hi,

i've mapped an image to a cylinder in processing. the texture is mapped to the xyzuv coordinates, however, the texture overlaps. if i double the number of sides, there's an extra space between the beginning and end of the texture.

import processing.opengl.*;

PImage img;

void setup()
{
    smooth();
   
    img = loadImage("lines2.png");
   
    size(1000, 1000, OPENGL);
}

void draw()
{
    background(255);
    noStroke();
    lights();
   
    int passedTime = millis() - savedTime;
    println(passedTime/1000);

    pushMatrix();
    translate(width/2, height/2);
   
    rotateY(map(mouseX, 0, width, -PI, PI));

    drawCylinder(30, img.width/(2 * PI), img.height); //the texture overlaps at 30 sides and, at 60 leaves a gap
    popMatrix();
}

void drawCylinder(int sides, float r, float h)
{
    float angle = 360 / sides;
    float halfHeight = h / 2;

    // draw top of the tube
    beginShape();
    for (int i = 0; i < sides; i++) {
        float x = cos( radians( i * angle ) ) * r;
        float z = sin( radians( i * angle ) ) * r;
        vertex( x, -halfHeight, z);
    }
    endShape(CLOSE);

    // draw bottom of the tube
    beginShape();
    for (int i = 0; i < sides; i++) {
        float x = cos( radians( i * angle ) ) * r;
        float z = sin( radians( i * angle ) ) * r;
        vertex( x, halfHeight, z);
    }
    endShape(CLOSE);

    // first texture
    beginShape(QUAD_STRIP);
    texture(img);
    for (int i = 0; i <= sides; i++) {
        float x = cos( radians( i * angle ) ) * r;
        float z = sin( radians( i * angle ) ) * r;
       
        vertex( x, -halfHeight, z, img.width/sides * i, 0);
        vertex( x, halfHeight, z, img.width/sides * i, img.height);
    }
    endShape(CLOSE);
}

thanks,

destro