Yes its backwards and it seems it doesn't work anymore ;)
Seems the loophole I was using got removed.
Problem remains that applications that could use an legacy extension
are not aware of it and will simply/usually not request it:
MESA_GL_VERSION_OVERRIDE=3.2 MESA_GLSL_VERSION_OVERRIDE=150 glxinfo | grep
shader5
-nothing-
MESA_GL_VERSION_OVERRIDE=3.2 MESA_GLSL_VERSION_OVERRIDE=400 glxinfo | grep
shader5
GL_ARB_gpu_shader5, GL_ARB_gpu_shader_fp64, GL_ARB_gpu_shader_int64,
GL_ARB_gpu_shader5, GL_ARB_half_float_pixel, GL_ARB_half_float_vertex,
GL_EXT_gpu_shader5, GL_EXT_map_buffer_range, GL_EXT_memory_object,
GL_OES_get_program_binary, GL_OES_gpu_shader5, GL_OES_mapbuffer,
If an application knows about GLSL 400 it doesn't need GL_ARB_gpu_shader5
anymore.
Am 18.05.2018 um 11:25 schrieb Timothy Arceri:
> Hi Benedikt,
>
> I think you have this backwards. compute_version() computes the version of
> OpenGL supported by the driver by checking what extensions it advertises. See
> version 2 of my patch to see where the
> extensions are enabled. I don't think this is something that can be
> automated, it really depends on the driver, just because an extension can be
> advertised at a certain level doesn't mean you must (or
> can) do it.
>
> Tim
>
> On 18/05/18 19:13, Benedikt Schemmer wrote:
>> Hi Timothy,
>>
>> I was looking into something similar myself.
>> Great to see someone working on getting legacy extensions available
>> to the applications that can actually use them!
>>
>> Another thing I noticed is that extensions aren't advertised at the
>> correct feature level.
>> The code below works and does a better job at it, but its probably also
>> the wrong way to go about it.
>>
>> Cheers,
>> Benedikt
>>
>> P.S. I grepped and sed together a file which describes the requirements
>> for every extension better, unfortunately the files on khronos
>> arent exactly machine readable
>> will send in next reply
>>
>> ---
>>
>> diff --git a/src/mesa/main/version.c b/src/mesa/main/version.c
>> --- a/src/mesa/main/version.c
>> +++ b/src/mesa/main/version.c
>> @@ -233,8 +233,15 @@ _mesa_override_glsl_version(struct gl_constants *consts)
>> }
>>
>> /**
>> - * Examine enabled GL extensions to determine GL version.
>> + * Enable GL Extensions according to the minimum version requirements as
>> per spec.
>> + * Careful: some extensions are implemented for the express purpose of being
>> + * used in a lower version context (legacy extensions).
>> + * Example:
>> + * ARB_gpu_shader5: first implementation in OpenGL 4.0 (GLSL 400) but
>> + * supposed to be advertised from OpenGL 3.2 (GLSL 150) upwards,
>> + * however early Nvidia FXAA could use it from GLSL 120 so advertise it
>> there
>> */
>> +
>> static GLuint
>> compute_version(const struct gl_extensions *extensions,
>> const struct gl_constants *consts, gl_api api)
>> @@ -242,25 +249,43 @@ compute_version(const struct gl_extensions *extensions,
>> GLuint major, minor, version;
>>
>> const bool ver_1_3 = (extensions->ARB_texture_border_clamp &&
>> + extensions->ARB_instanced_arrays &&
>> + extensions->ARB_shadow &&
>> + extensions->ARB_vertex_shader &&
>> + extensions->ARB_fragment_shader &&
>> + extensions->ARB_depth_texture &&
>> + extensions->ARB_occlusion_query2 &&
>> extensions->ARB_texture_cube_map &&
>> + extensions->ARB_seamless_cube_map &&
>> extensions->ARB_texture_env_combine &&
>> + extensions->ARB_texture_rg &&
>> + extensions->ARB_texture_compression_rgtc &&
>> + extensions->ARB_texture_compression_bptc &&
>> + extensions->ARB_texture_float &&
>> + extensions->ARB_framebuffer_object &&
>> + extensions->ARB_framebuffer_no_attachments &&
>> extensions->ARB_texture_env_dot3);
>> const bool ver_1_4 = (ver_1_3 &&
>> - extensions->ARB_depth_texture &&
>> - extensions->ARB_shadow &&
>> + extensions->ARB_stencil_texturing &&
>> extensions->ARB_texture_env_crossbar &&
>> + extensions->ARB_texture_mirror_clamp_to_edge &&
>> extensions->EXT_blend_color &&
>> extensions->EXT_blend_func_separate &&
>> extensions->EXT_blend_minmax &&
>> extensions->EXT_point_parameters);
>> const bool ver_1_5 = (ver_1_4 &&
>> + extensions->ARB_query_buffer_object &&
>> extensions->ARB_occlusion_query);
>> const bool ver_2_0 = (ver_1_5 &&
>> extensions->ARB_point_sprite &&
>> - extensions->ARB_vertex_shader &&
>> - extensions->ARB_fragment_shader &&
>> + extensions->ARB_blend_func_extended &&
>> extensions->ARB_texture_non_power_of_two &&
>> extensions->EXT_blend_equation_separate &&
>> + extensions->ARB_shader_texture_lod &&
>> + extensions->ARB_transform_feedback2 &&
>> + extensions->ARB_uniform_buffer_object &&
>> + extensions->ARB_texture_buffer_object &&
>> + extensions->ARB_texture_buffer_range &&
>>
>> /* Technically, 2.0 requires the functionality of
>> the
>> * EXT version. Enable 2.0 if either extension is
>> @@ -272,33 +297,44 @@ compute_version(const struct gl_extensions *extensions,
>> || extensions->ATI_separate_stencil));
>> const bool ver_2_1 = (ver_2_0 &&
>> extensions->EXT_pixel_buffer_object &&
>> + extensions->ARB_map_buffer_range &&
>> + extensions->ARB_draw_instanced &&
>> + extensions->ARB_shader_bit_encoding &&
>> + extensions->ARB_gpu_shader5 &&
>> extensions->EXT_texture_sRGB);
>> const bool ver_3_0 = (ver_2_1 &&
>> consts->GLSLVersion >= 130 &&
>> (consts->MaxSamples >= 4 || consts->FakeSWMSAA) &&
>> (api == API_OPENGL_CORE ||
>> extensions->ARB_color_buffer_float) &&
>> + extensions->ARB_conservative_depth &&
>> extensions->ARB_depth_buffer_float &&
>> extensions->ARB_half_float_vertex &&
>> - extensions->ARB_map_buffer_range &&
>> - extensions->ARB_shader_texture_lod &&
>> - extensions->ARB_texture_float &&
>> - extensions->ARB_texture_rg &&
>> - extensions->ARB_texture_compression_rgtc &&
>> + extensions->ARB_pipeline_statistics_query &&
>> + extensions->ARB_shader_image_load_store &&
>> + extensions->ARB_texture_rgb10_a2ui &&
>> + extensions->ARB_vertex_type_10f_11f_11f_rev &&
>> extensions->EXT_draw_buffers2 &&
>> - extensions->ARB_framebuffer_object &&
>> + extensions->ARB_transform_feedback_instanced &&
>> + extensions->ARB_internalformat_query &&
>> + extensions->ARB_internalformat_query2 &&
>> extensions->EXT_framebuffer_sRGB &&
>> extensions->EXT_packed_float &&
>> + extensions->ARB_sample_shading &&
>> + extensions->ARB_shader_atomic_counters &&
>> extensions->EXT_texture_array &&
>> + extensions->ARB_texture_query_lod &&
>> extensions->EXT_texture_shared_exponent &&
>> extensions->EXT_transform_feedback &&
>> - extensions->NV_conditional_render);
>> + extensions->NV_conditional_render &&
>> + extensions->ARB_texture_cube_map_array &&
>> + extensions->ARB_transform_feedback_overflow_query);
>> const bool ver_3_1 = (ver_3_0 &&
>> consts->GLSLVersion >= 140 &&
>> - extensions->ARB_draw_instanced &&
>> - extensions->ARB_texture_buffer_object &&
>> - extensions->ARB_uniform_buffer_object &&
>> extensions->EXT_texture_snorm &&
>> + extensions->ARB_shading_language_420pack &&
>> + extensions->ARB_sync &&
>> + extensions->ARB_draw_indirect &&
>> extensions->NV_primitive_restart &&
>> extensions->NV_texture_rectangle &&
>>
>> consts->Program[MESA_SHADER_VERTEX].MaxTextureImageUnits >= 16);
>> @@ -308,18 +344,17 @@ compute_version(const struct gl_extensions *extensions,
>> extensions->ARB_draw_elements_base_vertex &&
>> extensions->ARB_fragment_coord_conventions &&
>> extensions->EXT_provoking_vertex &&
>> - extensions->ARB_seamless_cube_map &&
>> - extensions->ARB_sync &&
>> + extensions->ARB_gpu_shader_fp64 &&
>> + extensions->ARB_vertex_attrib_64bit &&
>> extensions->ARB_texture_multisample &&
>> - extensions->EXT_vertex_array_bgra);
>> + extensions->ARB_tessellation_shader &&
>> + extensions->EXT_vertex_array_bgra &&
>> + extensions->ARB_fragment_layer_viewport &&
>> + extensions->ARB_viewport_array);
>> const bool ver_3_3 = (ver_3_2 &&
>> consts->GLSLVersion >= 330 &&
>> - extensions->ARB_blend_func_extended &&
>> extensions->ARB_explicit_attrib_location &&
>> - extensions->ARB_instanced_arrays &&
>> - extensions->ARB_occlusion_query2 &&
>> - extensions->ARB_shader_bit_encoding &&
>> - extensions->ARB_texture_rgb10_a2ui &&
>> + extensions->ARB_explicit_uniform_location &&
>> extensions->ARB_timer_query &&
>> extensions->ARB_vertex_type_2_10_10_10_rev &&
>> extensions->EXT_texture_swizzle);
>> @@ -328,67 +363,42 @@ compute_version(const struct gl_extensions *extensions,
>> const bool ver_4_0 = (ver_3_3 &&
>> consts->GLSLVersion >= 400 &&
>> extensions->ARB_draw_buffers_blend &&
>> - extensions->ARB_draw_indirect &&
>> - extensions->ARB_gpu_shader5 &&
>> - extensions->ARB_gpu_shader_fp64 &&
>> - extensions->ARB_sample_shading &&
>> - extensions->ARB_tessellation_shader &&
>> + extensions->ARB_derivative_control &&
>> extensions->ARB_texture_buffer_object_rgb32 &&
>> - extensions->ARB_texture_cube_map_array &&
>> - extensions->ARB_texture_query_lod &&
>> - extensions->ARB_transform_feedback2 &&
>> extensions->ARB_transform_feedback3);
>> const bool ver_4_1 = (ver_4_0 &&
>> consts->GLSLVersion >= 410 &&
>> extensions->ARB_ES2_compatibility &&
>> - extensions->ARB_shader_precision &&
>> - extensions->ARB_vertex_attrib_64bit &&
>> - extensions->ARB_viewport_array);
>> + extensions->ARB_shading_language_packing &&
>> + extensions->ARB_shader_precision);
>> const bool ver_4_2 = (ver_4_1 &&
>> consts->GLSLVersion >= 420 &&
>> extensions->ARB_base_instance &&
>> - extensions->ARB_conservative_depth &&
>> - extensions->ARB_internalformat_query &&
>> - extensions->ARB_shader_atomic_counters &&
>> - extensions->ARB_shader_image_load_store &&
>> - extensions->ARB_shading_language_420pack &&
>> - extensions->ARB_shading_language_packing &&
>> - extensions->ARB_texture_compression_bptc &&
>> - extensions->ARB_transform_feedback_instanced);
>> + extensions->ARB_compute_shader &&
>> + extensions->ARB_shader_atomic_counter_ops);
>> const bool ver_4_3 = (ver_4_2 &&
>> consts->GLSLVersion >= 430 &&
>>
>> consts->Program[MESA_SHADER_VERTEX].MaxUniformBlocks >= 14 &&
>> extensions->ARB_ES3_compatibility &&
>> extensions->ARB_arrays_of_arrays &&
>> - extensions->ARB_compute_shader &&
>> + extensions->ARB_buffer_storage &&
>> extensions->ARB_copy_image &&
>> - extensions->ARB_explicit_uniform_location &&
>> - extensions->ARB_fragment_layer_viewport &&
>> - extensions->ARB_framebuffer_no_attachments &&
>> - extensions->ARB_internalformat_query2 &&
>> extensions->ARB_robust_buffer_access_behavior &&
>> extensions->ARB_shader_image_size &&
>> extensions->ARB_shader_storage_buffer_object &&
>> - extensions->ARB_stencil_texturing &&
>> - extensions->ARB_texture_buffer_range &&
>> extensions->ARB_texture_query_levels &&
>> extensions->ARB_texture_view);
>> const bool ver_4_4 = (ver_4_3 &&
>> consts->GLSLVersion >= 440 &&
>> - extensions->ARB_buffer_storage &&
>> extensions->ARB_clear_texture &&
>> extensions->ARB_enhanced_layouts &&
>> - extensions->ARB_query_buffer_object &&
>> - extensions->ARB_texture_mirror_clamp_to_edge &&
>> - extensions->ARB_texture_stencil8 &&
>> - extensions->ARB_vertex_type_10f_11f_11f_rev);
>> + extensions->ARB_texture_stencil8);
>> const bool ver_4_5 = (ver_4_4 &&
>> consts->GLSLVersion >= 450 &&
>> extensions->ARB_ES3_1_compatibility &&
>> extensions->ARB_clip_control &&
>> extensions->ARB_conditional_render_inverted &&
>> extensions->ARB_cull_distance &&
>> - extensions->ARB_derivative_control &&
>> extensions->ARB_shader_texture_image_samples &&
>> extensions->NV_texture_barrier);
>> const bool ver_4_6 = (ver_4_5 &&
>> @@ -396,13 +406,10 @@ compute_version(const struct gl_extensions *extensions,
>> /* extensions->ARB_gl_spirv */ 0 &&
>> /* extensions->ARB_spirv_extensions */ 0 &&
>> extensions->ARB_indirect_parameters &&
>> - extensions->ARB_pipeline_statistics_query &&
>> extensions->ARB_polygon_offset_clamp &&
>> - extensions->ARB_shader_atomic_counter_ops &&
>> extensions->ARB_shader_draw_parameters &&
>> extensions->ARB_shader_group_vote &&
>> - extensions->ARB_texture_filter_anisotropic &&
>> - extensions->ARB_transform_feedback_overflow_query);
>> + extensions->ARB_texture_filter_anisotropic);
>>
>> if (ver_4_6) {
>> major = 4;
>>
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