My Planet and Normal Maps artefacts

[montify]

Hello guys, my Name is Alex, live in Austria and i try to make a lovely full size Planet using XNA 4.0.

2012 i made the first steps, and now i continue, because i saw Battlescape on Kickstarter

Here some Screenshots:
Planet
Planet2
I use the ChunkedLOD approach for Level of Detail, now i have big troubles with the NormalMapping.

Because i generate the Noise on the GPU, and for the normalmap i render the same Heightmap with a higher resolution and pass this Image into the Normal map Shader. When im at the ground ( or LOD-Level > 13) the float precision is not enough i think:

The normalmap shader look like:

float4 NormalPixelShader(in VertexOutput input) : COLOR0
{
float2 uv = input.UV;

uv.y = 1 - uv.y;

float du = 1.0 / PatchWidth;

float l = tex2D(heightmapSampler, uv + float2(-du, 0));
float r = tex2D(heightmapSampler, uv + float2(du, 0));
float t = tex2D(heightmapSampler, uv + float2(0, du));
float b = tex2D(heightmapSampler, uv + float2(0, -du));

float3 normal = normalize(float3((l - r) * NormalScale, 1.0, (b - t) * NormalScale));
return float4(normal * 0.5 + 0.5, 1.0);

};

Anybody have an Idea?

sorry for my bad English, i hope you can understand what i mean :))

Best regards

[Arkenbrien]

Welcome to the forums, @montify!

It’s great to see new faces around here.

I don’t know a lot about programming at all, but you might want to check out this thread:

Procedural Terrain Rendering How-To

So, this post started as a reply to @kamui on this thread, but by the time I was done I decided it deserved its own thread smile TLDR: This post gives a 'mid-level-overview' on how to render a planet procedurally. We'll go into issues with floating point precision and how to combat them, how to apply a quad-tree spatial partitioning system to a sphere, how to determine desired level of detail, perform occlusion culling, and how to actually render the terrain patches. Disclaimer/Backgroun…

It may have what you’re looking for. If not, I’m sure @Navyfish or @JoergZdarsky would be willing to help out!

[montify]

Thank you for the answer.

I think why i have artefacts on the normal map.

because SimplexNoise on GPU are still fine on higher Lod level.

Are @Navyfish / @JoergZdarsky the developer from Battlescape?

I know this site for many years, very sad that the old blog is offline so many usefull information

[Lomsor]

… old blog is offline so many usefull information

You mean this one: http://www.gamedev.net/blog/73-journal-of-ysaneya/ ?

[JoergZdarsky]

Are @Navyfish / @JoergZdarsky the developer from Battlescape?

No, we just all share the same hobbies in doing procedural terrain / planets. The thread which Arkenbrien suggested is indeed very usefull and full of valuable information especially of NavyFish, I’d underline his recommendation to look at it. Will look at your problem.

[montify]

Thank you for answer guys
I decided the maxLOD level is 13…

Here is a actual screenshot with traces <3