fade out effect

Graphics and GPU Programming Programming

Started by Saransh Shetty April 30, 2014 01:36 PM

0 comments, last by haegarr 10 years ago

Author

April 30, 2014 01:36 PM

So I have this polygon and I want to give it a fade out effect it needs to go from dark blue at top to light blue at the bottom... how do I do it?

glColor3f(0.0, 0.0, 1.0);
glBegin(GL_POLYGON);
glVertex2f(0.6,-1.0);
glVertex2f(2.0, -1.0);
glVertex2f(2.0,0.13);
glVertex2f(0.6, 0.13);
glEnd();

haegarr

7,408

April 30, 2014 01:58 PM

To give it a color gradient, you need to specify different colors to the particular vertices. The color which is set just before glVertex is called will be used for that vertex. E.g.


glBegin(GL_POLYGON);
// 1st vertex
glColor3f(0.5, 0.5, 1.0);
glVertex2f(0.6,-1.0);
// 2nd vertex
glColor3f(0.5, 0.5, 1.0);
glVertex2f(2.0, -1.0);
// 3rd vertex
glColor3f(0.0, 0.0, 1.0);
glVertex2f(2.0,0.13);
// 4th vertex
glColor3f(0.0, 0.0, 1.0);
glVertex2f(0.6, 0.13);
// done
glEnd();