Metal: MTLShader and MTLShaderGenerator implementation.

Full support for translation and compilation of shaders in Metal, using
GPUShaderCreateInfo. Includes render pipeline state creation and management,
enabling all standard GPU viewport rendering features in Metal.

Authored by Apple: Michael Parkin-White, Marco Giordano

Ref T96261

Reviewed By: fclem

Maniphest Tasks: T96261

Differential Revision: https://developer.blender.org/D15563

4 files changed, 67 insertions, 0 deletions

diff --git a/source/blender/gpu/intern/gpu_context.cc b/source/blender/gpu/intern/gpu_context.cc
index e29b0d5801d..bcc418169b7 100644
--- a/source/blender/gpu/intern/gpu_context.cc
+++ b/source/blender/gpu/intern/gpu_context.cc
@@ -56,11 +56,15 @@ static void gpu_backend_discard();
 
 namespace blender::gpu {
 
+int Context::context_counter = 0;
 Context::Context()
 {
   thread_ = pthread_self();
   is_active_ = false;
   matrix_state = GPU_matrix_state_create();
+
+  context_id = Context::context_counter;
+  Context::context_counter++;
 }
 
 Context::~Context()
diff --git a/source/blender/gpu/intern/gpu_context_private.hh b/source/blender/gpu/intern/gpu_context_private.hh
index f823a92893c..2217e5262ed 100644
--- a/source/blender/gpu/intern/gpu_context_private.hh
+++ b/source/blender/gpu/intern/gpu_context_private.hh
@@ -48,6 +48,14 @@ class Context {
 
   DebugStack debug_stack;
 
+  /* GPUContext counter used to assign a unique ID to each GPUContext.
+   * NOTE(Metal): This is required by the Metal Backend, as a bug exists in the global OS shader
+   * cache wherein compilation of identical source from two distinct threads can result in an
+   * invalid cache collision, result in a broken shader object. Appending the unique context ID
+   * onto compiled sources ensures the source hashes are different. */
+  static int context_counter;
+  int context_id = 0;
+
  protected:
   /** Thread on which this context is active. */
   pthread_t thread_;
diff --git a/source/blender/gpu/intern/gpu_shader.cc b/source/blender/gpu/intern/gpu_shader.cc
index 2d1b3dc2dca..4d059ae495e 100644
--- a/source/blender/gpu/intern/gpu_shader.cc
+++ b/source/blender/gpu/intern/gpu_shader.cc
@@ -95,6 +95,9 @@ static void standard_defines(Vector<const char *> &sources)
     case GPU_BACKEND_OPENGL:
       sources.append("#define GPU_OPENGL\n");
       break;
+    case GPU_BACKEND_METAL:
+      sources.append("#define GPU_METAL\n");
+      break;
     default:
       BLI_assert(false && "Invalid GPU Backend Type");
       break;
diff --git a/source/blender/gpu/intern/gpu_shader_create_info.hh b/source/blender/gpu/intern/gpu_shader_create_info.hh
index 8236e669288..3884c067c83 100644
--- a/source/blender/gpu/intern/gpu_shader_create_info.hh
+++ b/source/blender/gpu/intern/gpu_shader_create_info.hh
@@ -32,6 +32,7 @@ namespace blender::gpu::shader {
 #endif
 
 enum class Type {
+  /* Types supported natively across all GPU backends. */
   FLOAT = 0,
   VEC2,
   VEC3,
@@ -47,6 +48,21 @@ enum class Type {
   IVEC3,
   IVEC4,
   BOOL,
+  /* Additionally supported types to enable data optimisation and native
+   * support in some GPUBackends.
+   * NOTE: These types must be representable in all APIs. E.g. VEC3_101010I2 is aliased as vec3 in
+   * the GL backend, as implicit type conversions from packed normal attribute data to vec3 is
+   * supported. UCHAR/CHAR types are natively supported in Metal and can be used to avoid
+   * additional data conversions for GPU_COMP_U8 vertex attributes. */
+  VEC3_101010I2,
+  UCHAR,
+  UCHAR2,
+  UCHAR3,
+  UCHAR4,
+  CHAR,
+  CHAR2,
+  CHAR3,
+  CHAR4
 };
 
 /* All of these functions is a bit out of place */
@@ -86,6 +102,40 @@ static inline std::ostream &operator<<(std::ostream &stream, const Type type)
       return stream << "mat3";
     case Type::MAT4:
       return stream << "mat4";
+    case Type::VEC3_101010I2:
+      return stream << "vec3_1010102_Inorm";
+    case Type::UCHAR:
+      return stream << "uchar";
+    case Type::UCHAR2:
+      return stream << "uchar2";
+    case Type::UCHAR3:
+      return stream << "uchar3";
+    case Type::UCHAR4:
+      return stream << "uchar4";
+    case Type::CHAR:
+      return stream << "char";
+    case Type::CHAR2:
+      return stream << "char2";
+    case Type::CHAR3:
+      return stream << "char3";
+    case Type::CHAR4:
+      return stream << "char4";
+    case Type::INT:
+      return stream << "int";
+    case Type::IVEC2:
+      return stream << "ivec2";
+    case Type::IVEC3:
+      return stream << "ivec3";
+    case Type::IVEC4:
+      return stream << "ivec4";
+    case Type::UINT:
+      return stream << "uint";
+    case Type::UVEC2:
+      return stream << "uvec2";
+    case Type::UVEC3:
+      return stream << "uvec3";
+    case Type::UVEC4:
+      return stream << "uvec4";
     default:
       BLI_assert(0);
       return stream;
@@ -228,6 +278,8 @@ enum class PrimitiveOut {
   POINTS = 0,
   LINE_STRIP,
   TRIANGLE_STRIP,
+  LINES,
+  TRIANGLES,
 };
 
 struct StageInterfaceInfo {