entity: physics rewrite

internal/entity/entities/player.go

@@ -16,8 +16,11 @@ func init() {
 
 func (PlayerBehaviour) Name() string { return "player" }
 
-func (PlayerBehaviour) Hitbox(pos itype.Vec3d, dataset itype.Dataset) itype.Vec3d {
+func (PlayerBehaviour) Hitbox(pos itype.Vec3d, dataset itype.Dataset) []itype.Boxd {
-	return itype.Vec3d{0.6, 1.8, 0.6}
+	return []itype.Boxd{{
+		OffX: -0.3, OffY: 0, OffZ: -0.3,
+		SizeX: 0.6, SizeY: 1.8, SizeZ: 0.6,
+	}}
 }
 
 func (PlayerBehaviour) EyeHeight(pos itype.Vec3d, dataset itype.Dataset) float64 {

internal/entity/entity.go

@@ -3,27 +3,26 @@ package entity
 import (
 	"time"
 
-	"edgaru089.ml/go/gl01/internal/util"
 	"edgaru089.ml/go/gl01/internal/util/itype"
 	"edgaru089.ml/go/gl01/internal/world"
 )
 
 // EntityBehaviour describes the behaviour of a type of entity with the same Name.
+// It should hold no data of its own.
 type EntityBehaviour interface {
 	// Name returns the type Name of the behaviour.
 	Name() string
 
-	// Hitbox gets the size of the hitbox of the entity.
+	// Hitbox gets the hitbox(s) of the entity.
 	//
-	// The hitbox is positioned with the position coordinates pointing to
+	// The hitbox is in entity-local coordinates, originating from the position.
-	// the center of the bottom of the box.
+	Hitbox(pos itype.Vec3d, dataset itype.Dataset) []itype.Boxd
-	Hitbox(pos itype.Vec3d, dataset itype.Dataset) itype.Vec3d
 
 	// EyeHeight gets the height of the eye of the entity.
 	EyeHeight(pos itype.Vec3d, dataset itype.Dataset) float64
 
 	// Update is called on every frame.
-	// It should be used to update physics.
+	// It should be used to update the behaviour of the entity.
 	Update(pos itype.Vec3d, dataset itype.Dataset, world *world.World, deltaTime time.Duration)
 }
 
@@ -45,14 +44,14 @@ func RegisterEntityBehaviour(b EntityBehaviour) bool {
 // Entity is a struct holding a Behaviour, a Position and a Speed.
 type Entity struct {
 	b          EntityBehaviour
-	pos, speed itype.Vec3d // pos has a origin of the **center of the bottom** of the hitbox
+	pos, speed itype.Vec3d // pos should have a origin of the **center of the bottom** of the hitbox
 	ds         itype.Dataset
 
 	name string // a shortcut to b.Name(), the typename
 
+	// physics stuff
 	onGround bool
 	worldbox []itype.Boxd
-	hp       []itype.Vec3d
 }
 
 func NewEntity(typename string, pos itype.Vec3d) *Entity {
@@ -84,16 +83,16 @@ func (e *Entity) SetSpeed(speed itype.Vec3d) {
 	e.speed = speed
 }
 
-func (e *Entity) Hitbox() itype.Vec3d {
+func (e *Entity) Hitbox() []itype.Boxd {
 	return e.b.Hitbox(e.pos, e.ds)
 }
 
 func (e *Entity) Accelerate(x, y, z float64) {
-	/*e.speed[0] += x
+	e.speed[0] += x
 	e.speed[1] += y
-	e.speed[2] += z*/
+	e.speed[2] += z
-	vec := itype.Vec3d{x, y, z}
+	/*vec := itype.Vec3d{x, y, z}
-	e.speed = util.BunnyhopAccelerate(vec, e.speed, vec.Length(), 8)
+	e.speed = util.BunnyhopAccelerate(vec, e.speed, vec.Length(), 8)*/
 }
 
 func (e *Entity) OnGround() bool {

internal/entity/physics.go

@@ -9,262 +9,187 @@ import (
 	"edgaru089.ml/go/gl01/internal/world"
 )
 
