From 98d3980db7a9803f4ee965237599a87771a417d1 Mon Sep 17 00:00:00 2001 From: Crozet Sébastien Date: Thu, 21 Jan 2021 16:03:27 +0100 Subject: Allow several rules for combining friction/restitution coefficients. --- src/dynamics/coefficient_combine_rule.rs | 34 ++++++++++++++++++++++++++++++++ 1 file changed, 34 insertions(+) create mode 100644 src/dynamics/coefficient_combine_rule.rs (limited to 'src/dynamics/coefficient_combine_rule.rs') diff --git a/src/dynamics/coefficient_combine_rule.rs b/src/dynamics/coefficient_combine_rule.rs new file mode 100644 index 0000000..5e8b4a0 --- /dev/null +++ b/src/dynamics/coefficient_combine_rule.rs @@ -0,0 +1,34 @@ +use crate::math::Real; + +/// Rules used to combine two coefficients. +/// +/// This is used to determine the effective restitution and +/// friction coefficients for a contact between two colliders. +/// Each collider has its combination rule of type +/// `CoefficientCombineRule`. And the rule +/// actually used is given by `max(first_combine_rule as usize, second_combine_rule as usize)`. +#[derive(Copy, Clone, Debug, PartialEq, Eq)] +#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))] +pub enum CoefficientCombineRule { + /// The two coefficients are averaged. + Average = 0, + /// The smallest coefficient is chosen. + Min, + /// The two coefficients are multiplied. + Multiply, + /// The greatest coefficient is chosen. + Max, +} + +impl CoefficientCombineRule { + pub(crate) fn combine(coeff1: Real, coeff2: Real, rule_value1: u8, rule_value2: u8) -> Real { + let effective_rule = rule_value1.max(rule_value2); + + match effective_rule { + 0 => (coeff1 + coeff1) / 2.0, + 1 => coeff1.min(coeff2), + 2 => coeff1 * coeff2, + _ => coeff1.max(coeff2), + } + } +} -- cgit