fixes to get promote_affine, zero_expand to work in hlsl

Author: keptsecret

include/nbl/builtin/hlsl/math/linalg/transform.hlsl

@@ -4,12 +4,10 @@
 #ifndef _NBL_BUILTIN_HLSL_MATH_LINALG_TRANSFORM_INCLUDED_
 #define _NBL_BUILTIN_HLSL_MATH_LINALG_TRANSFORM_INCLUDED_
 
-
 #include <nbl/builtin/hlsl/mpl.hlsl>
 #include <nbl/builtin/hlsl/cpp_compat/intrinsics.hlsl>
 #include <nbl/builtin/hlsl/concepts.hlsl>
 
-
 namespace nbl
 {
 namespace hlsl
@@ -26,50 +24,70 @@ namespace linalg
 ///
 /// @tparam T A floating-point scalar type
 template <typename T>
-matrix<T, 3, 3> rotation_mat(T angle, vector<T, 3> const& axis)
+matrix<T, 3, 3> rotation_mat(T angle, const vector<T, 3> axis)
 {
-  T const a = angle;
-  T const c = cos(a);
-  T const s = sin(a);
+    const T a = angle;
+    const T c = cos(a);
+    const T s = sin(a);
+
+    vector<T, 3> temp = hlsl::promote<vector<T, 3> >((T(1.0) - c) * axis);
 
-  vector<T, 3> temp((T(1) - c) * axis);
+    matrix<T, 3, 3> rotation;
+    rotation[0][0] = c + temp[0] * axis[0];
+    rotation[0][1] = temp[1] * axis[0] - s * axis[2];
+    rotation[0][2] = temp[2] * axis[0] + s * axis[1];
 
-  matrix<T, 3, 3> rotation;
-  rotation[0][0] = c + temp[0] * axis[0];
-  rotation[0][1] = temp[1] * axis[0] - s * axis[2];
-  rotation[0][2] = temp[2] * axis[0] + s * axis[1];
+    rotation[1][0] = temp[0] * axis[1] + s * axis[2];
+    rotation[1][1] = c + temp[1] * axis[1];
+    rotation[1][2] = temp[2] * axis[1] - s * axis[0];
 
-  rotation[1][0] = temp[0] * axis[1] + s * axis[2];
-  rotation[1][1] = c + temp[1] * axis[1];
-  rotation[1][2] = temp[2] * axis[1] - s * axis[0];
+    rotation[2][0] = temp[0] * axis[2] - s * axis[1];
+    rotation[2][1] = temp[1] * axis[2] + s * axis[0];
+    rotation[2][2] = c + temp[2] * axis[2];
+
+    return rotation;
+}
 
-  rotation[2][0] = temp[0] * axis[2] - s * axis[1];
-  rotation[2][1] = temp[1] * axis[2] + s * axis[0];
-  rotation[2][2] = c + temp[2] * axis[2];
+namespace impl
+{
+template<uint16_t MOut, uint16_t MIn, typename T>
+struct zero_expand_helper
+{
+    static vector<T, MOut> __call(vector<T, MIn> inVec)
+    {
+        return vector<T, MOut>(inVec, vector<T, MOut - MIn>(0));
+    }
+};
+template<uint16_t M, typename T>
+struct zero_expand_helper<M,M,T>
+{
+    static vector<T, M> __call(vector<T, M> inVec)
+    {
+        return inVec;
+    }
+};
+}
 
-  return rotation;
+template<uint16_t MOut, uint16_t MIn, typename T NBL_FUNC_REQUIRES(MOut >= MIn)
+vector<T, MOut> zero_expand(vector<T, MIn> inVec)
+{
+    return impl::zero_expand_helper<MOut, MIn, T>::__call(inVec);
 }
 
-template <uint16_t NOut, uint16_t MOut, uint16_t NIn, uint16_t MIn, typename T>
-requires(NOut >= NIn && MOut >= MIn)
-matrix <T, NOut, MOut> promote_affine(const matrix<T, NIn, MIn> inMatrix)
+template <uint16_t NOut, uint16_t MOut, uint16_t NIn, uint16_t MIn, typename T NBL_FUNC_REQUIRES(NOut >= NIn && MOut >= MIn)
+matrix<T, NOut, MOut> promote_affine(const matrix<T, NIn, MIn> inMatrix)
 {
-  matrix<T, NOut, MOut> retval;
+    matrix<T, NOut, MOut> retval;
 
-  using out_row_t = hlsl::vector<T, MOut>;
-  auto expandVec = [](vector<T, MIn> inVec) -> vector<T, MOut>
-  {
-    if constexpr (MIn == MOut) return inVec;
-    return vector<T, MOut>(inVec, vector<T, MOut - MIn>(0));
-  };
+    using out_row_t = hlsl::vector<T, MOut>;
 
-  for (auto row_i = 0u; row_i < NOut; row_i++)
-  {
-    retval[row_i] = row_i < NIn ? expandVec(inMatrix[row_i]) : promote<out_row_t>(0.0f);
-    if ((row_i >= NIn || row_i >= MIn) && row_i < MOut) retval[row_i][row_i] = T(1);
-    
-  }
-  return retval;
+    for (uint32_t row_i = 0; row_i < NOut; row_i++)
+    {
+        retval[row_i] = hlsl::mix(promote<out_row_t>(0.0), zero_expand<MOut, MIn>(inMatrix[row_i]), row_i < NIn);
+        if ((row_i >= NIn || row_i >= MIn) && row_i < MOut)
+            retval[row_i][row_i] = T(1.0);
+    }
+    return retval;
 }
 
 }