How to display DDS images?

[jamsession]

Hey guys, I have been surfing these boards for while and figured I should finally join and contribute to the community :)

I am hoping this is a trivial issue for someone out there.

I have a ton of .dds images I want to create a simple thumbnail viewer for. I have tried QImage and Pixmap, but none of those currently support .dds file types. I know openGL, and QtOpenGL does, but will I need to create a Plane to apply an image to it? Is there a way to just display a .dds that I am overlooking? Does anyone have a simple example using .dds files?

Any help or direction is greatly appreciated,

Thanks
JAM

[minimoog]

DDS it's not image, it's a collection of texture images (1D, 2D, 3D, cubemap texture) with optional all mipmapping levels. And how do you show cubemap texture like a image?

But, there are tons of DDS loader on the internet, and you can "ripoff" code from QtOpenGL.

[wysota]

Write the texture into QGLPixelBuffer and then use QGLPixelBuffer::toImage() to write it to an image. Note that you may have to switch colour channels afterwards.

[jamsession]

Thanks guys for your help. Unfortunately I still can't get it to display anything.

Is the proper way to specify a "bindTexture" then convert it with "toImage"?

Obviously the png works great, but the dds isn't displaying anything.

Thanks Guys
JAM



from PyQt4 import QtGui
from PyQt4 import QtOpenGL

ddsPath = "C:/ddsImage.dds"
pngPath = "C:/pngImage.png"

class Example(QtGui.QWidget):
def __init__(self, parent=None):
QtGui.QWidget.__init__(self, parent)

self.initUI()


def initUI(self):

hbox = QtGui.QHBoxLayout(self)
pixmap = QtGui.QPixmap(pngPath)

GL = QtOpenGL.QGLPixelBuffer(512, 512)
GL_ID = GL.bindTexture(ddsPath)
GL.makeCurrent()
qimag = GL.toImage()

pixmap2 = QtGui.QPixmap.fromImage(qimag)

label = QtGui.QLabel(self)
label.setPixmap(pixmap)

label2 = QtGui.QLabel(self)
label2.setPixmap(pixmap2)

hbox.addWidget(label)
hbox.addWidget(label2)
self.setLayout(hbox)

self.setWindowTitle("DDS Test")


app = QtGui.QApplication([])
exm = Example()
exm.show()
app.exec_()

[wysota]

Correct me if I'm wrong but don't you have to use the GL_ARB_texture_compression extension or the glCompressedTexImage2D() function to load the compressed texture?

[bjorn]

I know this discussion is somewhat old, but I originally found it while looking for a way to load a DDS image in Qt. I figured out one way to do it eventually so if anybody else comes here looking for the answer, there it is:

https://gist.github.com/bjorn/4635382


QImage readDDSFile(const QString &filename)
{
QGLWidget glWidget;
glWidget.makeCurrent();

GLuint texture = glWidget.bindTexture(filename);
if (!texture)
return QImage();

// Determine the size of the DDS image
GLint width, height;
glBindTexture(GL_TEXTURE_2D, texture);
glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &width);
glGetTexLevelParameteriv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &height);

if (width == 0 || height == 0)
return QImage();

QGLPixelBuffer pbuffer(QSize(width, height), glWidget.format(), &glWidget);
if (!pbuffer.makeCurrent())
return QImage();

pbuffer.drawTexture(QRectF(-1, -1, 2, 2), texture);
return pbuffer.toImage();
}
For information on the supported formats see http://qt-project.org/doc/qt-4.8/qglcontext.html#bindTexture-2.

The main problem with the code snippet above is that it didn't actually draw the texture to the pixel buffer.