Transparency with textures
Okay... making progress with texturing, but I'm now having a problem with setting alpha values. The code below sets a BufferedImage from a url and then sets a 4 byte RGBA texture from it by copying the RGB bytes and adding an alpha byte as the maximum value of the RGB bytes.
Problems:
1. The bytes from the input image don't translate directly as RGB; to get the right colours I have to reverse them (see code).
2. The alpha values are strange: the texture seems too transparent; when I set alpha explicitly to zero it doesn't appear at all (Java specifies that zero = no transparency); and when I set alpha to 255 it is still quite transparent.
Any image experts that might have some idea what I'm doing wrong here?
publicvoid LoadTexture3D(URL url){
BufferedImage urlImage;
try{
urlImage = ImageIO.read(url);
}
catch (IOException e){
e.printStackTrace();
return;
}
width = urlImage.getWidth();
height = urlImage.getHeight();
depth = 4;// urlImage.getWidth();
byte[] origData = ((DataBufferByte)urlImage.getData().getDataBuffer()).getData();
ColorSpace cs = ColorSpace.getInstance(ColorSpace.CS_sRGB);
int[] nBits ={8, 8, 8, 8};
ComponentColorModel colorModel =new ComponentColorModel(cs, nBits, true, false, Transparency.TRANSLUCENT, DataBuffer.TYPE_BYTE);
WritableRaster raster = colorModel.createCompatibleWritableRaster(width, height);
BufferedImage bImage =new BufferedImage(colorModel, raster, false,null);
byte[] byteData = ((DataBufferByte)raster.getDataBuffer()).getData();
ImageComponent3D pArray =new ImageComponent3D(ImageComponent.FORMAT_RGBA, width, height, depth);
for (int j = 0; j < height; j++)
for (int i = 0; i < width; i++){
int indexb = ((j * width) + i) * 4;
int indexo = ((j * width) + i) * 3;
byteData[indexb + 2] = origData[indexo];
byteData[indexb + 1] = origData[indexo + 1];
byteData[indexb + 0] = origData[indexo + 2];
//calculate alpha
int alpha = Math.max(Math.max(byteToInt(origData[indexo]), byteToInt(origData[indexo + 1])), byteToInt(origData[indexo + 2]));
//alpha = 255;
byte test = (byte)alpha;
byteData[indexb + 3] = test;
}
for (int k = 0; k < depth; k++)
pArray.set(k, bImage);
texture3D =new Texture3D(Texture.BASE_LEVEL,
Texture.RGBA,
width,
height,
depth);
texture3D.setImage(0, pArray);
texture3D.setEnable(true);
texture3D.setMinFilter(Texture.BASE_LEVEL_LINEAR);
texture3D.setMagFilter(Texture.BASE_LEVEL_LINEAR);
texture3D.setBoundaryModeS(Texture.CLAMP);
texture3D.setBoundaryModeT(Texture.CLAMP);
texture3D.setBoundaryModeR(Texture.CLAMP);
}
privateint byteToInt(byte b){
int val = (int)b;
if (val < 0) val += 256;
return val;
}
To set the transparency node:
TransparencyAttributes t =new TransparencyAttributes();
t.setTransparencyMode(TransparencyAttributes.BLENDED);
t.setSrcBlendFunction(TransparencyAttributes.BLEND_SRC_ALPHA);
thisAppNode.setTransparencyAttributes(t);
