Distant Viewing

[Azamorn]

I was doing a test with setting my external cells to 2 and viewing distance to 20000 and standing on top of a hill overlooking Balmora, with Water Shaders turned on the framerate dropped to around 7 FPS, with the Water Shaders turned off the game run at around 20 FPS, which is still very playable for me!

The weird thing is that if you check the screenshots, hardly any water is visible at all, I believe that to get performance up for the Water Shader it will need some optimisations, so water that is behind objects aren't rendered so to speak, I think this could bring the FPS back up if it only needs to render the Water Shaders that are 'seen',
The large FPS drop is probably it trying to render the water from the river in the whole 20000 view distance ?

Here's the two screenshots I took:

with the water shaders turned off

&

with the water shaders turned on

The game is running between 30 FPS and 60 FPS with default viewing distance, I have an Asus HD 6970

[Chris]

The big FPS drain with water shaders is due mainly to the reflections. That causes it to render the scene twice... once upside-down for the reflection, and again right-side-up for the main view, and use the upside-down version as a texture for the water plane. The water plane itself is clipped to what you can see via the z-buffer, but the reflection itself still needs to be rendered because it can't know ahead of time what parts of the reflection are needed.

[Azamorn]

Very interesting, Hypothetically speaking if the reflections could prerender only the scene surrouding them, would that not drastically reduce the amount needed to be rendered while still looking the same.
I mean as you said it's litteraly rendering the whole scene twice just for a reflection and 95% of that isn't needed for an accurate reflection.

[raevol]

My ignorance is going to be showing here, but could you render the scene once, and then flip it?

[SquireNed]

My ignorance is going to be showing here, but could you render the scene once, and then flip it?

Never fear, you aren't alone in asking that question.

[Chris]

My ignorance is going to be showing here, but could you render the scene once, and then flip it?

Not really, because the reflection can "see" different parts of an object. Imagine an overhang where the camera is above the ledge, the reflection would show what's underneath where the camera can't see.

[lysol]

My ignorance is going to be showing here, but could you render the scene once, and then flip it?

Not really, because the reflection can "see" different parts of an object. Imagine an overhang where the camera is above the ledge, the reflection would show what's underneath where the camera can't see.

Excactly. The reflection isn't the exact same perspective as what you see.

[raevol]

I knew I was missing something- thanks!