-func (e *Entity) worldHitbox(hitbox itype.Vec3d) itype.Boxd {
+// WorldHitbox returns the hitboxes of the entity, in world coordinates.
-	return itype.Boxd{
+func (e *Entity) WorldHitbox() []itype.Boxd {
-		OffX:  e.pos[0] - hitbox[0]/2,
+	boxes := e.Hitbox()
-		OffY:  e.pos[1],
+	for i := range boxes {
-		OffZ:  e.pos[2] - hitbox[2]/2,
+		boxes[i] = boxes[i].Offset(e.pos)
-		SizeX: hitbox[0],
-		SizeY: hitbox[1],
-		SizeZ: hitbox[2],
 	}
-}
+	return boxes
-
-// WorldHitbox returns the hitbox of the entity, in world coordinates.
-func (e *Entity) WorldHitbox() itype.Boxd {
-	return e.worldHitbox(e.b.Hitbox(e.pos, e.ds))
-}
-
-// the distance between hitpoints, in blocks
-const HitpointMeshLen = 0.4
-
-func (e *Entity) boxHitpoints(points []itype.Vec3d, hitbox itype.Boxd) []itype.Vec3d {
-
-	box := hitbox
-	base := box.MinPoint()
-	points = points[0:0]
-
-	// add the bounding points first
-	points = append(points,
-		base,
-		base.Add(itype.Vec3d{box.SizeX, 0, 0}),
-		base.Add(itype.Vec3d{0, box.SizeY, 0}),
-		base.Add(itype.Vec3d{0, 0, box.SizeZ}),
-		base.Add(itype.Vec3d{box.SizeX, box.SizeY, 0}),
-		base.Add(itype.Vec3d{0, box.SizeY, box.SizeZ}),
-		base.Add(itype.Vec3d{box.SizeX, 0, box.SizeZ}),
-		base.Add(itype.Vec3d{box.SizeX, box.SizeY, box.SizeZ}),
-	)
-	return points
 }
 
 // MoveEps is a small value used to indicate a tiny amount more than zero.
 const MoveEps = 1e-7
 
-// tells if the point is already stuck inside a block hitbox
+// move attempts to move the entity by delta in the world.
-func pointStuck(point itype.Vec3d, w *world.World) bool {
+// It does not change anything in e.
-	blockid := point.Floor()
+func (e *Entity) move(delta itype.Vec3d, w *world.World) (finDelta itype.Vec3d, finVelocity itype.Vec3d, onGround bool) {
-	block := w.Block(blockid)
+
-	return block.Id != 0 &&
+	// Get the hitboxes and the blocks region covering it
-		block.Behaviour.Appearance(
+	hb := e.WorldHitbox()
-			point.Floor(),
+	hbmin, hbmax := itype.Vec3d{1000000000, 1000000000, 1000000000}, itype.Vec3d{-1000000000, -1000000000, -1000000000}
-			block.Aux,
+	for _, b := range hb {
-			block.Dataset,
+		bmin, bmax := b.MinPoint(), b.MaxPoint()
-			w,
+		hbmin[0] = util.Mind(hbmin[0], bmin[0])
-		).Hitbox.Offset(blockid.ToFloat64()).Contains(point)
+		hbmin[1] = util.Mind(hbmin[1], bmin[1])
+		hbmin[2] = util.Mind(hbmin[2], bmin[2])
+		hbmax[0] = util.Maxd(hbmax[0], bmax[0])
+		hbmax[1] = util.Maxd(hbmax[1], bmax[1])
+		hbmax[2] = util.Maxd(hbmax[2], bmax[2])
+	}
+
+	// So this is the region of blocks we should calculate
+	imin, imax := hbmin.Floor().Addv(-1, -1, -1), hbmax.Ceiling().Addv(1, 1, 1)
+
+	finDelta = delta
+	finVelocity = e.speed
+	for x := imin[0]; x <= imax[0]; x++ {
+		for y := imin[1]; y <= imax[1]; y++ {
+			for z := imin[2]; z <= imax[2]; z++ {
+				blockDelta, blockVelocity, blockOnGround := e.moveBlock(hb, delta, itype.Vec3i{x, y, z}, w)
+				finDelta[0] = util.AbsMind(finDelta[0], blockDelta[0])
+				finDelta[1] = util.AbsMind(finDelta[1], blockDelta[1])
+				finDelta[2] = util.AbsMind(finDelta[2], blockDelta[2])
+				finVelocity[0] = util.AbsMind(finVelocity[0], blockVelocity[0])
+				finVelocity[1] = util.AbsMind(finVelocity[1], blockVelocity[1])
+				finVelocity[2] = util.AbsMind(finVelocity[2], blockVelocity[2])
+				onGround = onGround || blockOnGround
+			}
+		}
+	}
+
+	// Y-
+	if delta[1] < 0 {
+		onGround = onGround || e.onGround
+	} else {
+		onGround = false
+	}
+
+	return
 }
 
