void Run()
{
float4x4 *allMat = stackalloc float4x4[6];
PerspCam persp = new PerspCam();
persp.aspect = 1;
persp.farClipPlane = 1;
persp.nearClipPlane = 0.1f;
persp.fov = 90f;
GetMatrix(allMat, ref persp, float3(0, 0, 0));
persp.UpdateProjectionMatrix();
for (int i = 0; i < 6; ++i)
{
float4x4 invvp = inverse(GL.GetGPUProjectionMatrix(mul(persp.projectionMatrix, allMat[i]), false));
string sb = "";
float4 value = mul(invvp, float4(-1, -1, 0, 1));
value /= value.w;
sb += "UV00: " + value.xyz;
value = mul(invvp, float4(-1, 1, 0, 1));
value /= value.w;
sb += " UV01: " + value.xyz;
value = mul(invvp, float4(1, 1, 0, 1));
value /= value.w;
sb += " UV11: " + value.xyz;
value = mul(invvp, float4(1, -1, 0, 1));
value /= value.w;
sb += " UV10: " + value.xyz;
Debug.Log(sb);
}
}
public static void GetFrustumPlanes(ref PerspCam perspCam, float4 *planes)
{
float3 *corners = stackalloc float3[4];
GetFrustumCorner(ref perspCam, perspCam.farClipPlane, corners);
planes[0] = VectorUtility.GetPlane(corners[1], corners[0], perspCam.position);
planes[1] = VectorUtility.GetPlane(corners[2], corners[3], perspCam.position);
planes[2] = VectorUtility.GetPlane(corners[0], corners[2], perspCam.position);
planes[3] = VectorUtility.GetPlane(corners[3], corners[1], perspCam.position);
planes[4] = VectorUtility.GetPlane(perspCam.forward, perspCam.position + perspCam.forward * perspCam.farClipPlane);
planes[5] = VectorUtility.GetPlane(-perspCam.forward, perspCam.position + perspCam.forward * perspCam.nearClipPlane);
}
public static void GetFrustumCorner(ref PerspCam perspCam, float distance, float3 *corners)
{
perspCam.fov = Mathf.Deg2Rad * perspCam.fov * 0.5f;
float upLength = distance * tan(perspCam.fov);
float rightLength = upLength * perspCam.aspect;
float3 farPoint = perspCam.position + distance * perspCam.forward;
float3 upVec = upLength * perspCam.up;
float3 rightVec = rightLength * perspCam.right;
corners[0] = farPoint - upVec - rightVec;
corners[1] = farPoint - upVec + rightVec;
corners[2] = farPoint + upVec - rightVec;
corners[3] = farPoint + upVec + rightVec;
}
private static void GetMatrix(float4x4 *allmat, ref PerspCam persp, float3 position)
{
persp.position = position;
//X
persp.up = float3(0, 1, 0);
persp.right = float3(0, 0, -1);
persp.forward = float3(1, 0, 0);
persp.UpdateTRSMatrix();
allmat[1] = persp.worldToCameraMatrix;
//-X
persp.up = float3(0, 1, 0);
persp.right = float3(0, 0, 1);
persp.forward = float3(-1, 0, 0);
persp.UpdateTRSMatrix();
allmat[0] = persp.worldToCameraMatrix;
//Y
persp.right = float3(-1, 0, 0);
persp.up = float3(0, 0, 1);
persp.forward = float3(0, 1, 0);
persp.UpdateTRSMatrix();
allmat[2] = persp.worldToCameraMatrix;
//-Y
persp.right = float3(-1, 0, 0);
persp.up = float3(0, 0, -1);
persp.forward = float3(0, -1, 0);
persp.UpdateTRSMatrix();
allmat[3] = persp.worldToCameraMatrix;
//Z
persp.right = float3(1, 0, 0);
persp.up = float3(0, 1, 0);
persp.forward = float3(0, 0, 1);
persp.UpdateTRSMatrix();
allmat[5] = persp.worldToCameraMatrix;
//-Z
persp.right = float3(-1, 0, 0);
persp.up = float3(0, 1, 0);
persp.forward = float3(0, 0, -1);
persp.UpdateTRSMatrix();
allmat[4] = persp.worldToCameraMatrix;
}
public static void GetFrustumCorner(ref PerspCam perspCam, float3 *corners)
{
float fov = tan(Mathf.Deg2Rad * perspCam.fov * 0.5f);
void GetCorner(float dist, ref PerspCam persp)
{
float upLength = dist * (fov);
float rightLength = upLength * persp.aspect;
float3 farPoint = persp.position + dist * persp.forward;
float3 upVec = upLength * persp.up;
float3 rightVec = rightLength * persp.right;
corners[0] = farPoint - upVec - rightVec;
corners[1] = farPoint - upVec + rightVec;
corners[2] = farPoint + upVec - rightVec;
corners[3] = farPoint + upVec + rightVec;
corners += 4;
}
GetCorner(perspCam.nearClipPlane, ref perspCam);
GetCorner(perspCam.farClipPlane, ref perspCam);
}
