Adding upstream version 0.0~git20250520.a1d9079+dfsg.

Signed-off-by: Daniel Baumann <daniel@debian.org>

exp/f32/affine_test.go

@@ -0,0 +1,140 @@
+// 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)
+	}
+}