From ba081fb6f567dd547cee86095480dd443aff2c4c Mon Sep 17 00:00:00 2001 From: Sébastien Crozet Date: Tue, 5 Jul 2022 14:59:14 +0200 Subject: Improve the API for initializing/setting mass-properties --- src/geometry/collider.rs | 100 +++++++++++++++++++++++++++++++++-------------- 1 file changed, 70 insertions(+), 30 deletions(-) (limited to 'src/geometry/collider.rs') diff --git a/src/geometry/collider.rs b/src/geometry/collider.rs index 2f2e4ac..421523f 100644 --- a/src/geometry/collider.rs +++ b/src/geometry/collider.rs @@ -241,10 +241,54 @@ impl Collider { pub fn density(&self) -> Option { match &self.mprops { ColliderMassProps::Density(density) => Some(*density), + ColliderMassProps::Mass(_) => None, ColliderMassProps::MassProperties(_) => None, } } + /// Sets the uniform density of this collider. + /// + /// This will override any previous mass-properties set by [`Self::set_density`], + /// [`Self::set_mass`], [`Self::set_mass_properties`], [`ColliderBuilder::density`], + /// [`ColliderBuilder::mass`], or [`ColliderBuilder::mass_properties`] + /// for this collider. + /// + /// The mass and angular inertia of this collider will be computed automatically based on its + /// shape. + pub fn set_density(&mut self, density: Real) { + self.do_set_mass_properties(ColliderMassProps::Density(density)); + } + + /// Sets the mass of this collider. + /// + /// This will override any previous mass-properties set by [`Self::set_density`], + /// [`Self::set_mass`], [`Self::set_mass_properties`], [`ColliderBuilder::density`], + /// [`ColliderBuilder::mass`], or [`ColliderBuilder::mass_properties`] + /// for this collider. + /// + /// The angular inertia of this collider will be computed automatically based on its shape + /// and this mass value. + pub fn set_mass(&mut self, mass: Real) { + self.do_set_mass_properties(ColliderMassProps::Mass(mass)); + } + + /// Sets the mass properties of this collider. + /// + /// This will override any previous mass-properties set by [`Self::set_density`], + /// [`Self::set_mass`], [`Self::set_mass_properties`], [`ColliderBuilder::density`], + /// [`ColliderBuilder::mass`], or [`ColliderBuilder::mass_properties`] + /// for this collider. + pub fn set_mass_properties(&mut self, mass_properties: MassProperties) { + self.do_set_mass_properties(ColliderMassProps::MassProperties(Box::new(mass_properties))) + } + + fn do_set_mass_properties(&mut self, mprops: ColliderMassProps) { + if mprops != self.mprops { + self.changes |= ColliderChanges::LOCAL_MASS_PROPERTIES; + self.mprops = mprops; + } + } + /// The geometric shape of this collider. pub fn shape(&self) -> &dyn Shape { self.shape.as_ref() @@ -284,10 +328,7 @@ impl Collider { /// Compute the local-space mass properties of this collider. pub fn mass_properties(&self) -> MassProperties { - match &self.mprops { - ColliderMassProps::Density(density) => self.shape.mass_properties(*density), - ColliderMassProps::MassProperties(mass_properties) => **mass_properties, - } + self.mprops.mass_properties(&*self.shape) } /// The total force magnitude beyond which a contact force event can be emitted. @@ -303,11 +344,8 @@ impl Collider { pub struct ColliderBuilder { /// The shape of the collider to be built. pub shape: SharedShape, - /// The uniform density of the collider to be built. - pub density: Option, - /// Overrides automatic computation of `MassProperties`. - /// If None, it will be computed based on shape and density. - pub mass_properties: Option, + /// Controls the way the collider’s mass-properties are computed. + pub mass_properties: ColliderMassProps, /// The friction coefficient of the collider to be built. pub friction: Real, /// The rule used to combine two friction coefficients. @@ -341,8 +379,7 @@ impl ColliderBuilder { pub fn new(shape: SharedShape) -> Self { Self { shape, - density: None, - mass_properties: None, + mass_properties: ColliderMassProps::default(), friction: Self::default_friction(), restitution: 0.0, position: Isometry::identity(), @@ -627,9 +664,6 @@ impl ColliderBuilder { } /// Sets whether or not the collider built by this builder is a sensor. - /// - /// Sensors will have a default density of zero, - /// but if you call [`Self::mass_properties`] you can assign a mass to a sensor. pub fn sensor(mut