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Trying to find a webpage that teaches you how to do normal maps for textures using simple graphics editor.

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Hello,

 

I've been trying to locate a webpage that teaches you how to create normal maps for textures using simple graphics editor, but I seemed to have lost the link I had bookmarked for a while ago.

 

The author of the article explains the making of normal maps by using an example texture, manipulating the bitmap pixels by grayscaling, then use blue and red channels, offset a bit, and then recombine them as a normal map.

 

I forgot some of the steps that the author did, but I only recalled that the author just uses GIMP, I think. The author did not use any plugins or external 3rd party programs to generate the normal maps.

 

If anyone can help me relocate the webpage, that would be very grateful.

 

Thank you.

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To be honest, it doesn't seems like this is the one.

 

The author didn't show how to offset the blue and red channels, nor show how to use a graphics editor to manipulate the texture itself.

 

That article linked above just explains the theory of the normal maps that are generated and how it is created.

 

Thank you though.

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Normally, you generate normal maps from a 3D model that has more detail than the model you plan to use in game -- you can sort of do normal maps by hand, and you can sort of get passable results for some images with image filters (the common 'emboss' filter produces a static result kind of like a normal map would under the same circumstances) but neither generall produce great results, and doing them by hand is fairly difficult.

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I figured I should try to analyze this by myself since the webpage is really gone. :(

 

I'm just doing a poor man's way of making normal maps for textures only, so don't worry about 3D models. It's all thanks to admin rights on the lab computers I'm using, I wasn't able to install those programs that generates normal maps from textures.

 

I figured that a normal map consists of cyan and magenta colors layered on top of each other. Here's what I did:

  1. I decided to use Adobe Photoshop.
  2. Create a new copy of the texture I was going to use.
  3. Change image mode to CYMK.
  4. Paint the yellow and black color channels to all white.
  5. Offset individual cyan and magenta color channels a bit in different directions and orientations.
  6. Re-save it as PNG.

What I got seems to work I guess. I know it's not perfect for a terrain texture, but it still gets the job done.

Edited by tom_mai78101

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You are never going to get a good enough normal map by simply messing around with color channels from a simple colored texture. That's why I mentioned that article, which actually explains why you should NOT try to do this, and hints at a possibly better and simpler technique: manually paint a grayscale height map, then use the Nvidia normal map plugin in Photoshop, or the GIMP normal map plugin in GIMP with their "height map source" options.

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Create a grayscale image. Save it.

Open a new window, the same size.
Fill it with the neutral color for a height map (Red 127, Blue 255, Green 127).

Use the layer effect, 'texturizer', and load that image of the grayscale you saved. Adjust the light angle to be horizontal. Apply pure red light from the right side, using ADD. Apply the same pure red light from the left side using SUBTRACT.
Apply texturizer again, with the same grayscale image, this time apply green light, using a vertical direction. The top is add, the bottom is subtract.

There you go.

If it comes out weird, you messed up and something was upside down, switch around add and subtract until it's right.
If it's too strong, you can apply the effects with lower opacity.

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