From f2289238df0451c5a9070d9a80c157fa2c00e5fa Mon Sep 17 00:00:00 2001
From: Thomas von Dein <tom@vondein.org>
Date: Sun, 2 Jun 2024 19:01:40 +0200
Subject: [PATCH] fixed initial cam pos, it's now always centered

---
 config.go     | 13 +++++++++++++
 scene-play.go | 14 ++++++++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/config.go b/config.go
index 3729a3d..6b547bc 100644
--- a/config.go
+++ b/config.go
@@ -29,6 +29,7 @@ type Config struct {
 	Restart, RestartGrid, RestartCache     bool
 	StartWithMenu                          bool
 	Zoomfactor                             int
+	InitialCamPos                          []float64
 	DelayedStart                           bool // if true game, we wait. like pause but program induced
 
 	// for internal profiling
@@ -91,6 +92,18 @@ func (config *Config) ParseGeom(geom string) error {
 	config.Cellsize = DEFAULT_CELLSIZE
 	config.Zoomfactor = DEFAULT_ZOOMFACTOR
 
+	// calculate the initial cam pos. It is negative if the total grid
+	// size  is smaller than  the screen  in a centered  position, but
+	// it's zero if it's equal or larger than the screen.
+	config.InitialCamPos = make([]float64, 2)
+	if config.Width*config.Cellsize < config.ScreenWidth {
+		config.InitialCamPos[0] = float64(((config.ScreenWidth - (config.Width * config.Cellsize)) / 2) * -1)
+	}
+
+	if config.Height*config.Cellsize < config.ScreenHeight {
+		config.InitialCamPos[1] = float64(((config.ScreenHeight - (config.Height * config.Cellsize)) / 2) * -1)
+	}
+
 	return nil
 }
 
diff --git a/scene-play.go b/scene-play.go
index b989cf1..99208e7 100644
--- a/scene-play.go
+++ b/scene-play.go
@@ -18,6 +18,10 @@ type Images struct {
 	Black, White, Age1, Age2, Age3, Age4, Old *ebiten.Image
 }
 
+const (
+	DEBUG_FORMAT = "FPS: %0.2f, TPG: %d, M: %0.2fMB, Generations: %d\nScale: %.02fZoom: %d, Cam: %.02f,%.02f Cursor: %d,%d  %s"
+)
+
 type ScenePlay struct {
 	Game   *Game
 	Config *Config
@@ -396,7 +400,7 @@ func (scene *ScenePlay) ToggleCellOnCursorPos(alive int64) {
 	x := int(worldX) / scene.Config.Cellsize
 	y := int(worldY) / scene.Config.Cellsize
 
-	if x > -1 && y > -1 {
+	if x > -1 && y > -1 && x < scene.Config.Width && y < scene.Config.Height {
 		scene.Grids[scene.Index].Data[y][x] = alive
 		scene.History.Data[y][x] = 1
 	}
@@ -485,11 +489,13 @@ func (scene *ScenePlay) DrawDebug(screen *ebiten.Image) {
 			paused = "-- paused --"
 		}
 
+		x, y := ebiten.CursorPosition()
 		debug := fmt.Sprintf(
-			"FPS: %0.2f, TPG: %d, Mem: %0.2fMB, Gen: %d, Scale: %.02f, Z: %d, Cam: %.02f,%.02f  %s",
+			DEBUG_FORMAT,
 			ebiten.ActualTPS(), scene.TPG, GetMem(), scene.Generations,
 			scene.Game.Scale, scene.Camera.ZoomFactor,
 			scene.Camera.Position[0], scene.Camera.Position[1],
+			x, y,
 			paused)
 
 		FontRenderer.Renderer.SetSizePx(10 + int(scene.Game.Scale*10))
@@ -503,6 +509,7 @@ func (scene *ScenePlay) DrawDebug(screen *ebiten.Image) {
 
 		fmt.Println(debug)
 	}
+
 }
 
 // load a pre-computed pattern from RLE file
@@ -648,6 +655,9 @@ func (scene *ScenePlay) Init() {
 	if scene.Config.Zoomfactor < 0 || scene.Config.Zoomfactor > 0 {
 		scene.Camera.ZoomFactor = scene.Config.Zoomfactor
 	}
+
+	scene.Camera.Position[0] = scene.Config.InitialCamPos[0]
+	scene.Camera.Position[1] = scene.Config.InitialCamPos[1]
 }
 
 // count the living neighbors of a cell