static WebTransformationMatrix orthoProjectionMatrix(float left, float right, float bottom, float top)
{
// Use the standard formula to map the clipping frustum to the cube from
// [-1, -1, -1] to [1, 1, 1].
float deltaX = right - left;
float deltaY = top - bottom;
WebTransformationMatrix proj;
if (!deltaX || !deltaY)
return proj;
proj.setM11(2.0f / deltaX);
proj.setM41(-(right + left) / deltaX);
proj.setM22(2.0f / deltaY);
proj.setM42(-(top + bottom) / deltaY);
// Z component of vertices is always set to zero as we don't use the depth buffer
// while drawing.
proj.setM33(0);
return proj;
}
