R600 Gallium3D Getting Close On OpenGL 3.3 Support

Written by Michael Larabel in AMD on 13 January 2013 at 03:08 PM EST. 35 Comments
AMD
The open-source AMD "R600g" Gallium3D driver is slowly but surely closing in on OpenGL 3.3 support for this open-source Linux graphics driver that supports from the Radeon HD 2000 through Radeon HD 6000 GPUs.

After writing on Friday about UBO and TBO support for R600g that now allows for GLSL 1.40 compliance, the end is near for OpenGL 3.3 in this widely-used AMD open-source driver. The uniform buffer object and texture buffer object support for the R600g driver was the last major missing piece for GL Shading Language 1.40 compliance, which is the GLSL version to match OpenGL 3.1.

As was then quickly pointed out in the forums, OpenGL 3.3 in R600g is not too far out. David Airlie chimed in about some of the missing features. "There is a tree on github with unproven geometry shader code for r600g, intel would need to add 965 support, it just needs a lot of piglit tests and a lot of review, the last missing bit then is GL_ARB_texture_multisample which is also under construction by another dev for 965, which could be fixed up for gallium fairly easily hopefully. but writing the piglit tests for geometry shaders is probably the biggest problem."

As luck would have it, this morning Airlie published R600/Gallium3D patches for GL_ARB_texture_multisample. So the missing work mostly comes down to geometry shaders and writing Piglit OpenGL regression tests for this OpenGL functionality.

There's more interesting comments in the forum thread.

As of Sunday morning, the official OpenGL 3.x support state in Mesa as listed per the bundled documentation in Git comes down to:
GL 3.0:

GLSL 1.30 DONE
glBindFragDataLocation, glGetFragDataLocation DONE
Conditional rendering (GL_NV_conditional_render) DONE (i965, r300, r600, swrast)
Map buffer subranges (GL_ARB_map_buffer_range) DONE (i965, r300, r600, swrast)
Clamping controls (GL_ARB_color_buffer_float) DONE (i965, r300, r600)
Float textures, renderbuffers (GL_ARB_texture_float) DONE (i965, r300, r600)
GL_EXT_packed_float DONE (i965, r600)
GL_EXT_texture_shared_exponent DONE (i965, r600, swrast)
Float depth buffers (GL_ARB_depth_buffer_float) DONE (i965, r600)
Framebuffer objects (GL_ARB_framebuffer_object) DONE (i965, r300, r600, swrast)
Half-float DONE
Non-normalized Integer texture/framebuffer formats DONE (i965, r600)
1D/2D Texture arrays DONE
Per-buffer blend and masks (GL_EXT_draw_buffers2) DONE (i965, r600, swrast)
GL_EXT_texture_compression_rgtc DONE (i965, r300, r600, swrast)
Red and red/green texture formats DONE (i965, swrast, gallium)
Transform feedback (GL_EXT_transform_feedback) DONE (i965, r600)
Vertex array objects (GL_APPLE_vertex_array_object) DONE (i965, r300, r600, swrast)
sRGB framebuffer format (GL_EXT_framebuffer_sRGB) DONE (i965, r600)
glClearBuffer commands DONE
glGetStringi command DONE
glTexParameterI, glGetTexParameterI commands DONE
glVertexAttribI commands DONE
Depth format cube textures DONE
GLX_ARB_create_context (GLX 1.4 is required) DONE


GL 3.1:

GLSL 1.40 DONE (i965, r600)
Forward compatibile context support/deprecations DONE (i965, r600)
Instanced drawing (GL_ARB_draw_instanced) DONE (i965, gallium, swrast)
Buffer copying (GL_ARB_copy_buffer) DONE (i965, r300, r600, swrast)
Primitive restart (GL_NV_primitive_restart) DONE (i965, r600)
16 vertex texture image units DONE
Texture buffer objs (GL_ARB_texture_buffer_object) DONE for OpenGL 3.1 contexts (i965, r600)
Rectangular textures (GL_ARB_texture_rectangle) DONE (i965, r300, r600, swrast)
Uniform buffer objs (GL_ARB_uniform_buffer_object) DONE (i965, r600, swrast)
Signed normalized textures (GL_EXT_texture_snorm) DONE (i965, r300, r600)


GL 3.2:

Core/compatibility profiles DONE
GLSL 1.50 not started
Geometry shaders (GL_ARB_geometry_shader4) partially done (Zack)
BGRA vertex order (GL_ARB_vertex_array_bgra) DONE (i965, r300, r600, swrast)
Base vertex offset(GL_ARB_draw_elements_base_vertex) DONE (i965, r300, r600, swrast)
Frag shader coord (GL_ARB_fragment_coord_conventions) DONE (i965, r300, r600, swrast)
Provoking vertex (GL_ARB_provoking_vertex) DONE (i965, r300, r600, swrast)
Seamless cubemaps (GL_ARB_seamless_cube_map) DONE (i965, r600)
Multisample textures (GL_ARB_texture_multisample) not started
Frag depth clamp (GL_ARB_depth_clamp) DONE (i965, r600, swrast)
Fence objects (GL_ARB_sync) DONE (i965, r300, r600, swrast)
GLX_ARB_create_context_profile DONE


