Spherical Billboard of a Line Strip with Geometry Shader

[Dark_Photon]

@pad-kan

My problem is very similar to this topic from 10 years ago … Billboard geometry shader posted by Vexator with topic id 6561

However, the solution posted there redirects me to the khronos forums home page.

Ok, here’s that forum thread you wanted to link to:

Billboard geometry shader

I’m writing my first geometry shader in glsl. I want to extrude points uploaded to the gpu to two triangles facing the camera (spherical billboards). The idea is to calculate the three axes of the billboard (typical lookat() function) and then position the vertices along these axes. What i’ve got somehow works but the billboards start rotating in the wrong direction when the camera moves close and/or spin around their z axis. Any ideas what i’m missing? What bothers me is that the camera’s rotat…

Finding a working link to the solution posted there took a few minutes, but I found it. Here you go:

The Internet Archive:

Icon drawing in 3d

Current link on the Khronos Forums:

Icon drawing in 3d

try: You have: vec3 IconPos; // where the icon is mat4 mvp; // model-view-projection matrix float invWidth = 1.0/640; float invHeight= 1.0/480; int iconSize=32; // if you want to see it always 32x32px big //----------------- vec4 clip = mvp * vec4(IconPos,1.0); float dx = iconSize * invWidth * 0.5 * clip.w; float dy = iconSize * invHeight * 0.5 * clip.w; vec4 vout[4]; vout[0] = vec4(clip.x - dx, clip.y + dy, clip.z,clip.w); vout[1] = vec4(clip.x - dx, clip.y - dy, clip.z,clip.w); vout[2] = …