How to draw a line from point x,y,z to x2,y2,z2 , ie. DrawLine() but for 3D ????

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PHeMoX

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Posted: 4th Dec 2018 16:31

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I'm basically trying to debug a raycasting issue that's fairly demanding in terms of performance (I'm trying to make some ants avoid eachother, there are thousands), but to be honest I can't really tell whether the rays shoot in the right direction, change when the angle of the ant is changing and so on. So I'd like to draw some kind of line to see where the ray tracing goes.

Any ideas, tips or tricks people want to share??

Also, I did notice raycasting loves to return the very object it spawned from. I feel AGK2 really needs some kind of flag to always ignore the object where tracing started. I know I can check the HitID and ignore the first object that way, but to me it always came across a bit weird it doesn't ignore that when the idea is 'collision check with another object' and virtually never itself, right?

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puzzler2018

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Posted: 4th Dec 2018 17:18 Edited at: 4th Dec 2018 17:20

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I did a 3D Line function which accepts

x1,y1,z1,x2,y2,z2

some time ago hidden in some of my thread somewhere - for the life of me, i cannot find it, once i do, ill let you know it

I did a rotation box made of drawline commands

can anyone remeber that bit of code and which thread it was at all?

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puzzler2018

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Posted: 4th Dec 2018 17:26

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Found it - it was in the Coding Train Conversions thread

// Project: 4d 
// Created: 2018-08-11
 
// show all errors
SetErrorMode(2)
 
// set window properties
SetWindowTitle( "4d" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window
 
// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts
 
 
 
 
 
type _pvector3d
    sphere
    x#
    y#
    z#
    w#
endtype 
 
pvector3d as _pvector3d[24]
 
size#=100
 
pvector3d[0].x#=-size# :pvector3d[0].y#=-size# : pvector3d[0].z#=-size#
pvector3d[1].x#=size# :pvector3d[1].y#=-size# : pvector3d[1].z#=-size#
 
pvector3d[2].x#=size# :pvector3d[2].y#=size# : pvector3d[2].z#=-size#
pvector3d[3].x#=-size# :pvector3d[3].y#=size# : pvector3d[3].z#=-size#
 
pvector3d[4].x#=-size# :pvector3d[4].y#=-size# : pvector3d[4].z#=-size#
pvector3d[5].x#=-size# :pvector3d[5].y#=-size# : pvector3d[5].z#=size#
 
 
pvector3d[6].x#=-size# :pvector3d[6].y#=size# : pvector3d[6].z#=size#
pvector3d[7].x#=-size# :pvector3d[7].y#=size# : pvector3d[7].z#=-size#
 
 
pvector3d[8].x#=size# :pvector3d[8].y#=size# : pvector3d[8].z#=-size#
pvector3d[9].x#=size# :pvector3d[9].y#=size# : pvector3d[9].z#=size#
 
 
pvector3d[10].x#=size# :pvector3d[10].y#=-size# : pvector3d[10].z#=size#
pvector3d[11].x#=size# :pvector3d[11].y#=-size# : pvector3d[11].z#=-size#
 
 
pvector3d[12].x#=size# :pvector3d[12].y#=-size# : pvector3d[12].z#=size#
pvector3d[13].x#=size# :pvector3d[13].y#=size# : pvector3d[13].z#=size#
 
 
pvector3d[14].x#=size# :pvector3d[14].y#=-size# : pvector3d[14].z#=-size#
pvector3d[15].x#=size# :pvector3d[15].y#=size# : pvector3d[15].z#=-size#
 
 
pvector3d[16].x#=-size# :pvector3d[16].y#=-size# : pvector3d[16].z#=-size#
pvector3d[17].x#=-size# :pvector3d[17].y#=size# : pvector3d[17].z#=-size#
 
 
pvector3d[18].x#=-size# :pvector3d[18].y#=-size# : pvector3d[18].z#=size#
pvector3d[19].x#=-size# :pvector3d[19].y#=size# : pvector3d[19].z#=size#
 
 
pvector3d[20].x#=-size# :pvector3d[20].y#=-size# : pvector3d[20].z#=size#
pvector3d[21].x#=size# :pvector3d[21].y#=-size# : pvector3d[21].z#=size#
 
 
pvector3d[22].x#=-size# :pvector3d[22].y#=size# : pvector3d[22].z#=size#
pvector3d[23].x#=size# :pvector3d[23].y#=size# : pvector3d[23].z#=size#
 
