From b7b863cdf008348806d6bcdc5724c6c55b3575fb Mon Sep 17 00:00:00 2001
From: Rose Hogenson <rosehogenson@posteo.net>
Date: Thu, 5 Sep 2024 22:10:35 -0700
Subject: Enable vsync.

---
 pongo.go | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

(limited to 'pongo.go')

diff --git a/pongo.go b/pongo.go
index 122044d..1c612c8 100644
--- a/pongo.go
+++ b/pongo.go
@@ -15,8 +15,9 @@ const (
 	screenWidth  = 1920
 	screenHeight = 1080
 
-	ballSpeed   = 5
-	paddleSpeed = 5
+	ticksPerSecond = 300
+	ballSpeed      = 10 * 60 / ticksPerSecond
+	paddleSpeed    = 10 * 60 / ticksPerSecond
 )
 
 // Imagine a digital clock. Do they still make those?
@@ -180,11 +181,15 @@ func pong() error {
 	}
 	defer ping.Free()
 
-	window, renderer, err := sdl.CreateWindowAndRenderer(screenWidth, screenHeight, sdl.WINDOW_BORDERLESS)
+	window, err := sdl.CreateWindow("pong", sdl.WINDOWPOS_CENTERED, sdl.WINDOWPOS_CENTERED, screenWidth, screenHeight, sdl.WINDOW_BORDERLESS)
 	if err != nil {
 		return err
 	}
 	defer window.Destroy()
+	renderer, err := sdl.CreateRenderer(window, -1, sdl.RENDERER_PRESENTVSYNC)
+	if err != nil {
+		return err
+	}
 	defer renderer.Destroy()
 
 	playerScore := 0
@@ -204,9 +209,7 @@ func pong() error {
 	lastFrameTime := time.Now()
 	accumulator := time.Duration(0)
 
-	renderRate := time.NewTicker(time.Second / 60)
-	defer renderRate.Stop()
-	for frameStart := range renderRate.C {
+	for {
 		for event := sdl.PollEvent(); event != nil; event = sdl.PollEvent() {
 			switch t := event.(type) {
 			case *sdl.QuitEvent:
@@ -224,11 +227,12 @@ func pong() error {
 			}
 		}
 
-		frameTime := frameStart.Sub(lastFrameTime)
-		lastFrameTime = frameStart
+		now := time.Now()
+		frameTime := now.Sub(lastFrameTime)
+		lastFrameTime = now
 		accumulator += frameTime
 
-		const simulationSpeed = time.Second / 120
+		const simulationSpeed = time.Second / ticksPerSecond
 		for ; accumulator >= simulationSpeed; accumulator -= simulationSpeed {
 			switch {
 			case (keyPressed(sdl.K_UP) || keyPressed(sdl.K_w)) && paddle1.bounds().Y >= 0:
@@ -339,7 +343,6 @@ func pong() error {
 
 		renderer.Present()
 	}
-	panic("unreachable")
 }
 
 func main() {
-- 
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