Demonstrating the use of Noise functions to generate textures.
These functions use a pseudo-random series of numbers, at various frequencies with interpolated values.
function Interpolation(float a,b,c) as float
============================================
return a+(b-a)*c*c*(3-2*c)
end function
function InterpLinear(float a,b,c) as float
===========================================
return a*(1-c)+b*c;
end function
function Noise(int v) as float
==============================
static double d=1/0x7fffffff
mov eax,v
rol eax,5
mul v
xor eax,0x9595adad
mul v
rol eax,3
and eax,0x7fffffff 'always positive
mov v,eax
return v*d 'range 0..1.0
end function
'FOR COLORS ETC
sub AddNoiseC(sys pp,wi,ht,st,r,g,b,a,off)
==========================================
'pixbase,width,height,stride,colorval,offset
sys x,y,mk
byte rr,gg,bb,aa
float v1,v2,v3,v4,v5,v6,v7,dv
dv=1/st
mk=-st
for y=0 to <ht
y1=y and mk
y2=y1+st
y3=y1*wi+off
y4=y2*wi+off
for x=0 to <wi
x1=x and mk
x2=x1+st
v1=noise(y3+x1)
v2=noise(y3+x2)
v3=noise(y4+x1)
v4=noise(y4+x2)
'
v5=interpolation(v1,v2,(x-x1)*dv)
v6=interpolation(v3,v4,(x-x1)*dv)
v7=interpolation(v5,v6,(y-y1)*dv)
rr=r*v7
gg=g*v7
bb=b*v7
aa=a*v7
if a<0 then aa=255 'max alpha (opaque)
*pp+=rr+gg*0x100+bb*0x10000+aa*0x1000000
pp+=4
next
next
end sub
static sys res=256,texspace
texspace=res*res*4
string imgs[2]
imgs[1]=nuls texspace
imgs[2]=nuls texspace
'GetTexImage "../images/crate.jpg",res,imgs[1]
'
'pixbase,width,height,stride,colorval,offset
--------------------------------------------
AddNoiseC strptr imgs[1],res,res,32,050,050,100,-1,0x53535353
AddNoiseC strptr imgs[1],res,res,08,050,050,100, 0,0x35353535
AddNoiseC strptr imgs[1],res,res,04,070,070,050, 0,0x53535353
MakeTexture strptr imgs[1],res,res,texn[1]
AddNoiseC strptr imgs[2],res,res,08,100,100,000,-1,0x35353535
AddNoiseC strptr imgs[2],res,res,02,100,100,000, 0,0x35353535
AddNoiseC strptr imgs[2],res,res,01,050,050,000, 0,0x35353535
MakeTexture strptr imgs[2],res,res,texn[2]
The 2 .inc files belong in inc/
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