Hi Robert,
thank you for the answer. I'm using a Camera with a PostDrawCallback,
which I hope read back the depth values immediatly. I already thought of
using FBOs. Is it right, that the RenderBuffer of the FBO provides a
fully functional depth buffer from which I can read within a Shader?
Oliver
Robert Osfield schrieb:
Hi Oliver,
Just case the image->data() to a GLfloat*, as long as the internal
format is float you'll be just fine.
As for occlusion of the viewport you are reading from producing
invalid values - this is an artifact introduced by some/many window
managers, and I'm afraid there is not much you can do about it. I
believe some window managers have options to ensure that the frame
buffer of overlapping windows is maintained, but I'm don't recall
specifics.
The proper way to do reliable read back is to use an FBO or a pbuffer.
Robert.
On 12/13/06, Oliver Kutter <[EMAIL PROTECTED]> wrote:
Hi everybody,
I want to use the osg::Image function readPixels to read back depth
buffer
values. But the depth buffer values are float values and I wonder how
to get
the float values of the image object. I set the image parameters like
this.
osg::Image* image = new osg::Image();
image->allocateImage(width, height, 1, GL_LUMINANCE, GL_FLOAT);
Then I call readPixels to read back the depth values:
image->readPixels(posx, posy, width, height, GL_DEPTH_COMPONENT,
GL_FLOAT);
But the function image->data() returns an unsigned char array
instead of a
float array. How do I get the float values of that image? Or is it even
impossible to return the float data of the image?
In that case, if I can't get the correct float values, I can use the
OpenGL
function glReadPixels instead. But then I have a problem reading back
the
depth values of viewports that are positioned behind the main
viewport. Does
anyone have a hint for me?
regards,
Oliver
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