From 6adefa81f7dd9dcdeb6476e276b1ce4fd20066ca Mon Sep 17 00:00:00 2001
From: bloeys <bloeys@outlook.com>
Date: Tue, 14 May 2024 06:06:00 +0400
Subject: [PATCH] Add Clamp

---
 README.md           |  2 ++
 gglm/scalar.go      | 24 ++++++++++++++++-
 gglm/scalar_test.go | 64 +++++++++++++++++++++++++++++++++++++++++++++
 go.mod              |  4 ++-
 go.sum              |  2 ++
 5 files changed, 94 insertions(+), 2 deletions(-)
 create mode 100755 gglm/scalar_test.go

diff --git a/README.md b/README.md
index 140aa45..8eba60c 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,8 @@ gglm currently has the following:
 
 ## Installation
 
+Note: gglm requires Go 1.18 or higher.
+
 `go get github.com/bloeys/gglm`
 
 ## Usage
diff --git a/gglm/scalar.go b/gglm/scalar.go
index 3c88dbe..6ed297a 100755
--- a/gglm/scalar.go
+++ b/gglm/scalar.go
@@ -1,6 +1,10 @@
 package gglm
 
-import "math"
+import (
+	"math"
+
+	"golang.org/x/exp/constraints"
+)
 
 // EqF32 true if abs(f1-f2) <= F32Epsilon
 func EqF32(f1, f2 float32) bool {
@@ -52,3 +56,21 @@ func Abs32(x float32) float32 {
 func Sqrt32(x float32) float32 {
 	return float32(math.Sqrt(float64(x)))
 }
+
+// Clamp returns:
+//
+//	min if x<min
+//	max if x>max
+//	x   if x>=min && x<=max
+func Clamp[T constraints.Ordered](x, min, max T) T {
+
+	if x < min {
+		return min
+	}
+
+	if x > max {
+		return max
+	}
+
+	return x
+}
diff --git a/gglm/scalar_test.go b/gglm/scalar_test.go
new file mode 100755
index 0000000..7606e83
--- /dev/null
+++ b/gglm/scalar_test.go
@@ -0,0 +1,64 @@
+package gglm_test
+
+import (
+	"testing"
+
+	"github.com/bloeys/gglm/gglm"
+)
+
+func TestClamp(t *testing.T) {
+
+	x := 5
+	ans := 5
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	x = 10
+	ans = 10
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	x = 20
+	ans = 10
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	x = -10
+	ans = 0
+	if gglm.Clamp(x, 0, 10) != ans {
+		t.Errorf("Got: %v; Expected: %v", x, ans)
+	}
+
+	xf := 1.5
+	ansf := 1.5
+	if gglm.Clamp(xf, 0, 10) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = 15
+	ansf = 10
+	if gglm.Clamp(xf, 0, 10) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = -1.5
+	ansf = 0
+	if gglm.Clamp(xf, 0, 10) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = 2
+	ansf = 1.5
+	if gglm.Clamp(xf, 0.5, 1.5) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+
+	xf = 1.2
+	ansf = 1.2
+	if gglm.Clamp(xf, 0.5, 1.5) != ansf {
+		t.Errorf("Got: %v; Expected: %v", xf, ansf)
+	}
+}
diff --git a/go.mod b/go.mod
index f1c57fc..4462ff6 100755
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,5 @@
 module github.com/bloeys/gglm
 
-go 1.17
+go 1.18
+
+require golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842
diff --git a/go.sum b/go.sum
index e69de29..d023c2f 100755
--- a/go.sum
+++ b/go.sum
@@ -0,0 +1,2 @@
+golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842 h1:vr/HnozRka3pE4EsMEg1lgkXJkTFJCVUX+S/ZT6wYzM=
+golang.org/x/exp v0.0.0-20240506185415-9bf2ced13842/go.mod h1:XtvwrStGgqGPLc4cjQfWqZHG1YFdYs6swckp8vpsjnc=