Commit Graph

4 Commits

Author SHA1 Message Date
Kristian Høgsberg
9a6c48d0fd cliptest: Use xmalloc in cliptest 2013-07-25 16:24:36 -07:00
Kristian Høgsberg
4172f668e7 Pass argc pointer to parse_options()
This lets us keep argc up to date as the backend picks out arguments
from the argv array.
2013-02-20 15:27:49 -05:00
Pekka Paalanen
0d64a0fa29 compositor: new intersection algorithm
The existing algorithm had some corner cases (pun!), where it failed to
produce correct vertices in the right order. This appeared only when the
surface was transformed (rotated). It also produced degenerate polygons
(3 or more vertices with zero polygon area) for non-transformed cases
where the clipping and surface rectangles were adjacent but not
overlapping.

Introduce a new algorithm for finding the boundary vertices of the
intersection of a coordinate axis aligned rectangle and an arbitrary
polygon (here a quadrilateral). The code is based on the
Sutherland-Hodgman algorithm, where a polygon is clipped by infinite
lines one at a time.

This new algorithm should always produce the correct vertices in the
clockwise winding order, and discard duplicate vertices and degenerate
polygons. It retains the fast paths of the existing algorithm for the
no-hit and non-transformed cases.

Benchmarking with earlier versions showed that the new algorithm is
a little slower (56 vs. 68 us/call) than the existing algorithm, for
the transformed case.  The 'cliptest f' command before and after this
commit can be used to compare the speed of the transformed case only.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
Acked-by: Rob Clark <rob.clark@linaro.org>
2012-09-12 12:27:35 -04:00
Pekka Paalanen
8c492b1293 clients: add cliptest program
Cliptest is for controlled testing of the calculate_edges() function in
compositor.c. The function is copied verbatim into cliptest.c.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
2012-09-12 12:24:40 -04:00