mapEntity.Step() benchmark and improvements. (#593)

* Initial test and benchmark for mapEntity.Step().

* Removed `&& !m.hasPath()` from mapEntity.atTarget

* Direction is now updated when the path node changes mid-step and target is updated when path is set.

* Test improvements.

* Deleted old benchmark function and tidying.

* d2math.Abs added.

* Abs benchmark and optimisation.

* Negate and Distance benchmark.

* Length and SetLength benchmark.

* Lerp and Dot benchmark.

* Cross and Normalize benchmark.

* Angle and SignedAngle benchmark.

* Trivial change to Vector.Abs()

d2common/d2math/d2vector/vector.go

@@ -150,18 +150,14 @@ func (v *Vector) DivideScalar(s float64) *Vector {
 
 // Abs sets the vector to it's absolute (positive) equivalent.
 func (v *Vector) Abs() *Vector {
-	xm, ym := 1.0, 1.0
 	if v.x < 0 {
-		xm = -1
+		v.x = -v.x
 	}
 
 	if v.y < 0 {
-		ym = -1
+		v.y = -v.y
 	}
 
-	v.x *= xm
-	v.y *= ym
-
 	return v
 }
 
@@ -183,7 +179,8 @@ func (v *Vector) Length() float64 {
 	return math.Sqrt(v.Dot(v))
 }
 
-// SetLength sets the length of this Vector without changing the direction.
+// SetLength sets the length of this Vector without changing the direction. The length will be exact within
+// d2math.Epsilon. See d2math.EqualsApprox.
 func (v *Vector) SetLength(length float64) *Vector {
 	v.Normalize()
 	v.Scale(length)

d2common/d2math/d2vector/vector_test.go

@@ -7,6 +7,19 @@ import (
 	"github.com/OpenDiablo2/OpenDiablo2/d2common/d2math"
 )
 
+/*func TestMain(m *testing.M) {
+	setup()
+	os.Exit(m.Run())
+}*/
+
+var outVector Vector
+var outFloat float64
+
+/*func setup() {
+}*/
+
+// TODO: Remove these evaluate functions. Throwing test errors outside the relevant functions means otherwise handly links to failed tests now point here which is annoying.
+
 func evaluateVector(description string, want, got Vector, t *testing.T) {
 	if !got.Equals(want) {
 		t.Errorf("%s: wanted %s: got %s", description, want, got)
@@ -236,84 +249,158 @@ func TestScale(t *testing.T) {
 	evaluateVector(fmt.Sprintf("scale %s by 2", v), want, got, t)
 }
 
-func TestAbs(t *testing.T) {
+func TestVector_Abs(t *testing.T) {
 	v := NewVector(-1, 1)
 	want := NewVector(1, 1)
 	got := v.Clone()
 	got.Abs()
 
-	evaluateVector(fmt.Sprintf("absolute value of %s", v), want, got, t)
+	if !want.Equals(got) {
+		t.Errorf("absolute value of %s: want %s: got %s", v, want, got)
+	}
 }
 
-func TestNegate(t *testing.T) {
+func BenchmarkVector_Abs(b *testing.B) {
+	v := NewVector(-1, -1)
+
+	for n := 0; n < b.N; n++ {
+		outVector = *v.Abs()
+	}
+}
+
+func TestVector_Negate(t *testing.T) {
 	v := NewVector(-1, 1)
 	want := NewVector(1, -1)
 	got := v.Clone()
 	got.Negate()
 
-	evaluateVector(fmt.Sprintf("inverse value of %s", v), want, got, t)
+	if !want.Equals(got) {
+		t.Errorf("inverse value of %s: want %s: got %s", v, want, got)
+	}
 }
 
-func TestDistance(t *testing.T) {
+func BenchmarkVector_Negate(b *testing.B) {
+	v := NewVector(1, 1)
+
+	for n := 0; n < b.N; n++ {
+		outVector = *v.Negate()
+	}
+}
+
+func TestVector_Distance(t *testing.T) {
 	v := NewVector(1, 3)
 	other := NewVector(1, -1)
 	want := 4.0
 	c := v.Clone()
 	got := c.Distance(other)
 
