uniform sampler2D normalSampler2D;
uniform vec3 lightDirection;
varying vec2 fetcher;
void main()
{
vec3 normal = texture2D(normalSampler2D,fetcher).rbg;
normal = normalize(normal * 2.0 - 1.0);
vec3 lightDir = normalize(lightDirection);
float NdotL = max(dot(normal,-lightDir), 0.0);
vec4 diffuse = vec4(1.0,1.0,1.0,1.0);
gl_FragColor = NdotL * diffuse;
}
void main()
{
vec3 normal = texture2D(normalSampler2D,fetcher).rbg;
normal = normalize(normal * 2.0 - 1.0);
gl_FragColor = normal*0.5+0.5;
}
That star pattern looks like... bilinear filtering.
What do your normals look like when you visualise them with:void main()
{
vec3 normal = texture2D(normalSampler2D,fetcher).rbg;
normal = normalize(normal * 2.0 - 1.0);
gl_FragColor = normal*0.5+0.5;
}
Off-topic, but this is a strange approach to terrain shading -- if the normals are supplied per vertex, then they should be output by the vertex shader and interpolated via a 'varying' param (fetching them per-fragment is a lot of extra work comparatively).
[/quote]
Wrong it is crap approach for several reasons:
1. This will not be per-pixel lighting, and since I'm using triangles it will interpolate between 3 normals of each triangle - and that will produce diamond pattern artifact, you have probably seen it somewhere (if not I can show you, if you ask) - this artifact is much more noticeable than this quaddy pattern artifact and looks ugly.
2. This is LOD-based terrain, therefore if you don't use per-pixel lighting you will see LOD switching, which looks extremely ugly and crappy. You may ask why - this happens because, when you switch LOD's - quantity of normals per block increases by 4 times (according to geo mipmapping) - because you are using discrete normals per vertex. But when I use per-pixel lighting - lighting stays consistent and constant across the whole terrain regardless my position in the world (i. e. the current LOD configuration) - you don't see this switching of lighting quality because you always use the same number of normals - i. e. all pixels of normal map.
But what's stopping you from using a higher-res normal map? and btw did you rotate the normals using TBN matrix?
I can't believe nobody has faced this problem before.
That's just the nature of bilinear filtering. If you want to improve it you'll need to try a higher order filtering method like Bicubic. Check out this chapter from GPU Gems 2: http://http.develope..._chapter20.html. Or you can fake it pretty well using smoothstep() in the shader: http://www.iquilezle...ure/texture.htm.
[quote name='Haroogan' timestamp='1302450389' post='4796711']
I can't believe nobody has faced this problem before.
