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Index › Programming Questions & Help › Syntax Questions › texture and directionalLight
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texture and directionalLight (Read 596 times)
Sjeiti
texture and directionalLight
Sep 20th, 2005, 9:39am  
Hi,

Should a texture disable the directionalLight?

In the example below mousePressed renders a texture onto a cube. Normally the cube respond to the light by having darker and lighter sides, with a texture attached it does not.

Code:
PImage eBgi;
float fRtX, fRtY;
void setup() {
fRtX = 0;
fRtY = 0;
size(300,300,P3D);
noStroke();
eBgi = new PImage(width,height);
for (int i=0;i<eBgi.pixels.length;i++) eBgi.pixels[i] = i<eBgi.pixels.length/2?color(51,102,126):color(102,126,51);
}
void draw() {
fRtX += 0.0001*(mouseY-height/2);
fRtY -= 0.0001*(mouseX-width/2);
background(0);
directionalLight(51, 102, 126, 0, 0, -1);
translate(width/2, height/2, 100);
rotateX(fRtX);
rotateY(fRtY);
textureMode(IMAGE);
int iSze = 90;
int iPsx = -iSze/2;
int iPsy = -iSze/2;
int iPsz = -iSze/2;
for (int i=0;i<8;i++) {
rotateX((i+0)%3*PI*.5);
rotateY((i+1)%3*PI*.5);
rotateZ((i+3)%3*PI*.5);
beginShape();
if (mousePressed) {
texture(eBgi);
vertex(iPsx, iPsy, iPsz, 0, 0); 
vertex(iPsx+iSze, iPsy, iPsz, eBgi.width,0); 
vertex(iPsx+iSze, iPsy+iSze, iPsz,eBgi.width,eBgi.height); 
vertex(iPsx, iPsy+iSze,iPsz, 0, eBgi.height);
} else {
vertex(iPsx, iPsy, iPsz); 
vertex(iPsx+iSze, iPsy, iPsz); 
vertex(iPsx+iSze, iPsy+iSze, iPsz); 
vertex(iPsx, iPsy+iSze,iPsz);
}
endShape();
}
}


gr...

...Ron
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mark hill
Re: texture and directionalLight
Reply #1 - Sep 20th, 2005, 12:42pm  
My understanding is that when the lights go on, the texture goes out.

I think that it's probably due to the lights using the texture map to do the light rendering.
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Sjeiti
Re: texture and directionalLight
Reply #2 - Sep 20th, 2005, 2:41pm  
I don't think that is entirely the case. I've tried other lights of course and both spotLight  an pointLight do work with a texture (although not exactly in the way you'd expect).
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Stephen Williams
Re: texture and directionalLight
Reply #3 - Mar 6th, 2007, 12:48pm  
To get lighting to work with textures you have to set the normal (http://processing.org/reference/normal_.html).

i.e.
normal(iPsx, iPsy, iPsz);  
vertex(iPsx, iPsy, iPsz, 0, 0);  
normal(iPsx+iSze, iPsy, iPsz);  
vertex(iPsx+iSze, iPsy, iPsz, eBgi.width,0);  
normal(iPsx+iSze, iPsy+iSze, iPsz);  
vertex(iPsx+iSze, iPsy+iSze, iPsz,eBgi.width,eBgi.height);  
normal(iPsx, iPsy+iSze,iPsz);
vertex(iPsx, iPsy+iSze,iPsz, 0, eBgi.height);
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