Vertex Normal Shader

[SpiderPig]

I've put together a quick shader that will show the object in wire-frame and draw lines to show the direction of each vertex normal. But the normal's don't seem to be acting correctly. Is somehow able to show me what I'm doing wrong? I have a feeling it something to do with the cameraprojection matrix, but unsure how to fix it.

 

I used the info from this site; http://www.geeks3d.com/20130905/exploring-glsl-normal-visualizer-with-geometry-shaders-shader-library/

diffuse_shownormals.zip

[macklebee]

Seems to work ok for me - maybe I am not seeing the issue you are referring to? Other than the warning about 'ex_texcoords0' and 'ex_normal' might be used prior to initializing, I am not seeing a problem. Do you have a particular item where the normals seem wrong?

 

To get rid of the warning, just initialize the variables prior to the for loop:

void main() {

ex_texcoords0 = vec2(0);

ex_normal = vec3(0);

for(int i = 0; i < gl_in.length(); i++) {

gl_Position = gl_in.gl_Position;

ex_color = g_ex_color;

ex_texcoords0 = g_ex_texcoords0;

ex_normal = g_ex_normal;

EmitVertex();

}

EndPrimitive();

...

...

[SpiderPig]

Sorry, I didn't explain it too well. The normal's seem to point towards the center of the world I think it is... in the editor if you move the object around or the camera, the normal's will change direction.

 

 

I've attached the model also if you wanted to see it.

terrain.zip

[nick.ace]

There's an error in the geometry shader where you define N. You should make the last component 0.0 instead of 1.0 because you mess up the homogeneous component (which causes the projection to be off). I didn't have any issues with moving the camera around, just the mesh, but changing the homogeneous coordinate fixes that.

 

Just FYI, you should be careful with outputting more primitives than you import. GPUs have internal buffers to store geometry shader results, but these tend to fill up pretty easily especially with higher primitive outputs (hence why tessellation shaders became a thing). So you may experience performance issues.

[SpiderPig]

Ah ha! Thanks very much. Knew it was something simple. Thanks for the tips too.