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Topic: Spherical texture map (Read 4287 times) |
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Mark Hill
 
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Spherical texture map
« on: Apr 7th, 2005, 2:25pm » |
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This code takes a drawing buffer and uses it as a texture map for a sphere (utilizing Toxi's sphere routine).
Is it possible to get a perfect continous wrap? I'm just doing a normal
x >width = 0 type wrapping for coordinates, but the mapping at the caps is wrong.
The cylindrical portion of the sphere is ok!
Anyway here it is: (apologies for dirty code)
Code:
BGraphics buf;
color pen;
void setup() {
size(300, 300);
buf = new BGraphics(150,150);
buf.background(0);
buf.format = ALPHA;
for (int i = 0; i < buf.width * buf.height; i++)
{
buf.pixels[i] = buf.pixels[i] & 0xff;
}
pen = color(0x77,0x77,0x77);
bx = buf.width/2;
by = buf.height/2;
buf.ellipseMode(CENTER_DIAMETER);
buf.strokeWeight(2);
buf.fill(pen);
buf.smooth();
buf.stroke(pen);
stroke(255,150,150);
noSmooth();
}
void loop() {
background(0);
oldbx = (int)bx;
oldby = (int)by;
updatePos();
// Blit buffer to screen, draw line and blit back modified section to buffer
smoothLine(buf, (int)oldbx, (int)oldby, (int)bx, (int)by, pen);
translate(width/2, height/2);
// rotateY(yrot+=ymag*0.0075);
rotateY(yrot+=xmag*0.0075);
rotateZ(yrot+=ymag*0.0075);
rotateX(xrot+=0.01);
sphereDetail(5);
texturedSphere(75, buf);
// image(buf,0,0,width,height);
}
float yrot,xrot,zrot;
float bx,by,oldbx,oldby;
float xmag, ymag = 0;
void updatePos() {
xmag = (pmouseX-width/2)*0.030;
ymag = (pmouseY-height/2)*0.030;
bx = (bx+xmag);
by = (by+ymag);
if(bx>buf.width) {bx=0; oldbx=0;}
else if (bx<0) {bx=width; oldbx=width;}
if(by>buf.height) {by=0; oldby=0;}
else if (by<0) {by=height; oldby=height;}
}
public void smoothLine(BGraphics g, int x1, int y1, int x2, int y2, color penCol) {
g.stroke(penCol); // Stroke on @ set weight
g.fill(penCol);
g.noSmooth();
g.line(x1,y1,x2,y2); // draw the line
if(g.strokeWeight>1) {
g.noStroke(); // strokeweight>1 causes strange behaviour, so noStroke to be safe, probably quicker, too.
g.ellipse(x1, y1, g.strokeWeight*2,g.strokeWeight*2); // cap previous line with rounded end
}
}
// Toxi
// generic routine to draw textured sphere,
// based on current settings of sphereDetail()
void texturedSphere(float r, BImage t) {
int v1,v11,v2;
float[] sphereX=g.sphereX;
float[] sphereY=g.sphereY;
float[] sphereZ=g.sphereZ;
int sphere_detail=g.sphere_detail;
beginShape(TRIANGLE_STRIP);
texture(t);
float iu=(float)(t.width-1)/(sphere_detail);
float iv=(float)(t.height-1)/(sphere_detail);
float u=0,v=iv;
for (int i = 0; i < sphere_detail; i++) {
vertex(0, -r, 0,u,0);
vertex(sphereX[i]*r, sphereY[i]*r, sphereZ[i]*r,u,v);
u+=iu;
}
vertex(0, -r, 0,u,0);
vertex(sphereX[0]*r, sphereY[0]*r, sphereZ[0]*r,u,v);
endShape();
// middle rings
int voff = 0;
for(int i = 2; i < sphere_detail; i++) {
v1=v11=voff;
voff += sphere_detail;
v2=voff;
u=0;
beginShape(TRIANGLE_STRIP);
texture(t);
for (int j = 0; j < sphere_detail; j++) {
vertex(sphereX[v1]*r, sphereY[v1]*r, sphereZ[v1++]*r,u,v);
vertex(sphereX[v2]*r, sphereY[v2]*r, sphereZ[v2++]*r,u,v+iv);
u+=iu;
}
// close each ring
v1=v11;
v2=voff;
vertex(sphereX[v1]*r, sphereY[v1]*r, sphereZ[v1]*r,u,v);
vertex(sphereX[v2]*r, sphereY[v2]*r, sphereZ[v2]*r,u,v+iv);
endShape();
v+=iv;
}
u=0;
// add the northern cap
beginShape(TRIANGLE_STRIP);
texture(t);
for (int i = 0; i < sphere_detail; i++) {
v2 = voff + i;
vertex(0, r, 0,u,v+iv);
vertex(sphereX[v2]*r, sphereY[v2]*r, sphereZ[v2]*r,u,v);
u+=iu;
}
vertex(0, r, 0,u,v+iv);
vertex(sphereX[voff]*r, sphereY[voff]*r, sphereZ[voff]*r,u,v);
endShape();
}
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