I have a quadtree terrain, but nearby quads are being culled. Like so:

I was thinking maybe its my frustum extraction code? This is in OpenGL by the way in case matrix layout has any bearing on the problem and I am using the glm mat4x4 and vec4 types to represent my projection matrices and frustum planes

void Frustum::Extract(const vec3& eye,const mat4x4& camMatrix) { m_pos = eye; m_modView = camMatrix; m_projMatrix = GraphicsApp::GetInstance()->GetProjection(); mat4x4 MVPMatrix = m_projMatrix * m_modView; for(int plane = 0; plane < 3; plane ++){ int index = plane * 2; m_planes[index] = MVPMatrix[3] - MVPMatrix[plane]; NormalizePlane(index); } for(int plane = 0; plane < 3; plane ++){ int index = plane * 2 + 1; m_planes[index] = MVPMatrix[3] + MVPMatrix[plane]; NormalizePlane(index); } } void Frustum::NormalizePlane(int index){ float normFactor = m_planes[index][0] * m_planes[index][0] + m_planes[index][1] * m_planes[index][1] + m_planes[index][2] * m_planes[index][2]; m_planes[index] /= normFactor; }