Cycles: merge of cycles-x branch, a major update to the renderer

This includes much improved GPU rendering performance, viewport interactivity,
new shadow catcher, revamped sampling settings, subsurface scattering anisotropy,
new GPU volume sampling, improved PMJ sampling pattern, and more.

Some features have also been removed or changed, breaking backwards compatibility.
Including the removal of the OpenCL backend, for which alternatives are under
development.

Release notes and code docs:
https://wiki.blender.org/wiki/Reference/Release_Notes/3.0/Cycles
https://wiki.blender.org/wiki/Source/Render/Cycles

Credits:
* Sergey Sharybin
* Brecht Van Lommel
* Patrick Mours (OptiX backend)
* Christophe Hery (subsurface scattering anisotropy)
* William Leeson (PMJ sampling pattern)
* Alaska (various fixes and tweaks)
* Thomas Dinges (various fixes)

For the full commit history, see the cycles-x branch. This squashes together
all the changes since intermediate changes would often fail building or tests.

Ref T87839, T87837, T87836
Fixes T90734, T89353, T80267, T80267, T77185, T69800

1 files changed, 173 insertions, 0 deletions

diff --git a/intern/cycles/integrator/shader_eval.cpp b/intern/cycles/integrator/shader_eval.cpp
new file mode 100644
index 00000000000..465b4a8d4da
--- /dev/null
+++ b/intern/cycles/integrator/shader_eval.cpp
@@ -0,0 +1,173 @@
+/*
+ * Copyright 2011-2021 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.
+ */
+
+#include "integrator/shader_eval.h"
+
+#include "device/device.h"
+#include "device/device_queue.h"
+
+#include "device/cpu/kernel.h"
+#include "device/cpu/kernel_thread_globals.h"
+
+#include "util/util_logging.h"
+#include "util/util_progress.h"
+#include "util/util_tbb.h"
+
+CCL_NAMESPACE_BEGIN
+
+ShaderEval::ShaderEval(Device *device, Progress &progress) : device_(device), progress_(progress)
+{
+  DCHECK_NE(device_, nullptr);
+}
+
+bool ShaderEval::eval(const ShaderEvalType type,
+                      const int max_num_points,
+                      const function<int(device_vector<KernelShaderEvalInput> &)> &fill_input,
+                      const function<void(device_vector<float4> &)> &read_output)
+{
+  bool first_device = true;
+  bool success = true;
+
+  device_->foreach_device([&](Device *device) {
+    if (!first_device) {
+      LOG(ERROR) << "Multi-devices are not yet fully implemented, will evaluate shader on a "
+                    "single device.";
+      return;
+    }
+    first_device = false;
+
+    device_vector<KernelShaderEvalInput> input(device, "ShaderEval input", MEM_READ_ONLY);
+    device_vector<float4> output(device, "ShaderEval output", MEM_READ_WRITE);
+
+    /* Allocate and copy device buffers. */
+    DCHECK_EQ(input.device, device);
+    DCHECK_EQ(output.device, device);
+    DCHECK_LE(output.size(), input.size());
+
+    input.alloc(max_num_points);
+    int num_points = fill_input(input);
+    if (num_points == 0) {
+      return;
+    }
+
+    input.copy_to_device();
+    output.alloc(num_points);
+    output.zero_to_device();
+
+    /* Evaluate on CPU or GPU. */
+    success = (device->info.type == DEVICE_CPU) ? eval_cpu(device, type, input, output) :
+                                                  eval_gpu(device, type, input, output);
+
+    /* Copy data back from device if not cancelled. */
+    if (success) {
+      output.copy_from_device(0, 1, output.size());
+      read_output(output);
+    }
+
+    input.free();
+    output.free();
+  });
+
+  return success;
+}
+
+bool ShaderEval::eval_cpu(Device *device,
+                          const ShaderEvalType type,
+                          device_vector<KernelShaderEvalInput> &input,
+                          device_vector<float4> &output)
+{
+  vector<CPUKernelThreadGlobals> kernel_thread_globals;
+  device->get_cpu_kernel_thread_globals(kernel_thread_globals);
+
+  /* Find required kernel function. */
+  const CPUKernels &kernels = *(device->get_cpu_kernels());
+
+  /* Simple parallel_for over all work items. */
+  const int64_t work_size = output.size();
+  KernelShaderEvalInput *input_data = input.data();
+  float4 *output_data = output.data();
+  bool success = true;
+
+  tbb::task_arena local_arena(device->info.cpu_threads);
+  local_arena.execute([&]() {
+    tbb::parallel_for(int64_t(0), work_size, [&](int64_t work_index) {
+      /* TODO: is this fast enough? */
+      if (progress_.get_cancel()) {
+        success = false;
+        return;
+      }
+
+      const int thread_index = tbb::this_task_arena::current_thread_index();
+      KernelGlobals *kg = &kernel_thread_globals[thread_index];
+
+      switch (type) {
+        case SHADER_EVAL_DISPLACE:
+          kernels.shader_eval_displace(kg, input_data, output_data, work_index);
+          break;
+        case SHADER_EVAL_BACKGROUND:
+          kernels.shader_eval_background(kg, input_data, output_data, work_index);
+          break;
+      }
+    });
+  });
+
+  return success;
+}
+
+bool ShaderEval::eval_gpu(Device *device,
+                          const ShaderEvalType type,
+                          device_vector<KernelShaderEvalInput> &input,
+                          device_vector<float4> &output)
+{
+  /* Find required kernel function. */
+  DeviceKernel kernel;
+  switch (type) {
+    case SHADER_EVAL_DISPLACE:
+      kernel = DEVICE_KERNEL_SHADER_EVAL_DISPLACE;
+      break;
+    case SHADER_EVAL_BACKGROUND:
+      kernel = DEVICE_KERNEL_SHADER_EVAL_BACKGROUND;
+      break;
+  };
+
+  /* Create device queue. */
+  unique_ptr<DeviceQueue> queue = device->gpu_queue_create();
+  queue->init_execution();
+
+  /* Execute work on GPU in chunk, so we can cancel.
+   * TODO : query appropriate size from device.*/
+  const int chunk_size = 65536;
+
+  const int work_size = output.size();
+  void *d_input = (void *)input.device_pointer;
+  void *d_output = (void *)output.device_pointer;
+
+  for (int d_offset = 0; d_offset < work_size; d_offset += chunk_size) {
+    int d_work_size = min(chunk_size, work_size - d_offset);
+    void *args[] = {&d_input, &d_output, &d_offset, &d_work_size};
+
+    queue->enqueue(kernel, d_work_size, args);
+    queue->synchronize();
+
+    if (progress_.get_cancel()) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
+CCL_NAMESPACE_END