HI! Long time I am bothering about one thing: what is harder to compute for hardware, one quad (two triangles) with texture 8bit channel 512x512
or
600-650 tris mesh, with no texture but with one vertex colour paint data.
For example, if I had multiple meshes (particles) what method is easier to compute.
I am really interested in working with vertex colour data, and I hope it beats traditional texture mapping.
Unfortunately, I am not a programmer and can not run some tests to find out myself.
I think a quad with a texture is going to be a LOT faster than 650 colored triangles, even batched.
One has to transform only 4 vertexes and the other has to transform some number greater than 650… at worst 650x3.
I don’t think you save much by avoiding the texture lookup in the frag shader. I guess it could depend on how big that one quad is on screen but the GPU is very good at texture fetches.
Well, I am asking this because I actually did some testing with blender game engine.
I dont know is my testing correct or not, but instances of textured squares and vertex colour squares showed similar results. BUT! One major difference is that the instances of vertex-coloured-models have over one million triangles, and work absolutely at the same frame rate as instances of textured squares which cost 8 000 tris. I can assume that vertex colour is better solution for some situations, as this one. First reason - geometry can be shaped as I want, because I have dense polycount and there is no such thing as mipmap or I dont have to bother with stupid bitmap artefacts, such as pixialisation or quality loose at small image resolution, my main resolution - is polycount, second - we dont need to generate any additional information such as UV maps and, I guess, no need to calculate all 3 channels of image, it is pure information about vertices.
So this testing made me think about benefits of vertex colours …also I heard that some games are actually use this technique, as I do, for lens flares and other similar effects .
Thank you for your answer. I don’t know whether I am right or wrong so that is why I am asking. I am planning to use this technique in space game. I am pretty tired trying to deal with image artefacts, this stupid stair effects with 8 bit textures wich can not be bigger than 256X256 because they eat memory… I guess there is no better alternatives for cheap and quality visuals without bitmap artefacts.
Also you have a lot more of artistic control with Textures I guess…
It is true indeed, but in some cases traditional textures are horrible choice, for example - gradients. Gradients are the most suffering part of bitmap textures. If we want good gradient we need to make texture not less than 16 bit/channel…it is terrible choise for simple gradient effects, like lence flaires or any “blaster trace”. Homeworld used vertex colours for backgrounds, oh…their beautiful backgrounds, still love it and think homeworld is really outstanding game.
Actually, 600 tris is alot of tris for this. I did retopology (lol retopology of 2D effects…) and got 114 tris. guess somewhere around 150-300 tris is good for similar effects
Ho and you can bake the texture to vertex color in blender?
Yap, that is how I did this effect.
pretty neat 
