transparency problem since java 1.6.0_20

OpenGL Development JOGL Development
#1

Hello,
I am loading some transparent pngs:

BufferedImage image = ImageIO.read(url);

then I want to draw them on the gl canvas surface:



width = image.getWidth();
height = image.getHeight();
					
gl.glWindowPos2i(win_x + 5, (win_y - height - 5));
					
byte[] imgRGBA = ((DataBufferByte)interfaceElements.get(i).image.getRaster().getDataBuffer()).getData();
ByteBuffer buffer = ByteBuffer.wrap(imgRGBA);
					
gl.glDrawPixels(width, height, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, buffer);

This was working fine until I installed the new java version 1.6.0_20, earlier I was using 1.6.0_14, which was workign nicely!
Now Instead of transparency I got these blueish looking colors.
I read somewhere here, that it has something to do with indexed colors?

Does somebody know how to fix these problem? I was searching for it here, there was an solution from NexusOne, which was not working for me.

kind regards

Knut

#2

What makes you so sure you get the bytes in RGBA format?

Sadly, that is an implementation detail.

Copy the image to a BufferedImage of type RGBA, then access the pixels.

#3

I have done it like this:


                 int width = image.getWidth();
                 int height = image.getHeight();
                
                 BufferedImage newImage = new BufferedImage(width,
                       height, BufferedImage.TYPE_4BYTE_ABGR);
              
                 for(int i = 0; i < width; i++){
                       for(int j = 0; j < height; j++){
                            int k = image.getRGB(i, j);
                            newImage.setRGB(i, j, k);
                       }
                 }      
                
           }

then used the newImage, but there was no difference. What do you exactly mean with accessing the pixels ?

#4

So… you put the pixels in a TYPE_4BYTE_ABGR format… and then tell OpenGL it is RGBA?

#5

I do this with the new BufferedImage.TYPE_4BYTE_ABGR

// get a byte array	
imgRGBA = ((DataBufferByte)interfaceElements.get(i).image.getRaster().getDataBuffer()).getData();

//create bytebuffer				
buffer = ByteBuffer.wrap(imgRGBA);

// draw pixel				
gl.glDrawPixels(width, height, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, buffer);

Do I have to set up different parameters? Is there something wrong with the commands I used?

#6

Let me make this very simple:

You feed the GPU ABGR, and tell it it is RGBA.

Why do you think the color-channels are swapped?

Besides that, please use textures. glDrawPixels() is very limited and very slow.

#7

Ah now the penny has swapped… aeh dropped! Thank you.
Currently I am fine with draw pixels. Maybe I change it later.

Ok thank you.

#8

Also note that using image.getRGB()/image.setRGB() is very slow compared to image.getGraphics().drawImage().