self, is_sensor: bool) -> Self { self.is_sensor = is_sensor; self @@ -679,19 +713,34 @@ impl ColliderBuilder { /// Sets the uniform density of the collider this builder will build. /// - /// This will be overridden by a call to [`Self::mass_properties`] so it only makes sense to call - /// either [`Self::density`] or [`Self::mass_properties`]. + /// This will be overridden by a call to [`Self::mass`] or [`Self::mass_properties`] so it only + /// makes sense to call either [`Self::density`] or [`Self::mass`] or [`Self::mass_properties`]. + /// + /// The mass and angular inertia of this collider will be computed automatically based on its + /// shape. pub fn density(mut self, density: Real) -> Self { - self.density = Some(density); + self.mass_properties = ColliderMassProps::Density(density); + self + } + + /// Sets the mass of the collider this builder will build. + /// + /// This will be overridden by a call to [`Self::density`] or [`Self::mass_properties`] so it only + /// makes sense to call either [`Self::density`] or [`Self::mass`] or [`Self::mass_properties`]. + /// + /// The angular inertia of this collider will be computed automatically based on its shape + /// and this mass value. + pub fn mass(mut self, mass: Real) -> Self { + self.mass_properties = ColliderMassProps::Mass(mass); self } /// Sets the mass properties of the collider this builder will build. /// - /// If this is set, [`Self::density`] will be ignored, so it only makes sense to call - /// either [`Self::density`] or [`Self::mass_properties`]. + /// This will be overridden by a call to [`Self::density`] or [`Self::mass`] so it only + /// makes sense to call either [`Self::density`] or [`Self::mass`] or [`Self::mass_properties`]. pub fn mass_properties(mut self, mass_properties: MassProperties) -> Self { - self.mass_properties = Some(mass_properties); + self.mass_properties = ColliderMassProps::MassProperties(Box::new(mass_properties)); self } @@ -745,16 +794,7 @@ impl ColliderBuilder { /// Builds a new collider attached to the given rigid-body. pub fn build(&self) -> Collider { - let mass_info = if let Some(mp) = self.mass_properties { - ColliderMassProps::MassProperties(Box::new(mp)) - } else { - let default_density = Self::default_density(); - let density = self.density.unwrap_or(default_density); - ColliderMassProps::Density(density) - }; - let shape = self.shape.clone(); - let mprops = mass_info; let material = ColliderMaterial { friction: self.friction, restitution: self.restitution, @@ -779,7 +819,7 @@ impl ColliderBuilder { Collider { shape, - mprops, + mprops: self.mass_properties.clone(), material, parent: None, changes, -- cgit From 7831ebfc3109d4a4c2029f50e432dd1d4be9ef82 Mon Sep 17 00:00:00 2001 From: Sébastien Crozet Date: Tue, 5 Jul 2022 15:15:17 +0200 Subject: Add methods to read the mass or volume of a collider. --- src/geometry/collider.rs | 30 +++++++++++++++++++++++++----- 1 file changed, 25 insertions(+), 5 deletions(-) (limited to 'src/geometry/collider.rs') diff --git a/src/geometry/collider.rs b/src/geometry/collider.rs index 421523f..7b0cc4c 100644 --- a/src/geometry/collider.rs +++ b/src/geometry/collider.rs @@ -237,12 +237,32 @@ impl Collider { &self.material } - /// The density of this collider, if set. - pub fn density(&self) -> Option { + /// The volume (or surface in 2D) of this collider. + pub fn volume(&self) -> Real { + self.shape.mass_properties(1.0).mass() + } + + /// The density of this collider. + pub fn density(&self) -> Real { + match &self.mprops { + ColliderMassProps::Density(density) => *density, + ColliderMassProps::Mass(mass) => { + let inv_volume = self.shape.mass_properties(1.0).inv_mass; + mass * inv_volume + } + ColliderMassProps::MassProperties(mprops) => { + let inv_volume = self.shape.mass_properties(1.0).inv_mass; + mprops.mass() * inv_volume + } + } + } + + /// The mass of this collider. + pub fn mass(&self) -> Real { match &self.mprops { - ColliderMassProps::Density(density) => Some(*density), - ColliderMassProps::Mass(_) => None, - ColliderMassProps::MassProperties(_) => None, + ColliderMassProps::Density(density) => self.shape.mass_properties(*density).mass(), + ColliderMassProps::Mass(mass) => *mass, + ColliderMassProps::MassProperties(mprops) => mprops.mass(), } } -- cgit