78 lines
3.4 KiB
C#
78 lines
3.4 KiB
C#
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#if UNITY_EDITOR
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using UnityEngine;
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using System.Collections.Generic;
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namespace GSpawn
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{
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public static class SpriteRendererEx
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{
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public static Vector3 calcWorldCenterPoint(this SpriteRenderer spriteRenderer)
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{
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return spriteRenderer.transform.TransformPoint(spriteRenderer.calcModelSpaceAABB().center);
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}
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public static Vector3 calcModelSpaceSize(this SpriteRenderer spriteRenderer)
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{
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return spriteRenderer.calcModelSpaceAABB().size;
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}
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public static AABB calcModelSpaceAABB(this SpriteRenderer spriteRenderer)
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{
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Sprite sprite = spriteRenderer.sprite;
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if (sprite == null) return AABB.getInvalid();
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List<Vector2> spriteVerts = new List<Vector2>(sprite.vertices);
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return new AABB(spriteVerts);
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}
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public static bool isPixelFullyTransparent(this SpriteRenderer spriteRenderer, Vector3 worldPos)
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{
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// No sprite?
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Sprite sprite = spriteRenderer.sprite;
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if (sprite == null) return true;
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// No texture?
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Texture2D spriteTexture = sprite.texture;
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if (spriteTexture == null) return true;
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// We need to work in the sprite's model space so the first step is to transform
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// the passed world position into a sprite local position.
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Transform spriteTransform = spriteRenderer.transform;
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Vector3 modelSpacePos = spriteTransform.InverseTransformPoint(worldPos);
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// Project the model space position onto the sprite's plane. The sprite's plane is
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// always the XY plane in its model space.
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Plane xyPlane = new Plane(Vector3.forward, 0.0f);
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Vector3 projectedPos = xyPlane.projectPoint(modelSpacePos);
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// Calculate the sprite's model space AABB and check if this AABB contains the model
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// space position. If it doesn't, it means the world position is outside the sprite's
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// bounds/area.
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AABB modelSpaceAABB = spriteRenderer.calcModelSpaceAABB();
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modelSpaceAABB.size = new Vector3(modelSpaceAABB.size.x, modelSpaceAABB.size.y, 1.0f);
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if (!modelSpaceAABB.containsPoint(projectedPos)) return true;
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// Build a vector which goes from the bottom left corner of the sprite to the projected world
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// position. This will help us calculate the coordinates of the pixel where the world point resides.
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Vector3 bottomLeft = xyPlane.projectPoint(modelSpaceAABB.min);
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Vector3 fromTopLeftToPos = projectedPos - bottomLeft;
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// Calculate the pixel coordinates of the projected position
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Vector2 pixelCoords = new Vector2(fromTopLeftToPos.x * sprite.pixelsPerUnit, fromTopLeftToPos.y * sprite.pixelsPerUnit);
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pixelCoords += sprite.textureRectOffset;
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// Try reading the sprite pixels and check the alpha value
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try
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{
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float alpha = spriteTexture.GetPixel((int)(pixelCoords.x + 0.5f), (int)(pixelCoords.y + 0.5f)).a;
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return alpha <= 1e-3f;
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}
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catch (UnityException e)
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{
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// Ternary operator needed to avoid 'variable not used' warning
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return e != null ? false : false;
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}
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}
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}
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}
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#endif
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