Split the broad-phase code into multiple files.

src/geometry/broad_phase_multi_sap/sap_endpoint.rs

@@ -0,0 +1,60 @@
+use super::SENTINEL_VALUE;
+use crate::math::Real;
+
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serde-serialize", derive(Serialize, Deserialize))]
+pub(crate) struct SAPEndpoint {
+    pub value: Real,
+    pub packed_flag_proxy: u32,
+}
+
+const START_FLAG_MASK: u32 = 0b1 << 31;
+const PROXY_MASK: u32 = u32::MAX ^ START_FLAG_MASK;
+const START_SENTINEL_TAG: u32 = u32::MAX;
+const END_SENTINEL_TAG: u32 = u32::MAX ^ START_FLAG_MASK;
+
+impl SAPEndpoint {
+    pub fn start_endpoint(value: Real, proxy: u32) -> Self {
+        Self {
+            value,
+            packed_flag_proxy: proxy | START_FLAG_MASK,
+        }
+    }
+
+    pub fn end_endpoint(value: Real, proxy: u32) -> Self {
+        Self {
+            value,
+            packed_flag_proxy: proxy & PROXY_MASK,
+        }
+    }
+
+    pub fn start_sentinel() -> Self {
+        Self {
+            value: -SENTINEL_VALUE,
+            packed_flag_proxy: START_SENTINEL_TAG,
+        }
+    }
+
+    pub fn end_sentinel() -> Self {
+        Self {
+            value: SENTINEL_VALUE,
+            packed_flag_proxy: END_SENTINEL_TAG,
+        }
+    }
+
+    pub fn is_sentinel(self) -> bool {
+        self.packed_flag_proxy & PROXY_MASK == PROXY_MASK
+    }
+
+    pub fn proxy(self) -> u32 {
+        self.packed_flag_proxy & PROXY_MASK
+    }
+
+    pub fn is_start(self) -> bool {
+        (self.packed_flag_proxy & START_FLAG_MASK) != 0
+    }
+
+    pub fn is_end(self) -> bool {
+        (self.packed_flag_proxy & START_FLAG_MASK) == 0
+    }
+}