一起嗨
第一次在这里发帖，因为我被卡住了...
网格离原点 (0, 0, 0) 越远，它在旋转或移动相机时“跳跃”/“闪烁”的次数就越多。有点难以描述这种效果：就像网格有点抖动/颤抖/颤抖，随着您与原点的距离越来越远，这种颤抖变得越来越大。
对我来说，它开始在距原点约 100000 单位距离处可观察到，例如在 (0, 0, 100000) 处。平移轴和网格类型（从 Mesh.Create... 创建的默认网格或使用 assimp.NET 导入的 3ds 网格）都不会影响此效果。发生这种效果时，网格位置的值不会改变，通过记录位置来检查这一点。
如果我没有遗漏什么，这会将其缩小为两种可能性：
- 我的相机代码
- DirectX 设备
至于 DirectX-Device，这是我的设备初始化代码：
private void InitializeDevice()
{
//Initialize D3D
_d3dObj = new D3D9.Direct3D();
//Set presentation parameters
_presParams = new D3D9.PresentParameters();
_presParams.Windowed = true;
_presParams.SwapEffect = D3D9.SwapEffect.Discard;
_presParams.AutoDepthStencilFormat = D3D9.Format.D16;
_presParams.EnableAutoDepthStencil = true;
_presParams.PresentationInterval = D3D9.PresentInterval.One;
_presParams.BackBufferFormat = _d3dObj.Adapters.DefaultAdapter.CurrentDisplayMode.Format;
_presParams.BackBufferHeight = _d3dObj.Adapters.DefaultAdapter.CurrentDisplayMode.Height;
_presParams.BackBufferWidth = _d3dObj.Adapters.DefaultAdapter.CurrentDisplayMode.Width;
//Set form width and height to current backbuffer width und height
this.Width = _presParams.BackBufferWidth;
this.Height = _presParams.BackBufferHeight;
//Checking device capabilities
D3D9.Capabilities caps = _d3dObj.GetDeviceCaps(0, D3D9.DeviceType.Hardware);
D3D9.CreateFlags devFlags = D3D9.CreateFlags.SoftwareVertexProcessing;
D3D9.DeviceType devType = D3D9.DeviceType.Reference;
//setting device flags according to device capabilities
if ((caps.VertexShaderVersion >= new Version(2, 0)) && (caps.PixelShaderVersion >= new Version(2, 0)))
{
//if device supports vertexshader and pixelshader >= 2.0
//then use the hardware device
devType = D3D9.DeviceType.Hardware;
if (caps.DeviceCaps.HasFlag(D3D9.DeviceCaps.HWTransformAndLight))
{
devFlags = D3D9.CreateFlags.HardwareVertexProcessing;
}
if (caps.DeviceCaps.HasFlag(D3D9.DeviceCaps.PureDevice))
{
devFlags |= D3D9.CreateFlags.PureDevice;
}
}
//initialize the device
_device = new D3D9.Device(_d3dObj, 0, devType, this.Handle, devFlags, _presParams);
//set culling
_device.SetRenderState(D3D9.RenderState.CullMode, D3D9.Cull.Counterclockwise);
//set texturewrapping (needed for seamless spheremapping)
_device.SetRenderState(D3D9.RenderState.Wrap0, D3D9.TextureWrapping.All);
//set lighting
_device.SetRenderState(D3D9.RenderState.Lighting, false);
//enabling the z-buffer
_device.SetRenderState(D3D9.RenderState.ZEnable, D3D9.ZBufferType.UseZBuffer);
//and setting write-access exlicitly to true...
