using?UnityEngine;

namespace?FreeDraw
{
????//?1.?將其附加到讀/寫的sprite圖像上
????//?2.?將繪圖層設置為在光線投射中使用
????//?3.?將繪圖層設置為在光線投射中使用
????//?4.?按住鼠標左鍵畫出這個紋理！
????public?class?Drawable?:?MonoBehaviour
????{
????????[Tooltip（“彩筆顏色【橡皮擦就是透明彩筆】“）]?
????????public?Color?Pen_Colour?=?new?Color（255f?255f?255f?0f）;
????????[Tooltip（“鋼筆寬度（實際上，它是一個半徑，以像素為單位）“）]
????????public?int?Pen_Width?=?20;
????????[Tooltip（“圖層面板“）]
????????public?layerMask?Drawing_layers;

????????//?在Unity的文件編輯器中必須有讀/寫權限
????????Sprite?drawable_sprite;
????????Texture2D?drawable_texture;

????????Vector2?previous_drag_position;
????????Color[]?clean_colours_array;
????????Color?transparent;
????????Color32[]?cur_colors;
????????bool?mouse_was_previously_held_down?=?false;
????????bool?no_drawing_on_current_drag?=?false;


????????void?Awake（）
????????{
????????????drawable_sprite?=?this.GetComponent（）.sprite;
????????????drawable_texture?=?drawable_sprite.texture;

????????????//?保存圖片所有顏色
????????????clean_colours_array?=?drawable_texture.GetPixels（0?0?1920?1080）;

????????}


????????void?Update（）
????????{
????????????//?用戶按住鼠標左鍵嗎？
????????????bool?mouse_held_down?=?Input.GetMouseButton（0）;
????????????if?（mouse_held_down?&&?!no_drawing_on_current_drag）
????????????{
????????????????//?將鼠標坐標轉換為世界坐標
????????????????Vector2?mouse_world_position?=?Camera.main.ScreenToWorldPoint（Input.mousePosition）;

????????????????//?檢查當前鼠標位置是否與我們的圖像重疊
????????????????Collider2D?hit?=?Physics2D.OverlapPoint（mouse_world_position?Drawing_layers.value）;
????????????????if?（hit?!=?null?&&?hit.transform?!=?null）
????????????????????//?我們已經超越了我們所描繪的紋理！改變像素的顏色
????????????????????ChangeColourAtPoint（mouse_world_position）;
????????????????else
????????????????{
????????????????????//?我們還沒有結束我們的目標紋理
????????????????????previous_drag_position?=?Vector2.zero;
????????????????????if?（!mouse_was_previously_held_down）
????????????????????{
????????????????????????//這是一個新的拖動用戶在畫布上點擊離開
????????????????????????//在新的阻力開始之前，確保不會發生繪圖
????????????????????????no_drawing_on_current_drag?=?true;
????????????????????}
????????????????}
????????????}
????????????//?鼠標釋放
????????????else?if?（!mouse_held_down）
????????????{
????????????????previous_drag_position?=?Vector2.zero;
????????????????no_drawing_on_current_drag?=?false;
????????????}
????????????mouse_was_previously_held_down?=?mouse_held_down;
????????}


????????//?在世界坐標中傳遞一個點
????????//?改變世界周圍的像素點指向靜態的鋼筆顏色
????????public?void?ChangeColourAtPoint（Vector2?world_point）
????????{
????????????//?改變坐標到這個圖像的局部坐標
????????????Vector3?local_pos?=?transform.InverseTransformPoint（world_point）;

????????????//?將這些轉換為像素坐標
????????????float?pixelWidth?=?drawable_sprite.rect.width;
????????????float?pixelHeight?=?drawable_sprite.rect.height;
????????????float?unitsToPixels?=?pixelWidth?/?drawable_sprite.bounds.size.x?*?transform.localScale.x;

????????????//?需要把我們的坐標居中
????????????f