-// the move series functions should be called with e.hp already filled
+// moveBlock simulates moving the entity by delta, and tests collision with the block hibbox.
+func (e *Entity) moveBlock(worldHitbox []itype.Boxd, delta itype.Vec3d, blockCoord itype.Vec3i, w *world.World) (blockDelta itype.Vec3d, finVelocity itype.Vec3d, onGround bool) {
+	blockDelta = delta
+	finVelocity = e.speed
+	onGround = false
 
-func (e *Entity) moveX(delta float64, hitbox itype.Boxd, w *world.World) {
+	var blockHitbox []itype.Boxd
-	if math.Abs(delta) < MoveEps*10 {
+	if block := w.Block(blockCoord); block.Id != 0 {
+		blocka := block.Appearance(blockCoord)
+		if !blocka.NotSolid {
+			blockHitbox = w.Block(blockCoord).Appearance(blockCoord).Hitbox
+			for i := range blockHitbox {
+				blockHitbox[i] = blockHitbox[i].Offset(blockCoord.ToFloat64())
+			}
+		}
+	}
+
+	if len(blockHitbox) == 0 {
 		return
 	}
 
-	var hit bool = false
+	for _, eb := range worldHitbox {
-	var deltaMin float64 = 10000
+		for _, bb := range blockHitbox {
+			// Already intersecting: return
+			if ok, _ := eb.Intersect(bb); ok {
+				continue
+			}
 
-	if delta > 1-MoveEps {
+			// X
-		delta = 1 - MoveEps
+			if ok, _ := eb.Offsetv(blockDelta[0], 0, 0).Intersect(bb); ok {
-	}
+				if blockDelta[0] > 0 {
-	if delta < -1+MoveEps {
+					blockDelta[0] = bb.OffX - (eb.OffX + eb.SizeX) - MoveEps
-		delta = -1 + MoveEps
+					//log.Printf("Hit(X+): On (X%d,Y%d,Z%d), delta=%v\n", blockCoord[0], blockCoord[1], blockCoord[2], blockDelta)
-	}
+				} else {
-
+					blockDelta[0] = (bb.OffX + bb.SizeX) - eb.OffX + MoveEps
-	// X+ / X-
+					//log.Printf("Hit(X-): On (X%d,Y%d,Z%d), delta=%v\n", blockCoord[0], blockCoord[1], blockCoord[2], blockDelta)
-	for _, p := range e.hp {
-		if pointStuck(p, w) {
-			continue
-		}
-
-		dest := p.Addv(delta, 0, 0)
-		blockid := dest.Floor()
-		block := w.Block(blockid)
-
-		var deltaDone float64
-		if block.Id == 0 {
-			deltaDone = delta
-		} else { // block.Id!=0
-			app := world.GetBlockAppearance(blockid, block.Id, block.Aux, block.Dataset, w)
-			blockBox := app.Hitbox.Offset(blockid.ToFloat64())
-			if !app.NotSolid && blockBox.Contains(dest) { // Hit!
-				hit = true
-				if delta > 0 { // moving X+, hit on the X- face
-					deltaDone = blockBox.OffX - (e.pos[0] + hitbox.SizeX/2) - MoveEps
-					//log.Print("Hit X+: On Block ", blockid, ", delta=", delta, ", coord=", e.pos, ", p=", p, ", dest=", dest, ", deltaDone=", deltaDone)
-				} else { // moving X-, hit on the X+ face
-					deltaDone = blockBox.OffX + blockBox.SizeX - (e.pos[0] - hitbox.SizeX/2) + MoveEps
-					//log.Print("Hit X-: On Block ", blockid, ", delta=", delta, ", coord=", e.pos, ", p=", p, ", dest=", dest, ", deltaDone=", deltaDone)
 				}
-			} else {
+				finVelocity[0] = 0
-				deltaDone = delta
+			}
+
+			// Y
+			if ok, _ := eb.Offsetv(0, blockDelta[1], 0).Intersect(bb); ok {
+				if blockDelta[1] > 0 {
+					blockDelta[1] = bb.OffY - (eb.OffY + eb.SizeY) - MoveEps
+					//log.Printf("Hit(Y+): On (X%d,Y%d,Z%d), delta=%v\n", blockCoord[0], blockCoord[1], blockCoord[2], blockDelta)
+				} else {
+					onGround = true
+					blockDelta[1] = (bb.OffY + bb.SizeY) - eb.OffY + MoveEps
+					//log.Printf("Hit(Y-): On (X%d,Y%d,Z%d), delta=%v\n", blockCoord[0], blockCoord[1], blockCoord[2], blockDelta)
+				}
+				finVelocity[1] = 0
+			}
+
+			// Z
+			if ok, _ := eb.Offsetv(0, 0, blockDelta[2]).Intersect(bb); ok {
+				if blockDelta[2] > 0 {
+					blockDelta[2] = bb.OffZ - (eb.OffZ + eb.SizeZ) - MoveEps
+					//log.Printf("Hit(Z+): On (X%d,Y%d,Z%d), delta=%v\n", blockCoord[0], blockCoord[1], blockCoord[2], blockDelta)
+				} else {
+					blockDelta[2] = (bb.OffZ + bb.SizeZ) - eb.OffZ + MoveEps
+					//log.Printf("Hit(Z-): On (X%d,Y%d,Z%d), delta=%v\n", blockCoord[0], blockCoord[1], blockCoord[2], blockDelta)
+				}
+				finVelocity[2] = 0
 			}
 		}
-
-		deltaMin = util.AbsMind(deltaMin, deltaDone)
 	}
 
