From 771329e12fa9327980a43ef22cb4b9b24211b0cc Mon Sep 17 00:00:00 2001
From: davidovski <david@davidovski.xyz>
Date: Sun, 21 Apr 2024 21:49:56 +0100
Subject: add offsets for placed items

---
 objects.go | 198 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 198 insertions(+)
 create mode 100644 objects.go

(limited to 'objects.go')

diff --git a/objects.go b/objects.go
new file mode 100644
index 0000000..9eb4167
--- /dev/null
+++ b/objects.go
@@ -0,0 +1,198 @@
+package main
+
+import (
+	"log"
+    "image"
+    "github.com/hajimehoshi/ebiten/v2"
+	"github.com/hajimehoshi/ebiten/v2/ebitenutil"
+)
+
+const (
+    SPRING_FORCE = 8
+)
+
+type GameObject struct {
+    startx, starty float32
+    x, y float32
+    vx, vy float32
+
+    offsetX, offsetY int
+
+    friction float32
+    resistance float32
+    image *ebiten.Image
+    onGround bool
+    onCollideX func(this, other *GameObject) bool
+    onCollideY func(this, other *GameObject) bool
+}
+
+
+type Player struct {
+    GameObject
+}
+
+func (o * GameObject) Update(tilemap Tilemap, others []*GameObject) {
+    o.vy += gravity
+
+    o.vx *= o.resistance
+    o.vy *= o.resistance
+
+    o.x += o.vx
+    if o.HasCollision(tilemap, others, true) {
+        o.x -= o.vx
+        o.vx = 0
+    }
+
+    o.y += o.vy
+    if o.HasCollision(tilemap, others, false) {
+        o.onGround = true;
+        o.vx *= o.friction
+
+        o.y -= o.vy
+        o.vy = 0
+    } else {
+        o.onGround = false;
+    }
+}
+
+func (o * GameObject) HasCollision(tilemap Tilemap, others []*GameObject, x bool) bool {
+    if tilemap.CollideObject(o) {
+        return true
+    }
+    for _, obj := range others {
+        if obj.Collide(o) {
+            var f func(this, other *GameObject) bool
+            if x {
+                f = obj.onCollideX
+            } else {
+                f = obj.onCollideY
+            }
+
+            if f == nil{
+                return true
+            }
+            return f(obj, o)
+        }
+    }
+    return false
+}
+
+func (o * GameObject) Draw(screen *ebiten.Image, tilemap Tilemap) {
+    op := &ebiten.DrawImageOptions{}
+    op.GeoM.Translate(float64(o.x), float64(o.y))
+    screen.DrawImage(o.image, op)
+}
+
+func (object * GameObject) Collide(other *GameObject) bool {
+    maxX1 := object.x + float32(object.image.Bounds().Dx())
+    maxY1 := object.y + float32(object.image.Bounds().Dy())
+    minX1 := object.x
+    minY1 := object.y
+
+    maxX2 := other.x + float32(other.image.Bounds().Dx())
+    maxY2 := other.y + float32(other.image.Bounds().Dy())
+    minX2 := other.x
+    minY2 := other.y
+
+    if (minX1 == minX2 && maxX1 == maxX2 && minY1 == minY2 && maxY1 == maxY2) {
+        return false
+    }
+
+    return ! ( minX2 >= maxX1 || maxX2 <= minX1 || minY2 >= maxY1 || maxY2 <= minY1)
+}
+
+func (object * GameObject) ToRect() image.Rectangle {
+    width := object.image.Bounds().Dx()
+    height := object.image.Bounds().Dy()
+    x := int(object.x)
+    y := int(object.y)
+    return image.Rect(x, y, x+width, y+height)
+}
+
+func OnCollideGeneric(this, other *GameObject) bool {
+    return true
+}
+
+func NewObject(x, y float32) *GameObject{
+    obj := &GameObject{
+        startx: x,
+        starty: y,
+    }
+
+    obj.friction = friction
+    obj.resistance = airResistance
+    obj.x = obj.startx
+    obj.y = obj.starty
+    return obj
+}
+
+func NewPlayer(x, y float32) *GameObject{
+    player := NewObject(x, y)
+
+    playerImage, _, err := ebitenutil.NewImageFromFile("Assets/Main Characters/Ninja Frog/Idle (32x32).png")
+	if err != nil {
+		log.Fatal(err)
+	}
+
+    player.image = playerImage.SubImage(image.Rect(4, 8, 27, 32)).(*ebiten.Image)
+
+    return player
+}
+
+func NewExit(x, y float32) *GameObject{
+    exit := NewObject(x, y)
+
+    exit.image = tilesImage.SubImage(image.Rect(0, 16, 32, 48)).(*ebiten.Image)
+
+    return exit
+}
+
+func NewBox(x, y float32) *GameObject{
+    box := NewObject(x, y)
+
+    box.image = tilesImage.SubImage(image.Rect(160, 0, 176, 16)).(*ebiten.Image)
+
+    return box
+}
+
+func NewSpring(x, y float32) *GameObject{
+    spring := NewObject(x, y)
+
+    spring.image = tilesImage.SubImage(image.Rect(176, 0, 192, 16)).(*ebiten.Image)
+    spring.onCollideY = OnCollideSpring
+
+    return spring
+}
+
+func NewSpike(x, y float32) *GameObject{
+    spike := NewObject(x, y)
+
+    spike.offsetY = 3
+    spike.image = tilesImage.SubImage(image.Rect(192, 3, 208, 16)).(*ebiten.Image)
+    spike.onCollideY = OnCollideSpike
+
+    return spike
+}
+
+func NewLeftSpike(x, y float32) *GameObject{
+    spike := NewObject(x, y)
+
+    spike.offsetX = 3
+    spike.image = tilesImage.SubImage(image.Rect(195, 16, 208, 32)).(*ebiten.Image)
+    spike.onCollideX = OnCollideSpike
+
+    return spike
+}
+
+func OnCollideSpring(this, other *GameObject) bool {
+    other.vy -= SPRING_FORCE
+    other.onGround = true
+    return false
+}
+
+func OnCollideSpike(this, other *GameObject) bool {
+    other.x = other.startx
+    other.y = other.starty
+    return true
+}
+
-- 
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