float att[] = { 1, 0, 0 };
glPointParameterfvEXT( GL_DISTANCE_ATTENUATION_EXT, att );
glPointParameterfEXT( GL_POINT_FADE_THRESHOLD_SIZE_EXT, 1 );
glPointParameterfEXT( GL_POINT_SIZE_MIN_EXT, 16 );
glPointParameterfEXT( GL_POINT_SIZE_MAX_EXT, 64 );
glTexEnvf( GL_POINT_SPRITE_NV, GL_COORD_REPLACE_NV, GL_TRUE );
glEnable( GL_POINT_SPRITE_NV );
glBegin(GL_POINTS);
glPointSize(32);
for(int i=0;i<1024;i++)
{
glVertex3f(16*i,0,128);
}
glEnd();
glDisable( GL_POINT_SPRITE_NV ); Point Sprite trouble
Author
i don t know what i am doing wrong but the attenuation values i pass are the default values
and by default the size of the sprite doesn t change when you move it around
but in my application the sprites get bigger and bigger the further they are away from the cam eye position
any idea what i am doing wrong?
It happened to me. I think that when the "camera" gets closer to the sprites the sprites get smaller because they can''t be bigger than 64(?) pixels.
"C lets you shoot yourself in the foot rather easily. C++ allows you to reuse the bullet!"
"C lets you shoot yourself in the foot rather easily. C++ allows you to reuse the bullet!"
Author
is there a way to keep their size? thats really annoying
[edited by - Basiror on July 3, 2003 3:07:31 AM]
[edited by - Basiror on July 3, 2003 3:07:31 AM]
I wonder about that too, I think it''s a typical property of point sprites. I do know that you can change it''s size, so you could make them smaller when you''re further away from the point sprite, but that''s not an ideal solution. My particle engine uses them because they''re hardware-accelerated, but I''m also still looking for a function that stabilizes their size.
Author
there doesn t seem to be any
the only thing you could do is setting the min and max size parameters for each sprite and calculate this parameter at runtime
thus you still have a little performance boost over the other billboarding methods with quads/triangles and so on
but you need to know the scale function
btw i have 25000 particles in a 2 sited linked list( next & prev)
when i update all of them my frame drop from 380 to 200
is that acceptable?
the only thing you could do is setting the min and max size parameters for each sprite and calculate this parameter at runtime
thus you still have a little performance boost over the other billboarding methods with quads/triangles and so on
but you need to know the scale function
btw i have 25000 particles in a 2 sited linked list( next & prev)
when i update all of them my frame drop from 380 to 200
is that acceptable?
quote:Original post by Basiror
[...]
btw i have 25000 particles in a 2 sited linked list( next & prev)
when i update all of them my frame drop from 380 to 200
is that acceptable?
I think that''s acceptable: updating 25.000 particles in 1/200th of a second is pretty fast in my opinion. I don''t know if my own code is that fast, but that''s because my GUI is also done with OpenGL code.
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