Specification doesn't define behaviour for rotation of 0-vector. Windows and Nvidia drivers have a workaround for that. For compatibility proposed that for 0-vector a rotation will be done around x-axis.
-v2: logic moved to _math_matrix_rotate Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=100960 Signed-off-by: Sergii Romantsov <[email protected]> --- src/mesa/math/m_matrix.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/src/mesa/math/m_matrix.c b/src/mesa/math/m_matrix.c index 57a4953..2b3adb3 100644 --- a/src/mesa/math/m_matrix.c +++ b/src/mesa/math/m_matrix.c @@ -824,6 +824,25 @@ _math_matrix_rotate( GLmatrix *mat, M(1,0) = s; } } + else { + /* https://bugs.freedesktop.org/show_bug.cgi?id=100960 + * https://github.com/KhronosGroup/OpenGL-API/issues/41 + * So that is kind of workaround for empty-vectors to have + * compatibility with Windows and Nvidia drivers. + */ + optimized = GL_TRUE; + /* rotate only around x-axis */ + M(1,1) = c; + M(2,2) = c; + if (x < 0.0F) { + M(1,2) = s; + M(2,1) = -s; + } + else { + M(1,2) = -s; + M(2,1) = s; + } + } } else if (z == 0.0F) { optimized = GL_TRUE; -- 2.7.4 _______________________________________________ mesa-dev mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/mesa-dev