-	if hit {
+	return
-		e.speed[0] = 0
-	}
-	e.pos[0] += deltaMin
-}
-func (e *Entity) moveY(delta float64, hitbox itype.Boxd, w *world.World) {
-	if math.Abs(delta) < MoveEps*10 {
-		return
-	}
-
-	var hit bool = false
-	var deltaMin float64 = 10000
-
-	if delta > 1-MoveEps {
-		delta = 1 - MoveEps
-	}
-	if delta < -1+MoveEps {
-		delta = -1 + MoveEps
-	}
-
-	// Y+ / Y-
-	for _, p := range e.hp {
-		if pointStuck(p, w) {
-			continue
-		}
-
-		dest := p.Addv(0, delta, 0)
-		blockid := dest.Floor()
-		block := w.Block(blockid)
-
-		var deltaDone float64
-		if block.Id == 0 {
-			deltaDone = delta
-		} else { // block.Id!=0
-			app := world.GetBlockAppearance(blockid, block.Id, block.Aux, block.Dataset, w)
-			blockBox := app.Hitbox.Offset(blockid.ToFloat64())
-			if !app.NotSolid && blockBox.Contains(dest) { // Hit!
-				hit = true
-				if delta > 0 { // moving Y+, hit on the Y- face
-					deltaDone = blockBox.OffY - (e.pos[1] + hitbox.SizeY) - MoveEps
-					//log.Print("Hit Y+: On Block ", blockid, ", delta=", delta, ", coord=", e.pos, ", p=", p, ", dest=", dest,", deltaDone=",deltaDone)
-				} else { // moving Y-, hit on the Y+ face (on the ground)
-					deltaDone = blockBox.OffY + blockBox.SizeY - e.pos[1] + MoveEps
-					//log.Print("Hit Y-: On Block ", blockid, ", delta=", delta, ", coord=", e.pos, ", p=", p, ", dest=", dest,", deltaDone=",deltaDone)
-					/*if !e.onGround {
-						log.Print("onGround = true")
-					}*/
-					e.onGround = true
-				}
-			} else {
-				deltaDone = delta
-			}
-		}
-
-		deltaMin = util.AbsMind(deltaMin, deltaDone)
-	}
-
-	if hit {
-		e.speed[1] = 0
-	}
-
-	if math.Abs(deltaMin) > MoveEps*10 {
-		/*if e.onGround {
-			log.Print("onGround = false")
-		}*/
-		e.onGround = false
-	}
-	e.pos[1] += deltaMin
-}
-func (e *Entity) moveZ(delta float64, hitbox itype.Boxd, w *world.World) {
-	if math.Abs(delta) < MoveEps*10 {
-		return
-	}
-
-	var hit bool = false
-	var deltaMin float64 = 10000
-
-	if delta > 1-MoveEps {
-		delta = 1 - MoveEps
-	}
-	if delta < -1+MoveEps {
-		delta = -1 + MoveEps
-	}
-
-	// Z+ / Z-
-	for _, p := range e.hp {
-		if pointStuck(p, w) {
-			continue
-		}
-
-		dest := p.Addv(0, 0, delta)
-		blockid := dest.Floor()
-		block := w.Block(blockid)
-
-		var deltaDone float64
-		if block.Id == 0 {
-			deltaDone = delta
-		} else { // block.Id!=0
-			app := world.GetBlockAppearance(blockid, block.Id, block.Aux, block.Dataset, w)
-			blockBox := app.Hitbox.Offset(blockid.ToFloat64())
-			if !app.NotSolid && blockBox.Contains(dest) { // Hit!
-				hit = true
-				if delta > 0 { // moving Z+, hit on the Z- face
-					deltaDone = util.Maxd(blockBox.OffZ-(e.pos[2]+hitbox.SizeZ/2)-MoveEps, 0)
-					//log.Print("Hit Z+: On Block ", blockid, ", delta=", delta, ", coord=", e.pos, ", p=", p, ", dest=", dest, ", deltaDone=", deltaDone)
-				} else { // moving Z-, hit on the Z+ face
-					deltaDone = util.Mind(blockBox.OffZ+blockBox.SizeZ-(e.pos[2]-hitbox.SizeZ/2)+MoveEps, 0)
-					//log.Print("Hit Z-: On Block ", blockid, ", delta=", delta, ", coord=", e.pos, ", p=", p, ", dest=", dest, ", deltaDone=", deltaDone)
-				}
-			} else {
-				deltaDone = delta
-			}
-		}
-
-		deltaMin = util.AbsMind(deltaMin, deltaDone)
-	}
-
-	if hit {
-		e.speed[2] = 0
-	}
-	e.pos[2] += deltaMin
 }
 
