Merge pull request #3 from prust/movement-tweaks

Introduce `player_velocity` constant & vector normalization for player

Author: servant-42

ebitengine-template.wasm

@@ -5,6 +5,7 @@ import (
 	"embed"
 	"io/fs"
 	"log"
+	"math"
 	"math/rand/v2"
 	"time"
 
@@ -30,6 +31,7 @@ const (
 	action_down
 	sample_rate = 48000
 	anim_rate   = time.Second / 8 // 8fps pixel art animation (looping 3-frame walk cycles)
+	player_speed = 4
 )
 
 var (
@@ -61,27 +63,39 @@ type Player struct {
 	rect *resolv.ConvexPolygon // DRY violation w/ x,y -- should we solely use the collision lib rect?
 }
 
+func (p *Player) NormalizeVelocity() {
+	length_squared := math.Sqrt(p.dx * p.dx + p.dy * p.dy)
+	if length_squared == 0 {
+		return
+	} else {
+		p.dx *= player_speed / length_squared
+		p.dy *= player_speed / length_squared
+	}
+}
+
 func (g *Game) Update() error {
 	g.input_system.Update()
 	was_walking := g.player.dx != 0 || g.player.dy != 0
 
 	if g.player_input.ActionIsPressed(action_left) {
-		g.player.dx = -4
+		g.player.dx = -player_speed
 	} else if g.player_input.ActionIsPressed(action_right) {
-		g.player.dx = 4
+		g.player.dx = player_speed
 	} else {
 		g.player.dx = 0
 	}
 
 	if g.player_input.ActionIsPressed(action_up) {
-		g.player.dy = -4
+		g.player.dy = -player_speed
 	} else if g.player_input.ActionIsPressed(action_down) {
-		g.player.dy = 4
+		g.player.dy = player_speed
 	} else {
 		g.player.dy = 0
 	}
 	is_walking := g.player.dx != 0 || g.player.dy != 0
 
+	g.player.NormalizeVelocity()
+
 	g.player.x += g.player.dx
 	g.player.y += g.player.dy
 	g.player.rect.Move(g.player.dx, g.player.dy)