diff --git a/include/d3d12.idl b/include/d3d12.idl
index 07edef73839c4367591013f01b8a8364600c4f55..7c10e51e9351596332ecb2f2a0e4dbc36a0b3be9 100644
--- a/include/d3d12.idl
+++ b/include/d3d12.idl
@@ -35,6 +35,13 @@ const UINT D3D12_DEFAULT_STENCIL_WRITE_MASK = 0xff;
 const UINT D3D12_DESCRIPTOR_RANGE_OFFSET_APPEND = 0xffffffff;
 cpp_quote("#define D3D12_FLOAT32_MAX (3.402823466e+38f)")
 const UINT D3D12_IA_VERTEX_INPUT_RESOURCE_SLOT_COUNT = 32;
+const UINT D3D12_REQ_MIP_LEVELS = 15;
+const UINT D3D12_REQ_TEXTURE1D_ARRAY_AXIS_DIMENSION = 2048;
+const UINT D3D12_REQ_TEXTURE1D_U_DIMENSION = 16384;
+const UINT D3D12_REQ_TEXTURE2D_ARRAY_AXIS_DIMENSION = 2048;
+const UINT D3D12_REQ_TEXTURE2D_U_OR_V_DIMENSION = 16384;
+const UINT D3D12_REQ_TEXTURE3D_U_V_OR_W_DIMENSION = 2048;
+const UINT D3D12_REQ_TEXTURECUBE_DIMENSION = 16384;
 const UINT D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES = 0xffffffff;
 const UINT D3D12_SHADER_COMPONENT_MAPPING_MASK = 0x7;
 const UINT D3D12_SHADER_COMPONENT_MAPPING_SHIFT = 3;