GL 3.3:

GLSL 3.30 new features in this version pretty much done
GL_ARB_blend_func_extended DONE (i965, r600, softpipe)
GL_ARB_explicit_attrib_location DONE (i915, i965, r300, r600, swrast)
GL_ARB_occlusion_query2 DONE (i965, r300, r600, swrast)
GL_ARB_sampler_objects DONE (i965, r300, r600)
GL_ARB_shader_bit_encoding DONE
GL_ARB_texture_rgb10_a2ui DONE (i965, r600)
GL_ARB_texture_swizzle DONE (same as EXT version) (i965, r300, r600, swrast)
GL_ARB_timer_query DONE (i965, r600)
GL_ARB_instanced_arrays DONE (i965, r300, r600)
GL_ARB_vertex_type_2_10_10_10_rev DONE (i965, r600)
While OpenGL 3.2/3.3 is getting close, OpenGL 4.x in Mesa is much further out:
GL 4.0:

GLSL 4.0 not started
GL_ARB_texture_query_lod not started
GL_ARB_draw_buffers_blend DONE (i965, r600, softpipe)
GL_ARB_draw_indirect not started
GL_ARB_gpu_shader5 not started
GL_ARB_gpu_shader_fp64 not started
GL_ARB_sample_shading not started
GL_ARB_shader_subroutine not started
GL_ARB_tessellation_shader not started
GL_ARB_texture_buffer_object_rgb32 DONE (softpipe)
GL_ARB_texture_cube_map_array DONE (i965, softpipe)
GL_ARB_texture_gather not started
GL_ARB_transform_feedback2 DONE
GL_ARB_transform_feedback3 DONE


GL 4.1:

GLSL 4.1 not started
GL_ARB_ES2_compatibility DONE (i965, r300, r600)
GL_ARB_get_program_binary not started
GL_ARB_separate_shader_objects some infrastructure done
GL_ARB_shader_precision not started
GL_ARB_vertex_attrib_64bit not started
GL_ARB_viewport_array not started


GL 4.2:

GLSL 4.2 not started
GL_ARB_texture_compression_bptc not started
GL_ARB_compressed_texture_pixel_storage not started
GL_ARB_shader_atomic_counters not started
GL_ARB_texture_storage DONE (r300, r600, swrast, gallium)
GL_ARB_transform_feedback_instanced DONE
GL_ARB_base_instance DONE (nv50, nvc0, r600, radeonsi)
GL_ARB_shader_image_load_store not started
GL_ARB_conservative_depth DONE (softpipe)
GL_ARB_shading_language_420pack not started
GL_ARB_internalformat_query not started
GL_ARB_map_buffer_alignment DONE (r300, r600, radeonsi)


GL 4.3:

GLSL 4.3 not started
ARB_arrays_of_arrays not started
ARB_ES3_compatibility not started
ARB_clear_buffer_object not started
ARB_compute_shader started (gallium)
ARB_copy_image not started
KHR_debug some work done (ARB_debug_output)
ARB_explicit_uniform_location not started
ARB_fragment_layer_viewport not started
ARB_framebuffer_no_attachments not started
ARB_internalformat_query2 not started
ARB_invalidate_subdata not started
ARB_multi_draw_indirect not started
ARB_program_interface_query not started
ARB_robust_buffer_access_behavior not started
ARB_shader_image_size not started
ARB_shader_storage_buffer_object not started
ARB_stencil_texturing not started
ARB_texture_buffer_range not started
ARB_texture_query_levels not started
ARB_texture_storage_multisample not started
ARB_texture_view not started
ARB_vertex_attrib_binding not started
There's also other details on the DRI Wiki.

We probably won't see the last remaining pieces of OpenGL 3.2/3.3 compliance land in time for next month's release of Mesa 9.1, but it will be very close. With Mesa still on a six-month release schedule, we should see the next Mesa release in the fall handle OpenGL 3.3. Unfortunately will likely not be until 2014 when we see OpenGL 4.0 compliance with this open-source graphics driver stack.
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Michael Larabel is the principal author of Phoronix.com and founded the site in 2004 with a focus on enriching the Linux hardware experience. Michael has written more than 20,000 articles covering the state of Linux hardware support, Linux performance, graphics drivers, and other topics. Michael is also the lead developer of the Phoronix Test Suite, Phoromatic, and OpenBenchmarking.org automated benchmarking software. He can be followed via Twitter, LinkedIn, or contacted via MichaelLarabel.com.

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