-	evaluateScalar(fmt.Sprintf("distance from %s to %s", v, other), want, got, t)
+	if got != want {
+		t.Errorf("distance from %s to %s: want %.3f: got %.3f", v, other, want, got)
+	}
 }
 
-func TestLength(t *testing.T) {
+func BenchmarkVector_Distance(b *testing.B) {
+	v := NewVector(1, 1)
+	d := NewVector(2, 2)
+
+	for n := 0; n < b.N; n++ {
+		outFloat = v.Distance(d)
+	}
+}
+
+func TestVector_Length(t *testing.T) {
 	v := NewVector(2, 0)
 	c := v.Clone()
 	want := 2.0
-	got := v.Length()
+	got := c.Length()
 
-	d := fmt.Sprintf("length of %s", c)
+	d := fmt.Sprintf("length of %s", v)
 
-	evaluateChanged(d, v, c, t)
+	if !c.Equals(v) {
+		t.Errorf("%s: changed vector %s to %s unexpectedly", d, v, c)
+	}
 
-	evaluateScalar(d, want, got, t)
+	if got != want {
+		t.Errorf("%s: want %.3f: got %.3f", d, want, got)
+	}
 }
 
-func TestSetLength(t *testing.T) {
+func BenchmarkVector_Length(b *testing.B) {
+	v := NewVector(1, 1)
+
+	for n := 0; n < b.N; n++ {
+		outFloat = v.Length()
+	}
+}
+
+func TestVector_SetLength(t *testing.T) {
 	v := NewVector(1, 1)
 	c := v.Clone()
 	want := 2.0
-	got := v.SetLength(want).Length()
+	got := c.SetLength(want).Length()
 
-	d := fmt.Sprintf("length of %s", c)
-
-	evaluateScalarApprox(d, want, got, t)
+	if !d2math.EqualsApprox(got, want) {
+		t.Errorf("set length of %s to %.3f :want %.3f: got %.3f", v, want, want, got)
+	}
 }
 
-func TestLerp(t *testing.T) {
+func BenchmarkVector_SetLength(b *testing.B) {
+	v := NewVector(1, 1)
+
+	for n := 0; n < b.N; n++ {
+		v.SetLength(5)
+	}
+}
+
+func TestVector_Lerp(t *testing.T) {
 	a := NewVector(0, 0)
 	b := NewVector(-20, 10)
 
-	x := 0.3
+	interp := 0.3
 
 	want := NewVector(-6, 3)
-	got := a.Lerp(&b, x)
+	got := a.Lerp(&b, interp)
 
-	evaluateVector(fmt.Sprintf("linear interpolation between %s and %s by %.2f", a, b, x), want, *got, t)
+	if !got.Equals(want) {
+		t.Errorf("linear interpolation between %s and %s by %.2f: want %s: got %s", a, b, interp, want, got)
+	}
 }
 
-func TestDot(t *testing.T) {
+func BenchmarkVector_Lerp(b *testing.B) {
+	v := NewVector(1, 1)
+	t := NewVector(1000, 1000)
+
+	for n := 0; n < b.N; n++ {
+		v.Lerp(&t, 1.01)
+	}
+}
+
+func TestVector_Dot(t *testing.T) {
 	v := NewVector(1, 1)
 	c := v.Clone()
 	want := 2.0
-	got := v.Dot(&v)
+	got := c.Dot(&c)
 
-	d := fmt.Sprintf("dot product of %s", c)
+	d := fmt.Sprintf("dot product of %s", v)
 
-	evaluateChanged(d, v, c, t)
+	if !c.Equals(v) {
+		t.Errorf("%s: changed vector %s to %s unexpectedly", d, v, c)
+	}
 
-	evaluateScalar(d, want, got, t)
+	if got != want {
+		t.Errorf("%s: want %.3f: got %.3f", d, want, got)
+	}
 }
 
-func TestCross(t *testing.T) {
+func BenchmarkVector_Dot(b *testing.B) {
+	v := NewVector(1, 1)
+
+	for n := 0; n < b.N; n++ {
+		outFloat = v.Dot(&v)
+	}
+}
+
+func TestVector_Cross(t *testing.T) {
 	v := NewVector(1, 1)
 
 	clock := NewVector(1, 0)
@@ -322,88 +409,156 @@ func TestCross(t *testing.T) {
 	want := -1.0
 	got := v.Cross(clock)
 
