# Parallax mapping

This topic is 4602 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

## Recommended Posts

I dont really know if this topic fits into the DirectX forum but I hope so since it's about shaders. I just wonder, what is parallax mapping? I know how to make bump mapping and some displacement mapping (to actual change the geometry) but what is parallax mapping? Anyone who has a good link where it's explained cause I couldnt find one

##### Share on other sites
Here

That gives a brief description of what parallax mapping is.

##### Share on other sites
Also, in case you are interested in an actual implementation, a Parallax Mapping sample has been recently added to the SDK samples. Grab the April '06 SDK to give it a go.

Hope this helps. :)

##### Share on other sites
thank you. Is there any tutorials available somewhere? I've only seen short descriptions when trying to google :(

##### Share on other sites
Its quite simple, actually. It only requires a heightmap texture for the shader pass.

float3 vEye = -TBNViewDir;float fBumpScale = 0.05f;float2 vCoord = texCoord;	float fDepth = tex2D(sHeightMapSampler, vCoord).w;	float2 vHalfOffset = normalize(vEye).xy * (fDepth) * fBumpScale;	fDepth = (fDepth + tex2D(sHeightMapSampler, vCoord + vHalfOffset).x) * 0.5;	vHalfOffset = normalize(vEye).xy * (fDepth) * fBumpScale;	fDepth = (fDepth + tex2D(sHeightMapSampler, vCoord + vHalfOffset).x) * 0.5;	vHalfOffset = normalize(vEye).xy * (fDepth) * fBumpScale;		return vCoord + vHalfOffset;

Then, sample the diffuse texture and the normal texture using the returned coordinates.

Basically, it samples the height map at the texture coordinate, and offsets the texture coordinates in the direction away from the viewer. I do 3 iterations to get good results. If you only do one, the effect is negligible.

In these 2 screenshots, I have doubled the parallax amount to make the difference clearly visible.

No parallax mapping

Parallax mapping

##### Share on other sites
Ah cool, I didn't think about multiple samples/calculations. Does that increase accuracy or create a larger offset?

##### Share on other sites
Cadef, in the second screenshot if seems like your parallax mapping goes off to the left. Maybe a projection problem?

##### Share on other sites
Multiple samples increase accuracy. If you take 1 sample, it will look wrong.

It is supposed to go off to the left, that is parallax mapping. It might seem a bit wrong, because I exaggerated the parallax scale to make the effect prominent.

##### Share on other sites
So parallax mapping is just about the texture coordinates? Would be great with a little more detailed explanation :)

and does anyone know any links where I can find a simple texture and a nice parallax map to work with :)

[Edited by - whathappened on April 16, 2006 7:25:58 AM]

1. 1
Rutin
65
2. 2
3. 3
4. 4
5. 5

• 18
• 10
• 30
• 20
• 9
• ### Forum Statistics

• Total Topics
633416
• Total Posts
3011771
• ### Who's Online (See full list)

There are no registered users currently online

×