Question

I’m having a problem trying to get my texture showing correctly on some geometry. Basically, I have some triangles which which describe the shape of a person’s face, and then have a png which I have to load with opencv.
I have the following code

void Geometry::loadTex(const char* fileName){

    RenderUtils * u = new RenderUtils();

    IplImage* img = u->getImg(fileName);

    GLuint texture;


    // allocate a texture name
    glGenTextures( 1, &texture );

    // select our current texture
    glBindTexture( GL_TEXTURE_2D, texture );

    // select modulate to mix texture with color for shading
    glTexEnvf( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);


    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texWidth, texHeight, 0, GL_RGBA, GL_UNSIGNED_BYTE, img->imageData);

    glEnable(GL_TEXTURE_2D);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

    //delete [] t;
}



IplImage* RenderUtils::getImg(const char *fileName){
    IplImage* img = 0;
    img = cvLoadImage(fileName, CV_LOAD_IMAGE_COLOR);
    if(!img) cout << "Couldn't load image " << fileName << endl;
    return img;
}



void Geometry::display(){


    glPushMatrix();
    glTranslatef(20.0f, 20.0f, -40.f);
    glRotatef(180.f, 0.0, 0.0, 1.0);
    for(int i = 0; i < numTris; i+=3){
        glBegin(GL_TRIANGLES);
        glTexCoord3f(mean[tri[i]] / texWidth, ((mean[meanLength/2 + tri[i]] - maximumMu) * -1) / texHeight, 0 ); 
        glVertex3f(mean[tri[i]], (mean[meanLength/2 + tri[i]] - maximumMu) * -1, 0);
        glTexCoord3f(mean[tri[i+1]] / texWidth, ((mean[meanLength/2 + tri[i+1]] - maximumMu) * -1) / texHeight, 0 );
        glVertex3f(mean[tri[i+1]], (mean[meanLength/2 + tri[i+1]] - maximumMu) * -1, 0);
        glTexCoord3f(mean[tri[i+2]] / texWidth, ((mean[meanLength/2 + tri[i+2]] - maximumMu) * -1) / texHeight, 0 );
        glVertex3f(mean[tri[i+2]], (mean[meanLength/2 + tri[i+2]] - maximumMu) * -1, 0);
        glEnd();
    }


    glPopMatrix();
    glutSwapBuffers();
    glFlush();

}

So loadTex is called first, which calls load getImg, and then the display method is called from Glut.

Answer 1

You might want to take a look at this. It does exactly what you want.