RayCast Target? hitting self fix?

[Altier Verwood]

Hey there LSL people, I am working on a vehicle with a raycast weapon on it, and I have it kind of working using this.

 

But I've run into a problem, when aiming straight a head the ray is blocked by something? but since i can't see the ray it's hard to tell whats blocking it. is there a way I can move the start of the ray projection forward by like 5 meters? I tried adding  llGetCameraPos()+<5,0,0>; but that doesn't seem to work either the ray just doesn't hit anything at that point.

                vector start = llGetCameraPos();
                list results = llCastRay(start, start+<range,0.0,0.0>*llGetCameraRot(),[RC_REJECT_TYPES,RC_REJECT_LAND,RC_DETECT_PHANTOM, FALSE,RC_DATA_FLAGS,RC_REJECT_PHYSICAL, TRUE,RC_GET_ROOT_KEY,RC_MAX_HITS,15]);
            llSleep(0.03);
            key target = llList2Key(results,0);
                llTriggerSound(fire_sound, 1.0);
                llResetOtherScript("Bolt1");
                llRegionSayTo(target,gTargetChan, damage_type);
                llResetOtherScript("m_f");
                llSleep(delay);

[Fenix Eldritch]

1 hour ago, Altier Verwood said:

I tried adding  llGetCameraPos()+<5,0,0>;

You forgot to multiply that start position by the camera rotation.

 

1 hour ago, Altier Verwood said:

but since i can't see the ray it's hard to tell whats blocking it.

It's good practice to add instrumentation/diagnostic code to help visualize things when you're trying to track down a problem. In this case, it would be helpful to rez an object at the ray's start and termination coordinates (and also the point of any ray hits).

As an example, the code below will check if it hit anything (the last value of the results list is always the number of hits). If we did hit something, the results list will always contain at minimum the uuid of the object hit, and the global position of the hit. You can use that to rez markers. (don't forget to add a prim called "marker" to the object's inventory. Also consider making it temporary to auto clean up)

llRezObject("marker", start, ZERO_VECTOR,ZERO_ROTATION, 0); //rez marker at ray origin point
if (llList2Integer(results, -1) > 0)   //check if we hit something
{
    llOwnerSay("Hit " + llKey2Name(llList2Key(results,0))); //say name of what we hit
    llRezObject("marker", llList2Vector(results,1), ZERO_VECTOR,ZERO_ROTATION, 0); //rez marker at impact position
}
else    //we didn't hit anything
{
    llOwnerSay("No hits");
    llRezObject("marker", start+<range,0.0,0.0>*llGetCameraRot(), ZERO_VECTOR,ZERO_ROTATION, 0); //rez marker at ray termination point
}
            

 

Edit: I had made a comment about RC_MAX_HITS 15 being potentially high for what I assumed is a hit-scan weapon. But I don't know your use case nor how you're processing the results list. Suffice to say, having as few max_hits as possible is preferable if possible, as it saves yourself some work. That of course depends entirely on what you're doing with the ray's hits, so take from that what you will.

Edited August 19, 2021 by Fenix Eldritch

[Altier Verwood]

Oh thank you for the replay! would you be able to elaborate on what i did wrong with the llGetCameraPos()+<5,0,0>;  ? how would i multiply that as you said?

[Fenix Eldritch]

You would do the same thing you already did for the ray's endpoint coordinate.

llGetCameraPos()+<5,0,0>*llGetCameraRot()

Literally use the multiply operator "*" and the results from llGetCameraRot()

Edited August 20, 2021 by Fenix Eldritch

[Altier Verwood]

but i have that already in the cast ray?  do i need to do it again?

              list results = llCastRay(start, start+<range,0.0,0.0>*llGetCameraRot(),[RC_REJECT_TYPES,RC_REJECT_LAND,RC_DETECT_PHANTOM, FALSE,RC_DATA_FLAGS,RC_REJECT_PHYSICAL, TRUE,RC_GET_ROOT_KEY,RC_MAX_HITS,15]);

[Altier Verwood]

it looks like you were right, I had to add

llGetCameraPos()+<5,0,0>*llGetCameraRot() to the "start" 

[Fenix Eldritch]

37 minutes ago, Altier Verwood said:

but i have that already in the cast ray?  do i need to do it again?

Yes, because both the start and end coordinates required by llCastRay are independent of each other.

Whenever you want to move a position in any direction relative to the current rotation, you need to multiply the  position (plus the offset) by that current rotation. This is necessary for the end position because it's some meters away. And once you try to move the start position forward of the current camera position, then that too needs to be multiplied by the current camera rotation in order to keep it along the same direction.

Edited August 20, 2021 by Fenix Eldritch

[Altier Verwood]

Thank you so much for this, you saved my project, I was getting so frustrated with the ray not hitting what i wanted!