 
 
 
ang#=0
do
     
    for a=1 to pvector3d.length step 2
    //  DrawEllipse(pvector3d[a].x#,pvector3d[a].y#,5,5,MakeColor(255,255,255),MakeColor(255,255,255),0)
        drawline3d(pvector3d[a].x#, pvector3d[a].y#, pvector3d[a].z#, pvector3d[a-1].x#, pvector3d[a-1].y#, pvector3d[a-1].z#, ang#, MakeColor(255,255,255))
     
    next
    inc ang#
//  RotateObjectLocalX(holder,1)
    Print( ScreenFPS() )
    Sync()
loop
 
 
function drawline3d(fromx#,fromy#,fromz#,tox#, toy#, toz#, ang#, col )
 
     
     
    // X rotation
    x0# = fromx#
    y0# = fromy# * cos(ang#) + fromz# * sin(ang#)
    z0# = fromz# * cos(ang#) - fromy# * sin(ang#)
     
    // Y rotation
    x1# = x0# * cos(ang#) - z0# * sin(ang#)
    y1# = y0#
    z1# = z0# * cos(ang#) + x0# * sin(ang#)
     
    // Z rotation
    x2# = x1# * cos (ang#) + y1# * sin(ang#)
    y2# = y1# * cos (ang#) - x1# * sin(ang#)
     
     
    // X rotation
    x0# = tox#
    y0# = toy# * cos(ang#) + toz# * sin(ang#)
    z0# = toz# * cos(ang#) - toy# * sin(ang#)
     
    // Y rotation
    xx1# = x0# * cos(ang#) - z0# * sin(ang#)
    yy1# = y0#
    zz1# = z0# * cos(ang#) + x0# * sin(ang#)
     
    // Z rotation
    xx2# = xx1# * cos (ang#) + yy1# * sin(ang#)
    yy2# = yy1# * cos (ang#) - xx1# * sin(ang#)
     
     
    DrawLine(1024/2+x2#,768/2+y2#, 1024/2+xx2#,768/2+yy2#, col,col)
     
endfunction

+ Code Snippet

// Project: 4d 
// Created: 2018-08-11
 
// show all errors
SetErrorMode(2)
 
// set window properties
SetWindowTitle( "4d" )
SetWindowSize( 1024, 768, 0 )
SetWindowAllowResize( 1 ) // allow the user to resize the window
 
// set display properties
SetVirtualResolution( 1024, 768 ) // doesn't have to match the window
SetOrientationAllowed( 1, 1, 1, 1 ) // allow both portrait and landscape on mobile devices
SetSyncRate( 30, 0 ) // 30fps instead of 60 to save battery
SetScissor( 0,0,0,0 ) // use the maximum available screen space, no black borders
UseNewDefaultFonts( 1 ) // since version 2.0.22 we can use nicer default fonts
 
 
 
 
 
type _pvector3d
    sphere
    x#
    y#
    z#
    w#
endtype 
 
pvector3d as _pvector3d[24]
 
size#=100
 
pvector3d[0].x#=-size# :pvector3d[0].y#=-size# : pvector3d[0].z#=-size#
pvector3d[1].x#=size# :pvector3d[1].y#=-size# : pvector3d[1].z#=-size#
 
pvector3d[2].x#=size# :pvector3d[2].y#=size# : pvector3d[2].z#=-size#
pvector3d[3].x#=-size# :pvector3d[3].y#=size# : pvector3d[3].z#=-size#
 
