Cycles: Adapt volumetric lambda functions to work on MSL

This patch adapts the existing volumetric read/write lambda functions for Metal. Lambda expressions are not supported on MSL, so two new macros `VOLUME_READ_LAMBDA` and `VOLUME_WRITE_LAMBDA` have been defined with a default implementation which, on Metal, is overridden to use inline function objects.

This patch also removes the last remaining mention of the now-unused `ccl_addr_space`.

Ref T92212

Reviewed By: leesonw

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D13234

5 files changed, 47 insertions, 31 deletions

diff --git a/intern/cycles/kernel/device/metal/compat.h b/intern/cycles/kernel/device/metal/compat.h
index a839917a907..4a2c39d90fd 100644
--- a/intern/cycles/kernel/device/metal/compat.h
+++ b/intern/cycles/kernel/device/metal/compat.h
@@ -150,6 +150,31 @@ void kernel_gpu_##name::run(thread MetalKernelContext& context, \
 
 // clang-format on
 
+/* volumetric lambda functions - use function objects for lambda-like functionality */
+#define VOLUME_READ_LAMBDA(function_call) \
+  struct FnObjectRead { \
+    KernelGlobals kg; \
+    ccl_private MetalKernelContext *context; \
+    int state; \
+\
+    VolumeStack operator()(const int i) const \
+    { \
+      return context->function_call; \
+    } \
+  } volume_read_lambda_pass{kg, this, state};
+
+#define VOLUME_WRITE_LAMBDA(function_call) \
+  struct FnObjectWrite { \
+    KernelGlobals kg; \
+    ccl_private MetalKernelContext *context; \
+    int state; \
+\
+    void operator()(const int i, VolumeStack entry) const \
+    { \
+      context->function_call; \
+    } \
+  } volume_write_lambda_pass{kg, this, state};
+
 /* make_type definitions with Metal style element initializers */
 #ifdef make_float2
 #  undef make_float2
diff --git a/intern/cycles/kernel/integrator/shade_shadow.h b/intern/cycles/kernel/integrator/shade_shadow.h
index 1de890aae29..a68fcaa7a64 100644
--- a/intern/cycles/kernel/integrator/shade_shadow.h
+++ b/intern/cycles/kernel/integrator/shade_shadow.h
@@ -95,8 +95,8 @@ ccl_device_inline void integrate_transparent_volume_shadow(KernelGlobals kg,
 
   shader_setup_from_volume(kg, shadow_sd, &ray);
 
-  const float step_size = volume_stack_step_size(
-      kg, [=](const int i) { return integrator_state_read_shadow_volume_stack(state, i); });
+  VOLUME_READ_LAMBDA(integrator_state_read_shadow_volume_stack(state, i));
+  const float step_size = volume_stack_step_size(kg, volume_read_lambda_pass);
 
   volume_shadow_heterogeneous(kg, state, &ray, shadow_sd, throughput, step_size);
 }
diff --git a/intern/cycles/kernel/integrator/shade_volume.h b/intern/cycles/kernel/integrator/shade_volume.h
index f42614cc87f..c5a80eb336f 100644
--- a/intern/cycles/kernel/integrator/shade_volume.h
+++ b/intern/cycles/kernel/integrator/shade_volume.h
@@ -78,9 +78,8 @@ ccl_device_inline bool shadow_volume_shader_sample(KernelGlobals kg,
                                                    ccl_private ShaderData *ccl_restrict sd,
                                                    ccl_private float3 *ccl_restrict extinction)
 {
-  shader_eval_volume<true>(kg, state, sd, PATH_RAY_SHADOW, [=](const int i) {
-    return integrator_state_read_shadow_volume_stack(state, i);
-  });
+  VOLUME_READ_LAMBDA(integrator_state_read_shadow_volume_stack(state, i))
+  shader_eval_volume<true>(kg, state, sd, PATH_RAY_SHADOW, volume_read_lambda_pass);
 
   if (!(sd->flag & SD_EXTINCTION)) {
     return false;
@@ -98,9 +97,8 @@ ccl_device_inline bool volume_shader_sample(KernelGlobals kg,
                                             ccl_private VolumeShaderCoefficients *coeff)
 {
   const uint32_t path_flag = INTEGRATOR_STATE(state, path, flag);
-  shader_eval_volume<false>(kg, state, sd, path_flag, [=](const int i) {
-    return integrator_state_read_volume_stack(state, i);
-  });
+  VOLUME_READ_LAMBDA(integrator_state_read_volume_stack(state, i))
+  shader_eval_volume<false>(kg, state, sd, path_flag, volume_read_lambda_pass);
 
   if (!(sd->flag & (SD_EXTINCTION | SD_SCATTER | SD_EMISSION))) {
     return false;
@@ -921,8 +919,8 @@ ccl_device VolumeIntegrateEvent volume_integrate(KernelGlobals kg,
                                                 VOLUME_SAMPLE_DISTANCE;
 
