make the sun glow?
I can get a decent "glow" effect by drawing slightly larger, slightly more translucent copies of an object at the same position as the actual object.
glScalef(1,1,1);
glColor4f(1.0f, 0.0f, 0.0f, 1);
DrawSphere();
glScalef(1.1, 1.1, 1.1);
glColor4f(1.0f, 0.0f, 0.0f, .5);
DrawSphere();
glScalef(1.2, 1.2, 1.2);
glColor4f(1.0f, 0.0f, 0.0f, .2);
DrawSphere();
where DrawSphere() is
GLUquadricObj *quadratic;
quadratic = gluNewQuadric();
gluQuadricNormals(quadratic, GLU_SMOOTH);
gluSphere(quadratic, 1.0f, 32, 32);
However, this makes perfect circles and looks very fake. See this image:
http://www.photoshoptalent.com/photoshop-picture/480f1bb99c1fe/Glowing-Planet.html
The red part is like what i'm getting (perfect cirlces) What I'm interested in doing is the white (rays) that are emanating in a non-uniform kind of way. How would you do this using opengl?
Thanks,
Dave
If what you want is something like this:
I think I would go with a GLSL shader to "cast" rays sparkling from the sun.
An other cool technique is to pre-render your sun in a Frame Buffer Object, draw your scene normally and them blend the FBO with the Framebuffer with a shader based on gaussian blur.
Check out the free online GPU gems 1 & 2, there is a tutorial about bloom effect.
I think I would go with a GLSL shader to "cast" rays sparkling from the sun.
An other cool technique is to pre-render your sun in a Frame Buffer Object, draw your scene normally and them blend the FBO with the Framebuffer with a shader based on gaussian blur.
Check out the free online GPU gems 1 & 2, there is a tutorial about bloom effect.
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