adding tests, removing pointers

geometry.go

@@ -1130,19 +1130,19 @@ var ZB = Constant(V(1, 0))
 // relative to start and end point so:
 //
 // pixel.B(ZV, ZV, ZV, V(1, 0)) == Bezier{ZV, ZV, V(1, 0), V(1, 0)}
-func B(start, startHandle, endHandle, end Vec) *Bezier {
-	return &Bezier{start, startHandle.Add(start), endHandle.Add(end), end, false}
+func B(start, startHandle, endHandle, end Vec) Bezier {
+	return Bezier{start, startHandle.Add(start), endHandle.Add(end), end, false}
 }
 
 // Linear returns linear Bezier curve
-func Linear(start, end Vec) *Bezier {
+func Linear(start, end Vec) Bezier {
 	return B(start, ZV, ZV, end)
 }
 
 // Constant returns Bezier curve that always return same point,
 // This is usefull as placeholder, because it skips calculation
-func Constant(constant Vec) *Bezier {
-	return &Bezier{
+func Constant(constant Vec) Bezier {
+	return Bezier{
 		Start:     constant,
 		redundant: true,
 	}
@@ -1151,7 +1151,7 @@ func Constant(constant Vec) *Bezier {
 // Point returns point along the curve determinate by t (0 - 1)
 // You can of course pass any value though its really hard to
 // predict what value will it return
-func (b *Bezier) Point(t float64) Vec {
+func (b Bezier) Point(t float64) Vec {
 	if b.redundant || b.Start == b.End {
 		b.redundant = true
 		return b.Start

geometry_test.go

@@ -1599,3 +1599,54 @@ func BenchmarkRect_IsIntersect(b *testing.B) {
 		// do a thing
 	}
 }
+
+type sub struct {
+	result pixel.Vec
+	t      float64
+}
+
+func TestBezier(t *testing.T) {
+	tests := []struct {
+		curve pixel.Bezier
+
+		subTest []sub
+		name    string
+	}{
+		{
+			pixel.Constant(pixel.V(1, 0)),
+			[]sub{
+				{pixel.V(1, 0), 0.0},
+				{pixel.V(1, 0), 100.0},
+			},
+			"constant",
+		},
+		{
+			pixel.Linear(pixel.V(1, 0), pixel.ZV),
+			[]sub{
+				{pixel.V(1, 0), 0.0},
+				{pixel.ZV, 1.0},
+			},
+			"lenear",
+		},
+		{
+			pixel.B(pixel.V(0, 1), pixel.V(1, 0), pixel.V(-1, 0), pixel.V(1, 0)),
+			[]sub{
+				{pixel.V(0, 1), 0.0},
+				{pixel.V(1, 0), 1.0},
+				{pixel.V(.5, .5), 0.5},
+			},
+			"curved",
+		},
+	}
+
+	for _, c := range tests {
+		t.Run(c.name, func(t *testing.T) {
+			for _, st := range c.subTest {
+				val := c.curve.Point(st.t)
+				if val != st.result {
+					t.Errorf("inputted: %v expected: %v got: %v", st.t, st.result, val)
+				}
+			}
+		})
+	}
+}

go.mod

@@ -5,7 +5,7 @@ go 1.12
 require (
 	github.com/faiface/glhf v0.0.0-20181018222622-82a6317ac380
 	github.com/faiface/mainthread v0.0.0-20171120011319-8b78f0a41ae3
-	github.com/go-gl/gl v0.0.0-20190320180904-bf2b1f2f34d7 // indirect
+	github.com/go-gl/gl v0.0.0-20190320180904-bf2b1f2f34d7
 	github.com/go-gl/glfw/v3.3/glfw v0.0.0-20191125211704-12ad95a8df72
 	github.com/go-gl/mathgl v0.0.0-20190416160123-c4601bc793c7
 	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0