- use DRW_engine prefix for engine types.
- use engine suffix for files that define a draw engine.
- remove engines from include path (they're only referenced once)
For now only compute GGX convolution. The GGX LUT used for the split sum approximation (UE4) is merged with the LTX mag LUT that uses the same parameters (theta and roughness)
Same as MEM_SAFE_FREE macro,
checks for NULL, runs free then sets NULL.
Blocks of code that do this many times are noisy and likely
errors here wouldn't be noticed immediately.
Also NULL's static vars which were being left set.
Using Texture Arrays to store shadow maps so less texture slots are used when shading. This means a large amount of shadows can be supported.
Support Projection Shadow Map for sun like in old BI/BGE.
Support Cube Shadow Map for Point/Spot/Area lights. the benefit of using it for spot light is that the spot angle does not change shadow resolution (at the cost of more memory used). The implementation of the cubemap sampling is targeted for 3.3 core. We rely on 2D texture arrays to store cubemaps faces and sample the right one manualy. Significant performance improvement can be done using Cubemap Arrays on supported hardware.
Shadows are only hardware filtered. Prefiltered shadows and settings comming next.
Using Linear Transform Cosines to compute area lighting. This is far more accurate than other techniques but also slower.
We use rotating quad to mimic sphere area light. For a better approximation, we use a rotating octogon.
