MVP行列

変換後の座標 = P * V * M * 返還前の座標

MVP座標変換の実行場所

MVP変換 (モデル空間からクリップ空間への変換) はシェーダー上で以下のように実装されている

code:UnityShaderUtilities.cginc

inline float4 UnityObjectToClipPos(in float3 pos)

{

return UnityObjectToClipPosODS(pos);

// More efficient than computing M*VP matrix product

return mul(UNITY_MATRIX_VP, mul(unity_ObjectToWorld, float4(pos, 1.0)));

}

カメラ行列の設定個所

code:cs

public static void SetCameraMatrices(CommandBuffer cmd, ref CameraData cameraData, bool setInverseMatrices)

{

if (cameraData.xr.enabled)

{

cameraData.xr.UpdateGPUViewAndProjectionMatrices(cmd, ref cameraData, cameraData.xr.renderTargetIsRenderTexture);

return;

}

Matrix4x4 viewMatrix = cameraData.GetViewMatrix();

Matrix4x4 projectionMatrix = cameraData.GetProjectionMatrix();

// TODO: Investigate why SetViewAndProjectionMatrices is causing y-flip / winding order issue

// for now using cmd.SetViewProjecionMatrices

//SetViewAndProjectionMatrices(cmd, viewMatrix, cameraData.GetDeviceProjectionMatrix(), setInverseMatrices);

cmd.SetViewProjectionMatrices(viewMatrix, projectionMatrix);

if (setInverseMatrices)

{

Matrix4x4 gpuProjectionMatrix = cameraData.GetGPUProjectionMatrix();

Matrix4x4 viewAndProjectionMatrix = gpuProjectionMatrix * viewMatrix;

Matrix4x4 inverseViewMatrix = Matrix4x4.Inverse(viewMatrix);

Matrix4x4 inverseProjectionMatrix = Matrix4x4.Inverse(gpuProjectionMatrix);

Matrix4x4 inverseViewProjection = inverseViewMatrix * inverseProjectionMatrix;

// There's an inconsistency in handedness between unity_matrixV and unity_WorldToCamera

// Unity changes the handedness of unity_WorldToCamera (see Camera::CalculateMatrixShaderProps)

// we will also change it here to avoid breaking existing shaders. (case 1257518)

Matrix4x4 worldToCameraMatrix = Matrix4x4.Scale(new Vector3(1.0f, 1.0f, -1.0f)) * viewMatrix;

Matrix4x4 cameraToWorldMatrix = worldToCameraMatrix.inverse;

cmd.SetGlobalMatrix(ShaderPropertyId.worldToCameraMatrix, worldToCameraMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.cameraToWorldMatrix, cameraToWorldMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.inverseViewMatrix, inverseViewMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.inverseProjectionMatrix, inverseProjectionMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.inverseViewAndProjectionMatrix, inverseViewProjection);

}

// TODO: Add SetPerCameraClippingPlaneProperties here once we are sure it correctly behaves in overlay camera for some time

}

VP行列の設定

VP行列は P * V という順番で乗じている

code:cs

public static void SetViewAndProjectionMatrices(CommandBuffer cmd, Matrix4x4 viewMatrix, Matrix4x4 projectionMatrix, bool setInverseMatrices)

{

Matrix4x4 viewAndProjectionMatrix = projectionMatrix * viewMatrix;

cmd.SetGlobalMatrix(ShaderPropertyId.viewMatrix, viewMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.projectionMatrix, projectionMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.viewAndProjectionMatrix, viewAndProjectionMatrix);

if (setInverseMatrices)

{

Matrix4x4 inverseViewMatrix = Matrix4x4.Inverse(viewMatrix);

Matrix4x4 inverseProjectionMatrix = Matrix4x4.Inverse(projectionMatrix);

Matrix4x4 inverseViewProjection = inverseViewMatrix * inverseProjectionMatrix;

cmd.SetGlobalMatrix(ShaderPropertyId.inverseViewMatrix, inverseViewMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.inverseProjectionMatrix, inverseProjectionMatrix);

cmd.SetGlobalMatrix(ShaderPropertyId.inverseViewAndProjectionMatrix, inverseViewProjection);

}

}