pvector3d[4].x#=-size# :pvector3d[4].y#=-size# : pvector3d[4].z#=-size#
pvector3d[5].x#=-size# :pvector3d[5].y#=-size# : pvector3d[5].z#=size#
 
 
pvector3d[6].x#=-size# :pvector3d[6].y#=size# : pvector3d[6].z#=size#
pvector3d[7].x#=-size# :pvector3d[7].y#=size# : pvector3d[7].z#=-size#
 
 
pvector3d[8].x#=size# :pvector3d[8].y#=size# : pvector3d[8].z#=-size#
pvector3d[9].x#=size# :pvector3d[9].y#=size# : pvector3d[9].z#=size#
 
 
pvector3d[10].x#=size# :pvector3d[10].y#=-size# : pvector3d[10].z#=size#
pvector3d[11].x#=size# :pvector3d[11].y#=-size# : pvector3d[11].z#=-size#
 
 
pvector3d[12].x#=size# :pvector3d[12].y#=-size# : pvector3d[12].z#=size#
pvector3d[13].x#=size# :pvector3d[13].y#=size# : pvector3d[13].z#=size#
 
 
pvector3d[14].x#=size# :pvector3d[14].y#=-size# : pvector3d[14].z#=-size#
pvector3d[15].x#=size# :pvector3d[15].y#=size# : pvector3d[15].z#=-size#
 
 
pvector3d[16].x#=-size# :pvector3d[16].y#=-size# : pvector3d[16].z#=-size#
pvector3d[17].x#=-size# :pvector3d[17].y#=size# : pvector3d[17].z#=-size#
 
 
pvector3d[18].x#=-size# :pvector3d[18].y#=-size# : pvector3d[18].z#=size#
pvector3d[19].x#=-size# :pvector3d[19].y#=size# : pvector3d[19].z#=size#
 
 
pvector3d[20].x#=-size# :pvector3d[20].y#=-size# : pvector3d[20].z#=size#
pvector3d[21].x#=size# :pvector3d[21].y#=-size# : pvector3d[21].z#=size#
 
 
pvector3d[22].x#=-size# :pvector3d[22].y#=size# : pvector3d[22].z#=size#
pvector3d[23].x#=size# :pvector3d[23].y#=size# : pvector3d[23].z#=size#
 
 
 
 
ang#=0
do
     
    for a=1 to pvector3d.length step 2
    //  DrawEllipse(pvector3d[a].x#,pvector3d[a].y#,5,5,MakeColor(255,255,255),MakeColor(255,255,255),0)
        drawline3d(pvector3d[a].x#, pvector3d[a].y#, pvector3d[a].z#, pvector3d[a-1].x#, pvector3d[a-1].y#, pvector3d[a-1].z#, ang#, MakeColor(255,255,255))
     
    next
    inc ang#
//  RotateObjectLocalX(holder,1)
    Print( ScreenFPS() )
    Sync()
loop
 
 
function drawline3d(fromx#,fromy#,fromz#,tox#, toy#, toz#, ang#, col )
 
     
     
    // X rotation
    x0# = fromx#
    y0# = fromy# * cos(ang#) + fromz# * sin(ang#)
    z0# = fromz# * cos(ang#) - fromy# * sin(ang#)
     
    // Y rotation
    x1# = x0# * cos(ang#) - z0# * sin(ang#)
    y1# = y0#
    z1# = z0# * cos(ang#) + x0# * sin(ang#)
     
    // Z rotation
    x2# = x1# * cos (ang#) + y1# * sin(ang#)
    y2# = y1# * cos (ang#) - x1# * sin(ang#)
     
     
    // X rotation
    x0# = tox#
    y0# = toy# * cos(ang#) + toz# * sin(ang#)
    z0# = toz# * cos(ang#) - toy# * sin(ang#)
     
    // Y rotation
    xx1# = x0# * cos(ang#) - z0# * sin(ang#)
    yy1# = y0#
    zz1# = z0# * cos(ang#) + x0# * sin(ang#)
     
