Second Life Forums Archive - ripple water issues

paulie Femto

Into the dark

Join date: 13 Sep 2003

Posts: 1,098

12-17-2005 13:11

Some objects underwater dont "ripple" at all.

This plant is completely underwater. It doesnt ripple at all.

_____________________

REUTERS on SL: "Thirty-five thousand people wearing their psyches on the outside and all the attendant unfettered freakishness that brings."

Thili Playfair

Registered User

Join date: 18 Aug 2004

Posts: 2,417

12-17-2005 17:05

Fractals dont work with ripples? or is that prims/alpha

Nathan Stewart

Registered User

Join date: 2 Feb 2005

Posts: 1,039

12-17-2005 20:11

From: Thili Playfair

Fractals dont work with ripples? or is that prims/alpha

It may be an alpha plant, linden plants do ripple. Im not sure if alpha textures dont ripple or in this case you cant see the ripple because the edge is clear.

_____________________

Runitai Linden

Linden Lab Employee

Join date: 29 Aug 2005

Posts: 52

12-17-2005 22:34

Transparent objects will never appear to be under water, which really sucks because every compelling underwater environment is full of plants.

This is because transparent objects are rendered AFTER the water is rendered, so they always appear to be in front, which is almost always what you want. Trees are rendered separately from other objects, I think before water, but I'm not sure from memory. This is why you'll often get nasty artifacts around the edges of transparent objects against trees.

Let me take a moment to talk about transparent objects. Transparent objects have to be sorted from back to front when drawn because they change the color of what's behind them on the screen when they are drawn. In order to change the color of what's behind them, what's behind them needs to be drawn first. Special transparent objects (like water and trees) are often rendered in a completely separate pass than other transparent objects because of their special needs.

In Second Life, sorting of transparent objects (alpha sorting) is done for each face of an object using the center position of the face. Wandering around the world, I see a lot of trees people have made by putting two or three intersecting boxes together (making an X or *). These trees will often draw incorrectly because their faces are intersecting each other and their center positions are all the same. A single face is both in front of and behind another. It is impossible to efficiently draw such a tree. It would be better to use 4 or 8 boxes so that none of the boxes intersect and it is always clear which face is in front of the other.

Argent Stonecutter

Emergency Mustelid

Join date: 20 Sep 2005

Posts: 20,263

12-18-2005 17:27

From: Runitai Linden

It is impossible to efficiently draw such a tree. It would be better to use 4 or 8 boxes so that none of the boxes intersect and it is always clear which face is in front of the other.

Unfortunately, that would mean using 2 or 4 times as many prims for the trees. This is one of the many prim-saving hacks people do that STAB ME IN THE EYE LIKE NEEDLES (ahem). Even when I do them.

What we really need is for the Linden trees to just become something else that can be applied to a prim, like a particle system, or textures.

CODE


llTreeSystem([
    TRUNK_RATIO,0.5,
    TRUNK_TEXTURE,"...",
    BRANCH_RATIO,0.3,
    BRANCH_TEXTURE,"...",
    ...]);

How about it for your next 2-week recreational hack?

ripple water issues
paulie Femto Into the dark Join date: 13 Sep 2003 Posts: 1,098	12-17-2005 13:11 Some objects underwater dont "ripple" at all. This plant is completely underwater. It doesnt ripple at all. _____________________ REUTERS on SL: "Thirty-five thousand people wearing their psyches on the outside and all the attendant unfettered freakishness that brings."
Thili Playfair Registered User Join date: 18 Aug 2004 Posts: 2,417	12-17-2005 17:05 Fractals dont work with ripples? or is that prims/alpha
Nathan Stewart Registered User Join date: 2 Feb 2005 Posts: 1,039	12-17-2005 20:11 From: Thili Playfair Fractals dont work with ripples? or is that prims/alpha It may be an alpha plant, linden plants do ripple. Im not sure if alpha textures dont ripple or in this case you cant see the ripple because the edge is clear. _____________________
Runitai Linden Linden Lab Employee Join date: 29 Aug 2005 Posts: 52	12-17-2005 22:34 Transparent objects will never appear to be under water, which really sucks because every compelling underwater environment is full of plants. This is because transparent objects are rendered AFTER the water is rendered, so they always appear to be in front, which is almost always what you want. Trees are rendered separately from other objects, I think before water, but I'm not sure from memory. This is why you'll often get nasty artifacts around the edges of transparent objects against trees. Let me take a moment to talk about transparent objects. Transparent objects have to be sorted from back to front when drawn because they change the color of what's behind them on the screen when they are drawn. In order to change the color of what's behind them, what's behind them needs to be drawn first. Special transparent objects (like water and trees) are often rendered in a completely separate pass than other transparent objects because of their special needs. In Second Life, sorting of transparent objects (alpha sorting) is done for each face of an object using the center position of the face. Wandering around the world, I see a lot of trees people have made by putting two or three intersecting boxes together (making an X or *). These trees will often draw incorrectly because their faces are intersecting each other and their center positions are all the same. A single face is both in front of and behind another. It is impossible to efficiently draw such a tree. It would be better to use 4 or 8 boxes so that none of the boxes intersect and it is always clear which face is in front of the other.
Argent Stonecutter Emergency Mustelid Join date: 20 Sep 2005 Posts: 20,263	12-18-2005 17:27 From: Runitai Linden It is impossible to efficiently draw such a tree. It would be better to use 4 or 8 boxes so that none of the boxes intersect and it is always clear which face is in front of the other. Unfortunately, that would mean using 2 or 4 times as many prims for the trees. This is one of the many prim-saving hacks people do that STAB ME IN THE EYE LIKE NEEDLES (ahem). Even when I do them. What we really need is for the Linden trees to just become something else that can be applied to a prim, like a particle system, or textures. CODE llTreeSystem([ TRUNK_RATIO,0.5, TRUNK_TEXTURE,"...", BRANCH_RATIO,0.3, BRANCH_TEXTURE,"...", ...]); How about it for your next 2-week recreational hack?

Welcome to the Second Life Forums Archive

ripple water issues