Separate out Chunks-related code, "fix" collisions to be less broken

src/Chunks.zig

@@ -0,0 +1,286 @@
+const Chunks = @This();
+const std = @import("std");
+
+const c = @import("const.zig");
+const math = @import("math.zig");
+const vk = @import("vulkan");
+
+const Blocks = @import("assets/Blocks.zig");
+const Chunk = @import("assets/Chunk.zig");
+const Engine = @import("engine/Engine.zig");
+const Iterator2 = math.Iterator2;
+const Vector2Int = math.Vector2Int;
+const Vector3Int = math.Vector3Int;
+
+chunks: std.AutoHashMapUnmanaged([3]i16, Chunk),
+
+const SweepHit = struct {
+    normal_frac: Vector3Int,
+    projected_distance_sv: i32,
+};
+
+pub fn deinit(self: *Chunks, engine: *Engine, descriptor_pool: vk.DescriptorPool, allocator: std.mem.Allocator) void {
+    var it = self.chunks.valueIterator();
+    while (it.next()) |chunk| {
+        chunk.deinit(engine, descriptor_pool);
+    }
+    self.chunks.deinit(allocator);
+    self.* = undefined;
+}
+
+pub fn getVoxelAt(self: *const Chunks, vx: Vector3Int) ?Blocks.Id {
+    const min_ck = Vector3Int.initScalar(std.math.minInt(i16));
+    const max_ck = Vector3Int.initScalar(std.math.maxInt(i16));
+    const ck = vx.divScalar(c.vx_per_ck);
+    if (@reduce(.Or, (ck.vector < min_ck.vector) | (ck.vector > max_ck.vector))) {
+        return null;
+    }
+
+    if (self.chunks.get(.{
+        @intCast(ck.getX()),
+        @intCast(ck.getY()),
+        @intCast(ck.getZ()),
+    })) |chunk| {
+        const ckvx = vx.modScalar(c.vx_per_ck);
+        return chunk.blocks[@intCast(ckvx.getZ())][@intCast(ckvx.getY())][@intCast(ckvx.getX())];
+    } else {
+        return .air;
+    }
+}
+
+pub fn isSolid(self: *const Chunks, vx: Vector3Int) bool {
+    const maybe_id = getVoxelAt(self, vx);
+    // NOTE `null` is considered solid, as it's out of bounds.
+    return maybe_id != .air;
+}
+
+pub fn sweepCastDown(self: *const Chunks, min_sv: Vector3Int, max_sv: Vector3Int, distance_sv: i32) ?SweepHit {
+    const min_x_vx = c.subvoxelsToVoxels(.border_up, min_sv.getX());
+    const min_y_vx = c.subvoxelsToVoxels(.border_up, min_sv.getY());
+    const max_x_vx = c.subvoxelsToVoxels(.border_down, max_sv.getX());
+    const max_y_vx = c.subvoxelsToVoxels(.border_down, max_sv.getY());
+
+    const start_z_vx = c.subvoxelsToVoxels(.border_up, min_sv.getZ()) - 1;
+    const end_z_vx = c.subvoxelsToVoxels(.border_up, min_sv.getZ() - distance_sv);
+
+    var z_vx: i32 = start_z_vx;
+    while (z_vx >= end_z_vx) : (z_vx -= 1) {
+        const z_sv = c.voxelsToSubvoxels(z_vx + 1);
+        var it = Iterator2(i32).init(.{
+            .min = .{ min_x_vx, min_y_vx },
+            .max = .{ max_x_vx, max_y_vx },
+        });
+        while (it.next()) |xy_vx| {
+            const x_vx, const y_vx = xy_vx;
+            if (!self.isSolid(.init(x_vx, y_vx, z_vx))) continue;
+
+            return .{
+                .projected_distance_sv = distance_sv - (min_sv.getZ() - z_sv),
+                .normal_frac = .unit_z_frac,
+            };
+        }
+    }
+
+    return null;
+}
+
+pub fn sweepCastUp(self: *const Chunks, min_sv: Vector3Int, max_sv: Vector3Int, distance_sv: i32) ?SweepHit {
+    const min_x_vx = c.subvoxelsToVoxels(.border_up, min_sv.getX());
+    const min_y_vx = c.subvoxelsToVoxels(.border_up, min_sv.getY());
+    const max_x_vx = c.subvoxelsToVoxels(.border_down, max_sv.getX());
+    const max_y_vx = c.subvoxelsToVoxels(.border_down, max_sv.getY());
+
+    const start_z_vx = c.subvoxelsToVoxels(.border_down, max_sv.getZ()) + 1;
+    const end_z_vx = c.subvoxelsToVoxels(.border_down, max_sv.getZ() + distance_sv);
+
+    var z_vx: i32 = start_z_vx;
+    while (z_vx <= end_z_vx) : (z_vx += 1) {
+        const z_sv = c.voxelsToSubvoxels(z_vx);
+        var it = Iterator2(i32).init(.{
+            .min = .{ min_x_vx, min_y_vx },
+            .max = .{ max_x_vx, max_y_vx },
+        });
+        while (it.next()) |xy_vx| {
+            const x_vx, const y_vx = xy_vx;
+            if (!self.isSolid(.init(x_vx, y_vx, z_vx))) continue;
+
+            return .{
+                .projected_distance_sv = distance_sv - (z_sv - max_sv.getZ()),
+                .normal_frac = .unit_nz_frac,
+            };
+        }
+    }
+
+    return null;
+}
+
+pub fn sweepCastHorizontal(self: *const Chunks, min_sv: Vector3Int, max_sv: Vector3Int, ray_sv: Vector2Int) ?SweepHit {
+    const min_z_vx = c.subvoxelsToVoxels(.border_up, min_sv.getZ());
+    const max_z_vx = c.subvoxelsToVoxels(.border_down, max_sv.getZ());
+
+    var hit: ?SweepHit = null;
+    var hit_distance_squared = std.math.inf(f32);
+
+    const fdydx: f32 = @as(f32, @floatFromInt(ray_sv.getY())) / @as(f32, @floatFromInt(ray_sv.getX()));
+    const fdxdy: f32 = @as(f32, @floatFromInt(ray_sv.getX())) / @as(f32, @floatFromInt(ray_sv.getY()));
+
+    // Positive X
+    if (ray_sv.getX() > 0) {
+        const x0_sv = max_sv.getX();
+        const y0_sv = min_sv.getY();
+        const y1_sv = max_sv.getY();
+
+        const start_x_vx = c.subvoxelsToVoxels(.border_down, x0_sv) + 1;
+        const end_x_vx = c.subvoxelsToVoxels(.border_down, x0_sv + ray_sv.getX());
+
+        var x_vx: i32 = start_x_vx;
+        px: while (x_vx <= end_x_vx) : (x_vx += 1) {
+            const x_sv = c.voxelsToSubvoxels(x_vx);
+            const min_y_vx = c.subvoxelsToVoxels(.border_up, math.wideMulDivFloor(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y0_sv);
+            const max_y_vx = c.subvoxelsToVoxels(.border_down, math.wideMulDivCeil(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y1_sv);
+            var it = Iterator2(i32).init(.{
+                .min = .{ min_y_vx, min_z_vx },
+                .max = .{ max_y_vx, max_z_vx },
+            });
+            while (it.next()) |yz_vx| {
+                const y_vx, const z_vx = yz_vx;
+                if (!self.isSolid(.init(x_vx, y_vx, z_vx))) continue;
+
+                const dx = x_sv - x0_sv;
+                const fdx: f32 = @floatFromInt(dx);
+                const fdy: f32 = fdx * fdydx;
+
+                hit = .{
+                    .projected_distance_sv = ray_sv.getX() - dx,