//i'm a little paranoid about this since i had to struggle for a few days with weirdly overlapping meshes
_device.SetRenderState(D3D9.RenderState.ZWriteEnable, true);
}
我是否缺少标志或渲染状态？有什么东西会导致这种奇怪/扭曲的行为吗？
我的相机类基于Michael Silvermans C++ Quaternion Camera：
//every variable prefixed with an underscore is
//a private static variable initialized beforehand
public static class Camera
{
//gets called every frame
public static void Update()
{
if (_filter)
{
_filteredPos = Vector3.Lerp(_filteredPos, _pos, _filterAlpha);
_filteredRot = Quaternion.Slerp(_filteredRot, _rot, _filterAlpha);
}
_device.SetTransform(D3D9.TransformState.Projection, Matrix.PerspectiveFovLH(_fov, _screenAspect, _nearClippingPlane, _farClippingPlane));
_device.SetTransform(D3D9.TransformState.View, GetViewMatrix());
}
public static void Move(Vector3 delta)
{
_pos += delta;
}
public static void RotationYaw(float theta)
{
_rot = Quaternion.Multiply(Quaternion.RotationAxis(_up, -theta), _rot);
}
public static void RotationPitch(float theta)
{
_rot = Quaternion.Multiply(_rot, Quaternion.RotationAxis(_right, theta));
}
public static void SetTarget(Vector3 target, Vector3 up)
{
SetPositionAndTarget(_pos, target, up);
}
public static void SetPositionAndTarget(Vector3 position, Vector3 target, Vector3 upVec)
{
_pos = position;
Vector3 up, right, lookAt = target - _pos;
lookAt = Vector3.Normalize(lookAt);
right = Vector3.Cross(upVec, lookAt);
right = Vector3.Normalize(right);
up = Vector3.Cross(lookAt, right);
up = Vector3.Normalize(up);
SetAxis(lookAt, up, right);
}
public static void SetAxis(Vector3 lookAt, Vector3 up, Vector3 right)
{
Matrix rot = Matrix.Identity;
rot.M11 = right.X;
rot.M12 = up.X;
rot.M13 = lookAt.X;
rot.M21 = right.Y;
rot.M22 = up.Y;
rot.M23 = lookAt.Y;
rot.M31 = right.Z;
rot.M32 = up.Z;
rot.M33 = lookAt.Z;
_rot = Quaternion.RotationMatrix(rot);
}
public static void ViewScene(BoundingSphere sphere)
{
SetPositionAndTarget(sphere.Center - new Vector3((sphere.Radius + 150) / (float)Math.Sin(_fov / 2), 0, 0), sphere.Center, new Vector3(0, 1, 0));
}
public static Vector3 GetLookAt()
{
Matrix rot = Matrix.RotationQuaternion(_rot);
return new Vector3(rot.M13, rot.M23, rot.M33);
}
public static Vector3 GetRight()
{
Matrix rot = Matrix.RotationQuaternion(_rot);
return new Vector3(rot.M11, rot.M21, rot.M31);
}
public static Vector3 GetUp()
{
Matrix rot = Matrix.RotationQuaternion(_rot);
return new Vector3(rot.M12, rot.M22, rot.M32);
}
public static Matrix GetViewMatrix()
{
Matrix viewMatrix, translation = Matrix.Identity;
Vector3 position;
Quaternion rotation;
if (_filter)
{
position = _filteredPos;
rotation = _filteredRot;
}
else
{
position = _pos;
rotation = _rot;
}
translation = Matrix.Translation(-position.X, -position.Y, -position.Z);
viewMatrix = Matrix.Multiply(translation, Matrix.RotationQuaternion(rotation));
return viewMatrix;
}
}
您是否在相机代码中发现任何可能导致此行为的内容？
我只是无法想象 DirectX 不能处理大于 100k 的距离。我应该渲染太阳系，我使用 1 个单位 = 1 公里。因此，地球将在 (0, 0, 152100000) 处与太阳的最大距离处渲染（仅作为示例）。如果这些“跳跃”不断发生，这将变得不可能。最后，我考虑缩小所有内容，以使系统与原点的距离永远不会超过 100k/-100k，但我认为这行不通，因为“抖动”会随着与原点的距离变大而变大。缩小所有内容 - 我认为 - 也会缩小跳跃行为。