The Khronos Group announces from the SIGGRAPH 2017 Conference the immediate public availability of the OpenGL 4.6 specification. OpenGL 4.6 integrates the functionality of numerous ARB and EXT extensions created by Khronos members AMD, Intel, and NVIDIA into core, including the capability to ingest SPIR-V™ shaders.
SPIR-V is a Khronos-defined standard intermediate language for parallel compute and graphics, which enables content creators to simplify their shader authoring and management pipelines while providing significant source shading language flexibility. OpenGL 4.6 adds support for ingesting SPIR-V shaders to the core specification, guaranteeing that SPIR-V shaders will be widely supported by OpenGL implementations.
OpenGL 4.6 adds the functionality of these ARB extensions to OpenGL’s core specification:

  • GL_ARB_gl_spirv and GL_ARB_spirv_extensions to standardize SPIR-V support for OpenGL
  • GL_ARB_indirect_parameters and GL_ARB_shader_draw_parameters for reducing the CPU overhead associated with rendering batches of geometry
  • GL_ARB_pipeline_statistics_query and GL_ARB_transform_feedback_overflow_query standardize OpenGL support for features available in Direct3D
  • GL_ARB_texture_filter_anisotropic (based on GL_EXT_texture_filter_anisotropic) brings previously IP encumbered functionality into OpenGL to improve the visual quality of textured scenes
  • GL_ARB_polygon_offset_clamp (based on GL_EXT_polygon_offset_clamp) suppresses a common visual artifact known as a “light leak” associated with rendering shadows
  • GL_ARB_shader_atomic_counter_ops and GL_ARB_shader_group_vote add shader intrinsics supported by all desktop vendors to improve functionality and performance
  • GL_KHR_no_error reduces driver overhead by allowing the application to indicate that it expects error-free operation so errors need not be generated

In addition to the above features being added to OpenGL 4.6, the following are being released as extensions:

  • GL_KHR_parallel_shader_compile allows applications to launch multiple shader compile threads to improve shader compile throughput
  • WGL_ARB_create_context_no_error and GXL_ARB_create_context_no_error allow no error contexts to be created with WGL or GLX that support the GL_KHR_no_error extension

The OpenGL 4.6 specification can be found at https://khronos.org/registry/OpenGL/index_gl.php. The GLSL to SPIR-V compiler glslang has been updated with GLSL 4.60 support, and can be found at https://github.com/KhronosGroup/glslang.
Sophisticated graphics applications will also benefit from a set of newly released extensions for both OpenGL and OpenGL ES to enable interoperability with Vulkan and Direct3D. These extensions are named:

  • GL_EXT_memory_object
  • GL_EXT_memory_object_fd
  • GL_EXT_memory_object_win32
  • GL_EXT_semaphore
  • GL_EXT_semaphore_fd
  • GL_EXT_semaphore_win32
  • GL_EXT_win32_keyed_mutex

They can be found at: https://khronos.org/registry/OpenGL/index_gl.php

Khronos invites and welcomes your feedback on this release. Tell us what you think.