feat(tools): toggleable fps counter

main.go

@@ -6,6 +6,7 @@ import (
 	"unsafe"
 
 	"github.com/veandco/go-sdl2/sdl"
+	"kisekinopureya.com.tr/go-raycasting/tools"
 	"kisekinopureya.com.tr/go-raycasting/worldMap"
 )
 
@@ -21,6 +22,8 @@ const (
 
 var posX, posY, dirX, dirY, planeX, planeY float64 = 2, 2, -1, 0, 0, 0.66
 
+var renderFps = false
+
 func render(renderer *sdl.Renderer, texture *sdl.Texture, pixels []uint32) {
 	err := texture.Update(nil, unsafe.Pointer(&pixels[0]), screenWidth*4)
 	if err != nil {
@@ -47,7 +50,7 @@ func main() {
 	}
 	defer window.Destroy()
 
-	renderer, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED)
+	renderer, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_ACCELERATED|sdl.RENDERER_PRESENTVSYNC)
 	if err != nil {
 		log.Fatalf("Renderer creation failed: %v", err)
 	}
@@ -64,6 +67,8 @@ func main() {
 		log.Fatalf("Texture creation failed: %v", err)
 	}
 
+	tools.InitFont("assets/DejaVuSans.ttf", 24)
+
 	pixels := make([]uint32, screenWidth*screenHeight)
 
 	running := true
@@ -105,6 +110,12 @@ func main() {
 						oldPlaneX := planeX
 						planeX = planeX*math.Cos(rotSpeed) - planeY*math.Sin(rotSpeed)
 						planeY = oldPlaneX*math.Sin(rotSpeed) + planeY*math.Cos(rotSpeed)
+					case sdl.K_F1:
+						if renderFps {
+							renderFps = false
+						} else {
+							renderFps = true
+						}
 					}
 				}
 			}
@@ -244,6 +255,10 @@ func main() {
 				}
 			}
 		}
+
+		if renderFps {
+			tools.FpsCounter(pixels, screenWidth, screenHeight)
+		}
 		// Render updated scene
 		render(renderer, texture, pixels)
 	}

tools/fps.go

@@ -0,0 +1,99 @@
+package tools
+
+import (
+	"fmt"
+	"log"
+	"time"
+
+	"github.com/veandco/go-sdl2/sdl"
+	"github.com/veandco/go-sdl2/ttf"
+)
+
+var (
+	oldTime = time.Now()
+	font    *ttf.Font
+)
+
+// Initialize font once (call this in setup)
+func InitFont(fontPath string, fontSize int) {
+	var err error
+	if err := ttf.Init(); err != nil {
+		log.Fatal(err)
+	}
+	font, err = ttf.OpenFont(fontPath, fontSize)
+	if err != nil {
+		log.Fatalf("Failed to load font: %v", err)
+	}
+}
+
+// Converts text to raw []uint32 pixels
+func textToPixels(text string, color sdl.Color) ([]uint32, int, int) {
+	surface, err := font.RenderUTF8Blended(text, color)
+	if err != nil {
+		log.Fatalf("Render failed: %v", err)
+	}
+	defer surface.Free()
+
+	w := int(surface.W)
+	h := int(surface.H)
+
+	if err := surface.Lock(); err != nil {
+		log.Fatalf("Failed to lock surface: %v", err)
+	}
+	defer surface.Unlock()
+
+	converted, err := surface.ConvertFormat(sdl.PIXELFORMAT_ARGB8888, 0)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer converted.Free()
+
+	pixelBytes := converted.Pixels()
+	pixels := make([]uint32, w*h)
+
+	for i := 0; i < w*h; i++ {
+		b := pixelBytes[i*4 : i*4+4]
+		pixels[i] = uint32(b[3])<<24 | uint32(b[2])<<16 | uint32(b[1])<<8 | uint32(b[0])
+	}
+	dst := make([]uint32, w*h)
+	copy(dst, pixels)
+	return dst, w, h
+}
+
+// Draws text pixels onto your screen framebuffer
+func blitTextToBuffer(dst []uint32, dstW, dstH, dstPitch int, src []uint32, srcW, srcH, posX, posY int) {
+	for y := 0; y < srcH; y++ {
+		for x := 0; x < srcW; x++ {
+			dx := posX + x
+			dy := posY + y
+			if dx < 0 || dx >= dstW || dy < 0 || dy >= dstH {
+				continue
+			}
+			srcPixel := src[y*srcW+x]
+
+			// Only draw non-transparent pixels
+			if (srcPixel>>24)&0xFF > 0 {
+				dst[dy*dstPitch+dx] = srcPixel
+			}
+		}
+	}
+}
+
+func FpsCounter(pixels []uint32, screenWidth, screenHeight int) {
+	now := time.Now()
+	frameTime := now.Sub(oldTime).Seconds()
+	oldTime = now
+
+	if frameTime == 0 {
+		return
+	}
+
+	fps := 1.0 / frameTime
+	fpsText := fmt.Sprintf("FPS: %.0f", fps)
+
+	color := sdl.Color{R: 255, G: 255, B: 255, A: 255}
+	textPixels, textW, textH := textToPixels(fpsText, color)
+
+	// Draw text at top-left (10,10)
+	blitTextToBuffer(pixels, screenWidth, screenHeight, screenWidth, textPixels, textW, textH, 10, 10)
+}