Implementation

• Modeling the Meshes and UV Mapping in Blender.
• Creating the Textures in Affinity, for Masking and doing the Tunnel and Glow VFX.
• Using ZWrite Off to make the shaders not write to the Depth Buffer.
• Using the Blend command from Shader Lab to implement traditional transparency and additive transparency.
• Portal entrance implemented by writing a custom value to the Stencil Buffer to use as a Mask.
• Masking the Tunnel, Hemisphere and Particles using the Stencil Test, checking if the Stencil Buffer has the required value written on.
• Tunnel implemented animating the texture across the UV.y coordinates using _Time.
• Particle System with custom Shader to also do the Stencil Test to Mask the particles inside the portal.
• Defining the Vertex Color property so Color Over Time works in the Particle System.
• Parametrizing Color, Intensity and Velocity in all the parts of the VFX, for full customization.