MDL SDK 2024.0.4 (377400.3959): 07 Oct 2024

ABI compatible with the MDL SDK 2024.0.4 (377400.3959) binary release
(see https://developer.nvidia.com/mdl-sdk)

Added and Changed Features

• MDL 1.9 Language Specification

  • Updated to document version 1.9.2.

• General

  • The default value for the backend option enable_exceptions is now off,
    as this is the behavior described by the MDL specification.

• MDL Compiler and Backends

  • Implemented folding of ::tex function calls with invalid textures on the DAG.
  • Added “max_const_data” backend option to limit the size of global constants in the
    generated code when the “enable_ro_segment” option is enabled. Larger constants are put
    into read-only data segment. The default is “1024” bytes, which corresponds to
    the old behavior.

• MDL SDK examples

  • MDL Core code_gen example:
    • Added support for single-init mode.
  • MDL SDK df_vulkan example:
    • Added support for read-only data segments and max_const_data backend option.
  • MDL Example Execution Native:
    • It now supports the -p abbreviation for –mdl_path as in all other examples.
  • MDL Example df_native:
    • Added support for argument blocks in Class Compilation mode.
    • Added OpenGL GUI for editing material parameters and displaying stats during rendering.
    • Changed default compilation mode to Class Compilation.
    • Removed command line option --cc which is now replaced
      by --nocc (or disable Class Compilation mode).

Fixed Bugs

• General

  • libbsdf: Fixed issues for df::thin_film over df::custom_curve_layer and
    df::directional_factor with normal reflectivity approaching zero.
  • Fixed a build error if image plugins are disabled.
  • Fixed a build error caused by picking up LLVM header files from a different location.
  • Fixed documented return codes for IExpression_factory::create_cast() and
    create_decl_cast() (error codes are negative as usual, not positive).
  • Fixed missing build dependencies for the distiller plugins and the distiller example plugin.

• MDL Compiler and Backends

  • Allow material sub structs to be used inside a declarative struct and declarative functions.
  • Improved error message in case a select operator cannot be executed because of the
    left-hand-side type was not imported.
  • Fixed wrong HLSL/GLSL read functions used for shadow copies of function parameters.
  • Fixed crash when compiling a function which receives a material parameter but doesn't
    use the state (GLSL backend with rodata segment disabled).
  • Avoid undefined behavior with "%" operator for negative values for GLSL
    by implementing “a % b” as “a - (a / b) * b”.
  • Report when a standard library module is imported with a weak relative import names from
    a module in a search path root. This is needed because standard library modules are
    loaded from a high-priority search path and would shadow any relative import. This will
    trigger a warning for MDL versions between 1.6 and 1.9, and an error for MDL versions
    greater than 1.9.
  • Fixed the documentation of the backend option "hlsl_use_resource_data" and
    "glsl_use_resource_data". These are recognized but not supported at the moment.
  • Fixed compilation of calls to non-inlined functions which receive material parameters as
    arguments for GLSL/HLSL.
  • Return identity matrix instead of zero for unimplemented tex::grid_to_object_space().
  • Fixed crash when compiling an expression as const which only becomes const after
    optimization (e.g. by getting rid of state access).
  • libbsdf: Fixed wrong shadow mask in microfacet BSDFs.
  • libbsdf: Avoid NaNs due to out-of-range roundings during random number updates.
  • MDL Core: Fixed resource indices for native code if a custom texture runtime is used.
  • Fixed crashes if a non-constant default constructor occurred during code generation
    in various backends.