+                    .normal_frac = .unit_nx_frac,
+                };
+                hit_distance_squared = fdx * fdx + fdy * fdy;
+                // std.debug.print("HIT +X ({X}->{X}) at ({X}, {X}, {X}) [VX] | min_sv={X} max_sv={X} ray_sv={X} | proj_dist={X} \n", .{ start_x_vx, end_x_vx, x_vx, y_vx, z_vx, min_sv.vector, max_sv.vector, ray_sv.vector, hit.?.projected_distance_sv });
+
+                break :px;
+            }
+        }
+    }
+
+    // Negative X
+    if (ray_sv.getX() < 0) {
+        const x0_sv = min_sv.getX();
+        const y0_sv = min_sv.getY();
+        const y1_sv = max_sv.getY();
+
+        const start_x_vx = c.subvoxelsToVoxels(.border_up, x0_sv) - 1;
+        const end_x_vx = c.subvoxelsToVoxels(.border_up, x0_sv + ray_sv.getX());
+
+        var x_vx: i32 = start_x_vx;
+        nx: while (x_vx >= end_x_vx) : (x_vx -= 1) {
+            const x_sv = c.voxelsToSubvoxels(x_vx + 1);
+            const min_y_vx = c.subvoxelsToVoxels(.border_up, math.wideMulDivFloor(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y0_sv);
+            const max_y_vx = c.subvoxelsToVoxels(.border_down, math.wideMulDivCeil(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y1_sv);
+            var it = Iterator2(i32).init(.{
+                .min = .{ min_y_vx, min_z_vx },
+                .max = .{ max_y_vx, max_z_vx },
+            });
+            while (it.next()) |yz_vx| {
+                const y_vx, const z_vx = yz_vx;
+                if (!self.isSolid(.init(x_vx, y_vx, z_vx))) continue;
+
+                const dx = x_sv - x0_sv;
+                const fdx: f32 = @floatFromInt(dx);
+                const fdy: f32 = fdx * fdydx;
+
+                hit = .{
+                    .projected_distance_sv = -(ray_sv.getX() - dx),
+                    .normal_frac = .unit_x_frac,
+                };
+                hit_distance_squared = fdx * fdx + fdy * fdy;
+                // std.debug.print("HIT -X ({X}->{X}) at ({X}, {X}, {X}) [VX] | min_sv={X} max_sv={X} ray_sv={X} | proj_dist={X} \n", .{ start_x_vx, end_x_vx, x_vx, y_vx, z_vx, min_sv.vector, max_sv.vector, ray_sv.vector, hit.?.projected_distance_sv });
+
+                break :nx;
+            }
+        }
+    }
+
+    // Positive Y
+    if (ray_sv.getY() > 0) {
+        const y0_sv = max_sv.getY();
+        const x0_sv = min_sv.getX();
+        const x1_sv = max_sv.getX();
+
+        const start_y_vx = c.subvoxelsToVoxels(.border_down, y0_sv) + 1;
+        const end_y_vx = c.subvoxelsToVoxels(.border_down, y0_sv + ray_sv.getY());
+
+        var y_vx = start_y_vx;
+        py: while (y_vx <= end_y_vx) : (y_vx += 1) {
+            const y_sv = c.voxelsToSubvoxels(y_vx);
+            const min_x_vx = c.subvoxelsToVoxels(.border_up, math.wideMulDivFloor(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x0_sv);
+            const max_x_vx = c.subvoxelsToVoxels(.border_down, math.wideMulDivCeil(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x1_sv);
+            var it = Iterator2(i32).init(.{
+                .min = .{ min_x_vx, min_z_vx },
+                .max = .{ max_x_vx, max_z_vx },
+            });
+            while (it.next()) |xz_vx| {
+                const x_vx, const z_vx = xz_vx;
+                if (!self.isSolid(.init(x_vx, y_vx, z_vx))) continue;
+
+                const dy = y_sv - y0_sv;
+                const fdy: f32 = @floatFromInt(dy);
+                const fdx: f32 = fdy * fdxdy;
+
+                const this_hit_distance_squared = fdx * fdx + fdy * fdy;
+                if (this_hit_distance_squared < hit_distance_squared) {
+                    hit = .{
+                        .projected_distance_sv = ray_sv.getY() - dy,
+                        .normal_frac = .unit_ny_frac,
+                    };
+                    hit_distance_squared = this_hit_distance_squared;
+                    // std.debug.print("HIT +Y ({X}->{X}) at ({X}, {X}, {X}) [VX] | min_sv={X} max_sv={X} ray_sv={X} | proj_dist={X} \n", .{ start_y_vx, end_y_vx, x_vx, y_vx, z_vx, min_sv.vector, max_sv.vector, ray_sv.vector, hit.?.projected_distance_sv });
+                }
+
+                break :py;
+            }
+        }
+    }
+
+    // Negative Y
+    if (ray_sv.getY() < 0.0) {
+        const y0_sv = min_sv.getY();
+        const x0_sv = min_sv.getX();
+        const x1_sv = max_sv.getX();
+
+        const start_y_vx = c.subvoxelsToVoxels(.border_up, y0_sv) - 1;
+        const end_y_vx = c.subvoxelsToVoxels(.border_up, y0_sv + ray_sv.getY());
+
+        var y_vx = start_y_vx;
+        ny: while (y_vx >= end_y_vx) : (y_vx -= 1) {
+            const y_sv = c.voxelsToSubvoxels(y_vx + 1);
+            const min_x_vx = c.subvoxelsToVoxels(.border_up, math.wideMulDivFloor(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x0_sv);
+            const max_x_vx = c.subvoxelsToVoxels(.border_down, math.wideMulDivCeil(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x1_sv);
+            var it = Iterator2(i32).init(.{
+                .min = .{ min_x_vx, min_z_vx },
+                .max = .{ max_x_vx, max_z_vx },
+            });
+            while (it.next()) |xz_vx| {
+                const x_vx, const z_vx = xz_vx;
+                if (!self.isSolid(.init(x_vx, y_vx, z_vx))) continue;
+
+                const dy = y_sv - y0_sv;
+                const fdy: f32 = @floatFromInt(dy);
+                const fdx: f32 = fdy * fdxdy;
+
+                const this_hit_distance_squared = fdx * fdx + fdy * fdy;
+                if (this_hit_distance_squared < hit_distance_squared) {
+                    hit = .{
+                        .projected_distance_sv = -(ray_sv.getY() - dy),
+                        .normal_frac = .unit_y_frac,
+                    };
+                    hit_distance_squared = this_hit_distance_squared;
+                    // std.debug.print("HIT -Y ({X}->{X}) at ({X}, {X}, {X}) [VX] | min_sv={X} max_sv={X} ray_sv={X} | proj_dist={X} \n", .{ start_y_vx, end_y_vx, x_vx, y_vx, z_vx, min_sv.vector, max_sv.vector, ray_sv.vector, hit.?.projected_distance_sv });
+                }
+
+                break :ny;
+            }
+        }
+    }
+
+    return hit;
+}

