pathfinder can now handle slabs, stairs, and dirt paths

5 files changed, 88 insertions, 8 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 74f2d23a..6cddfee6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -18,6 +18,7 @@ write down most non-trivial breaking changes.
 - `StartJoinServerEvent` can now be used to join servers exclusively from the ECS without a Tokio runtime.
 - `FormattedText::to_html` and `FormattedText::to_custom_format`.
 - Add auto-reconnecting which is enabled by default.
+- The pathfinder no longer avoids slabs, stairs, and dirt path blocks.
 
 ### Changed
 
diff --git a/azalea/src/pathfinder/moves/basic.rs b/azalea/src/pathfinder/moves/basic.rs
index 4955ed08..d23bb894 100644
--- a/azalea/src/pathfinder/moves/basic.rs
+++ b/azalea/src/pathfinder/moves/basic.rs
@@ -135,7 +135,10 @@ fn execute_ascend_move(mut ctx: ExecuteCtx) {
     }
 
     if BlockPos::from(position) == start {
-        ctx.jump();
+        // only jump if the target is more than 0.5 blocks above us
+        if target.y as f64 - position.y > 0.5 {
+            ctx.jump();
+        }
     }
 }
 #[must_use]
diff --git a/azalea/src/pathfinder/moves/mod.rs b/azalea/src/pathfinder/moves/mod.rs
index 150dad52..f79f7249 100644
--- a/azalea/src/pathfinder/moves/mod.rs
+++ b/azalea/src/pathfinder/moves/mod.rs
@@ -191,10 +191,19 @@ pub struct IsReachedCtx<'a> {
 #[must_use]
 pub fn default_is_reached(
     IsReachedCtx {
-        position, target, ..
+        position,
+        target,
+        physics,
+        ..
     }: IsReachedCtx,
 ) -> bool {
-    BlockPos::from(position) == target
+    if BlockPos::from(position) == target {
+        return true;
+    }
+
+    // this is to make it handle things like slabs correctly, if we're on the block
+    // below the target but on_ground
+    BlockPos::from(position).up(1) == target && physics.on_ground()
 }
 
 pub struct PathfinderCtx<'a> {
diff --git a/azalea/src/pathfinder/moves/parkour.rs b/azalea/src/pathfinder/moves/parkour.rs
index 1816a5e1..d4f136be 100644
--- a/azalea/src/pathfinder/moves/parkour.rs
+++ b/azalea/src/pathfinder/moves/parkour.rs
@@ -6,6 +6,11 @@ use super::{Edge, ExecuteCtx, IsReachedCtx, MoveData, PathfinderCtx};
 use crate::pathfinder::{astar, costs::*, rel_block_pos::RelBlockPos};
 
 pub fn parkour_move(ctx: &mut PathfinderCtx, node: RelBlockPos) {
+    if !ctx.world.is_block_solid(node.down(1)) {
+        // we can only parkour from solid blocks (not just standable blocks like slabs)
+        return;
+    }
+
     parkour_forward_1_move(ctx, node);
     parkour_forward_2_move(ctx, node);
     parkour_forward_3_move(ctx, node);
@@ -232,9 +237,18 @@ fn execute_parkour_move(mut ctx: ExecuteCtx) {
 #[must_use]
 pub fn parkour_is_reached(
     IsReachedCtx {
-        position, target, ..
+        position,
+        target,
+        physics,
+        ..
     }: IsReachedCtx,
 ) -> bool {
     // 0.094 and not 0 for lilypads
-    BlockPos::from(position) == target && (position.y - target.y as f64) < 0.094
+    if BlockPos::from(position) == target && (position.y - target.y as f64) < 0.094 {
+        return true;
+    }
+
+    // this is to make it handle things like slabs correctly, if we're on the block
+    // below the target but on_ground
+    BlockPos::from(position).up(1) == target && physics.on_ground()
 }
diff --git a/azalea/src/pathfinder/world.rs b/azalea/src/pathfinder/world.rs
index b89f0761..45d05810 100644
--- a/azalea/src/pathfinder/world.rs
+++ b/azalea/src/pathfinder/world.rs
@@ -81,8 +81,12 @@ impl CachedSections {
 
 pub struct CachedSection {
     pub pos: ChunkSectionPos,
+    /// Blocks that we can fully pass through (like air).
     pub passable_bitset: FixedBitSet<{ 4096_usize.div_ceil(8) }>,
+    /// Blocks that we can stand on and do parkour from.
     pub solid_bitset: FixedBitSet<{ 4096_usize.div_ceil(8) }>,
+    /// Blocks that we can stand on but might not be able to parkour from.
+    pub standable_bitset: FixedBitSet<{ 4096_usize.div_ceil(8) }>,
 }
 
