Cycles: code refactor to bake using regular render session and tiles

There should be no user visible change from this, except that tile size
now affects performance. The goal here is to simplify bake denoising in
D3099, letting it reuse more denoising tiles and pass code.

A lot of code is now shared with regular rendering, with the two main
differences being that we read some render result passes from the bake API
when starting to render a tile, and call the bake kernel instead of the
path trace kernel.

With this kind of design where Cycles asks for tiles from the bake API,
it should eventually be easier to reduce memory usage, show tiles as
they are baked, or bake multiple passes at once, though there's still
quite some work needed for that.

Reviewers: #cycles

Subscribers: monio, wmatyjewicz, lukasstockner97, michaelknubben

Differential Revision: https://developer.blender.org/D3108

3 files changed, 23 insertions, 10 deletions

diff --git a/intern/cycles/kernel/kernels/cpu/kernel_cpu.h b/intern/cycles/kernel/kernels/cpu/kernel_cpu.h
index 683f4b88d79..ea3103f12c3 100644
--- a/intern/cycles/kernel/kernels/cpu/kernel_cpu.h
+++ b/intern/cycles/kernel/kernels/cpu/kernel_cpu.h
@@ -46,6 +46,9 @@ void KERNEL_FUNCTION_FULL_NAME(shader)(KernelGlobals *kg,
                                        int offset,
                                        int sample);
 
+void KERNEL_FUNCTION_FULL_NAME(bake)(
+    KernelGlobals *kg, float *buffer, int sample, int x, int y, int offset, int stride);
+
 /* Split kernels */
 
 void KERNEL_FUNCTION_FULL_NAME(data_init)(KernelGlobals *kg,
diff --git a/intern/cycles/kernel/kernels/cpu/kernel_cpu_impl.h b/intern/cycles/kernel/kernels/cpu/kernel_cpu_impl.h
index 091e53cfd83..5aa3fb14318 100644
--- a/intern/cycles/kernel/kernels/cpu/kernel_cpu_impl.h
+++ b/intern/cycles/kernel/kernels/cpu/kernel_cpu_impl.h
@@ -132,6 +132,18 @@ void KERNEL_FUNCTION_FULL_NAME(convert_to_half_float)(KernelGlobals *kg,
 #  endif /* KERNEL_STUB */
 }
 
+/* Bake */
+
+void KERNEL_FUNCTION_FULL_NAME(bake)(
+    KernelGlobals *kg, float *buffer, int sample, int x, int y, int offset, int stride)
+{
+#  ifdef KERNEL_STUB
+  STUB_ASSERT(KERNEL_ARCH, bake);
+#  else
+  kernel_bake_evaluate(kg, buffer, sample, x, y, offset, stride);
+#  endif /* KERNEL_STUB */
+}
+
 /* Shader Evaluate */
 
 void KERNEL_FUNCTION_FULL_NAME(shader)(KernelGlobals *kg,
@@ -146,12 +158,7 @@ void KERNEL_FUNCTION_FULL_NAME(shader)(KernelGlobals *kg,
 #  ifdef KERNEL_STUB
   STUB_ASSERT(KERNEL_ARCH, shader);
 #  else
-  if (type >= SHADER_EVAL_BAKE) {
-#    ifdef __BAKING__
-    kernel_bake_evaluate(kg, input, output, (ShaderEvalType)type, filter, i, offset, sample);
-#    endif
-  }
-  else if (type == SHADER_EVAL_DISPLACE) {
+  if (type == SHADER_EVAL_DISPLACE) {
     kernel_displace_evaluate(kg, input, output, i);
   }
   else {
diff --git a/intern/cycles/kernel/kernels/cuda/kernel.cu b/intern/cycles/kernel/kernels/cuda/kernel.cu
index c4c810c6a82..d4f41132a11 100644
--- a/intern/cycles/kernel/kernels/cuda/kernel.cu
+++ b/intern/cycles/kernel/kernels/cuda/kernel.cu
@@ -214,13 +214,16 @@ kernel_cuda_background(uint4 *input,
 #ifdef __BAKING__
 extern "C" __global__ void
 CUDA_LAUNCH_BOUNDS(CUDA_THREADS_BLOCK_WIDTH, CUDA_KERNEL_MAX_REGISTERS)
-kernel_cuda_bake(uint4 *input, float4 *output, int type, int filter, int sx, int sw, int offset, int sample)
+kernel_cuda_bake(WorkTile *tile, uint total_work_size)
 {
-	int x = sx + blockDim.x*blockIdx.x + threadIdx.x;
+	int work_index = ccl_global_id(0);
+
+	if(work_index < total_work_size) {
+		uint x, y, sample;
+		get_work_pixel(tile, work_index, &x, &y, &sample);
 
-	if(x < sx + sw) {
 		KernelGlobals kg;
-		kernel_bake_evaluate(&kg, input, output, (ShaderEvalType)type, filter, x, offset, sample);
+		kernel_bake_evaluate(&kg, tile->buffer, sample, x, y, tile->offset, tile->stride);
 	}
 }
 #endif