src/Game.zig

@@ -10,6 +10,7 @@ const worldgen = @import("worldgen.zig");
 
 const Blocks = @import("assets/Blocks.zig");
 const Chunk = @import("assets/Chunk.zig");
+const Chunks = @import("Chunks.zig");
 const CommandBuffer = @import("engine/CommandBuffer.zig");
 const Engine = @import("engine/Engine.zig");
 const Iterator2 = math.Iterator2;
@@ -50,7 +51,7 @@ deferred_command_buffers: std.ArrayList(CommandBuffer),
 blocks: Blocks,
 materials: Materials,
 textures: Textures,
-chunks: std.AutoHashMapUnmanaged([3]i16, Chunk),
+chunks: Chunks,
 skybox: Skybox,
 
 player: Player,
@@ -659,7 +660,7 @@ pub fn init(allocator: std.mem.Allocator, engine: *Engine, swapchain: *Swapchain
         .blocks = blocks,
         .materials = materials,
         .textures = textures,
-        .chunks = chunks,
+        .chunks = .{ .chunks = chunks },
         .skybox = skybox,
 
         .player = .init(player_position_sv, 0, 0),
@@ -677,11 +678,7 @@ pub fn deinit(self: *Game) void {
     self.vertex_buffer.deinit(self.engine);
     self.index_buffer.deinit(self.engine);
 
-    var it = self.chunks.valueIterator();
-    while (it.next()) |chunk| {
-        chunk.deinit(self.engine, self.descriptor_pool);
-    }
-    self.chunks.deinit(self.allocator);
+    self.chunks.deinit(self.engine, self.descriptor_pool, self.allocator);
     self.skybox.deinit(self.engine);
 
     self.global_uniforms.deinit(self.engine);
@@ -889,7 +886,7 @@ fn render(self: *Game) !void {
         command_buffer.bindIndexBuffer(self.index_buffer.buffer, 0, .uint16);
         command_buffer.bindDescriptorSet(.graphics, self.pipeline_layout, 0, self.global_descriptor_set, null);
 
-        var it = self.chunks.valueIterator();
+        var it = self.chunks.chunks.valueIterator();
         while (it.next()) |chunk| {
             chunk.draw(self.pipeline_layout, command_buffer);
         }

src/Player.zig

@@ -6,7 +6,7 @@ const glfw = @import("zglfw");
 const math = @import("math.zig");
 
 const Blocks = @import("assets/Blocks.zig");
-const Chunk = @import("assets/Chunk.zig");
+const Chunks = @import("Chunks.zig");
 const Iterator2 = math.Iterator2;
 const Vector2 = math.Vector2;
 const Vector3 = math.Vector3;
@@ -226,7 +226,7 @@ pub fn onMouseMove(self: *Player, dx: f32, dy: f32) void {
     self.yaw_rad = @mod(self.yaw_rad - dx * self.mouse_sensitivity, std.math.tau);
 }
 
-pub fn update(self: *Player, dt: f32, chunks: *const std.AutoHashMapUnmanaged([3]i16, Chunk)) void {
+pub fn update(self: *Player, dt: f32, chunks: *const Chunks) void {
     defer self.resetAllButtons();
 
     // --- GATHER INPUTS -------------------------------------------------------
@@ -272,17 +272,21 @@ pub fn update(self: *Player, dt: f32, chunks: *const std.AutoHashMapUnmanaged([3
             var vertical_displacement_sv = math.mulIntFloat(vertical_velocity_sv, dt);
 
             var position_sv = self.position_sv;
+            var min_sv = position_sv.add(.init(-collision_half_width_sv, -collision_half_width_sv, 0));
+            var max_sv = position_sv.add(.init(collision_half_width_sv, collision_half_width_sv, collision_height_sv));
 
             if (vertical_displacement_sv > 0) {
-                if (sweepCastUp(position_sv, vertical_displacement_sv, chunks)) |hit| {
+                if (chunks.sweepCastUp(min_sv, max_sv, vertical_displacement_sv)) |hit| {
                     vertical_displacement_sv -= hit.projected_distance_sv;
                 }
                 position_sv = .add(position_sv, .init(0, 0, vertical_displacement_sv));
+                min_sv = .add(min_sv, .init(0, 0, vertical_displacement_sv));
+                max_sv = .add(max_sv, .init(0, 0, vertical_displacement_sv));
             }
 
