private void UpdateViewMatrix()
{
Vector3 lookAtTarget = this.position + this.viewDirection;
Matrix newViewMatrix = Matrix.CreateLookAt(this.position, lookAtTarget, this.upDirection);
this.viewMatrix = newViewMatrix;
this.dirtyFlags ^= CameraDirtyFlags.ViewMatrix;
this.dirtyFlags |= CameraDirtyFlags.UpdateId;
}
/// <summary>
/// Updates the projection matrix used by this camera.
/// </summary>
private void UpdateProjectionMatrix()
{
// Monogame expects the vertical FOV to be specified as half aperture angle in radians.
float verticalFovMonogame = MathHelper.ToRadians(this.verticalFieldOfViewDegree / 2.0f);
this.projectionMatrix = Matrix.CreatePerspectiveFieldOfView(verticalFovMonogame, this.aspectRatio, this.nearClippingPlaneDistance, this.farClippingPlaneDistance);
this.dirtyFlags ^= CameraDirtyFlags.ProjectionMatrix;
this.dirtyFlags |= CameraDirtyFlags.UpdateId;
}
/// <summary>
/// Updates the view frustrum of this camera.
/// </summary>
private void UpdateViewFrustrum()
{
this.viewFrustrum = new BoundingFrustum(this.ViewMatrix * this.ProjectionMatrix);
this.dirtyFlags ^= CameraDirtyFlags.ViewFrustrum;
this.dirtyFlags |= CameraDirtyFlags.UpdateId;
}
/// <summary>
/// Creates a new FreeCamera instance.
/// </summary>
/// <param name="position">The starting position of the camera in world space.</param>
/// <param name="viewDirection">The initial viewing direction (not the target point!) of the camera in world space.</param>
/// <param name="upDirection">The initial up direction of the camera.</param>
/// <param name="verticalFieldOfView">The vertical field of view / the vertical aperture angle (https://en.wikipedia.org/wiki/Field_of_view_in_video_games) of the camera in degrees.</param>
/// <param name="aspectRatio">The aspect ratio of the camera.</param>
/// <param name="nearClippingPlaneDistance">The distance to the near clipping plane.</param>
/// <param name="farClippingPlaneDistance">The distance to the far clipping plane.</param>
internal FreeCamera(Vector3 position, Vector3 viewDirection, Vector3 upDirection, float verticalFieldOfView, float aspectRatio,
float nearClippingPlaneDistance, float farClippingPlaneDistance)
{
// Default values.
this.rotation = Quaternion.Identity;
this.projectionMatrix = Matrix.Identity;
this.viewMatrix = Matrix.Identity;
this.dirtyFlags = CameraDirtyFlags.UpdateId | CameraDirtyFlags.ProjectionMatrix | CameraDirtyFlags.ViewMatrix | CameraDirtyFlags.ViewFrustrum;
// Check and transfer values from call.
if (aspectRatio < 0.0f)
{
throw new ArgumentOutOfRangeException(nameof(aspectRatio), "The aspect ration has to be greater than zero.");
}
else
{
this.aspectRatio = aspectRatio;
}
if (farClippingPlaneDistance <= 0.0f)
{
throw new ArgumentOutOfRangeException(nameof(farClippingPlaneDistance), "The far clipping plane has to have a disctance > 0.0 to the camera.");
}
else
{
this.farClippingPlaneDistance = farClippingPlaneDistance;
}
if (nearClippingPlaneDistance <= 0.0f)
{
throw new ArgumentOutOfRangeException(nameof(farClippingPlaneDistance), "The near clipping plane has to have a distance > 0.0 to the camera.");
}
else if (nearClippingPlaneDistance >= farClippingPlaneDistance)
{
throw new ArgumentException(nameof(nearClippingPlaneDistance) + " / " + nameof(farClippingPlaneDistance),
"The far clipping plane has to be further away from the camera than the near clipping plane.");
}
else
{
this.nearClippingPlaneDistance = nearClippingPlaneDistance;
}
this.position = position;
if (upDirection.Length() == 0.0f)
{
throw new ArgumentOutOfRangeException(nameof(upDirection), "The up Direction has to be a direction. A vector of length 0.0 does not have a direction.");
}
else
{
this.upDirection = Vector3.Normalize(upDirection);
}
if (verticalFieldOfView <= 0.0f)
{
throw new ArgumentOutOfRangeException(nameof(verticalFieldOfView), "The field of view has to be wider than 0.0°.");
}
else if (verticalFieldOfView > 360.0f)
{
throw new ArgumentOutOfRangeException(nameof(verticalFieldOfView), "The field of view may not be wider than 360°.");
}
else
{
this.verticalFieldOfViewDegree = verticalFieldOfView;
}
if (viewDirection.Length() == 0.0f)
{
throw new ArgumentOutOfRangeException(nameof(upDirection), "The upDirection has to be a direction. A vector of length 0.0 does not have a direction.");
}
else
{
this.viewDirection = viewDirection;
}
}
