Hi,
I've attached a sample script that shows how to move a texture across a surface:
Code:
import viz
viz.go()
viz.clearcolor(viz.SKYBLUE)
#Create a quad to display texture
quad = viz.add(viz.TEXQUAD)
quad.translate(0,1.8,3)
CLOUD_SPEED = 0.1
#Create texture with repeating wrap mode
tex = viz.add('ball.jpg')
tex.wrap(viz.WRAP_S,viz.REPEAT)
tex.wrap(viz.WRAP_T,viz.REPEAT)
tex.pos = 0
#Apply texture to quad
quad.texture(tex)
def ontimer(num):
#Increment texture position
tex.pos += CLOUD_SPEED * viz.elapsed()
#Create transform for texture
mat = viz.Transform()
mat.setTrans(tex.pos,0,0)
#Apply transform to texture
quad.texmat(mat)
viz.callback(viz.TIMER_EVENT,ontimer)
viz.starttimer(0,0,viz.FOREVER)
There is no built-in command to set a transparent color on a texture. You can set the transparent level on an object though. If you want only a certain color to be transparent then you will have to use a shader or simply edit the image with a program like Photoshop and save it to a format that supports transparency (png,tiff,etc..).
Also, I've attached a sample script that uses shaders to creating a moving sky with two cloud layers. I think it might be usefull for you.