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Diffstat (limited to 'src/gallium/docs/source')
| -rw-r--r-- | src/gallium/docs/source/context.rst | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/src/gallium/docs/source/context.rst b/src/gallium/docs/source/context.rst index 6a8238e7779..ede89be6ed6 100644 --- a/src/gallium/docs/source/context.rst +++ b/src/gallium/docs/source/context.rst @@ -382,15 +382,19 @@ Conditional Rendering ^^^^^^^^^^^^^^^^^^^^^ A drawing command can be skipped depending on the outcome of a query -(typically an occlusion query). The ``render_condition`` function specifies -the query which should be checked prior to rendering anything. +(typically an occlusion query, or streamout overflow predicate). +The ``render_condition`` function specifies the query which should be checked +prior to rendering anything. Functions honoring render_condition include +(and are limited to) draw_vbo, clear, clear_render_target, clear_depth_stencil. If ``render_condition`` is called with ``query`` = NULL, conditional rendering is disabled and drawing takes place normally. If ``render_condition`` is called with a non-null ``query`` subsequent -drawing commands will be predicated on the outcome of the query. If -the query result is zero subsequent drawing commands will be skipped. +drawing commands will be predicated on the outcome of the query. +Commands will be skipped if ``condition`` is equal to the predicate result +(for non-boolean queries such as OCCLUSION_QUERY, zero counts as FALSE, +non-zero as TRUE). If ``mode`` is PIPE_RENDER_COND_WAIT the driver will wait for the query to complete before deciding whether to render. @@ -401,7 +405,7 @@ has completed, drawing will be predicated on the outcome of the query. If ``mode`` is PIPE_RENDER_COND_BY_REGION_WAIT or PIPE_RENDER_COND_BY_REGION_NO_WAIT rendering will be predicated as above -for the non-REGION modes but in the case that an occulusion query returns +for the non-REGION modes but in the case that an occlusion query returns a non-zero result, regions which were occluded may be ommitted by subsequent drawing commands. This can result in better performance with some GPUs. Normally, if the occlusion query returned a non-zero result subsequent |