-	evaluateScalar(fmt.Sprintf("cross product of %s and %s", v, clock), want, got, t)
+	if got != want {
+		t.Errorf("cross product of %s and %s: want %.3f: got %.3f", v, clock, want, got)
+	}
 
 	want = 1.0
 	got = v.Cross(anti)
 
-	evaluateScalar(fmt.Sprintf("cross product of %s and %s", v, anti), want, got, t)
+	if got != want {
+		t.Errorf("cross product of %s and %s: want %.3f: got %.3f", v, clock, want, got)
+	}
 }
 
-func TestNormalize(t *testing.T) {
+func BenchmarkVector_Cross(b *testing.B) {
+	v := NewVector(1, 1)
+	o := NewVector(0, 1)
+
+	for n := 0; n < b.N; n++ {
+		outFloat = v.Cross(o)
+	}
+}
+
+func TestVector_Normalize(t *testing.T) {
 	v := NewVector(10, 0)
 	c := v.Clone()
 	want := NewVector(1, 0)
 
-	v.Normalize()
+	c.Normalize()
 
-	evaluateVector(fmt.Sprintf("normalize %s", c), want, v, t)
+	if !want.Equals(c) {
+		t.Errorf("normalize %s: want %s: got %s", v, want, c)
+	}
 
 	v = NewVector(0, 10)
 	c = v.Clone()
 	want = NewVector(0, 1)
-	reverse := v.Normalize()
+	reverse := c.Normalize()
 
-	evaluateVector(fmt.Sprintf("normalize %s", c), want, v, t)
+	if !want.Equals(c) {
+		t.Errorf("normalize %s: want %s: got %s", v, want, c)
+	}
 
 	want = NewVector(0, 10)
 
-	v.Scale(reverse)
+	c.Scale(reverse)
 
-	evaluateVector(fmt.Sprintf("reverse normalizing of %s", c), want, v, t)
+	if !want.Equals(c) {
+		t.Errorf("reverse normalizing of %s: want %s: got %s", v, want, c)
+	}
 
 	v = NewVector(0, 0)
 	c = v.Clone()
 	want = NewVector(0, 0)
 
-	v.Normalize()
+	c.Normalize()
 
-	evaluateVector(fmt.Sprintf("normalize zero vector should do nothing %s", c), want, v, t)
+	if !want.Equals(c) {
+		t.Errorf("normalize zero vector %s should do nothing: want %s: got %s", v, want, c)
+	}
 }
 
-func TestAngle(t *testing.T) {
+func BenchmarkVector_Normalize(b *testing.B) {
+	v := NewVector(1, 1)
+
+	for n := 0; n < b.N; n++ {
+		v.Normalize()
+	}
+}
+
+func TestVector_Angle(t *testing.T) {
 	v := NewVector(0, 1)
 	c := v.Clone()
 	other := NewVector(1, 0.3)
 
-	d := fmt.Sprintf("angle from %s to %s", c, other)
-
 	want := 1.2793395323170293
-	got := v.Angle(other)
+	got := c.Angle(other)
 
-	evaluateScalar(d, want, got, t)
-	evaluateChanged(d, v, c, t)
+	d := fmt.Sprintf("angle from %s to %s", v, other)
+
+	if got != want {
+		t.Errorf("%s: want %g: got %g", d, want, got)
+	}
+
+	if !c.Equals(v) {
+		t.Errorf("%s: changed vector %s to %s unexpectedly", d, v, c)
+	}
 
 	other.Set(-1, 0.3)
-	c = other.Clone()
+	co := other.Clone()
+	got = c.Angle(other)
 
 	d = fmt.Sprintf("angle from %s to %s", c, other)
 
-	got = v.Angle(other)
+	if got != want {
+		t.Errorf("%s: want %g: got %g", d, want, got)
+	}
 
-	evaluateScalar(d, want, got, t)
-	evaluateChanged(d, other, c, t)
+	if !co.Equals(other) {
+		t.Errorf("%s: changed vector %s to %s unexpectedly", d, co, other)
+	}
 }
 
