Cycles: Kernel address space changes for MSL

This is the first of a sequence of changes to support compiling Cycles kernels as MSL (Metal Shading Language) in preparation for a Metal GPU device implementation.

MSL requires that all pointer types be declared with explicit address space attributes (device, thread, etc...). There is already precedent for this with Cycles' address space macros (ccl_global, ccl_private, etc...), therefore the first step of MSL-enablement is to apply these consistently. Line-for-line this represents the largest change required to enable MSL. Applying this change first will simplify future patches as well as offering the emergent benefit of enhanced descriptiveness.

The vast majority of deltas in this patch fall into one of two cases:

- Ensuring ccl_private is specified for thread-local pointer types
- Ensuring ccl_global is specified for device-wide pointer types

Additionally, the ccl_addr_space qualifier can be removed. Prior to Cycles X, ccl_addr_space was used as a context-dependent address space qualifier, but now it is either redundant (e.g. in struct typedefs), or can be replaced by ccl_global in the case of pointer types. Associated function variants (e.g. lcg_step_float_addrspace) are also redundant.

In cases where address space qualifiers are chained with "const", this patch places the address space qualifier first. The rationale for this is that the choice of address space is likely to have the greater impact on runtime performance and overall architecture.

The final part of this patch is the addition of a metal/compat.h header. This is partially complete and will be extended in future patches, paving the way for the full Metal implementation.

Ref T92212

Reviewed By: brecht

Maniphest Tasks: T92212

Differential Revision: https://developer.blender.org/D12864

1 files changed, 25 insertions, 22 deletions

diff --git a/intern/cycles/kernel/closure/volume.h b/intern/cycles/kernel/closure/volume.h
index 69959a3f21b..023fb3ac4ea 100644
--- a/intern/cycles/kernel/closure/volume.h
+++ b/intern/cycles/kernel/closure/volume.h
@@ -20,7 +20,7 @@ CCL_NAMESPACE_BEGIN
 
 /* VOLUME EXTINCTION */
 
-ccl_device void volume_extinction_setup(ShaderData *sd, float3 weight)
+ccl_device void volume_extinction_setup(ccl_private ShaderData *sd, float3 weight)
 {
   if (sd->flag & SD_EXTINCTION) {
     sd->closure_transparent_extinction += weight;
@@ -33,7 +33,7 @@ ccl_device void volume_extinction_setup(ShaderData *sd, float3 weight)
 
 /* HENYEY-GREENSTEIN CLOSURE */
 
-typedef ccl_addr_space struct HenyeyGreensteinVolume {
+typedef struct HenyeyGreensteinVolume {
   SHADER_CLOSURE_BASE;
 
   float g;
@@ -51,7 +51,7 @@ ccl_device float single_peaked_henyey_greenstein(float cos_theta, float g)
          (M_1_PI_F * 0.25f);
 };
 
-ccl_device int volume_henyey_greenstein_setup(HenyeyGreensteinVolume *volume)
+ccl_device int volume_henyey_greenstein_setup(ccl_private HenyeyGreensteinVolume *volume)
 {
   volume->type = CLOSURE_VOLUME_HENYEY_GREENSTEIN_ID;
 
@@ -61,10 +61,10 @@ ccl_device int volume_henyey_greenstein_setup(HenyeyGreensteinVolume *volume)
   return SD_SCATTER;
 }
 
-ccl_device float3 volume_henyey_greenstein_eval_phase(const ShaderVolumeClosure *svc,
+ccl_device float3 volume_henyey_greenstein_eval_phase(ccl_private const ShaderVolumeClosure *svc,
                                                       const float3 I,
                                                       float3 omega_in,
-                                                      float *pdf)
+                                                      ccl_private float *pdf)
 {
   float g = svc->g;
 
@@ -81,7 +81,7 @@ ccl_device float3 volume_henyey_greenstein_eval_phase(const ShaderVolumeClosure
 }
 
 ccl_device float3
-henyey_greenstrein_sample(float3 D, float g, float randu, float randv, float *pdf)
+henyey_greenstrein_sample(float3 D, float g, float randu, float randv, ccl_private float *pdf)
 {
   /* match pdf for small g */
   float cos_theta;
@@ -112,17 +112,17 @@ henyey_greenstrein_sample(float3 D, float g, float randu, float randv, float *pd
   return dir;
 }
 
-ccl_device int volume_henyey_greenstein_sample(const ShaderVolumeClosure *svc,
+ccl_device int volume_henyey_greenstein_sample(ccl_private const ShaderVolumeClosure *svc,
                                                float3 I,
                                                float3 dIdx,
                                                float3 dIdy,
                                                float randu,
                                                float randv,
-                                               float3 *eval,
-                                               float3 *omega_in,
-                                               float3 *domega_in_dx,
-                                               float3 *domega_in_dy,
-                                               float *pdf)
+                                               ccl_private float3 *eval,
+                                               ccl_private float3 *omega_in,
+                                               ccl_private float3 *domega_in_dx,
+                                               ccl_private float3 *domega_in_dy,
+                                               ccl_private float *pdf)
 {
   float g = svc->g;
 
@@ -141,22 +141,22 @@ ccl_device int volume_henyey_greenstein_sample(const ShaderVolumeClosure *svc,
 
 /* VOLUME CLOSURE */
 
-ccl_device float3 volume_phase_eval(const ShaderData *sd,
-                                    const ShaderVolumeClosure *svc,
+ccl_device float3 volume_phase_eval(ccl_private const ShaderData *sd,
+                                    ccl_private const ShaderVolumeClosure *svc,
                                     float3 omega_in,
-                                    float *pdf)
+                                    ccl_private float *pdf)
 {
   return volume_henyey_greenstein_eval_phase(svc, sd->I, omega_in, pdf);
 }
 
-ccl_device int volume_phase_sample(const ShaderData *sd,
-                                   const ShaderVolumeClosure *svc,
+ccl_device int volume_phase_sample(ccl_private const ShaderData *sd,
+                                   ccl_private const ShaderVolumeClosure *svc,
                                    float randu,
                                    float randv,
-                                   float3 *eval,
-                                   float3 *omega_in,
-                                   differential3 *domega_in,
-                                   float *pdf)
+                                   ccl_private float3 *eval,
+                                   ccl_private float3 *omega_in,
+                                   ccl_private differential3 *domega_in,
+                                   ccl_private float *pdf)
 {
   return volume_henyey_greenstein_sample(svc,
                                          sd->I,
@@ -187,7 +187,10 @@ ccl_device float volume_channel_get(float3 value, int channel)
   return (channel == 0) ? value.x : ((channel == 1) ? value.y : value.z);
 }
 
-ccl_device int volume_sample_channel(float3 albedo, float3 throughput, float rand, float3 *pdf)
+ccl_device int volume_sample_channel(float3 albedo,
+                                     float3 throughput,
+                                     float rand,
+                                     ccl_private float3 *pdf)
 {
   /* Sample color channel proportional to throughput and single scattering
    * albedo, to significantly reduce noise with many bounce, following: