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diff --git a/src/gallium/docs/source/context.rst b/src/gallium/docs/source/context.rst new file mode 100644 index 00000000000..21f5f9111a0 --- /dev/null +++ b/src/gallium/docs/source/context.rst @@ -0,0 +1,128 @@ +Context +======= + +The context object represents the purest, most directly accessible, abilities +of the device's 3D rendering pipeline. + +Methods +------- + +CSO State +^^^^^^^^^ + +All CSO state is created, bound, and destroyed, with triplets of methods that +all follow a specific naming scheme. For example, ``create_blend_state``, +``bind_blend_state``, and ``destroy_blend_state``. + +CSO objects handled by the context object: + +* :ref:`Blend`: ``*_blend_state`` +* :ref:`Sampler`: These are special; they can be bound to either vertex or + fragment samplers, and they are bound in groups. + ``bind_fragment_sampler_states``, ``bind_vertex_sampler_states`` +* :ref:`Rasterizer`: ``*_rasterizer_state`` +* :ref:`Depth, Stencil, & Alpha`: ``*_depth_stencil_alpha_state`` +* :ref:`Shader`: These have two sets of methods. ``*_fs_state`` is for + fragment shaders, and ``*_vs_state`` is for vertex shaders. + + +Resource Binding State +^^^^^^^^^^^^^^^^^^^^^^ + +This state describes how resources in various flavours (textures, +buffers, surfaces) are bound to the driver. + + +* ``set_constant_buffer`` +* ``set_framebuffer_state`` +* ``set_fragment_sampler_textures`` +* ``set_vertex_sampler_textures`` +* ``set_vertex_buffers`` + + +Non-CSO State +^^^^^^^^^^^^^ + +These pieces of state are too small, variable, and/or trivial to have CSO +objects. They all follow simple, one-method binding calls, e.g. +``set_edgeflags``. + +* ``set_edgeflags`` +* ``set_blend_color`` +* ``set_clip_state`` +* ``set_polygon_stipple`` +* ``set_scissor_state`` +* ``set_viewport_state`` +* ``set_vertex_elements`` + + +Clearing +^^^^^^^^ + +``clear`` initializes some or all of the surfaces currently bound to +the framebuffer to particular RGBA, depth, or stencil values. + +Clear is one of the most difficult concepts to nail down to a single +interface and it seems likely that we will want to add additional +clear paths, for instance clearing surfaces not bound to the +framebuffer, or read-modify-write clears such as depth-only or +stencil-only clears of packed depth-stencil buffers. + + +Drawing +^^^^^^^ + +``draw_arrays`` + +``draw_elements`` + +``draw_range_elements`` + + +Queries +^^^^^^^ + +Queries gather some statistic from the 3D pipeline over one or more +draws. Queries may be nested, though no state tracker currently +exercises this. + +Queries can be created with ``create_query`` and deleted with +``destroy_query``. To enable a query, use ``begin_query``, and when finished, +use ``end_query`` to stop the query. Finally, ``get_query_result`` is used +to retrieve the results. + +Flushing +^^^^^^^^ + +``flush`` + + +Resource Busy Queries +^^^^^^^^^^^^^^^^^^^^^ + +``is_texture_referenced`` + +``is_buffer_referenced`` + + + +Blitting +^^^^^^^^ + +These methods emulate classic blitter controls. They are not guaranteed to be +available; if they are set to NULL, then they are not present. + +These methods operate directly on ``pipe_surface`` objects, and stand +apart from any 3D state in the context. Blitting functionality may be +moved to a separate abstraction at some point in the future. + +``surface_fill`` performs a fill operation on a section of a surface. + +``surface_copy`` blits a region of a surface to a region of another surface, +provided that both surfaces are the same format. The source and destination +may be the same surface, and overlapping blits are permitted. + +The interfaces to these calls are likely to change to make it easier +for a driver to batch multiple blits with the same source and +destination. + |