Issues with inbuilt shadows

Game Engine Game Engine Support and Discussion
1

Hello,

I have a mostly closed off room environment (couple holes in the roof) with a shadow casting sun lamp above shining from the right hand side of the pictures below. This light should be blocked by the right hand wall in the pictures and for the most part, it is.

Here is the scene:

normal.png1380×596 34.1 KB


Here is the in game version (running several custom HDR/bloom/etc. shaders):
rendered.png1381×596 224 KB

The problem is that the very bottom of the wall does not cast a shadow because the shadow appears to be a flattened image of the object instead of a true shadow. As a result of the sun’s tilt, this image is slightly too far up and leaves a part of the floor where the light still gets through, despite this being physically nonsensical.
How can I resolve this issue? (Changing the sun’s tilt would ruin the scene and is really not a solution at all). Do I need to get Blender’s source and modify the code behind this myself? (Something I’m not sure I’m up to doing, my C skills are decent but my knowledge of render algorithms really isn’t). Can I write a shader of some description to circumvent this? Or can this be fixed by changing pre-existing options?

2

You can change the sun bias in the lamp settings, (assuming it’s a variance lamp). You could also add a small outside-wall that you can’t see to create that shadow. You could increase the sun’s texture resolution.

There are a lot of things you can do before you have to edit blenders code. I haven’t ever edited blenders code, 5 years after starting using it.

4

Urgh, shadows that huge?! I don’t know how your computer runs ones that big. Normally I stay 256-512 region.

5

I suspect turning down the shadow size will make a huge difference, even if you think it’s the shaders. It’s probably graphics ram, which both shaders and shadows use a lot of.