Blitz3D+ Command Reference

VertexColor surface,index,red#,green#,blue#[,alpha#]

Parameters

surface - surface handle
index - index of the vertex, from 0 to CountVertices( surface )-1
red# - red value, 0 to 255
green# - green value, 0 to 255
blue# - blue value, 0 to 255

alpha# (optional) - vertex transparency, 0.0 to 1.0; 1.0 (default)

Description

Sets the colour of an existing vertex.

Vertex colours blend smoothly across each triangle, which makes them a very cheap way to shade a mesh: baked lighting, gradients on skies, tinted terrain-style geometry, glowing tips on effects - all without a single texture. New vertices start at 255,255,255 with alpha 1.

Vertex colours are enabled by EntityFX/BrushFX flag 2. In Blitz3D+ their RGB values multiply the material colour; use white entity and brush colours to display them unchanged. For per-vertex alpha# to show as transparency, also add flag 32: flags 2+32 together. EntityAlpha and vertex alpha combine.

Colour values outside 0-255 are clamped.

See also: EntityFX, BrushFX, VertexRed, VertexGreen, VertexBlue, VertexAlpha.

Example

; VertexColor Example
; -------------------

; VertexColor tints a single vertex; the GPU blends the colours
; smoothly across each triangle. Vertex colours only show when the
; entity has EntityFX flag 2 set. Here each corner of a quad cycles
; through colours at its own pace.

Graphics3D 640,480
SetBuffer BackBuffer()

camera=CreateCamera()
PositionEntity camera,0,0,-4

panel=CreateMesh()
surf=CreateSurface(panel)

; A simple quad with one vertex per corner
v0=AddVertex(surf,-1.5,1.5,0)
v1=AddVertex(surf,1.5,1.5,0)
v2=AddVertex(surf,1.5,-1.5,0)
v3=AddVertex(surf,-1.5,-1.5,0)
AddTriangle surf,v0,v1,v2
AddTriangle surf,v0,v2,v3

; Flag 2 enables vertex colours; flag 1 would also disable scene lighting.
EntityFX panel,2

While Not KeyDown(1)

    ; Cycle each corner's colour with offset phases - the documented
    ; command, called once per vertex per frame
    t#=MilliSecs()*0.1
    r0#=127+128*Sin(t)
    g0#=127+128*Sin(t+120)
    b0#=127+128*Sin(t+240)
    VertexColor surf,v0,r0,g0,b0
    VertexColor surf,v1,g0,b0,r0
    VertexColor surf,v2,b0,r0,g0
    VertexColor surf,v3,255-r0,255-g0,255-b0

    ; Arrow keys move the camera
    If KeyDown(200) Then MoveEntity camera,0,0,0.1
    If KeyDown(208) Then MoveEntity camera,0,0,-0.1
    If KeyDown(203) Then TurnEntity camera,0,1,0
    If KeyDown(205) Then TurnEntity camera,0,-1,0

    RenderWorld

    Text 0,0,"Arrow keys: move camera   Esc: exit"
    Text 0,20,"VertexColor surf,v0,"+Int(r0)+","+Int(g0)+","+Int(b0)

    Flip

Wend

End

Index