From 2f310aa9f3f1cb1d51e8f62a6d5e3dda4821b82b Mon Sep 17 00:00:00 2001
From: chai <chaifix@163.com>
Date: Wed, 22 Sep 2021 19:25:56 +0800
Subject: *effect

---
 Assets/Scripts/Rendering/RenderingUtility.cs | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

(limited to 'Assets/Scripts/Rendering')

diff --git a/Assets/Scripts/Rendering/RenderingUtility.cs b/Assets/Scripts/Rendering/RenderingUtility.cs
index 297a9b79..90ef84fd 100644
--- a/Assets/Scripts/Rendering/RenderingUtility.cs
+++ b/Assets/Scripts/Rendering/RenderingUtility.cs
@@ -63,4 +63,31 @@ public static class RenderingUtility
     {
         return renderingEventToCameraEventDic[e];
     }
+
+    /// <summary>
+    /// 计算在rt里面的区域
+    /// </summary>
+    /// <param name="camera">相机</param>
+    /// <param name="worldPos">世界空间坐标</param>
+    /// <param name="size">异体矩形(billboard)的相机空间大小</param>
+    /// <returns></returns>
+    public static Vector4 GetTillingOffset(Camera camera, Vector3 worldPos, float size)
+    {
+        Vector4 tileOffset = new Vector4(1,1,0,0);
+        Vector3 camPos = camera.WorldToCameraSpace(worldPos);
+
+        Vector3 bottomLeft = new Vector3(camPos.x - size / 2, camPos.y - size / 2, camPos.z);
+        Vector3 topRight = new Vector3(camPos.x + size / 2, camPos.y + size / 2, camPos.z);
+        Vector2 blViewPos = camera.CameraToViewportSpace(bottomLeft);
+        Vector2 trViewPos = camera.CameraToViewportSpace(topRight);
+        float width = trViewPos.x - blViewPos.x;
+        float height = trViewPos.y - blViewPos.y;
+
+        tileOffset.x = width;
+        tileOffset.y = height;
+        tileOffset.z = blViewPos.x;
+        tileOffset.w = blViewPos.y;
+        return tileOffset;
+    }
+
 }
-- 
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