-func TestSignedAngle(t *testing.T) {
+func BenchmarkVector_Angle(b *testing.B) {
+	v := NewVector(1, 1)
+	o := NewVector(0, 1)
+
+	for n := 0; n < b.N; n++ {
+		outFloat = v.Angle(o)
+	}
+}
+
+func TestVector_SignedAngle(t *testing.T) {
 	v := NewVector(0, 1)
 	c := v.Clone()
 	other := NewVector(1, 0.3)
 	want := 1.2793395323170293
-	got := v.SignedAngle(other)
+	got := c.SignedAngle(other)
 
 	d := fmt.Sprintf("angle from %s to %s", v, other)
-	evaluateScalar(d, want, got, t)
-	evaluateChanged(d, v, c, t)
+
+	if got != want {
+		t.Errorf("%s: want %g: got %g", d, want, got)
+	}
+
+	if !c.Equals(v) {
+		t.Errorf("%s: changed vector %s to %s unexpectedly", d, v, c)
+	}
 
 	other.Set(-1, 0.3)
-	c = other.Clone()
+	co := other.Clone()
 	want = 5.0038457214660585
-	got = v.SignedAngle(other)
+	got = c.SignedAngle(other)
 
 	d = fmt.Sprintf("angle from %s to %s", v, other)
-	evaluateScalar(d, want, got, t)
-	evaluateChanged(d, other, c, t)
+
+	if got != want {
+		t.Errorf("%s: want %g: got %g", d, want, got)
+	}
+
+	if !co.Equals(other) {
+		t.Errorf("%s: changed vector %s to %s unexpectedly", d, co, other)
+	}
+}
+
+func BenchmarkVector_SignedAngle(b *testing.B) {
+	v := NewVector(1, 1)
+	o := NewVector(0, 1)
+
+	for n := 0; n < b.N; n++ {
+		outFloat = v.SignedAngle(o)
+	}
 }
 
 func TestReflect(t *testing.T) {

d2common/d2math/math.go

@@ -1,7 +1,5 @@
 package d2math
 
-import "math"
-
 const (
 	// Epsilon is used as the threshold for 'almost equal' operations.
 	Epsilon float64 = 0.0001
@@ -16,7 +14,7 @@ const (
 
 // EqualsApprox returns true if the difference between a and b is less than Epsilon.
 func EqualsApprox(a, b float64) bool {
-	return math.Abs(a-b) < Epsilon
+	return Abs(a-b) < Epsilon
 }
 
 // CompareFloat64Fuzzy returns an integer between -1 and 1 describing
@@ -24,7 +22,8 @@ func EqualsApprox(a, b float64) bool {
 // absolute difference between a and b is less than Epsilon.
 func CompareFloat64Fuzzy(a, b float64) int {
 	delta := a - b
-	if math.Abs(delta) < Epsilon {
+
+	if Abs(delta) < Epsilon {
 		return 0
 	}
 
@@ -35,6 +34,15 @@ func CompareFloat64Fuzzy(a, b float64) int {
 	return -1
 }
 
+// Abs returns the absolute value of a. It is a less CPU intensive version of the standard library math.Abs().
+func Abs(a float64) float64 {
+	if a < 0 {
+		return a * -1
+	}
+
+	return a
+}
+
 // ClampFloat64 returns a clamped to min and max.
 func ClampFloat64(a, min, max float64) float64 {
 	if a > max {

d2core/d2map/d2mapentity/animated_entity.go

@@ -17,7 +17,7 @@ type AnimatedEntity struct {
 // CreateAnimatedEntity creates an instance of AnimatedEntity
 func CreateAnimatedEntity(x, y int, animation d2interface.Animation) *AnimatedEntity {
 	entity := &AnimatedEntity{
-		mapEntity: createMapEntity(x, y),
+		mapEntity: newMapEntity(x, y),
 		animation: animation,
 	}
 	entity.mapEntity.directioner = entity.rotate
@@ -30,7 +30,7 @@ func (ae *AnimatedEntity) Render(target d2interface.Surface) {
 	renderOffset := ae.Position.RenderOffset()
 	target.PushTranslation(
 		int((renderOffset.X()-renderOffset.Y())*16),
-		int(((renderOffset.X() + renderOffset.Y()) * 8)),
+		int(((renderOffset.X()+renderOffset.Y())*8)-5),
 	)
 
 	defer target.Pop()

d2core/d2map/d2mapentity/map_entity.go

@@ -11,6 +11,7 @@ import (
 type mapEntity struct {
 	Position d2vector.Position
 	Target   d2vector.Position
+	velocity d2vector.Vector
 
