Best way to Draw a cube for 3D Picking
- by Kenneth Bray
Currently I am drawing a cube for a game that I am making and the cube draw method is below. My question is, what is the best way to draw a cube and to be able to easily find the face that the cursor is over? My draw method works just fine, but I am getting ready to start to add picking (this will be used to mold the cubes into other shaps), and would like to know the best way to find a face of the cube.
public void Draw() {
// center point posX, posY, posZ
float radius = size / 2;
//top
glPushMatrix();
glBegin(GL_QUADS);
{
glColor3f(1.0f,0.0f,0.0f); // red
glVertex3f(posX + radius, posY + radius, posZ - radius);
glVertex3f(posX - radius, posY + radius, posZ - radius);
glVertex3f(posX - radius, posY + radius, posZ + radius);
glVertex3f(posX + radius, posY + radius, posZ + radius);
}
glEnd();
glPopMatrix();
//bottom
glPushMatrix();
glBegin(GL_QUADS);
{
glColor3f(1.0f,1.0f,0.0f); // ?? color
glVertex3f(posX + radius, posY - radius, posZ + radius);
glVertex3f(posX - radius, posY - radius, posZ + radius);
glVertex3f(posX - radius, posY - radius, posZ - radius);
glVertex3f(posX + radius, posY - radius, posZ - radius);
}
glEnd();
glPopMatrix();
//right side
glPushMatrix();
glBegin(GL_QUADS);
{
glColor3f(1.0f,0.0f,1.0f); // ?? color
glVertex3f(posX + radius, posY + radius, posZ + radius);
glVertex3f(posX + radius, posY - radius, posZ + radius);
glVertex3f(posX + radius, posY - radius, posZ - radius);
glVertex3f(posX + radius, posY + radius, posZ - radius);
}
glEnd();
glPopMatrix();
//left side
glPushMatrix();
glBegin(GL_QUADS);
{
glColor3f(0.0f,1.0f,1.0f); // ?? color
glVertex3f(posX - radius, posY + radius, posZ - radius);
glVertex3f(posX - radius, posY - radius, posZ - radius);
glVertex3f(posX - radius, posY - radius, posZ + radius);
glVertex3f(posX - radius, posY + radius, posZ + radius);
}
glEnd();
glPopMatrix();
//front side
glPushMatrix();
glBegin(GL_QUADS);
{
glColor3f(0.0f,0.0f,1.0f); // blue
glVertex3f(posX + radius, posY + radius, posZ + radius);
glVertex3f(posX - radius, posY + radius, posZ + radius);
glVertex3f(posX - radius, posY - radius, posZ + radius);
glVertex3f(posX + radius, posY - radius, posZ + radius);
}
glEnd();
glPopMatrix();
//back side
glPushMatrix();
glBegin(GL_QUADS);
{
glColor3f(0.0f,1.0f,0.0f); // green
glVertex3f(posX + radius, posY - radius, posZ - radius);
glVertex3f(posX - radius, posY - radius, posZ - radius);
glVertex3f(posX - radius, posY + radius, posZ - radius);
glVertex3f(posX + radius, posY + radius, posZ - radius);
}
glEnd();
glPopMatrix();
}
