My frustum culling is culling from the wrong point
- by Xbetas
I'm having problems with my frustum being in the wrong origin.
It follows the rotation of my camera but not the position.
In my camera class I'm generating a view-matrix:
void Camera::Update()
{
UpdateViewMatrix();
glMatrixMode(GL_MODELVIEW);
//glLoadIdentity();
glLoadMatrixf(GetViewMatrix().m);
}
Then extracting the planes using the projection matrix and modelview matrix:
void UpdateFrustum()
{
Matrix4x4 projection, model, clip;
glGetFloatv(GL_PROJECTION_MATRIX, projection.m);
glGetFloatv(GL_MODELVIEW_MATRIX, model.m);
clip = model * projection;
m_Planes[RIGHT][0] = clip.m[ 3] - clip.m[ 0];
m_Planes[RIGHT][1] = clip.m[ 7] - clip.m[ 4];
m_Planes[RIGHT][2] = clip.m[11] - clip.m[ 8];
m_Planes[RIGHT][3] = clip.m[15] - clip.m[12];
NormalizePlane(RIGHT);
m_Planes[LEFT][0] = clip.m[ 3] + clip.m[ 0];
m_Planes[LEFT][1] = clip.m[ 7] + clip.m[ 4];
m_Planes[LEFT][2] = clip.m[11] + clip.m[ 8];
m_Planes[LEFT][3] = clip.m[15] + clip.m[12];
NormalizePlane(LEFT);
m_Planes[BOTTOM][0] = clip.m[ 3] + clip.m[ 1];
m_Planes[BOTTOM][1] = clip.m[ 7] + clip.m[ 5];
m_Planes[BOTTOM][2] = clip.m[11] + clip.m[ 9];
m_Planes[BOTTOM][3] = clip.m[15] + clip.m[13];
NormalizePlane(BOTTOM);
m_Planes[TOP][0] = clip.m[ 3] - clip.m[ 1];
m_Planes[TOP][1] = clip.m[ 7] - clip.m[ 5];
m_Planes[TOP][2] = clip.m[11] - clip.m[ 9];
m_Planes[TOP][3] = clip.m[15] - clip.m[13];
NormalizePlane(TOP);
m_Planes[NEAR][0] = clip.m[ 3] + clip.m[ 2];
m_Planes[NEAR][1] = clip.m[ 7] + clip.m[ 6];
m_Planes[NEAR][2] = clip.m[11] + clip.m[10];
m_Planes[NEAR][3] = clip.m[15] + clip.m[14];
NormalizePlane(NEAR);
m_Planes[FAR][0] = clip.m[ 3] - clip.m[ 2];
m_Planes[FAR][1] = clip.m[ 7] - clip.m[ 6];
m_Planes[FAR][2] = clip.m[11] - clip.m[10];
m_Planes[FAR][3] = clip.m[15] - clip.m[14];
NormalizePlane(FAR);
}
void NormalizePlane(int side)
{
float length = 1.0/(float)sqrt(m_Planes[side][0] * m_Planes[side][0] +
m_Planes[side][1] * m_Planes[side][1] +
m_Planes[side][2] * m_Planes[side][2]);
m_Planes[side][0] /= length;
m_Planes[side][1] /= length;
m_Planes[side][2] /= length;
m_Planes[side][3] /= length;
}
And check against it with:
bool PointInFrustum(float x, float y, float z)
{
for(int i = 0; i < 6; i++)
{
if( m_Planes[i][0] * x + m_Planes[i][1] * y + m_Planes[i][2] * z + m_Planes[i][3] <= 0 )
return false;
}
return true;
}
Then i render using:
camera->Update();
UpdateFrustum();
int numCulled = 0;
for(int i = 0; i < (int)meshes.size(); i++)
{
if(!PointInFrustum(meshCenter.x, meshCenter.y, meshCenter.z))
{
meshes[i]->SetDraw(false);
numCulled++;
}
else
meshes[i]->SetDraw(true);
}
What am i doing wrong?