 	Speed     float64
 	path      []d2astar.Pather
@@ -20,8 +21,8 @@ type mapEntity struct {
 	directioner func(direction int)
 }
 
-// createMapEntity creates an instance of mapEntity
-func createMapEntity(x, y int) mapEntity {
+// newMapEntity creates an instance of mapEntity
+func newMapEntity(x, y int) mapEntity {
 	locX, locY := float64(x), float64(y)
 
 	return mapEntity{
@@ -43,6 +44,7 @@ func (m *mapEntity) GetLayer() int {
 func (m *mapEntity) SetPath(path []d2astar.Pather, done func()) {
 	m.path = path
 	m.done = done
+	m.nextPath()
 }
 
 // ClearPath clears the entity movement path.
@@ -60,14 +62,9 @@ func (m *mapEntity) GetSpeed() float64 {
 	return m.Speed
 }
 
-// IsAtTarget returns true if the distance between entity and target is almost zero.
-func (m *mapEntity) IsAtTarget() bool {
-	return m.Position.EqualsApprox(m.Target.Vector) && !m.HasPathFinding()
-}
-
 // Step moves the entity along it's path by one tick. If the path is complete it calls entity.done() then returns.
 func (m *mapEntity) Step(tickTime float64) {
-	if m.IsAtTarget() {
+	if m.atTarget() && !m.hasPath() {
 		if m.done != nil {
 			m.done()
 			m.done = nil
@@ -76,47 +73,39 @@ func (m *mapEntity) Step(tickTime float64) {
 		return
 	}
 
-	velocity := m.velocity(tickTime)
+	// Set velocity (speed and direction)
+	m.setVelocity(tickTime * m.Speed)
 
+	// This loop handles the situation where the velocity exceeds the distance to the current target. Each repitition applies
+	// the remaining velocity in the direction of the next path target.
 	for {
-		// Add the velocity to the position and set new velocity to remainder
-		applyVelocity(&m.Position.Vector, &velocity, &m.Target.Vector)
+		applyVelocity(&m.Position.Vector, &m.velocity, &m.Target.Vector)
 
-		// New position is at target
-		if m.Position.EqualsApprox(m.Target.Vector) {
-			if len(m.path) > 0 {
-				// Set next path node
-				m.SetTarget(m.path[0].(*d2common.PathTile).X*5, m.path[0].(*d2common.PathTile).Y*5, m.done)
-
-				if len(m.path) > 1 {
-					m.path = m.path[1:]
-				} else {
-					m.path = []d2astar.Pather{}
-				}
-			} else {
-				// End of path.
-				m.Position.Copy(&m.Target.Vector)
-			}
+		if m.atTarget() {
+			m.nextPath()
 		}
 
-		if velocity.IsZero() {
+		if m.velocity.IsZero() {
 			break
 		}
 	}
 }
 
-// velocity returns a vector describing the change in position this tick.
-func (m *mapEntity) velocity(tickTime float64) d2vector.Vector {
-	length := tickTime * m.Speed
-	v := m.Target.Vector.Clone()
-	v.Subtract(&m.Position.Vector)
-	v.SetLength(length)
-
-	return v
+// atTarget returns true if the distance between entity and target is almost zero.
+func (m *mapEntity) atTarget() bool {
+	return m.Position.EqualsApprox(m.Target.Vector)
 }
 
-// applyVelocity adds velocity to position. If the new position extends beyond target from the original position, the
-// position is set to the target and velocity is set to the overshot amount.
+// setVelocity returns a vector describing the given length and the direction to the current target.
+func (m *mapEntity) setVelocity(length float64) {
+	m.velocity.Copy(&m.Target.Vector)
+	m.velocity.Subtract(&m.Position.Vector)
+	m.velocity.SetLength(length)
+}
+
+// applyVelocity adds velocity to position. If the new position extends beyond the target: Target is set to the next
+// path node, Position is set to target and velocity is set to the over-extended length with the direction of to the
+// next node.
 func applyVelocity(position, velocity, target *d2vector.Vector) {
 	// Set velocity values to zero if almost zero
 	x, y := position.CompareApprox(*target)
@@ -149,21 +138,49 @@ func applyVelocity(position, velocity, target *d2vector.Vector) {
 	}
 }
 
