Reason is that 4 haven't been enough anymore for even pretty common graphic pipelines for a while now.
8 might still not be enough, but let's see first if people are happy with it.
This has some costs for people not needing more textures, as we have fatter Materials now.
- Memory usage increases by 64 bytes per SMaterial.
- Serialization files for the irr-format are now larger.
- Slight speed cost, thought mainly in debug
For people who don't need this and want to avoid some of the costs there is a new variable irr::video::MATERIAL_MAX_TEXTURES_USED which can be set to the maximal number of textures a project will need
before creating any device. This avoids pretty much all speed-costs involved with this change.
Software drivers are not much affected as they use their own texture-limits (2).
I did a few speed-comparison with varying numbers of _IRR_MATERIAL_MAX_TEXTURES_. The numbers displayed are FPS, so higher is better. I had 2 tests - one which forced many material changes and the other used a single material for all nodes. When there are 2 numbers in a result then I got different (generally lower) FPS when forcing material changes. The test used a simple model with 500 polygons and rendered it 4500 times.
OLD means - before working on all changes related to increasing texture-numbers and without changing materials (found a bunch of places to decrease the impact of this change which also sometimes did speed up Irrlicht generally). 1.8 refers to Irrlicht 1.8 with same test. All tests done on Windows/VisualStudio.
Max.textures 4 8 16 64 64 MATERIAL_MAX_TEXTURES_USED=4
GL/debug 50/68 44/58 35/45
GL/release 117 117 117 80/100 117
D3D9/debug 51/56 45/49 37/39
D3D9/release 168 168 152/168 90/87 168
OLD GL/debug 63
OLD GL/release 117
OLD D3D9/debug 44
OLD D3D9/rel 168
1.8 GL/debug 23/29
1.8 GL/release 94/117
1.8 D3D9/debug 59/63
1.8 D3D9/rel 142/152
Take all results with a grain of salt, it probably often is limited by fill-rate and doesn't even notice the texture-number changes (especially in release).
git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@5682 dfc29bdd-3216-0410-991c-e03cc46cb475
957d34ff0e