-const gravity float64 = 26
+const gravity = 26
-const deaclc float64 = 28
+const deaclc = 28
+const maxspeed = 8
 
 func (e *Entity) Update(world *world.World, deltaTime time.Duration) {
 
-	hitbox := e.b.Hitbox(e.pos, e.ds)
+	/*
-	box := e.worldHitbox(hitbox)
+		delta, vec, onGround := e.move(itype.Vec3d{e.speed[0] * deltaTime.Seconds()}, world)
+		e.pos = e.pos.Add(delta)
+		e.speed = vec
+		delta, vec, onGround = e.move(e.speed.Multiply(deltaTime.Seconds()), world)
+		e.pos = e.pos.Add(delta)
+		e.speed = vec
+		delta, vec, onGround = e.move(e.speed.Multiply(deltaTime.Seconds()), world)
+		e.pos = e.pos.Add(delta)
+		e.speed = vec
 
-	e.hp = e.hp[0:0]
+		e.onGround = onGround
-	e.hp = e.boxHitpoints(e.hp, box)
+	*/
 
-	e.moveX(e.speed[0]*deltaTime.Seconds(), box, world)
+	var deltaSpeed itype.Vec3d
-	e.moveY(e.speed[1]*deltaTime.Seconds(), box, world)
+	if e.onGround {
-	e.moveZ(e.speed[2]*deltaTime.Seconds(), box, world)
+		speed := math.Sqrt(e.speed[0]*e.speed[0] + e.speed[2]*e.speed[2])
+		if speed > MoveEps {
+			decrease := deaclc * deltaTime.Seconds()
+			factor := util.Maxd(util.Mind(speed-decrease, 6), 0) / speed
 