-// HasPathFinding returns false if the length of the entity movement path is 0.
-func (m *mapEntity) HasPathFinding() bool {
+// Returns false if the path has ended.
+func (m *mapEntity) nextPath() {
+	if m.hasPath() {
+		// Set next path node
+		m.setTarget(
+			m.path[0].(*d2common.PathTile).X*5,
+			m.path[0].(*d2common.PathTile).Y*5,
+			m.done,
+		)
+
+		if len(m.path) > 1 {
+			m.path = m.path[1:]
+		} else {
+			m.path = []d2astar.Pather{}
+		}
+	} else {
+		// End of path.
+		m.Position.Copy(&m.Target.Vector)
+	}
+}
+
+// hasPath returns false if the length of the entity movement path is 0.
+func (m *mapEntity) hasPath() bool {
 	return len(m.path) > 0
 }
 
-// SetTarget sets target coordinates and changes animation based on proximity and direction.
-func (m *mapEntity) SetTarget(tx, ty float64, done func()) {
+// setTarget sets target coordinates and changes animation based on proximity and direction.
+func (m *mapEntity) setTarget(tx, ty float64, done func()) {
+	// Set the target
 	m.Target.Set(tx, ty)
 	m.done = done
 
+	// Update the direction
 	if m.directioner != nil {
 		d := m.Position.DirectionTo(m.Target.Vector)
 
 		m.directioner(d)
 	}
+
+	// Update the velocity direction
+	if !m.velocity.IsZero() {
+		m.setVelocity(m.velocity.Length())
+	}
 }
 
 // GetPosition returns the entity's current tile position, always a whole number.

d2core/d2map/d2mapentity/map_entity_test.go

@@ -0,0 +1,93 @@
+package d2mapentity
+
+import (
+	"os"
+	"testing"
+
+	"github.com/OpenDiablo2/OpenDiablo2/d2common/d2math/d2vector"
+
+	"github.com/OpenDiablo2/OpenDiablo2/d2common"
+	"github.com/OpenDiablo2/OpenDiablo2/d2common/d2astar"
+)
+
+var stepEntity mapEntity
+
+const (
+	normalTickTime float64 = 0.05
+)
+
+func TestMain(m *testing.M) {
+	setup()
+	os.Exit(m.Run())
+}
+
+func setup() {
+	setupBenchmarkMapEntityStep()
+}
+
+func entity() mapEntity {
+	return newMapEntity(10, 10)
+}
+
+func movingEntity() mapEntity {
+	e := entity()
+	e.SetSpeed(9)
+	newPath := path(10, e.Position)
+	e.SetPath(newPath, func() {})
+
+	return e
+}
+
+func path(length int, origin d2vector.Position) []d2astar.Pather {
+	path := make([]d2astar.Pather, length)
+
+	for i := 0; i < length; i++ {
+		origin.AddScalar(float64(i+1) / 5)
+		tile := origin.World()
+		path[i] = pathTile(tile.X(), tile.Y())
+	}
+
+	return path
+}
+
+func pathTile(x, y float64) *d2common.PathTile {
+	return &d2common.PathTile{X: x, Y: y}
+}
+
+func TestMapEntity_Step(t *testing.T) {
+	stepCount := 10
+	e := movingEntity()
+	start := e.Position.Clone()
+
+	for i := 0; i < stepCount; i++ {
+		e.Step(normalTickTime)
+	}
+
+	// velocity
+	change := d2vector.NewVector(0, 0)
+	change.Copy(&e.Target.Vector)
+	change.Subtract(&e.Position.Vector)
+	change.SetLength(e.Speed * normalTickTime)
+	// change in position
+	change.Scale(float64(stepCount))
+
+	want := change.Add(&start)
+
+	if !e.Position.EqualsApprox(*want) {
+		t.Errorf("entity position after %d steps: want %s: got %s", stepCount, want, e.Position.Vector)
+	}
+
+	if e.Position.Equals(start) {
+		t.Errorf("entity did not move, still at position %s", start)
+	}
+}
+
+func setupBenchmarkMapEntityStep() {
+	stepEntity = movingEntity()
+}
+
+func BenchmarkMapEntity_Step(b *testing.B) {
+	for n := 0; n < b.N; n++ {
+		stepEntity.Step(normalTickTime)
+	}
+}