             var i: usize = 0;
             while (i < 2) : (i += 1) {
-                if (sweepCastHorizontal(position_sv, horizontal_displacement_sv, chunks)) |hit| {
+                if (chunks.sweepCastHorizontal(min_sv, max_sv, horizontal_displacement_sv)) |hit| {
                     const adjustment = hit.normal_frac
                         .asVector2Int()
                         .mulScalarFrac(hit.projected_distance_sv);
@@ -306,7 +310,9 @@ pub fn update(self: *Player, dt: f32, chunks: *const std.AutoHashMapUnmanaged([3
             position_sv = .add(position_sv, horizontal_displacement_sv.asVector3Int(0));
 
             if (vertical_displacement_sv < 0.0) {
-                if (sweepCastDown(position_sv, -vertical_displacement_sv, chunks)) |hit| {
+                min_sv = .add(min_sv, horizontal_displacement_sv.asVector3Int(0));
+                max_sv = .add(max_sv, horizontal_displacement_sv.asVector3Int(0));
+                if (chunks.sweepCastDown(min_sv, max_sv, -vertical_displacement_sv)) |hit| {
                     vertical_displacement_sv += hit.projected_distance_sv;
                 }
                 position_sv = .add(position_sv, .init(0, 0, vertical_displacement_sv));
@@ -317,251 +323,6 @@ pub fn update(self: *Player, dt: f32, chunks: *const std.AutoHashMapUnmanaged([3
     }
 }
 
