All block shapes & collisions (#22)

* start adding shapes

* add more collision stuff

* DiscreteCubeMerger

* more mergers

* start adding BitSetDiscreteVoxelShape::join

* i love rust :smiley: :smiley: :smiley:

* r

* IT COMPILES????

* fix warning

* fix error

* fix more clippy issues

* add box_shape

* more shape stuff

* make DiscreteVoxelShape an enum

* Update shape.rs

* also make VoxelShape an enum

* implement BitSet::clear

* add more missing things

* it compiles

W

* start block shape codegen

* optimize shape codegen

* make az-block/blocks.rs look better (broken)

* almost new block macro

* make the codegen not generate 'type'

* try to fix

* work more on the blocks macro

* wait it compiles

* fix clippy issues

* shapes codegen works

* well it's almost working

* simplify some shape codegen

* enum type names are correct

* W it compiles

* cargo check no longer warns

* fix some clippy issues

* start making it so the shape impl is on BlockStates

* insane code

* new impl compiles

* fix wrong find_bits + TESTS PASS!

* add a test for slab collision

* fix clippy issues

* ok rust

* fix error that happens when on stairs

* add test for top slabs

* start adding join_is_not_empty

* add more to join_is_not_empty

* top slabs still don't work!!

* x..=0 doesn't work in rust :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley: :smiley:

* remove comment since i added more useful names

* remove some printlns

* fix walls in some configurations erroring

* fix some warnings

* change comment to \`\`\`ignore instead of \`\`\`no_run

* players are .6 wide not .8

* fix clippy's complaints

* i missed one clippy warning

1 files changed, 102 insertions, 4 deletions

diff --git a/azalea-physics/src/lib.rs b/azalea-physics/src/lib.rs
index f80d1bad..56923577 100644
--- a/azalea-physics/src/lib.rs
+++ b/azalea-physics/src/lib.rs
@@ -1,3 +1,6 @@
+#![feature(trait_alias)]
+#![feature(let_chains)]
+
 pub mod collision;
 
 use azalea_block::{Block, BlockState};
@@ -191,11 +194,10 @@ mod tests {
                 },
             ),
         );
-        let old_block_state =
-            dim.set_block_state(&BlockPos { x: 0, y: 69, z: 0 }, BlockState::Stone);
+        let block_state = dim.set_block_state(&BlockPos { x: 0, y: 69, z: 0 }, BlockState::Stone);
         assert!(
-            old_block_state.is_some(),
-            "Old block state should exist, if this fails that means the chunk wasn't loaded and the block didn't get placed"
+            block_state.is_some(),
+            "Block state should exist, if this fails that means the chunk wasn't loaded and the block didn't get placed"
         );
         let mut entity = dim.entity_mut(0).unwrap();
         entity.ai_step();
@@ -206,4 +208,100 @@ mod tests {
         // the second tick applies the delta to the position, but it also does collision
         assert_eq!(entity.pos().y, 70.);
     }
+
+    #[test]
+    fn test_slab_collision() {
+        let mut dim = Dimension::default();
+        dim.set_chunk(&ChunkPos { x: 0, z: 0 }, Some(Chunk::default()))
+            .unwrap();
+        dim.add_entity(
+            0,
+            EntityData::new(
+                Uuid::from_u128(0),
+                Vec3 {
+                    x: 0.5,
+                    y: 71.,
+                    z: 0.5,
+                },
+            ),
+        );
+        let block_state = dim.set_block_state(
+            &BlockPos { x: 0, y: 69, z: 0 },
+            BlockState::StoneSlab_BottomFalse,
+        );
+        assert!(
+            block_state.is_some(),
+            "Block state should exist, if this fails that means the chunk wasn't loaded and the block didn't get placed"
+        );
+        let mut entity = dim.entity_mut(0).unwrap();
+        // do a few steps so we fall on the slab
+        for _ in 0..20 {
+            entity.ai_step();
+        }
+        assert_eq!(entity.pos().y, 69.5);
+    }
+
+    #[test]
+    fn test_top_slab_collision() {
+        let mut dim = Dimension::default();
+        dim.set_chunk(&ChunkPos { x: 0, z: 0 }, Some(Chunk::default()))
+            .unwrap();
+        dim.add_entity(
+            0,
+            EntityData::new(
+                Uuid::from_u128(0),
+                Vec3 {
+                    x: 0.5,
+                    y: 71.,
+                    z: 0.5,
+                },
+            ),
+        );
+        let block_state = dim.set_block_state(
+            &BlockPos { x: 0, y: 69, z: 0 },
+            BlockState::StoneSlab_TopFalse,
+        );
+        assert!(
+            block_state.is_some(),
+            "Block state should exist, if this fails that means the chunk wasn't loaded and the block didn't get placed"
+        );
+        let mut entity = dim.entity_mut(0).unwrap();
+        // do a few steps so we fall on the slab
+        for _ in 0..20 {
+            entity.ai_step();
+        }
+        assert_eq!(entity.pos().y, 70.);
+    }
+
+    #[test]
+    fn test_weird_wall_collision() {
+        let mut dim = Dimension::default();
+        dim.set_chunk(&ChunkPos { x: 0, z: 0 }, Some(Chunk::default()))
+            .unwrap();
+        dim.add_entity(
+            0,
+            EntityData::new(
+                Uuid::from_u128(0),
+                Vec3 {
+                    x: 0.5,
+                    y: 73.,
+                    z: 0.5,
+                },
+            ),
+        );
+        let block_state = dim.set_block_state(
+            &BlockPos { x: 0, y: 69, z: 0 },
+            BlockState::CobblestoneWall_LowLowLowFalseFalseLow,
+        );
+        assert!(
+            block_state.is_some(),
+            "Block state should exist, if this fails that means the chunk wasn't loaded and the block didn't get placed"
+        );
+        let mut entity = dim.entity_mut(0).unwrap();
+        // do a few steps so we fall on the slab
+        for _ in 0..20 {
+            entity.ai_step();
+        }
+        assert_eq!(entity.pos().y, 70.5);
+    }
 }