PImage myTexture;

void setup() {
    size(500,500,P3D);
    myTexture = loadImage("tex1.png");
}

void draw() {
    background(#CCCCCC);
    textureMode(NORMAL);

    pushMatrix();
        translate(width/2,height/2);
        scale(300);

        strokeWeight(0);
        noStroke();
        noFill();
        tint(#FF3300);

        beginShape(QUADS);
            texture(myTexture);
            vertex(-0.5, -0.5,   0,0);
            vertex( 0.5, -0.5,   1,0);
            vertex( 0.5,  0.5,   1,1);
            vertex(-0.5,  0.5,   0,1);
        endShape();
    popMatrix();
}