Code refactor: remove rng_state buffer and compute hash on the fly.

A little faster on some benchmark scenes, a little slower on others, seems
about performance neutral on average and saves a little memory.

3 files changed, 2 insertions, 24 deletions

diff --git a/intern/cycles/kernel/split/kernel_buffer_update.h b/intern/cycles/kernel/split/kernel_buffer_update.h
index e8547767480..5e9db821f7b 100644
--- a/intern/cycles/kernel/split/kernel_buffer_update.h
+++ b/intern/cycles/kernel/split/kernel_buffer_update.h
@@ -108,10 +108,6 @@ ccl_device void kernel_buffer_update(KernelGlobals *kg,
 			uint x, y, sample;
 			get_work_pixel(tile, work_index, &x, &y, &sample);
 
-			/* Remap rng_state to current pixel. */
-			ccl_global uint *rng_state = kernel_split_params.tile.rng_state;
-			rng_state += tile->offset + x + y*tile->stride;
-
 			/* Store buffer offset for writing to passes. */
 			uint buffer_offset = (tile->offset + x + y*tile->stride) * kernel_data.film.pass_stride;
 			ccl_global float *buffer = tile->buffer + buffer_offset;
@@ -119,7 +115,7 @@ ccl_device void kernel_buffer_update(KernelGlobals *kg,
 
 			/* Initialize random numbers and ray. */
 			uint rng_hash;
-			kernel_path_trace_setup(kg, rng_state, sample, x, y, &rng_hash, ray);
+			kernel_path_trace_setup(kg, sample, x, y, &rng_hash, ray);
 
 			if(ray->t != 0.0f) {
 				/* Initialize throughput, path radiance, Ray, PathState;
diff --git a/intern/cycles/kernel/split/kernel_data_init.h b/intern/cycles/kernel/split/kernel_data_init.h
index 2da3ca47466..f4df949fdb1 100644
--- a/intern/cycles/kernel/split/kernel_data_init.h
+++ b/intern/cycles/kernel/split/kernel_data_init.h
@@ -49,7 +49,6 @@ void KERNEL_FUNCTION_FULL_NAME(data_init)(
         ccl_global void *split_data_buffer,
         int num_elements,
         ccl_global char *ray_state,
-        ccl_global uint *rng_state,
 
 #ifdef __KERNEL_OPENCL__
 		KERNEL_BUFFER_PARAMS,
@@ -84,7 +83,6 @@ void KERNEL_FUNCTION_FULL_NAME(data_init)(
 	kernel_split_params.tile.offset = offset;
 	kernel_split_params.tile.stride = stride;
 
-	kernel_split_params.tile.rng_state = rng_state;
 	kernel_split_params.tile.buffer = buffer;
 
 	kernel_split_params.total_work_size = sw * sh * num_samples;
@@ -122,7 +120,7 @@ void KERNEL_FUNCTION_FULL_NAME(data_init)(
 		*use_queues_flag = 0;
 	}
 
-	/* zero the tiles pixels and initialize rng_state if this is the first sample */
+	/* zero the tiles pixels if this is the first sample */
 	if(start_sample == 0) {
 		int pass_stride = kernel_data.film.pass_stride;
 
@@ -130,9 +128,6 @@ void KERNEL_FUNCTION_FULL_NAME(data_init)(
 		for(int y = sy; y < sy + sh; y++) {
 			int index = offset + y * stride;
 			memset(buffer + (sx + index) * pass_stride, 0, sizeof(float) * pass_stride * sw);
-			for(int x = sx; x < sx + sw; x++) {
-				rng_state[index + x] = hash_int_2d(x, y);
-			}
 		}
 #else
 		parallel_for(kg, i, sw * sh * pass_stride) {
@@ -146,14 +141,6 @@ void KERNEL_FUNCTION_FULL_NAME(data_init)(
 
 			*(buffer + index) = 0.0f;
 		}
-
-		parallel_for(kg, i, sw * sh) {
-			int x = sx + i % sw;
-			int y = sy + i / sw;
-
-			int index = (offset + x + y*stride);
-			*(rng_state + index) = hash_int_2d(x, y);
-		}
 #endif
 	}
 
diff --git a/intern/cycles/kernel/split/kernel_path_init.h b/intern/cycles/kernel/split/kernel_path_init.h
index 701d39403ad..1bd641b031d 100644
--- a/intern/cycles/kernel/split/kernel_path_init.h
+++ b/intern/cycles/kernel/split/kernel_path_init.h
@@ -45,10 +45,6 @@ ccl_device void kernel_path_init(KernelGlobals *kg) {
 	uint x, y, sample;
 	get_work_pixel(tile, work_index, &x, &y, &sample);
 
-	/* Remap rng_state and buffer to current pixel. */
-	ccl_global uint *rng_state = kernel_split_params.tile.rng_state;
-	rng_state += tile->offset + x + y*tile->stride;
-
 	/* Store buffer offset for writing to passes. */
 	uint buffer_offset = (tile->offset + x + y*tile->stride) * kernel_data.film.pass_stride;
 	ccl_global float *buffer = tile->buffer + buffer_offset;
@@ -57,7 +53,6 @@ ccl_device void kernel_path_init(KernelGlobals *kg) {
 	/* Initialize random numbers and ray. */
 	uint rng_hash;
 	kernel_path_trace_setup(kg,
-	                        rng_state,
 	                        sample,
 	                        x, y,
 	                        &rng_hash,