   /* Step through volume. */
-  const float step_size = volume_stack_step_size(
-      kg, [=](const int i) { return integrator_state_read_volume_stack(state, i); });
+  VOLUME_READ_LAMBDA(integrator_state_read_volume_stack(state, i))
+  const float step_size = volume_stack_step_size(kg, volume_read_lambda_pass);
 
   /* TODO: expensive to zero closures? */
   VolumeIntegrateResult result = {};
diff --git a/intern/cycles/kernel/integrator/volume_stack.h b/intern/cycles/kernel/integrator/volume_stack.h
index cf69826ffff..ea3fa901e2d 100644
--- a/intern/cycles/kernel/integrator/volume_stack.h
+++ b/intern/cycles/kernel/integrator/volume_stack.h
@@ -18,6 +18,14 @@
 
 CCL_NAMESPACE_BEGIN
 
+/* Volumetric read/write lambda functions - default implementations */
+#ifndef VOLUME_READ_LAMBDA
+#  define VOLUME_READ_LAMBDA(function_call) \
+    auto volume_read_lambda_pass = [=](const int i) { return function_call; };
+#  define VOLUME_WRITE_LAMBDA(function_call) \
+    auto volume_write_lambda_pass = [=](const int i, VolumeStack entry) { function_call; };
+#endif
+
 /* Volume Stack
  *
  * This is an array of object/shared ID's that the current segment of the path
@@ -88,26 +96,18 @@ ccl_device void volume_stack_enter_exit(KernelGlobals kg,
                                         IntegratorState state,
                                         ccl_private const ShaderData *sd)
 {
-  volume_stack_enter_exit(
-      kg,
-      sd,
-      [=](const int i) { return integrator_state_read_volume_stack(state, i); },
-      [=](const int i, const VolumeStack entry) {
-        integrator_state_write_volume_stack(state, i, entry);
-      });
+  VOLUME_READ_LAMBDA(integrator_state_read_volume_stack(state, i))
+  VOLUME_WRITE_LAMBDA(integrator_state_write_volume_stack(state, i, entry))
+  volume_stack_enter_exit(kg, sd, volume_read_lambda_pass, volume_write_lambda_pass);
 }
 
 ccl_device void shadow_volume_stack_enter_exit(KernelGlobals kg,
                                                IntegratorShadowState state,
                                                ccl_private const ShaderData *sd)
 {
-  volume_stack_enter_exit(
-      kg,
-      sd,
-      [=](const int i) { return integrator_state_read_shadow_volume_stack(state, i); },
-      [=](const int i, const VolumeStack entry) {
-        integrator_state_write_shadow_volume_stack(state, i, entry);
-      });
+  VOLUME_READ_LAMBDA(integrator_state_read_shadow_volume_stack(state, i))
+  VOLUME_WRITE_LAMBDA(integrator_state_write_shadow_volume_stack(state, i, entry))
+  volume_stack_enter_exit(kg, sd, volume_read_lambda_pass, volume_write_lambda_pass);
 }
 
 /* Clean stack after the last bounce.
diff --git a/intern/cycles/kernel/types.h b/intern/cycles/kernel/types.h
index 495838adfe9..196c7c92a80 100644
--- a/intern/cycles/kernel/types.h
+++ b/intern/cycles/kernel/types.h
@@ -36,13 +36,6 @@
 #  define __KERNEL_CPU__
 #endif
 
-/* TODO(sergey): This is only to make it possible to include this header
- * from outside of the kernel. but this could be done somewhat cleaner?
- */
-#ifndef ccl_addr_space
-#  define ccl_addr_space
-#endif
-
 CCL_NAMESPACE_BEGIN
 
 /* Constants */