fps counter

chatgpt.go

@@ -1,15 +1,22 @@
 package main
 
 import (
+	"fmt"
 	"image"
 	"image/color"
 	"image/draw"
 	"math"
+	"time"
 
 	"git.niplace.ru/XoxJlopeZi4BB/dev/fb"
+	"github.com/golang/freetype"
+	"github.com/golang/freetype/truetype"
+	"golang.org/x/image/font"
+	"golang.org/x/image/font/gofont/gomono"
 )
 
 var Width, Height = fb.Resolution()
+
 const (
 	cubeSize     = 50
 	Zoom         = 1000.0
@@ -118,12 +125,31 @@ func main() {
 
 	// Palette for the GIF
 	palette := []color.Color{color.Black, color.White}
+	var (
+		fontSize = 96.0
+		DPI      = 72.0
+		spacing  = 1.5
+	)
+	f, err := truetype.Parse(gomono.TTF)
+	if err != nil {
+		panic(err)
+	}
+	ctx := freetype.NewContext()
+	ctx.SetDPI(DPI)
+	ctx.SetFont(f)
+	ctx.SetFontSize(fontSize)
+	ctx.SetClip(image.Rect(0, 0, Width, Height))
+	ctx.SetSrc(image.NewUniform(palette[1]))
+	ctx.SetHinting(font.HintingNone)
 
+	var text string = "text"
+	var fps int
 	// Generate frames
 	for i := 0; i < frameCount; i++ {
 		angle := float64(i) * rotationStep
 		img := image.NewPaletted(image.Rect(0, 0, Width, Height), palette)
 		draw.Draw(img, img.Bounds(), &image.Uniform{color.Black}, image.Point{}, draw.Src)
+		ctx.SetDst(img)
 
 		// Rotate and project vertices
 		projVertices := make([]Point2D, len(vertices))
@@ -139,9 +165,20 @@ func main() {
 			drawLine(img, p1, p2, color.White)
 		}
 
+		text = fmt.Sprint(fps)
+		pt := freetype.Pt(30, 30+int(ctx.PointToFixed(fontSize)>>6))
+		_, err = ctx.DrawString(text, pt)
+		if err != nil {
+			panic(err)
+		}
+		pt.Y += ctx.PointToFixed(fontSize * spacing)
+
+		t := time.Now()
 		err := fb.Draw(img)
 		if err != nil {
 			panic(err)
 		}
+		d := time.Since(t)
+		fps = int(time.Second / d)
 	}
 }