-	speed := math.Sqrt(e.speed[0]*e.speed[0] + e.speed[2]*e.speed[2])
+			deltaSpeed[0] = -e.speed[0] * (1 - factor)
-	if speed > MoveEps {
+			deltaSpeed[2] = -e.speed[2] * (1 - factor)
-		decrease := deaclc * deltaTime.Seconds()
+		} else {
-		if !e.onGround {
+			e.speed[0] = 0
-			decrease /= 10
+			e.speed[2] = 0
 		}
-		factor := util.Maxd(util.Mind(speed-decrease, 9), 0) / speed
-
-		e.speed[0] *= factor
-		e.speed[2] *= factor
 	}
+	deltaSpeed[1] = -gravity * deltaTime.Seconds()
 
-	e.speed[1] -= gravity * deltaTime.Seconds()
+	delta := e.speed.Multiply(deltaTime.Seconds()).Add(deltaSpeed.Multiply(deltaTime.Seconds() / 2))
+	e.speed = e.speed.Add(deltaSpeed)
+
+	findelta, vec, onGround := e.move(delta, world)
+	e.pos = e.pos.Add(findelta)
+	e.speed = vec
+	e.onGround = onGround
+
+	if !e.onGround {
+		vecXZ := itype.Vec2d{e.speed[0], e.speed[2]}
+		if vecXZ.Length() > maxspeed {
+			vecXZ = vecXZ.Normalize().Multiply(maxspeed)
+		}
+		e.speed[0] = vecXZ[0]
+		e.speed[2] = vecXZ[1]
+	}
 
 	e.b.Update(e.pos, e.ds, world, deltaTime)
 }

internal/game/imgui.go

@@ -3,6 +3,7 @@ package game
 import (
 	"fmt"
 	"log"
+	"math"
 	"os"
 	"runtime"
 
@@ -52,7 +53,8 @@ func (g *Game) imgui() {
 	if imgui.BeginV("Player", nil, imgui.WindowFlagsAlwaysAutoResize) {
 		pos := g.player.Position()
 		vel := g.player.Speed()
-		imgui.Text(fmt.Sprintf("Pos: (%.5f, %.5f, %.5f), Vel: (%.5f, %.5f, %.5f)", pos[0], pos[1], pos[2], vel[0], vel[1], vel[2]))
+		igwrap.Text("Pos: (%.5f, %.5f, %.5f), Vel: (%.5f, %.5f, %.5f)", pos[0], pos[1], pos[2], vel[0], vel[1], vel[2])
+		igwrap.Text("VelXZ=%.5f, VelXYZ=%.5f", math.Sqrt(vel[0]*vel[0]+vel[2]*vel[2]), vel.Length())
 	}
 	imgui.End()
 

internal/game/logic.go

@@ -166,6 +166,7 @@ func (g *Game) Init(win *glfw.Window) {
 			igwrap.MouseScrollCallback(xpos, ypos)
 		}
 	})
+
 }
 
 const airAccel = 0.1
@@ -234,7 +235,7 @@ func (g *Game) Update(win *glfw.Window, delta time.Duration) {
 	io.ViewPos = g.player.EyePosition()
 	io.ViewDir = itype.Vec3d(mgl64.Rotate3DY(float64(g.rotY.Radians())).Mul3(mgl64.Rotate3DZ(float64(itype.Degrees(g.rotZ)))).Mul3x1(mgl64.Vec3{1, 0, 0}))
 
-	render.Framewire.PushBox(g.player.WorldHitbox().ToFloat32(), color.White)
+	render.Framewire.PushBox(g.player.WorldHitbox()[0].ToFloat32(), color.White)
 
 	if g.player.Position()[1] < -100 {
 		g.player.SetPosition(itype.Vec3d{18, 80, 18})

internal/util/itype/rect.go

@@ -137,15 +137,15 @@ func pointIntersect(n, m, p, q float64) (min, len float64) {
 	return arr[1], arr[2] - arr[1]
 }
 