    // Z rotation
    xx2# = xx1# * cos (ang#) + yy1# * sin(ang#)
    yy2# = yy1# * cos (ang#) - xx1# * sin(ang#)
     
     
    DrawLine(1024/2+x2#,768/2+y2#, 1024/2+xx2#,768/2+yy2#, col,col)
     
endfunction

Hope this is what your looking for

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PHeMoX

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Posted: 4th Dec 2018 17:45

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Thanks so much! yes that does look very useful! I will have to do some experiments to see if it helps with my ray tracing debugging

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puzzler2018

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Posted: 4th Dec 2018 17:48

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Your welcome and happy it will come in use. I never thought to do debugging with it though, awesome

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blink0k

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Posted: 4th Dec 2018 21:11

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You could also use GetScreenXFrom3D() and GetScreenYFrom3D()

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GaborD

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Posted: 5th Dec 2018 12:07 Edited at: 5th Dec 2018 12:22

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You could go with a 3D quad and just send x1,y1,z1 and x2,y2,z2 to a shader that is applied to it and set the vertex positions accordingly.
Based on the uv coords it's easy to know which vertex belongs to which end.
You can also calculate the perpendicular vector to the plane that the view vector and the line direction build and use that to add thickness to the line object. This way the thickness offset will always rotate with your cam view and you don't get ultra thin lines from certain angles.
The thickness is ofcourse set in 3D world space, so it will vary with the perspective (a true 3D line object). But if you are debugging linepicks that's a good thing I guess, makes it easier to immediately see where the line is in 3D space.
Sidenote: If you want to have non 3D distance reliant thickness, you can move the thickness part to after the ViewProj transform. If you take the line direction to clip space too, it should be simple to do a 90 degree 2D rotation to get the thickness offset direction.

Here is a simple shader that you can use as starting point. Make sure the quad you use has UVs set to 0,0 to 1,1. (so basically what any 3D app will set as default anyway)

Vertex shader:

+ Code Snippet

attribute vec3 position;
attribute mediump vec2 uv;

uniform mat4 agk_ViewProj;
uniform vec3 agk_CameraPos;

uniform vec4 pos1;
uniform vec4 pos2;
uniform float thickness;

void main(){	
	vec4 pos = vec4(mix(pos1.xyz,pos2.xyz,step(0.5,uv.x)),1);
	pos.xyz += cross(normalize(agk_CameraPos-pos.xyz),normalize(pos2.xyz-pos1.xyz))*thickness*uv.y;
	gl_Position = agk_ViewProj * pos;
}

Basically, the first line in the main vertex shader function sets each pair of vertices to the appropiate end points of the line, then line 2 adds some thickness.

For the pixel shader you can just use the simplest pixel shader of all times and write out a color of your choice (which can also be set from AppGameKit code)

+ Code Snippet

uniform vec3 col;
void main() {
    gl_FragColor = vec4(col, 1);
}

To set the end points and thickness from AGK:
SetShaderConstantByName(shaderID, "pos1", x1, y1, z1, 0)
SetShaderConstantByName(shaderID, "pos2", x2, y2, z2, 0)
SetShaderConstantByName(shaderID, "thickness", thickness, 0,0,0)

I just quickly threw it together, could be improved a lot!
But it seems to work, I added it to a random test scene and had no issues. (screens attached)

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Ortu

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Posted: 5th Dec 2018 17:36

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Nice! Seems like that could easily be adapted to something like weapon / bullet trails also

http://games.joshkirklin.com/sulium

A single player RPG featuring a branching, player driven storyline of meaningful choices and multiple endings alongside challenging active combat and intelligent AI.

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PHeMoX

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Posted: 16th Jan 2019 00:16

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Thanks GaborD, by the way, amazing scene with the mushroom there!

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AppGameKit Classic Chat / How to draw a line from point x,y,z to x2,y2,z2 , ie. DrawLine() but for 3D ????

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