Vertex Color vs Material ID
polycounter lvl 6
Hello.
Assume we have a plane object and we want to assign it two different looks. One is sandy and an other one is muddy, so for this case we can color the vertexes of upper half of the plane and then color the rest of it a different color, we then can use it for a Shader to make it half sandy and half muddy. The other way is to set material ID for each areas of the object (I guess when we choose two different materials for the plane in 3DS Max in the editable mesh modifier, it does so).
But which way is game-friendly and uses less ram? would be glad if you explain your answer.
Assume we have a plane object and we want to assign it two different looks. One is sandy and an other one is muddy, so for this case we can color the vertexes of upper half of the plane and then color the rest of it a different color, we then can use it for a Shader to make it half sandy and half muddy. The other way is to set material ID for each areas of the object (I guess when we choose two different materials for the plane in 3DS Max in the editable mesh modifier, it does so).
But which way is game-friendly and uses less ram? would be glad if you explain your answer.
Replies
Vertex color giver better performance but less blending quality,
material ID giver less performance but more blending quality.
NOTE: less performance doesn't mean BAD performance.
Material IDs cause the vertices to be duplicated along the seam between the two IDs. This increases the in-game vertex count, which is not really a performance cost (unless you have a lot of ID seams). The cost of using Material IDs comes from increasing the draw calls for the model. Each material change = more draw calls.
http://wiki.polycount.com/wiki/GameRenderingTerminology
If you want to blend by using a texture instead of using vertex colors:
http://wiki.polycount.com/wiki/MultiTexture#Texture_Splatting
And thank you Mr.Chadwick, You always effectively help.