Metal: Support for Storage Buffers.

Adds support for SSBOs to the Metal backend. Also includes small compilation fixes for EEVEE Next shaders which are now compiled under build time testing.

One requirement being explicit address space tagging on reference types pased into functions which write to SSBOs, if an SSBO buffer reference is passed. Previously, all reference types were treated as being within thread address space.

For testing and stability, storage buffer feature flag remains disabled on macOS, however, this can now be toggled in mtl_backend for testing of future work.

Authored by Apple: Michael Parkin-White

Ref #96261

@@ -37,3 +37,3 @@
 BLI_INLINE eParticleRefineShaderType drw_hair_shader_type_get()
 {
-  if (GPU_compute_shader_support() && GPU_shader_storage_buffer_objects_support()) {
+  /* NOTE: Hair refine is faster using transform feedback via vertex processing pipeline with Metal

@@ -74,3 +71,1 @@
-                         out vec4 top,
-                         out vec4 near,
-                         out vec4 far)
+                         DEVICE_OUT(vec4, left),

@@ -90,3 +90,3 @@
 }
 
-void frustum_culling_planes_calc(mat4 winmat, mat4 viewmat, out vec4 planes[6])
+void frustum_culling_planes_calc(mat4 winmat, mat4 viewmat, DEVICE_OUT_ARRAY(vec4, planes, 6))

@@ -101,3 +101,3 @@
 }
 
-vec4 frustum_culling_sphere_calc(vec4 corners[8])
+vec4 frustum_culling_sphere_calc(device vec4 corners[8])

@@ -22,0 +23,4 @@
+ * - Argument buffer for bindless resources (e.g. samplers)
+ * - Transform feedback buffer
+ * - Default push constant block
+ * Along with up to 6+1 buffers for vertex data, and index data. */

@@ -1180,0 +1226,4 @@
+        BLI_assert(ssbo_size > 0);
+      }
+      else {
+        MTL_LOG_INFO(

@@ -108,0 +116,4 @@
+ * Default Push constant block for uniforms <-- MTL_uniform_buffer_base_index
+ * Uniform buffers                          <-- MTL_uniform_buffer_base_index+1
+ * Storage buffers                          <-- MTL_storage_buffer_base_index
+ * Samplers/argument buffer table           <-- last buffer + 1

@@ -1125,0 +1156,4 @@
+
+template<typename T> T findMSB(T x)
+{
+  /* clz returns the number of leading zeroes. To fetch the index of the LSB, we can also use this

@@ -1125,0 +1158,4 @@
+{
+  /* clz returns the number of leading zeroes. To fetch the index of the LSB, we can also use this
+   * value as index when offset by 1. however need to filter out the case where the input value is
+   * zero to match GLSL functionality. 000000010*/

@@ -1125,0 +1159,4 @@
+  /* clz returns the number of leading zeroes. To fetch the index of the LSB, we can also use this
+   * value as index when offset by 1. however need to filter out the case where the input value is
+   * zero to match GLSL functionality. 000000010*/
+  return (x == T(0)) ? T(-1) : (clz(T(0)) - clz(x) - T(1));

@@ -16,2 +16,4 @@
 #define depth2DArrayShadow sampler2DArrayShadow
 
+/* Memory scope and pass by reference types.
+ * NOTE: These are required by Metal, but are not required in all cases by GLSL. */