My initial implementation with AutoTransform is not fast enough for my
application. I have thousands of MatrixTransforms sharing a single
AutoTransform with a child Geode, containing a geometry with two lines. I was
getting around 17 fps. Removing the AutoTransforms improved the framerate to
20-25 fps (20 is sufficient for my application).
Since I still need the constant size, I am attempting to use an alternate
implementation with PointSprites to see if that performs any better. I used
the osgpointsprite example as a guide. However, I'm having trouble getting
transparency to work. I want a white 'X' to overlay the rest of the scene at
each point. What I am getting is a black opaque box at each point, with the
white X inside the box. I've set the alpha to 0 in the point color array, and
in the texture outside the X. Can someone help me figure out what I'm doing
wrong?
Here's the code:
Code:
osg::ref_ptr<osg::Geode> geode = new osg::Geode;
osg::ref_ptr<osg::Geometry> geom = new osg::Geometry;
osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
vertices->push_back(osg::Vec3(0.0, 0.0, 10.0));
osg::ref_ptr<osg::Vec4Array> colors = new osg::Vec4Array;
colors->push_back(osg::Vec4(0.0, 0.0, 0.0, 0.0));
geom->setVertexArray(vertices);
geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::POINTS, 0, 1));
geom->setColorArray(colors);
geom->setColorBinding(osg::Geometry::BIND_PER_VERTEX);
geode->addDrawable(geom);
// Give it an initial bound so it doesn't get culled (osg can't calculate a
bounding volume for a single point)
geode->setInitialBound( osg::BoundingSphere( osg::Vec3(0.0, 0.0, 0.0), 100.0 )
);
const int pixelsX = 50;
const int pixelsY = 50;
const int bytesPerPixel = 4;
unsigned char *buf = new unsigned char[pixelsX * pixelsY * bytesPerPixel];
memset(buf, 0x00, pixelsX*pixelsY*bytesPerPixel);
for (int i = 0; i < pixelsX; i++)
{
for (int j = 0; j < pixelsY; j++)
{
if (i == j || pixelsX - i - 1 == j)
{
for (int k = 0; k < bytesPerPixel; k++)
{
buf[i * pixelsY * bytesPerPixel + j * bytesPerPixel + k] = 0xFF;
}
}
}
}
osg::ref_ptr<osg::Image> img = new osg::Image;
img->setImage(pixelsX,
pixelsY,
1,
GL_RGBA8, // internal format
GL_RGBA, // pixel format
GL_UNSIGNED_INT_8_8_8_8_REV, // pixel data type
buf, // data buffer
osg::Image::USE_NEW_DELETE); // allocation mode
osg::ref_ptr<osg::Texture2D> tex = new osg::Texture2D;
tex->setImage(img);
tex->setBorderColor(osg::Vec4(0.0, 0.0, 0.0, 0.0));
osg::ref_ptr<osg::PointSprite> sprite = new osg::PointSprite;
osg::ref_ptr<osg::Point> point = new osg::Point;
point->setSize(100.0);
osg::ref_ptr<osg::StateSet> ss = geode->getOrCreateStateSet();
ss->setTextureAttributeAndModes(0, sprite, osg::StateAttribute::ON);
ss->setTextureAttributeAndModes(0, tex, osg::StateAttribute::ON);
ss->setAttribute(point);
ss->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
osg::ref_ptr<osg::TexEnv> texenv = new osg::TexEnv;
texenv->setMode(osg::TexEnv::DECAL);
ss->setTextureAttribute(0, texenv);
Thanks,
Mike
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=48668#48668
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