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, 19 insertions, 17 deletions

diff --git a/intern/cycles/kernel/closure/bsdf.h b/intern/cycles/kernel/closure/bsdf.h
index bb80b9636bb..e115bef3170 100644
--- a/intern/cycles/kernel/closure/bsdf.h
+++ b/intern/cycles/kernel/closure/bsdf.h
@@ -41,32 +41,32 @@ CCL_NAMESPACE_BEGIN
 
 /* Returns the square of the roughness of the closure if it has roughness,
  * 0 for singular closures and 1 otherwise. */
-ccl_device_inline float bsdf_get_specular_roughness_squared(const ShaderClosure *sc)
+ccl_device_inline float bsdf_get_specular_roughness_squared(ccl_private const ShaderClosure *sc)
 {
   if (CLOSURE_IS_BSDF_SINGULAR(sc->type)) {
     return 0.0f;
   }
 
   if (CLOSURE_IS_BSDF_MICROFACET(sc->type)) {
-    MicrofacetBsdf *bsdf = (MicrofacetBsdf *)sc;
+    ccl_private MicrofacetBsdf *bsdf = (ccl_private MicrofacetBsdf *)sc;
     return bsdf->alpha_x * bsdf->alpha_y;
   }
 
   return 1.0f;
 }
 
-ccl_device_inline float bsdf_get_roughness_squared(const ShaderClosure *sc)
+ccl_device_inline float bsdf_get_roughness_squared(ccl_private const ShaderClosure *sc)
 {
   /* This version includes diffuse, mainly for baking Principled BSDF
    * where specular and metallic zero otherwise does not bake the
    * specified roughness parameter. */
   if (sc->type == CLOSURE_BSDF_OREN_NAYAR_ID) {
-    OrenNayarBsdf *bsdf = (OrenNayarBsdf *)sc;
+    ccl_private OrenNayarBsdf *bsdf = (ccl_private OrenNayarBsdf *)sc;
     return sqr(sqr(bsdf->roughness));
   }
 
   if (sc->type == CLOSURE_BSDF_PRINCIPLED_DIFFUSE_ID) {
-    PrincipledDiffuseBsdf *bsdf = (PrincipledDiffuseBsdf *)sc;
+    ccl_private PrincipledDiffuseBsdf *bsdf = (ccl_private PrincipledDiffuseBsdf *)sc;
     return sqr(sqr(bsdf->roughness));
   }
 
@@ -111,15 +111,15 @@ ccl_device_inline float shift_cos_in(float cos_in, const float frequency_multipl
   return val;
 }
 
-ccl_device_inline int bsdf_sample(const KernelGlobals *kg,
-                                  ShaderData *sd,
-                                  const ShaderClosure *sc,
+ccl_device_inline int bsdf_sample(ccl_global const KernelGlobals *kg,
+                                  ccl_private ShaderData *sd,
+                                  ccl_private const ShaderClosure *sc,
                                   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)
 {
   /* For curves use the smooth normal, particularly for ribbons the geometric
    * normal gives too much darkening otherwise. */
@@ -467,12 +467,12 @@ ccl_device
 ccl_device_inline
 #endif
     float3
-    bsdf_eval(const KernelGlobals *kg,
-              ShaderData *sd,
-              const ShaderClosure *sc,
+    bsdf_eval(ccl_global const KernelGlobals *kg,
+              ccl_private ShaderData *sd,
+              ccl_private const ShaderClosure *sc,
               const float3 omega_in,
               const bool is_transmission,
-              float *pdf)
+              ccl_private float *pdf)
 {
   float3 eval = zero_float3();
 
@@ -652,7 +652,9 @@ ccl_device_inline
   return eval;
 }
 
-ccl_device void bsdf_blur(const KernelGlobals *kg, ShaderClosure *sc, float roughness)
+ccl_device void bsdf_blur(ccl_global const KernelGlobals *kg,
+                          ccl_private ShaderClosure *sc,
+                          float roughness)
 {
   /* TODO: do we want to blur volume closures? */
 #ifdef __SVM__