koobas.hobune.stream
Pixel of a Sprite under the MousePosition
It sounds almost easy, but I can't find any solution for two days already: I have a 2d object(its a sheet of paper) with some coordinates, and when I click on it I want to get the pixel where I clicked. And then draw around this pixel. This specific pixel where I clicked must be not in world coordinates(not a screen pixel), but a pixel of this sheet of paper. How do I do it?
Solved it with big effort. To get the needed pixel, I had to cast two rays: one ray from the bottom middle, another from left middle parts of the screen. This gave me two Vector2 with the least X and Y positions of my sheet of paper in world coordinates. Then I get the mouse position in world coordinates, and calculate the length of X line from the least X position to mousePosition.x and the length of the same line in Y axis. Then I calculate the relation of these two lines to the full X and Y length, and use this relations to calculate the needed pixel. Here is the code example:
Vector2 screenMidX = new Vector2(Screen.width * 0.5f, 0); Vector2 screenMidY = new Vector2(0, Screen.height * 0.5f); RaycastHit2D YPointHit = Physics2D.Raycast(Camera.main.ScreenToWorldPoint(screenMidX), Vector2.up); YLowerPoint = YPointHit.point; RaycastHit2D XPointHit = Physics2D.Raycast(Camera.main.ScreenToWorldPoint(screenMidY), Vector2.right); XLowerPoint = XPointHit.point; float XdeltaPoint = Camera.main.ScreenToWorldPoint(Input.mousePosition).x - XLowerPoint.x; float YdeltaPoint = Camera.main.ScreenToWorldPoint(Input.mousePosition).y - YLowerPoint.y; float Xpart = 1 /( (paper_currentSprite.bounds.size.x * paper_current.transform.lossyScale.x) / XdeltaPoint); float Ypart = 1 /( (paper_currentSprite.bounds.size.y * paper_current.transform.lossyScale.y) / YdeltaPoint); int pixelsX = paper_currentSprite.texture.width; int pixelsY = paper_currentSprite.texture.height; int posX = (int)(pixelsX * Xpart); int posY = (int)(pixelsY * Ypart); And the posX and posY integers represent the position of the needed pixel. Hope somebody will find this post useful one day!
