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authorMarek Olšák <[email protected]>2011-12-15 18:42:21 +0100
committerChristoph Bumiller <[email protected]>2011-12-15 18:51:48 +0100
commit861a029ddb31e91bb4d8e18ab708d0d172f63aad (patch)
treea938450d80ee5dbda670f7fe37bb51b10c1982c4 /src/gallium/docs/source/screen.rst
parent4f4a1be2009863ea34a69b22f58aa1ca08cd710f (diff)
gallium: interface changes necessary to implement transform feedback (v5)
Namely: - EXT_transform_feedback - ARB_transform_feedback2 - ARB_transform_feedback_instanced The old interface was not useful for OpenGL and had to be reworked. This interface was originally designed for OpenGL, but additional changes have been made in order to make st/d3d1x support easier. The most notable change is the stream-out info must be linked with a vertex or geometry shader and cannot be set independently. This is due to limitations of existing hardware (special shader instructions must be used to write into stream-out buffers), and it's also how OpenGL works (stream outputs must be specified prior to linking shaders). Other than that, each stream output buffer has a "view" into it that internally maintains the number of bytes which have been written into it. (one buffer can be bound in several different transform feedback objects in OpenGL, so we must be able to have several views around) The set_stream_output_targets function contains a parameter saying whether new data should be appended or not. Also, the view can optionally be used to provide the vertex count for draw_vbo. Note that the count is supposed to be stored in device memory and the CPU never gets to know its value. OpenGL way | Gallium way ------------------------------------ BeginTF = set_so_targets(append_bitmask = 0) PauseTF = set_so_targets(num_targets = 0) ResumeTF = set_so_targets(append_bitmask = ~0) EndTF = set_so_targets(num_targets = 0) DrawTF = use pipe_draw_info::count_from_stream_output v2: * removed the reset_stream_output_targets function * added a parameter append_bitmask to set_stream_output_targets, each bit specifies whether new data should be appended to each buffer or not. v3: * added PIPE_CAP_STREAM_OUTPUT_PAUSE_RESUME for ARB_tfb2, note that the draw-auto subset is always required (for d3d10), only the pause/resume functionality is limited if the CAP is not advertised v4: * update gallium/docs v5: * compactified struct pipe_stream_output_info, updated dump/trace
Diffstat (limited to 'src/gallium/docs/source/screen.rst')
-rw-r--r--src/gallium/docs/source/screen.rst3
1 files changed, 3 insertions, 0 deletions
diff --git a/src/gallium/docs/source/screen.rst b/src/gallium/docs/source/screen.rst
index 8b504201b3e..a1cd075e309 100644
--- a/src/gallium/docs/source/screen.rst
+++ b/src/gallium/docs/source/screen.rst
@@ -51,6 +51,8 @@ The integer capabilities:
from color blend equations, in :ref:`Blend` state.
* ``PIPE_CAP_SM3``: Whether the vertex shader and fragment shader support equivalent
opcodes to the Shader Model 3 specification. XXX oh god this is horrible
+* ``PIPE_CAP_MAX_STREAM_OUTPUT_BUFFERS``: The maximum number of stream buffers.
+* ``PIPE_CAP_PRIMITIVE_RESTART``: Whether primitive restart is supported.
* ``PIPE_CAP_MAX_COMBINED_SAMPLERS``: The total number of samplers accessible from
the vertex and fragment shader, inclusive.
* ``PIPE_CAP_INDEP_BLEND_ENABLE``: Whether per-rendertarget blend enabling and channel
@@ -179,6 +181,7 @@ resources might be created and handled quite differently.
* ``PIPE_BIND_CONSTANT_BUFFER``: A buffer of shader constants.
* ``PIPE_BIND_TRANSFER_WRITE``: A transfer object which will be written to.
* ``PIPE_BIND_TRANSFER_READ``: A transfer object which will be read from.
+* ``PIPE_BIND_STREAM_OUTPUT``: A stream output buffer.
* ``PIPE_BIND_CUSTOM``:
* ``PIPE_BIND_SCANOUT``: A front color buffer or scanout buffer.
* ``PIPE_BIND_SHARED``: A sharable buffer that can be given to another