 impl CachedWorld {
@@ -193,6 +197,7 @@ impl CachedWorld {
         self.with_section(section_pos, |section| {
             let mut passable_bitset = FixedBitSet::<{ 4096_usize.div_ceil(8) }>::new();
             let mut solid_bitset = FixedBitSet::<{ 4096_usize.div_ceil(8) }>::new();
+            let mut standable_bitset = FixedBitSet::<{ 4096_usize.div_ceil(8) }>::new();
             for i in 0..4096 {
                 let block_state = section.get_at_index(i);
                 if is_block_state_passable(block_state) {
@@ -201,11 +206,15 @@ impl CachedWorld {
                 if is_block_state_solid(block_state) {
                     solid_bitset.set(i);
                 }
+                if is_block_state_standable(block_state) {
+                    standable_bitset.set(i);
+                }
             }
             CachedSection {
                 pos: section_pos,
                 passable_bitset,
                 solid_bitset,
+                standable_bitset,
             }
         })
     }
@@ -235,6 +244,9 @@ impl CachedWorld {
     pub fn is_block_solid(&self, pos: RelBlockPos) -> bool {
         self.is_block_pos_solid(pos.apply(self.origin))
     }
+    pub fn is_block_standable(&self, pos: RelBlockPos) -> bool {
+        self.is_block_pos_standable(pos.apply(self.origin))
+    }
 
     fn is_block_pos_solid(&self, pos: BlockPos) -> bool {
         let (section_pos, section_block_pos) =
@@ -253,6 +265,23 @@ impl CachedWorld {
         cached_blocks.insert(cached);
         solid
     }
+    fn is_block_pos_standable(&self, pos: BlockPos) -> bool {
+        let (section_pos, section_block_pos) =
+            (ChunkSectionPos::from(pos), ChunkSectionBlockPos::from(pos));
+        let index = u16::from(section_block_pos) as usize;
+        // SAFETY: we're only accessing this from one thread
+        let cached_blocks = unsafe { &mut *self.cached_blocks.get() };
+        if let Some(cached) = cached_blocks.get_mut(section_pos) {
+            return cached.standable_bitset.index(index);
+        }
+
+        let Some(cached) = self.calculate_bitsets_for_section(section_pos) else {
+            return false;
+        };
+        let solid = cached.standable_bitset.index(index);
+        cached_blocks.insert(cached);
+        solid
+    }
 
     /// Returns how much it costs to break this block. Returns 0 if the block is
     /// already passable.
@@ -434,11 +463,11 @@ impl CachedWorld {
         self.is_standable_at_block_pos(pos.apply(self.origin))
     }
     fn is_standable_at_block_pos(&self, pos: BlockPos) -> bool {
-        self.is_block_pos_solid(pos.down(1)) && self.is_passable_at_block_pos(pos)
+        self.is_block_pos_standable(pos.down(1)) && self.is_passable_at_block_pos(pos)
     }
 
     pub fn cost_for_standing(&self, pos: RelBlockPos, mining_cache: &MiningCache) -> f32 {
-        if !self.is_block_solid(pos.down(1)) {
+        if !self.is_block_standable(pos.down(1)) {
             return f32::INFINITY;
         }
         self.cost_for_passing(pos, mining_cache)
@@ -501,7 +530,8 @@ pub fn is_block_state_passable(block: BlockState) -> bool {
     true
 }
 
-/// whether this block has a solid hitbox (i.e. we can stand on it)
+/// whether this block has a solid hitbox at the top (i.e. we can stand on it
+/// and do parkour from it)
 pub fn is_block_state_solid(block: BlockState) -> bool {
     if block.is_air() {
         // fast path
@@ -510,6 +540,29 @@ pub fn is_block_state_solid(block: BlockState) -> bool {
     block.is_collision_shape_full()
 }
 
+pub fn is_block_state_standable(block: BlockState) -> bool {
+    if block.is_air() {
+        // fast path
+        return false;
+    }
+    if block.is_collision_shape_full() {
+        return true;
+    }
+
+    let registry_block = azalea_registry::Block::from(block);
+    if azalea_registry::tags::blocks::SLABS.contains(&registry_block)
+        || azalea_registry::tags::blocks::STAIRS.contains(&registry_block)
+    {
+        return true;
+    }
+
+    if registry_block == azalea_registry::Block::DirtPath {
+        return true;
+    }
+
+    false
+}
+
 #[cfg(test)]
 mod tests {