-func (box1 Boxd) Intersects(box2 Boxd) (result Boxd) {
+func (box1 Boxd) Intersect(box2 Boxd) (ok bool, intersect Boxd) {
 	a, b := pointIntersect(box1.OffX, box1.OffX+box1.SizeX, box2.OffX, box2.OffX+box2.SizeX)
 	c, d := pointIntersect(box1.OffY, box1.OffY+box1.SizeY, box2.OffY, box2.OffY+box2.SizeY)
 	e, f := pointIntersect(box1.OffZ, box1.OffZ+box1.SizeZ, box2.OffZ, box2.OffZ+box2.SizeZ)
 
 	if b == 0 || d == 0 || f == 0 {
-		return Boxd{}
+		return false, Boxd{}
 	} else {
-		return Boxd{
+		return true, Boxd{
 			OffX:  a,
 			SizeX: b,
 			OffY:  c,

internal/util/itype/vec.go

@@ -205,6 +205,14 @@ func (v Vec3d) Floor() Vec3i {
 	}
 }
 
+func (v Vec3d) Ceiling() Vec3i {
+	return Vec3i{
+		int(math.Ceil(v[0])),
+		int(math.Ceil(v[1])),
+		int(math.Ceil(v[2])),
+	}
+}
+
 func (v Vec3d) ToFloat32() Vec3f {
 	return Vec3f{float32(v[0]), float32(v[1]), float32(v[2])}
 }

internal/world/block.go

@@ -20,10 +20,10 @@ const (
 type BlockAppearance struct {
 	Name        string // A short name, like "stone" or "dirt", used for texture lookups
 	Transparent bool   // Is block transparent?
-	NotSolid    bool   // Is block not solid, i.e., has no solid hitbox? (this makes the zero value reasonable)
+	NotSolid    bool   // Is block not solid, i.e., has no hitbox at all? (this makes the zero value reasonable)
 	Light       int    // The light level it emits, 0 is none
 
-	Hitbox itype.Boxd // Hitbox, in block-local coordinates; empty slice means a default hitbox of 1x1x1
+	Hitbox []itype.Boxd // Hitbox, in block-local coordinates; empty slice means a default hitbox of 1x1x1
 
 	RenderType BlockRenderType // Rendering type, defaults to OneTexture (zero value)
 
@@ -124,11 +124,11 @@ func DoneRegisteringBlockBehaviour() {
 // GetBlockAppearance gets the block appearance of the given block in the fastest way possible.
 func GetBlockAppearance(position itype.Vec3i, id, aux int, data itype.Dataset, world *World) BlockAppearance {
 	if app, ok := appearance[id]; ok { // Cache
-		if app.Hitbox == (itype.Boxd{}) {
+		if len(app.Hitbox) == 0 {
-			app.Hitbox = itype.Boxd{
+			app.Hitbox = []itype.Boxd{{
 				OffX: 0, OffY: 0, OffZ: 0,
 				SizeX: 1, SizeY: 1, SizeZ: 1,
-			}
+			}}
 		}
 		return app
 	}
@@ -140,11 +140,11 @@ func GetBlockAppearance(position itype.Vec3i, id, aux int, data itype.Dataset, w
 	}
 
 	app := b.Appearance(position, aux, data, world)
-	if app.Hitbox == (itype.Boxd{}) {
+	if len(app.Hitbox) == 0 {
-		app.Hitbox = itype.Boxd{
+		app.Hitbox = []itype.Boxd{{
 			OffX: 0, OffY: 0, OffZ: 0,
 			SizeX: 1, SizeY: 1, SizeZ: 1,
-		}
+		}}
 	}
 	return app
 }
@@ -165,7 +165,14 @@ type Block struct {
 // Appearance is a shortcut for Behaviour.Appearance().
 // It returns the Appearance of the block with the given parameters.
 func (b Block) Appearance(position itype.Vec3i) BlockAppearance {
-	return b.Behaviour.Appearance(position, b.Aux, b.Dataset, b.World)
+	app := b.Behaviour.Appearance(position, b.Aux, b.Dataset, b.World)
+	if !app.NotSolid && len(app.Hitbox) == 0 {
+		app.Hitbox = []itype.Boxd{{
+			OffX: 0, OffY: 0, OffZ: 0,
+			SizeX: 1, SizeY: 1, SizeZ: 1,
+		}}
+	}
+	return app
 }
 
 // BlockUpdate is a shortcut for Behaviour.BlockUpdate().