Merge pull request #4886 from shimaowo/fix_gltf2_camera_fov

Fix: fix incorrect math for calculating the horizontal FOV of a perspective camera in gltf2 import #4435

code/AssetLib/glTF2/glTF2Importer.cpp

@@ -853,7 +853,7 @@ void glTF2Importer::ImportCameras(glTF2::Asset &r) {
 
         if (cam.type == Camera::Perspective) {
             aicam->mAspect = cam.cameraProperties.perspective.aspectRatio;
-            aicam->mHorizontalFOV = cam.cameraProperties.perspective.yfov * ((aicam->mAspect == 0.f) ? 1.f : aicam->mAspect);
+            aicam->mHorizontalFOV = 2.0f * std::atan(std::tan(cam.cameraProperties.perspective.yfov * 0.5f) * ((aicam->mAspect == 0.f) ? 1.f : aicam->mAspect));
             aicam->mClipPlaneFar = cam.cameraProperties.perspective.zfar;
             aicam->mClipPlaneNear = cam.cameraProperties.perspective.znear;
         } else {