-const SweepHit = struct {
-    normal_frac: Vector3Int,
-    projected_distance_sv: i32,
-};
-
-fn sweepCastDown(origin_sv: Vector3Int, distance_sv: i32, chunks: *const std.AutoHashMapUnmanaged([3]i16, Chunk)) ?SweepHit {
-    const min_origin_sv = origin_sv.add(.init(-collision_half_width_sv, -collision_half_width_sv, 0));
-    const max_origin_sv = origin_sv.add(.init(collision_half_width_sv, collision_half_width_sv, collision_height_sv));
-
-    const min_x_vx = c.subvoxelsToVoxels(.border_up, min_origin_sv.getX());
-    const min_y_vx = c.subvoxelsToVoxels(.border_up, min_origin_sv.getY());
-    const max_x_vx = c.subvoxelsToVoxels(.border_down, max_origin_sv.getX());
-    const max_y_vx = c.subvoxelsToVoxels(.border_down, max_origin_sv.getY());
-
-    const start_z_vx = c.subvoxelsToVoxels(.border_up, min_origin_sv.getZ()) - 1;
-    const end_z_vx = c.subvoxelsToVoxels(.border_up, min_origin_sv.getZ() - distance_sv);
-
-    var z_vx: i32 = start_z_vx;
-    while (z_vx >= end_z_vx) : (z_vx -= 1) {
-        const z_sv = c.voxelsToSubvoxels(z_vx + 1);
-        var it = Iterator2(i32).init(.{
-            .min = .{ min_x_vx, min_y_vx },
-            .max = .{ max_x_vx, max_y_vx },
-        });
-        while (it.next()) |xy_vx| {
-            const x_vx, const y_vx = xy_vx;
-            if (!isSolid(chunks, .init(x_vx, y_vx, z_vx))) continue;
-
-            return .{
-                .projected_distance_sv = distance_sv - (min_origin_sv.getZ() - z_sv),
-                .normal_frac = .unit_z_frac,
-            };
-        }
-    }
-
-    return null;
-}
-
-fn sweepCastUp(origin_sv: Vector3Int, distance_sv: i32, chunks: *const std.AutoHashMapUnmanaged([3]i16, Chunk)) ?SweepHit {
-    const min_origin_sv = origin_sv.add(.init(-collision_half_width_sv, -collision_half_width_sv, 0));
-    const max_origin_sv = origin_sv.add(.init(collision_half_width_sv, collision_half_width_sv, collision_height_sv));
-
-    const min_x_vx = c.subvoxelsToVoxels(.border_up, min_origin_sv.getX());
-    const min_y_vx = c.subvoxelsToVoxels(.border_up, min_origin_sv.getY());
-    const max_x_vx = c.subvoxelsToVoxels(.border_down, max_origin_sv.getX());
-    const max_y_vx = c.subvoxelsToVoxels(.border_down, max_origin_sv.getY());
-
-    const start_z_vx = c.subvoxelsToVoxels(.border_down, max_origin_sv.getZ()) + 1;
-    const end_z_vx = c.subvoxelsToVoxels(.border_down, max_origin_sv.getZ() + distance_sv);
-
-    var z_vx: i32 = start_z_vx;
-    while (z_vx <= end_z_vx) : (z_vx += 1) {
-        const z_sv = c.voxelsToSubvoxels(z_vx);
-        var it = Iterator2(i32).init(.{
-            .min = .{ min_x_vx, min_y_vx },
-            .max = .{ max_x_vx, max_y_vx },
-        });
-        while (it.next()) |xy_vx| {
-            const x_vx, const y_vx = xy_vx;
-            if (!isSolid(chunks, .init(x_vx, y_vx, z_vx))) continue;
-
-            return .{
-                .projected_distance_sv = distance_sv - (z_sv - max_origin_sv.getZ()),
-                .normal_frac = .unit_nz_frac,
-            };
-        }
-    }
-
-    return null;
-}
-
-fn sweepCastHorizontal(origin_sv: Vector3Int, ray_sv: Vector2Int, chunks: *const std.AutoHashMapUnmanaged([3]i16, Chunk)) ?SweepHit {
-    const min_origin_sv = origin_sv.add(.init(-collision_half_width_sv, -collision_half_width_sv, 0));
-    const max_origin_sv = origin_sv.add(.init(collision_half_width_sv, collision_half_width_sv, collision_height_sv));
-
-    const min_z_vx = c.subvoxelsToVoxels(.border_up, min_origin_sv.getZ());
-    const max_z_vx = c.subvoxelsToVoxels(.border_down, max_origin_sv.getZ());
-
-    var hit: ?SweepHit = null;
-    var hit_distance_squared = std.math.inf(f32);
-
-    const fdydx: f32 = @as(f32, @floatFromInt(ray_sv.getY())) / @as(f32, @floatFromInt(ray_sv.getX()));
-    const fdxdy: f32 = @as(f32, @floatFromInt(ray_sv.getX())) / @as(f32, @floatFromInt(ray_sv.getY()));
-
-    // Positive X
-    if (ray_sv.getX() > 0) {
-        const x0_sv = max_origin_sv.getX();
-        const y0_sv = min_origin_sv.getY();
-        const y1_sv = max_origin_sv.getY();
-
-        const start_x_vx = c.subvoxelsToVoxels(.border_down, x0_sv) + 1;
-        const end_x_vx = c.subvoxelsToVoxels(.border_down, x0_sv + ray_sv.getX());
-
-        var x_vx: i32 = start_x_vx;
-        px: while (x_vx <= end_x_vx) : (x_vx += 1) {
-            const x_sv = c.voxelsToSubvoxels(x_vx);
-            const min_y_vx = c.subvoxelsToVoxels(.border_up, wideMulDivFloor(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y0_sv);
-            const max_y_vx = c.subvoxelsToVoxels(.border_down, wideMulDivCeil(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y1_sv);
-            var it = Iterator2(i32).init(.{
-                .min = .{ min_y_vx, min_z_vx },
-                .max = .{ max_y_vx, max_z_vx },
-            });
-            while (it.next()) |yz_vx| {
-                const y_vx, const z_vx = yz_vx;
-                if (!isSolid(chunks, .init(x_vx, y_vx, z_vx))) continue;
-
-                const dx = x_sv - x0_sv;
-                const fdx: f32 = @floatFromInt(dx);
-                const fdy: f32 = fdx * fdydx;
-
-                hit = .{
-                    .projected_distance_sv = ray_sv.getX() - dx,
-                    .normal_frac = .unit_nx_frac,
-                };
-                hit_distance_squared = fdx * fdx + fdy * fdy;
-                std.debug.print("+X fdx={d} fdy={d} dist2={d}\n", .{ fdx, fdy, hit_distance_squared });
-
-                break :px;
-            }
-        }
-    }
