output passes that encode automatic object and material masks
for the entire scene. It is an implementation of the Cryptomatte standard as
introduced by Psyop. A good future extension would be to add a manifest to the
export and to do plenty of testing to ensure that it is fully compatible with other
renderers and compositing programs that use Cryptomatte.

Internally, it adds the ability for Cycles to have several passes of the same type
that are distinguished by their name.

Differential Revision: https://developer.blender.org/D3538

1 files changed, 94 insertions, 0 deletions

diff --git a/intern/cycles/kernel/kernel_id_passes.h b/intern/cycles/kernel/kernel_id_passes.h
new file mode 100644
index 00000000000..486c61d2ae5
--- /dev/null
+++ b/intern/cycles/kernel/kernel_id_passes.h
@@ -0,0 +1,94 @@
+/*
+* Copyright 2018 Blender Foundation
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+CCL_NAMESPACE_BEGIN
+
+ccl_device_inline void kernel_write_id_slots(ccl_global float *buffer, int num_slots, float id, float weight)
+{
+	kernel_assert(id != ID_NONE);
+	if(weight == 0.0f) {
+		return;
+	}
+	
+	for(int slot = 0; slot < num_slots; slot++) {
+		ccl_global float2 *id_buffer = (ccl_global float2*)buffer;
+#ifdef __ATOMIC_PASS_WRITE__
+		/* If the loop reaches an empty slot, the ID isn't in any slot yet - so add it! */
+		if(id_buffer[slot].x == ID_NONE) {
+			/* Use an atomic to claim this slot.
+			* If a different thread got here first, try again from this slot on. */
+			float old_id = atomic_compare_and_swap_float(buffer+slot*2, ID_NONE, id);
+			if(old_id != ID_NONE && old_id != id) {
+				continue;
+			}
+			atomic_add_and_fetch_float(buffer+slot*2+1, weight);
+			break;
+		}
+		/* If there already is a slot for that ID, add the weight.
+		 * If no slot was found, add it to the last. */
+		else if(id_buffer[slot].x == id || slot == num_slots - 1) {
+			atomic_add_and_fetch_float(buffer+slot*2+1, weight);
+			break;
+		}
+#else /* __ATOMIC_PASS_WRITE__ */
+		/* If the loop reaches an empty slot, the ID isn't in any slot yet - so add it! */
+		if(id_buffer[slot].x == ID_NONE) {
+			id_buffer[slot].x = id;
+			id_buffer[slot].y = weight;
+			break;
+		}
+		/* If there already is a slot for that ID, add the weight.
+		* If no slot was found, add it to the last. */
+		else if(id_buffer[slot].x == id || slot == num_slots - 1) {
+			id_buffer[slot].y += weight;
+			break;
+		}
+#endif /* __ATOMIC_PASS_WRITE__ */
+	}
+}
+
+ccl_device_inline void kernel_sort_id_slots(ccl_global float *buffer, int num_slots)
+{
+	ccl_global float2 *id_buffer = (ccl_global float2*)buffer;
+	for(int slot = 1; slot < num_slots; ++slot) {
+		if(id_buffer[slot].x == ID_NONE) {
+			return;
+		}
+		/* Since we're dealing with a tiny number of elements, insertion sort should be fine. */
+		int i = slot;
+		while(i > 0 && id_buffer[i].y > id_buffer[i - 1].y) {
+			float2 swap = id_buffer[i];
+			id_buffer[i] = id_buffer[i - 1];
+			id_buffer[i - 1] = swap;
+			--i;
+		}
+	}
+}
+
+#ifdef __KERNEL_GPU__
+/* post-sorting for Cryptomatte */
+ccl_device void kernel_cryptomatte_post(KernelGlobals *kg, ccl_global float *buffer, uint sample, int x, int y, int offset, int stride)
+{
+	if(sample - 1 == kernel_data.integrator.aa_samples) {
+		int index = offset + x + y * stride;
+		int pass_stride = kernel_data.film.pass_stride;
+		ccl_global float *cryptomatte_buffer = buffer + index * pass_stride + kernel_data.film.pass_cryptomatte;
+		kernel_sort_id_slots(cryptomatte_buffer, 2 * kernel_data.film.cryptomatte_depth);
+	}
+}
+#endif
+
+CCL_NAMESPACE_END