Get screen bounds of an actor

[argv]

I want to draw a rectangle around an actor in ZScript. To do this, I need to know where that actor is on the screen, and its width and height on the screen. Is there a way to find out?

[Pixel Eater]

Apeirogon is a champ at this. They've done exactly that for Fill Spectre (it can be enabled in the menu).
There's also Nash's cube version which could be useful: RadiusDebug.

How it's done is over my head but looking through the code might be helpful

[argv]

Those don't actually compute actor bounds at all. Fill Spectre's shader scans the whole screen using chroma key to figure out which pixels contain a spectre. RadiusDebug just places an actor with a cube-shaped model around the target actor. That doesn't solve my problem…

[Pixel Eater]

The last page I linked to has a newer method we've been testing that almost does away with the chroma keying. The chroma is only used to determine what's the foreground/background. The rest is handled by Apeirogon's bounding box code which calculates the on screen vertices of your chosen actor. Here I've enabled the outline from the menu:

[Nash]

I think you want world -> screen projection? Gutamatics helps you do this, but there's currently no documentation.

There's this example that's floating on Discord, should help you figure out how to use the projection API

Code: Select all

class PRJ_ProjectionTestHandler : StaticEventHandler {
    override void renderOverlay(RenderEvent e) {
        if (automapactive) return;
        
        PRJ_Matrix worldToClip = PRJ_Matrix.worldToClip(e.viewPos, e.viewAngle, e.viewPitch, e.viewRoll, players[consoleplayer].FOV);
        
        Actor projActor;
        ThinkerIterator iter = ThinkerIterator.create("Actor", Thinker.STAT_DEFAULT);
        while ((projActor = Actor(iter.next())) != NULL) {
            Vector3 adjustedWorldPos = e.viewPos + LevelLocals.vec3Diff(e.viewPos, projActor.pos);
            Vector3 ndcPos = worldToClip.multiplyVector3(adjustedWorldPos + (0, 0, projActor.height / 2.0)).asVector3();
            if (ndcPos.z <= 1 && ndcPos.z >= -1) {
                // this is the coordinates where you're drawing to:
                Vector2 drawPos = PRJ_GlobalMaths.ndcToViewPort(ndcPos);
                Screen.drawText(smallfont, Font.CR_White, drawPos.x - (smallfont.stringWidth("+") * cleanXFac / 2.0), drawPos.y - (smallfont.getHeight() * cleanYFac / 2.0), "+", DTA_CleanNoMove, true);
            }
        }
    }
}

[Apeirogon]

There's this example that's floating on Discord

Marvelous...I spent three days in mathcad, gzdoom console.printf and other stuff, analyzing what is responsible for what, to understand how it work, when there are already ready example how it works...

[Gutawer]

[imgur]https://i.imgur.com/AClSXri[/imgur]
I assume you mean like this. I've done this before, using Gutamatics:
https://gist.github.com/Gutawer/389966d ... 687cdbf52c

This will draw this box on all actors, which will look messy with corner textures, so you'll obviously want to filter out most actors using a hitscan or something to determine what the player's looking at. The corner textures use offsets to be drawn in the correct positions, and are offset by a triangle wave, since this was modelled after how Deus Ex' version of this looks which has fluctuating corners. You can remove that.

Replace #### with your chosen prefix to get this working, and you'll need to provide your own corner textures.

[argv]

Neat! But I already got it working in my mod, which draws basically that but for items that can be picked up.

[Gutawer]

Heh, fair enough, forgot to look at when this thread was made!

[ramon.dexter]

Neat! But I already got it working in my mod, which draws basically that but for items that can be picked up.

This should really go into the scripting resources as a major resource, cause it's perfect

[argv]

[imgur]https://i.imgur.com/AClSXri[/imgur]
I assume you mean like this. I've done this before, using Gutamatics:
https://gist.github.com/Gutawer/389966d ... 687cdbf52c

This will draw this box on all actors, which will look messy with corner textures, so you'll obviously want to filter out most actors using a hitscan or something to determine what the player's looking at. The corner textures use offsets to be drawn in the correct positions, and are offset by a triangle wave, since this was modelled after how Deus Ex' version of this looks which has fluctuating corners. You can remove that.

Replace #### with your chosen prefix to get this working, and you'll need to provide your own corner textures.

Although I have it working in my mod, I notice that your version looks like it accounts for the actor's entire 3D volume, rather than assuming that it's a flat sprite (with no billboarding on the pitch axis) like my implementation. This is obviously important if the actor in question is represented by voxels or a model, or if sprites are billboarded on both axes. I'll need to give your code another look. I've posted a GitHub issue to that effect.

By the way, you only need one corner texture, not four. DTA_FlipX and DTA_FlipY can be used to rotate them when drawing the other three corners.

Also, the texture name doesn't have to be in eight-letter form. The engine also accepts full paths like “UseToPickup/bracket.png” as a texture name. I use that to avoid namespace collisions with other mods—“UseToPickup” isn't normally considered a texture folder, so textures in that folder can only be found by their full path, and are therefore very unlikely to collide with anything.

[Gutawer]

By the way, you only need one corner texture, not four. DTA_FlipX and DTA_FlipY can be used to rotate them when drawing the other three corners.

Also, the texture name doesn't have to be in eight-letter form. The engine also accepts full paths like “UseToPickup/bracket.png” as a texture name. I use that to avoid namespace collisions with other mods—“UseToPickup” isn't normally considered a texture folder, so textures in that folder can only be found by their full path, and are therefore very unlikely to collide with anything.

Good points, but keep in mind that I made this quickly just to test that Gutamatics could do it, so not a whole lot of effort was put into that sort of thinking.

By the way, that's a pretty nice mod. You've nailed the presentation, with all the subtle fades and transitions.

[Graf Zahl]

I know people won't like what I'm saying now, but doing any unprojection from the 3D view to the 2D screen on the script side is a dangerous thing.
Just imagine the HUD code gets rewritten to draw on the upscaled result from the renderer, e.g. do draw the menu in higher resolution than the rest - which is actually seriously being considered. This all would completely fall apart in such a case because the 3D view's extent no longer matches the 2D view.

[Gutawer]

I understand what you mean, but to be honest, people clearly want to be able to do this (as this thread evidences, plus a large number of times from Discord) - there was a feature suggestion to do this here viewtopic.php?f=54&t=56168 but it was put on hold, so it didn't look like any progress was being made there, hence why I added this functionality to my maths library. I suppose it might be worth considering doing this now as an engine feature, because otherwise, unless there's an in-engine solution, people are going to continue doing this on the scripting side.

[Nash]

I'll stop using scripted solution when engine natively supports projection and deprojection. Otherwise, this is all I've got...