-
-    // Negative X
-    if (ray_sv.getX() < 0) {
-        const x0_sv = min_origin_sv.getX();
-        const y0_sv = min_origin_sv.getY();
-        const y1_sv = max_origin_sv.getY();
-
-        const start_x_vx = c.subvoxelsToVoxels(.border_up, x0_sv) - 1;
-        const end_x_vx = c.subvoxelsToVoxels(.border_up, x0_sv + ray_sv.getX());
-
-        var x_vx: i32 = start_x_vx;
-        nx: while (x_vx >= end_x_vx) : (x_vx -= 1) {
-            const x_sv = c.voxelsToSubvoxels(x_vx + 1);
-            const min_y_vx = c.subvoxelsToVoxels(.border_up, wideMulDivFloor(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y0_sv);
-            const max_y_vx = c.subvoxelsToVoxels(.border_down, wideMulDivCeil(x_sv - x0_sv, ray_sv.getY(), ray_sv.getX()) + y1_sv);
-            var it = Iterator2(i32).init(.{
-                .min = .{ min_y_vx, min_z_vx },
-                .max = .{ max_y_vx, max_z_vx },
-            });
-            while (it.next()) |yz_vx| {
-                const y_vx, const z_vx = yz_vx;
-                if (!isSolid(chunks, .init(x_vx, y_vx, z_vx))) continue;
-
-                const dx = x_sv - x0_sv;
-                const fdx: f32 = @floatFromInt(dx);
-                const fdy: f32 = fdx * fdydx;
-
-                hit = .{
-                    .projected_distance_sv = -(ray_sv.getX() - dx),
-                    .normal_frac = .unit_x_frac,
-                };
-                hit_distance_squared = fdx * fdx + fdy * fdy;
-                std.debug.print("-X fdx={d} fdy={d} dist2={d}\n", .{ fdx, fdy, hit_distance_squared });
-
-                break :nx;
-            }
-        }
-    }
-
-    // Positive Y
-    if (ray_sv.getY() > 0) {
-        const y0_sv = max_origin_sv.getY();
-        const x0_sv = min_origin_sv.getX();
-        const x1_sv = max_origin_sv.getX();
-
-        const start_y_vx = c.subvoxelsToVoxels(.border_down, y0_sv) + 1;
-        const end_y_vx = c.subvoxelsToVoxels(.border_down, y0_sv + ray_sv.getY());
-
-        var y_vx = start_y_vx;
-        py: while (y_vx <= end_y_vx) : (y_vx += 1) {
-            const y_sv = c.voxelsToSubvoxels(y_vx);
-            const min_x_vx = c.subvoxelsToVoxels(.border_up, wideMulDivFloor(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x0_sv);
-            const max_x_vx = c.subvoxelsToVoxels(.border_down, wideMulDivCeil(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x1_sv);
-            var it = Iterator2(i32).init(.{
-                .min = .{ min_x_vx, min_z_vx },
-                .max = .{ max_x_vx, max_z_vx },
-            });
-            while (it.next()) |xz_vx| {
-                const x_vx, const z_vx = xz_vx;
-                if (!isSolid(chunks, .init(x_vx, y_vx, z_vx))) continue;
-
-                const dy = y_sv - y0_sv;
-                const fdy: f32 = @floatFromInt(dy);
-                const fdx: f32 = fdy * fdxdy;
-
-                const this_hit_distance_squared = fdx * fdx + fdy * fdy;
-                std.debug.print("+Y fdx={d} fdy={d} dist2={d}\n", .{ fdx, fdy, this_hit_distance_squared });
-                if (this_hit_distance_squared < hit_distance_squared) {
-                    hit = .{
-                        .projected_distance_sv = ray_sv.getY() - dy,
-                        .normal_frac = .unit_ny_frac,
-                    };
-                    hit_distance_squared = this_hit_distance_squared;
-                }
-
-                break :py;
-            }
-        }
-    }
-
-    // Negative Y
-    if (ray_sv.getY() < 0.0) {
-        const y0_sv = min_origin_sv.getY();
-        const x0_sv = min_origin_sv.getX();
-        const x1_sv = max_origin_sv.getX();
-
-        const start_y_vx = c.subvoxelsToVoxels(.border_up, y0_sv) - 1;
-        const end_y_vx = c.subvoxelsToVoxels(.border_up, y0_sv + ray_sv.getY());
-
-        var y_vx = start_y_vx;
-        ny: while (y_vx >= end_y_vx) : (y_vx -= 1) {
-            const y_sv = c.voxelsToSubvoxels(y_vx + 1);
-            const min_x_vx = c.subvoxelsToVoxels(.border_up, wideMulDivFloor(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x0_sv);
-            const max_x_vx = c.subvoxelsToVoxels(.border_down, wideMulDivCeil(y_sv - y0_sv, ray_sv.getX(), ray_sv.getY()) + x1_sv);
-            var it = Iterator2(i32).init(.{
-                .min = .{ min_x_vx, min_z_vx },
-                .max = .{ max_x_vx, max_z_vx },
-            });
-            while (it.next()) |xz_vx| {
-                const x_vx, const z_vx = xz_vx;
-                if (!isSolid(chunks, .init(x_vx, y_vx, z_vx))) continue;
-
-                const dy = y_sv - y0_sv;
-                const fdy: f32 = @floatFromInt(dy);
-                const fdx: f32 = fdy * fdxdy;
-
-                const this_hit_distance_squared = fdx * fdx + fdy * fdy;
-                std.debug.print("-Y fdx={d} fdy={d} dist2={d}\n", .{ fdx, fdy, this_hit_distance_squared });
-                if (this_hit_distance_squared < hit_distance_squared) {
-                    hit = .{
-                        .projected_distance_sv = -(ray_sv.getY() - dy),
-                        .normal_frac = .unit_y_frac,
-                    };
-                    hit_distance_squared = this_hit_distance_squared;
-                }
-
-                break :ny;
-            }
-        }
-    }
-
-    return hit;
-}
-
 fn resetAllButtons(self: *Player) void {
     inline for (@typeInfo(Player).@"struct".fields) |field| {
         if (field.type == Button) {
@@ -570,40 +331,6 @@ fn resetAllButtons(self: *Player) void {
     }
 }
 
