When set, EXPAND_LINE_WIDTH expands the line width by 1/cos(a),
where a is the minimum angle from horizontal or vertical. This
seems required by OpenGL line rasterization but not by Vulkan.
Similar to what AMDVLK and AMDGPU-PRO do for AA wide lines.
This fixes
dEQP-VK.rasterization.interpolation_multisample_*_bit.*lines_wide.
Signed-off-by: Samuel Pitoiset <samuel.pitoiset@gmail.com>
Reviewed-by: Bas Nieuwenhuizen <bas@basnieuwenhuizen.nl>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/5698>
asin(x) is now implemented using a piecewise approximation, which
improves the precision for |x| < 0.5
Previously, we were using a polynomial approximation for both the
asin() and acos() functions. Unfortunately, for asin(), this polynomial
does not have enough precision to satisfy the Vulkan CTS requiremenents,
which define the asin() precision based on the precision of
atan2(x, sqrt(1.0 - x*x)). The piecewise approximation gives the needed
precision in the problematic range.
v2: Skip the piecewise approximation for acos
Closes: #1843
Acked-by: Francisco Jerez <currojerez@riseup.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/3809>
