From e18d9347683d64e6548d0b5917abba551a344686 Mon Sep 17 00:00:00 2001
From: caelunshun <caelum12321@gmail.com>
Date: Fri, 13 Sep 2019 23:49:29 -0600
Subject: [PATCH] Support bounding boxes for non-cubic blocks

---
 server/src/physics/block_bboxes.rs | 51 ++++++++++++++++++++++++++++++
 server/src/physics/math.rs         | 31 ++++++++++--------
 server/src/physics/mod.rs          |  1 +
 3 files changed, 70 insertions(+), 13 deletions(-)
 create mode 100644 server/src/physics/block_bboxes.rs

diff --git a/server/src/physics/block_bboxes.rs b/server/src/physics/block_bboxes.rs
new file mode 100644
index 000000000..12cee06ee
--- /dev/null
+++ b/server/src/physics/block_bboxes.rs
@@ -0,0 +1,51 @@
+//! Bounding boxes for every non-cubic block.
+
+use crate::physics::component::bbox;
+use feather_blocks::Block;
+use ncollide3d::bounding_volume::AABB;
+
+/// Returns the bounding box for the given block.
+///
+/// Non-solid blocks have no bounding box,
+/// and the bounding box for a non-solid block
+/// is undefined.
+pub fn bbox_for_block(block: &Block) -> AABB<f64> {
+    match block {
+        Block::WhiteBed(_)
+        | Block::OrangeBed(_)
+        | Block::MagentaBed(_)
+        | Block::LightBlueBed(_)
+        | Block::YellowBed(_)
+        | Block::LimeBed(_)
+        | Block::PinkBed(_)
+        | Block::GrayBed(_)
+        | Block::LightGrayBed(_)
+        | Block::CyanBed(_)
+        | Block::PurpleBed(_)
+        | Block::BlueBed(_)
+        | Block::BrownBed(_)
+        | Block::GreenBed(_)
+        | Block::RedBed(_)
+        | Block::BlackBed(_)
+        | Block::PrismarineSlab(_)
+        | Block::PrismarineBrickSlab(_)
+        | Block::DarkPrismarineSlab(_)
+        | Block::OakSlab(_)
+        | Block::SpruceSlab(_)
+        | Block::BirchSlab(_)
+        | Block::JungleSlab(_)
+        | Block::AcaciaSlab(_)
+        | Block::DarkOakSlab(_)
+        | Block::StoneSlab(_)
+        | Block::SandstoneSlab(_)
+        | Block::PetrifiedOakSlab(_)
+        | Block::CobblestoneSlab(_)
+        | Block::BrickSlab(_)
+        | Block::StoneBrickSlab(_)
+        | Block::NetherBrickSlab(_)
+        | Block::QuartzSlab(_)
+        | Block::RedSandstoneSlab(_)
+        | Block::PurpurSlab(_) => bbox(1.0, 0.5),
+        _ => bbox(1.0, 1.0),
+    }
+}
diff --git a/server/src/physics/math.rs b/server/src/physics/math.rs
index 8751d061d..9b53b7077 100644
--- a/server/src/physics/math.rs
+++ b/server/src/physics/math.rs
@@ -2,7 +2,9 @@
 //! the physics system.
 
 use crate::entity::{ChunkEntities, PositionComponent};
+use crate::physics::block_bboxes::bbox_for_block;
 use crate::physics::BoundingBoxComponent;
+use feather_blocks::Block;
 use feather_core::world::{BlockPosition, ChunkMap, Position};
 use feather_core::{BlockExt, ChunkPosition};
 use glm::{vec3, DVec3, Vec3};
@@ -157,12 +159,14 @@ pub fn block_impacted_by_ray(
                 // Calculate world-space position of
                 // impact using `ncollide`.
                 let ray = Ray::new(Point3::from(origin), direction);
-                let shape = block_shape();
+                let shape = block_shape(&block);
                 let isometry = block_isometry(current_pos);
 
-                let impact = shape
-                    .toi_and_normal_with_ray(&isometry, &ray, true)
-                    .unwrap(); // Unwrap is safe because we know the ray intersects the block
+                let impact = match shape.toi_and_normal_with_ray(&isometry, &ray, true) {
+                    Some(toi) => toi,
+                    None => continue,
+                };
+
                 let pos = Position::from(origin + impact.toi * direction);
 
                 return Some(RayImpact {
@@ -418,7 +422,7 @@ pub fn adjacent_to_bbox(
     let sign = f64::from(sign);
 
     let size = bbox.size() / 2.0;
-    let mut blocks: SmallVec<[BlockPosition; 4]> = smallvec![];
+    let mut blocks: SmallVec<[(BlockPosition, Block); 4]> = smallvec![];
 
     let other_axis1 = match axis {
         0 => 1,
@@ -473,7 +477,7 @@ pub fn adjacent_to_bbox(
             Some(block) => {
                 if block.is_solid() {
                     checked.insert(block_pos).unwrap();
-                    blocks.push(block_pos);
+                    blocks.push((block_pos, block));
                 }
             }
             None => continue,
@@ -481,19 +485,20 @@ pub fn adjacent_to_bbox(
     }
 
     let mut shapes = Vec::with_capacity(4);
-    let block_shape = block_shape();
 
-    for block in &blocks {
-        let isometry = block_isometry(*block);
-        shapes.push((isometry, ShapeHandle::new(block_shape.clone())));
+    for (block_pos, block) in &blocks {
+        let isometry = block_isometry(*block_pos);
+        let shape = block_shape(&block);
+        shapes.push((isometry, ShapeHandle::new(shape)));
     }
 
     Compound::new(shapes)
 }
 
-/// Returns an `ncollide` `Cuboid` corresponding to a block.
-pub fn block_shape() -> Cuboid<f64> {
-    Cuboid::new(vec3(0.5, 0.5, 0.5))
+/// Returns an `ncollide` `Cuboid` corresponding to the given block.
+pub fn block_shape(block: &Block) -> Cuboid<f64> {
+    let bbox = bbox_for_block(block);
+    Cuboid::new(bbox.half_extents())
 }
 
 /// Returns an `Isometry` representing a block's translation.
diff --git a/server/src/physics/mod.rs b/server/src/physics/mod.rs
index 077f183fe..cd02ace5c 100644
--- a/server/src/physics/mod.rs
+++ b/server/src/physics/mod.rs
@@ -1,5 +1,6 @@
 //! Module for calculating physics interactions.
 
+mod block_bboxes;
 mod component;
 mod entity;
 mod math;