gallium/st: add pipe_context::generate_mipmap()

This patch adds a new interface to support hardware mipmap generation.
PIPE_CAP_GENERATE_MIPMAP is added to allow a driver to specify
if this new interface is supported; if not supported, the state tracker will
fallback to mipmap generation by rendering/texturing.

v2: add PIPE_CAP_GENERATE_MIPMAP to the disabled section for all drivers
v3: add format to the generate_mipmap interface to allow mipmap generation
    using a format other than the resource format
v4: fix return type of trace_context_generate_mipmap()

Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>
Reviewed-by: Jose Fonseca <[email protected]>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/gallium/docs/source/context.rst b/src/gallium/docs/source/context.rst
index 9a32716f921..4c03e00008c 100644
--- a/src/gallium/docs/source/context.rst
+++ b/src/gallium/docs/source/context.rst
@@ -648,3 +648,14 @@ In addition, normal texture sampling is allowed from the compute
 program: ``bind_sampler_states`` may be used to set up texture
 samplers for the compute stage and ``set_sampler_views`` may
 be used to bind a number of sampler views to it.
+
+Mipmap generation
+^^^^^^^^^^^^^^^^^
+
+If PIPE_CAP_GENERATE_MIPMAP is true, ``generate_mipmap`` can be used
+to generate mipmaps for the specified texture resource.
+It replaces texel image levels base_level+1 through
+last_level for layers range from first_layer through last_layer.
+It returns TRUE if mipmap generation succeeds, otherwise it
+returns FALSE. Mipmap generation may fail when it is not supported
+for particular texture types or formats.