-fn getVoxelAt(chunks: *const std.AutoHashMapUnmanaged([3]i16, Chunk), vx: Vector3Int) ?Blocks.Id {
-    const min_ck = Vector3Int.initScalar(std.math.minInt(i16));
-    const max_ck = Vector3Int.initScalar(std.math.maxInt(i16));
-    const ck = vx.divScalar(c.vx_per_ck);
-    if (@reduce(.Or, (ck.vector < min_ck.vector) | (ck.vector > max_ck.vector))) {
-        return null;
-    }
-
-    if (chunks.get(.{
-        @intCast(ck.getX()),
-        @intCast(ck.getY()),
-        @intCast(ck.getZ()),
-    })) |chunk| {
-        const ckvx = vx.modScalar(c.vx_per_ck);
-        return chunk.blocks[@intCast(ckvx.getZ())][@intCast(ckvx.getY())][@intCast(ckvx.getX())];
-    } else {
-        return .air;
-    }
-}
-
-fn isSolid(chunks: *const std.AutoHashMapUnmanaged([3]i16, Chunk), vx: Vector3Int) bool {
-    const maybe_id = getVoxelAt(chunks, vx);
-    // NOTE `null` is considered solid, as it's out of bounds.
-    return maybe_id != .air;
-}
-
-inline fn wideMulDivFloor(a: i32, mul: i32, div: i32) i32 {
-    return @intCast(@divFloor(@as(i64, a) * @as(i64, mul), div));
-}
-
-inline fn wideMulDivCeil(a: i32, mul: i32, div: i32) i32 {
-    return @intCast(@divFloor(@as(i64, a) * @as(i64, mul) + @as(i64, div) - 1, div));
-}
-
 inline fn sv(comptime vx: comptime_float) comptime_int {
     return @intFromFloat(@round(vx * c.sv_per_vx));
 }

