Can I ask why these vertices are arranged so oddly?

m_verticies[0].x = -1.0f; m_verticies[1].y = 1.0f; m_verticies[1].z = 0.0f;
		m_verticies[0].u = 0.0f; m_verticies[1].v = 0.0f;

		m_verticies[1].x = -1.0f; m_verticies[0].y = -1.0f; m_verticies[0].z = 0.0f;
		m_verticies[1].u = 0.0f; m_verticies[0].v = 1.0f;

		m_verticies[2].x = 1.0f; m_verticies[3].y = -1.0f; m_verticies[3].z = 0.0f;
		m_verticies[2].u = 1.0f; m_verticies[3].v = 1.0f;

		m_verticies[3].x = 1.0f; m_verticies[2].y = 1.0f; m_verticies[2].z = 0.0f;
		m_verticies[3].u = 1.0f; m_verticies[2].v = 0.0f;

Note that if you draw out the triangles (0,1,2) and (3,2,1) it doesn't make a quad, but rather a weird shape that only covers 75% of a quad (the second triangle should be (3,2,0))

Also your two triangles as they are are wound in opposing directions. (0,1,2) is clockwise, and (3,2,1) is counterclockwise. Do you have any face culling enabled?

Can I ask why these vertices are arranged so oddly?

m_verticies[0].x = -1.0f; m_verticies[1].y = 1.0f; m_verticies[1].z = 0.0f;
m_verticies[0].u = 0.0f; m_verticies[1].v = 0.0f;

m_verticies[1].x = -1.0f; m_verticies[0].y = -1.0f; m_verticies[0].z = 0.0f;
m_verticies[1].u = 0.0f; m_verticies[0].v = 1.0f;

m_verticies[2].x = 1.0f; m_verticies[3].y = -1.0f; m_verticies[3].z = 0.0f;
m_verticies[2].u = 1.0f; m_verticies[3].v = 1.0f;

m_verticies[3].x = 1.0f; m_verticies[2].y = 1.0f; m_verticies[2].z = 0.0f;
m_verticies[3].u = 1.0f; m_verticies[2].v = 0.0f;

Note that if you draw out the triangles (0,1,2) and (3,2,1) it doesn't make a quad, but rather a weird shape that only covers 75% of a quad (the second triangle should be (3,2,0))

Also your two triangles as they are are wound in opposing directions. (0,1,2) is clockwise, and (3,2,1) is counterclockwise. Do you have any face culling enabled?