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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package f32
import (
"math"
"testing"
)
var xyTests = []struct {
x, y float32
}{
{0, 0},
{1, 1},
{2, 3},
{6.5, 4.3},
}
var a = Affine{
{3, 4, 5},
{6, 7, 8},
}
func TestInverse(t *testing.T) {
wantInv := Affine{
{-2.33333, 1.33333, 1},
{2, -1, -2},
}
var gotInv Affine
gotInv.Inverse(&a)
if !gotInv.Eq(&wantInv, 0.01) {
t.Errorf("Inverse: got %s want %s", gotInv, wantInv)
}
var wantId, gotId Affine
wantId.Identity()
gotId.Mul(&a, &wantInv)
if !gotId.Eq(&wantId, 0.01) {
t.Errorf("Identity #0: got %s want %s", gotId, wantId)
}
gotId.Mul(&wantInv, &a)
if !gotId.Eq(&wantId, 0.01) {
t.Errorf("Identity #1: got %s want %s", gotId, wantId)
}
}
func TestAffineScale(t *testing.T) {
for _, test := range xyTests {
want := a
want.Mul(&want, &Affine{{test.x, 0, 0}, {0, test.y, 0}})
got := a
got.Scale(&got, test.x, test.y)
if !got.Eq(&want, 0.01) {
t.Errorf("(%.2f, %.2f): got %s want %s", test.x, test.y, got, want)
}
}
}
func TestAffineTranslate(t *testing.T) {
for _, test := range xyTests {
want := a
want.Mul(&want, &Affine{{1, 0, test.x}, {0, 1, test.y}})
got := a
got.Translate(&got, test.x, test.y)
if !got.Eq(&want, 0.01) {
t.Errorf("(%.2f, %.2f): got %s want %s", test.x, test.y, got, want)
}
}
}
func TestAffineRotate(t *testing.T) {
want := Affine{
{-4.000, 3.000, 5.000},
{-7.000, 6.000, 8.000},
}
got := a
got.Rotate(&got, math.Pi/2)
if !got.Eq(&want, 0.01) {
t.Errorf("rotate π: got %s want %s", got, want)
}
want = a
got = a
got.Rotate(&got, 2*math.Pi)
if !got.Eq(&want, 0.01) {
t.Errorf("rotate 2π: got %s want %s", got, want)
}
got = a
got.Rotate(&got, math.Pi)
got.Rotate(&got, math.Pi)
if !got.Eq(&want, 0.01) {
t.Errorf("rotate π then π: got %s want %s", got, want)
}
got = a
got.Rotate(&got, math.Pi/3)
got.Rotate(&got, -math.Pi/3)
if !got.Eq(&want, 0.01) {
t.Errorf("rotate π/3 then -π/3: got %s want %s", got, want)
}
}
func TestAffineScaleTranslate(t *testing.T) {
mulVec := func(m *Affine, v [2]float32) (mv [2]float32) {
mv[0] = m[0][0]*v[0] + m[0][1]*v[1] + m[0][2]
mv[1] = m[1][0]*v[0] + m[1][1]*v[1] + m[1][2]
return mv
}
v := [2]float32{1, 10}
var sThenT Affine
sThenT.Identity()
sThenT.Scale(&sThenT, 13, 17)
sThenT.Translate(&sThenT, 101, 151)
wantSTT := [2]float32{
13 * (101 + 1),
17 * (151 + 10),
}
if got := mulVec(&sThenT, v); got != wantSTT {
t.Errorf("S then T: got %v, want %v", got, wantSTT)
}
var tThenS Affine
tThenS.Identity()
tThenS.Translate(&tThenS, 101, 151)
tThenS.Scale(&tThenS, 13, 17)
wantTTS := [2]float32{
101 + (13 * 1),
151 + (17 * 10),
}
if got := mulVec(&tThenS, v); got != wantTTS {
t.Errorf("T then S: got %v, want %v", got, wantTTS)
}
}
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