Hi
Okay, I’ve spent quite a lot of time creating a self-contained example to show you what I mean, and it seems to me that the problem I have been seeing is related to the “noisiness” of the specular maps.
I was using specular maps generated by CrazyBump (which creates specular maps derived from the diffuse texture), or in some cases custom specular maps derived from the diffuse texture using various filters. In either case the specular maps are quite “textured” by which I mean “diffuse/noisy/high frequency”, hopefully I am describing that intelligibly.
So I have created an example based on HelloMaterial which either uses a low-noise map (checkerboard of darkish green/magenta), or uses a darkened version of the diffuse texture as a specular map (high noise).
[java]
package jme3test.helloworld;
import bumpnshine.swing.;
import com.jme3.app.SimpleApplication;
import com.jme3.light.DirectionalLight;
import com.jme3.material.Material;
import com.jme3.material.RenderState.BlendMode;
import com.jme3.math.ColorRGBA;
import com.jme3.math.Vector3f;
import com.jme3.renderer.queue.RenderQueue.Bucket;
import com.jme3.scene.Geometry;
import com.jme3.scene.shape.Box;
import com.jme3.scene.shape.Sphere;
import com.jme3.texture.Texture;
import com.jme3.texture.Texture2D;
import com.jme3.texture.plugins.AWTLoader;
import com.jme3.util.TangentBinormalGenerator;
import java.awt.;
import java.awt.image.;
import jme3tools.converters.;
public class HelloSpecularMaterial extends SimpleApplication {
public static void main(String[] args) {
HelloSpecularMaterial app = new HelloSpecularMaterial();
app.start();
}
private Geometry sphereGeo;
@Override
public void simpleInitApp() {
flyCam.setEnabled(false);
/**
* A bumpy rock with a shiny light effect. To make bumpy objects you must create a NormalMap.
*/
Sphere sphereMesh = new Sphere(32, 32, 2f);
sphereGeo = new Geometry("Shiny rock", sphereMesh);
sphereMesh.setTextureMode(Sphere.TextureMode.Projected); // better quality on spheres
TangentBinormalGenerator.generate(sphereMesh); // for lighting effect
Material sphereMat = new Material(assetManager, "Common/MatDefs/Light/Lighting.j3md");
final Texture diffuse = assetManager.loadTexture("Textures/Terrain/Pond/Pond.jpg");
final int width = diffuse.getImage().getWidth();
final int height = diffuse.getImage().getHeight();
sphereMat.setTexture("DiffuseMap", diffuse);
sphereMat.setTexture("NormalMap", assetManager.loadTexture("Textures/Terrain/Pond/Pond_normal.png"));
boolean patterned = false;
if (patterned) {
BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
final Graphics2D graphics2D = (Graphics2D) bufferedImage.getGraphics();
graphics2D.setColor(new Color(128, 0, 128));
graphics2D.fillRect(0, 0, width, height);
graphics2D.setColor(new Color(0, 128, 0));
int patternSize = 7;
for (int x = 0; x < width; x += patternSize) {
for (int y = 0; y < height; y += patternSize) {
if ((x + y) % 2 == 0) {
graphics2D.fillRect(x, y, patternSize, patternSize);
}
}
}
sphereMat.setTexture("SpecularMap", new Texture2D(new AWTLoader().load(bufferedImage, true)));
} else {
float darkness = .5f; // [0.0f to 1.0f]
BufferedImage bufferedImage = ImageToAwt.convert(diffuse.getImage(), false, true, 0);
//Images.dumpDebugImage(bufferedImage, "diffuse-plain");
final Graphics2D graphics2D = (Graphics2D) bufferedImage.getGraphics();
graphics2D.setColor(new Color(0, 0, 0, Math.round(darkness * 255)));
graphics2D.fillRect(0, 0, width, height);
//Images.dumpDebugImage(bufferedImage, "diffuse-darkened");
sphereMat.setTexture("SpecularMap", new Texture2D(new AWTLoader().load(bufferedImage, true)));
}
sphereMat.setBoolean("UseMaterialColors", true);
sphereMat.setColor("Diffuse", ColorRGBA.White);
sphereMat.setColor("Specular", ColorRGBA.White);
sphereMat.setFloat("Shininess", 10f); // [0,128]
sphereGeo.setMaterial(sphereMat);
sphereGeo.rotate(1.6f, 0, 0); // Rotate it a bit
sphereGeo.setLocalTranslation(0, 0, 4);
rootNode.attachChild(sphereGeo);
/**
* Must add a light to make the lit object visible!
*/
DirectionalLight sun = new DirectionalLight();
sun.setDirection(new Vector3f(1, 0, -2).normalizeLocal());
sun.setColor(ColorRGBA.White);
rootNode.addLight(sun);
}
@Override
public void simpleUpdate(float tpf) {
sphereGeo.rotate(tpf / 2f, tpf / 3f, tpf / 5f);
}
}[/java]
If you set patterned = false then it uses the darkened diffuse map. You will see that even though the specular map is fairly dark (you can adjust how dark with the “darkness” variable), the rendered glints contain large areas of pure white. (The “Specular” colour property is set to White, and I by changing that you can get the glints to contain large areas of pure e.g. Yellow, still not really right).
If you set patterned = true so it uses the checkerboard, then for the most part you do not get bright glints of pure white, the color seems to much more closely respect specular map’s colours.
But what I noticed, and I think is the key to my problem, is that if you look closely at the borders between the checker squares, you see that the specular glints there are much brighter than the squares themselves (the pattern itself is just magenta/green, but it look as if the pattern has white grid-lines between the squares).
So in short, wherever the colour in the specular map changes sharply from one pixel to the next, the resulting glint comes out much too bright.
The clincher for this is that if you set patterned = true and patternSize = 1 (so the specular map is a checkerboard of 1x1 pixel squares), then all the glints come out more-or-less pure white.
So it is not surprising that any noisy specular map (e.g. one derived from the diffuse texture) is going to have the same issue as the 1x1 checkerboard, i.e. overly bright wherever it is noisy.
Sorry if the use of noisy (high frequency) specular maps seems a bit of a niche case, though given the popularity of CrazyBump (similar tools probably also generate noisy specular maps too), it may not be all that niche.
In particular, I think that the standard way to make a specular effect look more matte (i.e. less glossy or wet) is to add noise to the specular map - but this seems to have the opposite effect in JME.
Hope I have made all of this clear!
Thanks
Barney
