Multitexturing

Given:
G=Grass
D=Dirt
R=Rock
S=Stone

I created 512x512 texture called tex0.
It's made up of 4 256x256 grass textures.
G G
G G

Also created 512x512 texture called tex1.
it's made up of 4 256x256 textures.

G R
D S

finally, create 512x512 texture called tex2.
it's made up of 4 256x256 textures each being a gradient fill.

GF GF
GF GF


The goal is to blend my two textures together using the gradient fill to provide a seamless transition. A more advanced version would allow a base texture, tiled texture, and the 2nd UV would control the alpha tile to be used.

I can't seem to get the alpha to cause the blend to work very well.

Here is the basic sample code I'm using. All help appreciated.

Dim u1#(4), V1#(4)
Dim M(2)


Global mesh, surf

;Graphics3D 800,600,32,2
Graphics3D 800,600,32
cam=CreateCamera()
MoveEntity cam ,10,100,10

AmbientLight 128,128,128
;AmbientLight 256,256,256


M(1)=CREATEGRID(32,100)


;Smoothing off
ClearTextureFilters 

;Filter Flags

;1: Color
;2: Alpha
;4: Masked
;8: Mipmapped
;16: Clamp U
;32: Clamp V
;64: Spherical reflection map

TextureFilter "",1+2
;TextureFilter "",1+8 ; Mip Mapped

; Load texture 
;tex0=LoadTexture("alphaL.png") 
tex1=LoadTexture(".\textures\nutarg.tga") 

ClearTextureFilters 

TextureFilter "",8
;tex1=LoadTexture("raw3.jpg") 
tex0=LoadTexture(".\textures\G0.jpg")

TextureFilter "",8
tex2=LoadTexture(".\textures\T0.jpg") 

; Create brush 
brush=CreateBrush() 

; Apply texture to brush 
BrushTexture brush,tex0,0,0
BrushTexture brush,tex1,0,1
BrushTexture brush,tex2,0,2

;Blend - Blend mode of texture. 
;0: Do Not blend 
;1: No blend Or Alpha (alpha when texture loaded with alpha flag - Not recommended For multitexturing - see below) 
;2: Multiply (Default) 
;3: Add 
TextureBlend tex0,2
TextureBlend tex1,1
TextureBlend tex2,2

; And some shininess 
;BrushShininess brush,1 

; Paint mesh with brush 
PaintSurface surf,brush 


PointEntity cam,m(1)

While Not KeyHit(1)

; Toggle wireframe enable value between true and false when spacebar is pressed 
If KeyHit( 57 )=True Then enable=1-enable 

; Enable/disable wireframe rendering 
WireFrame enable 

If T=0 Then T=MilliSecs() ;Prime time
 
T2=MilliSecs()

DeltaT# = (T2-T) / 1000.0 
T=MilliSecs() 


; Execute every 25ms ( 40/sec )
If T > Time2 + 0 Then
	Time2=T

	mxs#=mxs#+(MouseXSpeed()-mxs#)/3
	mys#=mys#+(MouseYSpeed()-mys#)/3

	If MouseDown(2) Then 
		MoveMouse GraphicsWidth()/2,GraphicsHeight()/2
		p1#=p1#-mys#
		y1#=y1#-mxs#
		RotateEntity cam,-p1#,y1#,0
	EndIf

End If

RenderWorld
Flip
Wend

Function CreateGrid( Segs, Siz )

mesh=CreateMesh()
surf=CreateSurface(mesh)

For y=0 To Segs
	For x=0 To Segs
	
		tex=Rnd(1,2)
		Select tex
			Case 1
				u1(1)=0:v1(1)=0
				u1(2)=0:v1(2)=.4
				u1(3)=.4:v1(3)=.4
				u1(4)=.4:v1(4)=0

			Case 2
				u1(1)=0:v1(1)=.6
				u1(2)=0:v1(2)=1
				u1(3)=.4:v1(3)=1
				u1(4)=.4:v1(4)=.6


			Case 3
				u1(1)=.6:v1(1)=.6
				u1(2)=.6:v1(2)=1
				u1(3)=1:v1(3)=1
				u1(4)=1:v1(4)=.6


			Case 4
				u1(1)=.6:v1(1)=0
				u1(2)=.6:v1(2)=.4
				u1(3)=1:v1(3)=.4
				u1(4)=1:v1(4)=0
	End Select


		;u1(1)=1:v1(1)=1
		;u1(2)=1:v1(2)=0
		;u1(3)=0:v1(3)=0
		;u1(4)=0:v1(4)=1
		
		;u1(1)=0:v1(1)=0
		;u1(2)=0:v1(2)=1
		;u1(3)=1:v1(3)=1
		;u1(4)=1:v1(4)=0
		
		vert0=AddVertex(surf, x*siz+siz,0, y*siz-siz,u1(1),v1(1))
		vert1=AddVertex(surf, x*siz+siz,0, y*siz,u1(2),v1(2))
		vert2=AddVertex(surf, x*siz,0, y*siz,u1(3),v1(3))
		vert3=AddVertex(surf, x*siz,0, y*siz-siz,u1(4),v1(4))
		
		AddTriangle(surf,vert0,vert2,vert1)
		AddTriangle(surf,vert2,vert0,vert3)

	Next
Next
UpdateNormals mesh
Return mesh
End Function