Since real time hard and soft shadows are Unity 3D Pro only features I thought I will learn Cg programming and create my own shadow mapping shader. But after some digging I found that the shadow mapping technique uses depth textures, and in Unity depth values can be accessed through a Render Texture object, which is Unity Pro only again. So is it true, that I cannot create real time shadow shaders as a workaround to the limitations of the free version?