Make `__BuiltinFloatingPointType` conform to `IDifferentiable`. (#2499)

1 files changed, 76 insertions, 3 deletions

diff --git a/source/slang/core.meta.slang b/source/slang/core.meta.slang
index 05963bd11..a37124bdc 100644
--- a/source/slang/core.meta.slang
+++ b/source/slang/core.meta.slang
@@ -162,7 +162,7 @@ interface __BuiltinRealType : __BuiltinSignedArithmeticType {}
 /// A type that uses a floating-point representation
 [sealed]
 [builtin]
-interface __BuiltinFloatingPointType : __BuiltinRealType
+interface __BuiltinFloatingPointType : __BuiltinRealType, IDifferentiable
 {
         /// Initialize from a 32-bit floating-point value.
     __init(float value);
@@ -369,6 +369,26 @@ ${{{{
     case BaseType::Double:
 }}}}
         static $(kBaseTypes[tt].name) getPi() { return $(kBaseTypes[tt].name)(3.14159265358979323846264338328); }
+
+        typedef $(kBaseTypes[tt].name) Differential;
+    
+        [__unsafeForceInlineEarly]
+        static Differential dzero()
+        {
+            return Differential(0);
+        }
+
+        [__unsafeForceInlineEarly]
+        static Differential dadd(Differential a, Differential b)
+        {
+            return a + b;
+        }
+
+        [__unsafeForceInlineEarly]
+        static Differential dmul(Differential a, Differential b)
+        {
+            return a * b;
+        }
 ${{{{
         break;
     }
@@ -891,7 +911,6 @@ for (int tt = 0; tt < kBaseTypeCount; ++tt)
             sb << "    __init(" << kBaseTypes[ff].name << " value);\n";
         }
     }
-
     sb << "}\n";
 }
 
@@ -926,7 +945,6 @@ for( int C = 2; C <= 4; ++C )
         if(rr == R && cc == C) continue;
         sb << "__init(matrix<T," << rr << "," << cc << "> value);\n";
     }
-
     sb << "}\n";
 }
 
@@ -935,6 +953,7 @@ for (int tt = 0; tt < kBaseTypeCount; ++tt)
     if(kBaseTypes[tt].tag == BaseType::Void) continue;
     auto toType = kBaseTypes[tt].name;
 }}}}
+
 __generic<let R : int, let C : int> extension matrix<$(toType),R,C>
 {
 ${{{{
@@ -958,6 +977,60 @@ ${{{{
 }
 }}}}
 
+__generic<T, U>
+__intrinsic_op(0)
+T __slang_noop_cast(U u);
+
+__generic<T:__BuiltinFloatingPointType, let N: int>
+extension vector<T, N> : IDifferentiable
+{
+    typedef vector<T, N> Differential;
+
+    [__unsafeForceInlineEarly]
+    static Differential dzero()
+    {
+        return Differential(__slang_noop_cast<T>(T.dzero()));
+    }
+
+    [__unsafeForceInlineEarly]
+    static Differential dadd(Differential a, Differential b)
+    {
+        return a + b;
+    }
+
+    [__unsafeForceInlineEarly]
+    static Differential dmul(This a, Differential b)
+    {
+        return a * b;
+    }
+}
+
+__generic<T:__BuiltinFloatingPointType, let R: int, let C: int>
+extension matrix<T, R, C> : IDifferentiable
+{
+    typedef matrix<T, R, C> Differential;
+
+    __init(T val);
+
+    [__unsafeForceInlineEarly]
+    static Differential dzero()
+    {
+        return matrix<T, R, C>(__slang_noop_cast<T>(T.dzero()));
+    }
+
+    [__unsafeForceInlineEarly]
+    static Differential dadd(Differential a, Differential b)
+    {
+        return a + b;
+    }
+
+    [__unsafeForceInlineEarly]
+    static Differential dmul(This a, Differential b)
+    {
+        return a * b;
+    }
+}
+
 //@ public:
 
     /// Sampling state for filtered texture fetches.