src/const.zig

@@ -46,7 +46,7 @@ pub const RoundingMode = enum {
 /// SV to VX
 pub inline fn subvoxelsToVoxels(comptime rounding_mode: RoundingMode, sv: i32) i32 {
     return switch (rounding_mode) {
-        .border_down => @divFloor(sv, sv_per_vx - 1),
+        .border_down => @divFloor(sv - 1, sv_per_vx),
         .border_up => @divFloor(sv, sv_per_vx),
     };
 }
@@ -54,7 +54,7 @@ pub inline fn subvoxelsToVoxels(comptime rounding_mode: RoundingMode, sv: i32) i
 /// SV to CK
 pub inline fn subvoxelsToChunks(comptime rounding_mode: RoundingMode, sv: i32) i32 {
     return switch (rounding_mode) {
-        .border_down => @divFloor(sv, sv_per_ck - 1),
+        .border_down => @divFloor(sv - 1, sv_per_ck),
         .border_up => @divFloor(sv, sv_per_ck),
     };
 }
@@ -77,7 +77,7 @@ pub inline fn voxelsToSubvoxels(vx: i32) i32 {
 /// VX to CK
 pub inline fn voxelsToChunks(comptime rounding_mode: RoundingMode, vx: i32) i32 {
     return switch (rounding_mode) {
-        .border_down => @divFloor(vx, vx_per_ck - 1),
+        .border_down => @divFloor(vx - 1, vx_per_ck),
         .border_up => @divFloor(vx, vx_per_ck),
     };
 }

src/math.zig

@@ -73,3 +73,11 @@ pub inline fn mulFracFrac(a: i32, b: i32) i32 {
     const b_wide: i64 = b;
     return .{ .vector = @intCast(@divFloor(a_wide * b_wide + rounding_bias, denominator)) };
 }
+
+pub inline fn wideMulDivFloor(a: i32, mul: i32, div: i32) i32 {
+    return @intCast(@divFloor(@as(i64, a) * @as(i64, mul), div));
+}
+
+pub inline fn wideMulDivCeil(a: i32, mul: i32, div: i32) i32 {
+    return @intCast(@divFloor(@as(i64, a) * @as(i64, mul) + @as(i64, div) - 1, div));
+}