Hi !
Now I’m printing a circle with ofCircle and I d like to print an image inside it.
I would prefer to maintain this structure rather than using an alpha image showing a circle.
Any suggestion ? Thanks for advance
Hi there!
I have the same question !
How do you bind a texture to a 2d (and maybe 3d too) polygonal shape ?
Anybody out there willing to help a beginner ?
thanks !
Here’s an idea on one way to do this, but it’s not the really the right way:
#include "testApp.h"
void testApp::setup(){
img.loadImage("ok.jpg");
text.allocate(512, 512, GL_RGB, false);
quadraticObj = gluNewQuadric(); // declare GLUquadricObj *quadraticObj; in yr .h file
text.loadData(img.getPixels(), 512, 512, GL_RGB);
}
void testApp::draw() {
glTranslatef(350, 250, 0);
glEnable(text.texData.textureTarget);
gluQuadricDrawStyle(quadraticObj, GLU_FILL);
gluQuadricTexture(quadraticObj, GL_TRUE);
gluDisk(quadraticObj, 0, 200, 50, 10);
glDisable(GL_TEXTURE_2D);
glDisable(text.texData.textureTarget);
}
Another idea that I can’t quite get to work right is like this:
void testApp::setup(){
img.loadImage("ok.jpg");
text.allocate(512, 512, GL_RGB, false);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexEnvf(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_REPLACE);
text.loadData(img.getPixels(), 512, 512, GL_RGB);
ofSetCircleResolution(360);
}
void testApp::draw() {
glTranslatef(350, 250, 0);
glEnable(text.texData.textureTarget);
int numFanVertices = 360; // make a constant for this
GLfloat textureAngle = 0.0f;
//make coordinates for the texture
GLfloat textureCoordinates[2*numFanVertices];
angle = 0.0f;
textureCoordinates[0] = 0.5f;
textureCoordinates[1] = 0.5f;
for(int i=2; i<(2*numFanVertices); i++){
textureCoordinates[i++] = 0.5f * cos(angle) + 0.5f;
textureCoordinates[i] = 0.5f * sin(angle) + 0.5f;
textureAngle += (PI/180.0f);
}
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
// set the texture to get drawn in the glDrawArrays that's inside ofCircle
glTexCoordPointer(2,GL_FLOAT,0,textureCoordinates);
ofCircle(0, 0, 200);
glPopMatrix();
glDisable(text.texData.textureTarget);
}
Maybe someone a little more texturing savvy can get find a cool way to get all the coords for the texture set correctly.
Hey - here is a quick example:
//--------------------------------------------------------------
void testApp::setup(){
//note because we use the ARB method - texture coordinates are measured in pixels not 0.0-1.0
//this has the advantage in that we can work with a non power of two image and not need to worry about the extra pixel padding.
sqImg.loadImage("squareImage.jpg");
circleTexture.allocate(sqImg.width, sqImg.height, GL_RGB);
circleTexture.loadData(sqImg.getPixels(), sqImg.width, sqImg.height, GL_RGB);
int numPts = 64;
float angle = 0.0;
float step = TWO_PI / (float)(numPts-1);
for(int i = 0; i < numPts; i++){
//get the -1 to 1 values - we will use these for drawing our pts.
float px = cos(angle);
float py = sin(angle);
NormCirclePts.push_back( ofPoint(px, py) );
//map the -1 to 1 range produced by cos/sin
//to the dimensions of the image we need for our texture coords
float tx = ofMap( px, -1.0, 1.0, 0, circleTexture.getWidth());
float ty = ofMap( py, -1.0, 1.0, 0, circleTexture.getHeight());
NormCircleCoords.push_back( ofPoint(tx, ty) );
angle += step;
}
}
//--------------------------------------------------------------
void testApp::draw(){
ofSetColor(255, 255, 255);
float radius = 200.0; //change this to scale your circle
circleTexture.bind();
glBegin(GL_POLYGON);
for(int i = 0; i < NormCirclePts.size(); i++){
glTexCoord2f(NormCircleCoords[i].x, NormCircleCoords[i].y);
glVertex2f( NormCirclePts[i].x * radius + mouseX, NormCirclePts[i].y * radius + mouseY);
}
glEnd();
circleTexture.unbind();
}
class testApp : public ofBaseApp{
public:
void setup();
void update();
void draw();
void keyPressed (int key);
void keyReleased(int key);
void mouseMoved(int x, int y );
void mouseDragged(int x, int y, int button);
void mousePressed(int x, int y, int button);
void mouseReleased(int x, int y, int button);
void windowResized(int w, int h);
ofImage sqImg;
ofTexture circleTexture;
vector <ofPoint> NormCirclePts;
vector <ofPoint> NormCircleCoords;
};
You need to pass in a square image though.
Theo
Ah, cool. I had tried something like that but having this:
text.allocate(512, 512, GL_RGB, false);
threw everything off, into GL_TEXTURE_2D and I didn’t notice. GL_TEXTURE_RECTANGLE_ARB is pretty cool.
This is awesome, thanks Theo.
Also, glad to see it still works after 3 years!