Transparency
Notes on rendering transparency.
Rendering transparent objects is generally more expensive than rendering opaque objects. Opaque objects are rendered front to back with a depth buffer write. This means fragments are calculated and written to by the front-most object. Sorting can even be ignored where performance isn't as crucial. Transparent objects must be sorted back to front and each object rendered in their entirely.
Ignoring internal transparency
If you want to render a mesh as if it's opaque and apply transparency:
- Render the object opaquely to an intermediate render texture. Then render that texture to the scene.
- Render to a depth buffer than render with depth test as equal.
- Sort the indices front to back and render with depth write and depth test.
- If the mesh is convex, render just the front triangles.
Resources: