Hello everyone.
I am using custom vertex attributes but running into a strange issue. I
do not seem to be able to use:
BIND_PER_PRIMITIVE
..when using custom vertex attributes. Is this a known limitation, or is
it likely a bug/me doing something wrong? I have attached a simple
example of this failure; if you uncomment "GridCoordinates", nothing is
rendered at all (nor do I receive any information via OSG_NOTIFY).
If you keep this commented out, the grid renders.
Curious...
#include <osg/Geometry>
#include <osg/Geode>
#include <osg/PrimitiveSet>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
class Grid: public osg::Geometry {
public:
enum {
GRID_POSITION = 6,
GRID_COORDINATE = 7
};
Grid(const osg::Vec2s& size, const osg::Vec2& gridSize = osg::Vec2(1.0f, 1.0f)):
_size (size),
_gridSize (gridSize) {
setUseDisplayList(false);
}
bool allocate() {
osg::Program* program = new osg::Program();
osg::Shader* vert = osg::Shader::readShaderFile(osg::Shader::VERTEX, "vert.glsl");
osg::Shader* frag = osg::Shader::readShaderFile(osg::Shader::FRAGMENT, "frag.glsl");
// osg::Uniform* texture = new osg::Uniform(osg::Uniform::SAMPLER_2D, "Texture");
program->addShader(vert);
program->addShader(frag);
program->addBindAttribLocation("GridPosition", GRID_POSITION);
program->addBindAttribLocation("GridCoordinate", GRID_COORDINATE);
osg::Vec4Array* gridPositions = new osg::Vec4Array();
osg::Vec2Array* gridCoordinates = new osg::Vec2Array();
for(short x = 0; x < _size.x(); x++) {
for(short y = 0; y < _size.y(); y++) {
osg::Vec4 bl(x, y, 0.0f, 0.0f);
osg::Vec4 br(x + _gridSize.x(), y, 0.0f, 1.0f);
osg::Vec4 ur(x + _gridSize.x(), y + _gridSize.y(), 0.0f, 2.0f);
osg::Vec4 ul(x, y + _gridSize.y(), 0.0f, 3.0f);
gridPositions->push_back(bl);
gridPositions->push_back(br);
gridPositions->push_back(ur);
gridPositions->push_back(ul);
gridCoordinates->push_back(osg::Vec2(x, y));
}
}
// GridPosition
setVertexAttribArray(GRID_POSITION, gridPositions);
setVertexAttribBinding(GRID_POSITION, osg::Geometry::BIND_PER_VERTEX);
/*
// GridCoordinates
setVertexAttribArray(GRID_COORDINATE, gridCoordinates);
setVertexAttribBinding(GRID_COORDINATE, osg::Geometry::BIND_PER_PRIMITIVE);
u*/
// Finish seting up the Geometry...
addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS, 0, _size.x() * _size.y() * 4));
// texture->set(0);
osg::StateSet* state = getOrCreateStateSet();
state->setAttributeAndModes(program);
// state->addUniform(texture);
return true;
}
virtual osg::BoundingBox computeBound() const {
return osg::BoundingBox(
osg::Vec3(0.0f, 0.0f, 0.0f),
osg::Vec3(_size.x() * _gridSize.x(), _size.y() * _gridSize.y(), 0.0f)
);
}
private:
osg::Vec2s _size;
osg::Vec2 _gridSize;
};
int main(int argc, char** argv) {
osgViewer::Viewer viewer;
Grid* grid = new Grid(osg::Vec2s(10, 10));
grid->allocate();
osg::Geode* geode = new osg::Geode();
geode->addDrawable(grid);
viewer.setSceneData(geode);
viewer.addEventHandler(new osgViewer::StatsHandler());
return viewer.run();
}
varying float color;
void main() {
gl_FragColor = vec4(color, color, color, 1.0);
}
in vec4 GridPosition;
in vec2 GridCoordinate;
varying float color;
void main() {
color = GridPosition.w / 3.0;
gl_Position = gl_ModelViewProjectionMatrix * vec4(GridPosition.xyz,
1.0);
}
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