d2core/d2map/d2mapentity/missile.go

@@ -54,7 +54,7 @@ func (m *Missile) SetRadians(angle float64, done func()) {
 	x := m.Position.X() + (r * math.Cos(angle))
 	y := m.Position.Y() + (r * math.Sin(angle))
 
-	m.SetTarget(x, y, done)
+	m.setTarget(x, y, done)
 }
 
 // Advance is called once per frame and processes a

d2core/d2map/d2mapentity/npc.go

@@ -31,7 +31,7 @@ type NPC struct {
 // CreateNPC creates a new NPC and returns a pointer to it.
 func CreateNPC(x, y int, monstat *d2datadict.MonStatsRecord, direction int) *NPC {
 	result := &NPC{
-		mapEntity:     createMapEntity(x, y),
+		mapEntity:     newMapEntity(x, y),
 		HasPaths:      false,
 		monstatRecord: monstat,
 		monstatEx:     d2datadict.MonStats2[monstat.ExtraDataKey],
@@ -75,7 +75,7 @@ func (v *NPC) Render(target d2interface.Surface) {
 	renderOffset := v.Position.RenderOffset()
 	target.PushTranslation(
 		int((renderOffset.X()-renderOffset.Y())*16),
-		int(((renderOffset.X() + renderOffset.Y()) * 8)),
+		int(((renderOffset.X()+renderOffset.Y())*8)-5),
 	)
 
 	defer target.Pop()
@@ -116,7 +116,7 @@ func (v *NPC) Advance(tickTime float64) {
 		// If at the target, set target to the next path.
 		v.isDone = false
 		path := v.NextPath()
-		v.SetTarget(
+		v.setTarget(
 			float64(path.X),
 			float64(path.Y),
 			v.next,
@@ -159,7 +159,7 @@ func (v *NPC) next() {
 // rotate sets direction and changes animation
 func (v *NPC) rotate(direction int) {
 	var newMode d2enum.MonsterAnimationMode
-	if !v.IsAtTarget() {
+	if !v.atTarget() {
 		newMode = d2enum.MonsterAnimationModeWalk
 	} else {
 		newMode = d2enum.MonsterAnimationModeNeutral

d2core/d2map/d2mapentity/player.go

@@ -57,7 +57,7 @@ func CreatePlayer(id, name string, x, y int, direction int, heroType d2enum.Hero
 
 	result := &Player{
 		Id:        id,
-		mapEntity: createMapEntity(x, y),
+		mapEntity: newMapEntity(x, y),
 		composite: composite,
 		Equipment: equipment,
 		Stats:     stats,
@@ -147,7 +147,7 @@ func (v *Player) Render(target d2interface.Surface) {
 	renderOffset := v.Position.RenderOffset()
 	target.PushTranslation(
 		int((renderOffset.X()-renderOffset.Y())*16),
-		int(((renderOffset.X() + renderOffset.Y()) * 8)),
+		int(((renderOffset.X()+renderOffset.Y())*8)-5),
 	)
 
 	defer target.Pop()
@@ -159,19 +159,19 @@ func (v *Player) Render(target d2interface.Surface) {
 
 // GetAnimationMode returns the current animation mode based on what the player is doing and where they are.
 func (v *Player) GetAnimationMode() d2enum.PlayerAnimationMode {
-	if v.IsRunning() && !v.IsAtTarget() {
+	if v.IsRunning() && !v.atTarget() {
 		return d2enum.PlayerAnimationModeRun
 	}
 
 	if v.IsInTown() {
-		if !v.IsAtTarget() {
+		if !v.atTarget() {
 			return d2enum.PlayerAnimationModeTownWalk
 		}
 
 		return d2enum.PlayerAnimationModeTownNeutral
 	}
 
-	if !v.IsAtTarget() {
+	if !v.atTarget() {
 		return d2enum.PlayerAnimationModeWalk
 	}