void
PolygonizeLinesOperator::installShaders(osg::Node* node) const
{
if ( !node )
return;
float minPixels = _stroke.minPixels().getOrUse( 0.0f );
if ( minPixels <= 0.0f )
return;
osg::StateSet* stateset = node->getOrCreateStateSet();
VirtualProgram* vp = VirtualProgram::getOrCreate(stateset);
// bail if already installed.
if ( vp->getName().compare( SHADER_NAME ) == 0 )
return;
vp->setName( SHADER_NAME );
const char* vs =
"#version " GLSL_VERSION_STR "\n"
GLSL_DEFAULT_PRECISION_FLOAT "\n"
"in vec3 oe_polyline_center; \n"
"uniform float oe_polyline_scale; \n"
"uniform float oe_polyline_min_pixels; \n"
"uniform vec4 oe_PixelSizeVector; \n"
"void oe_polyline_scalelines(inout vec4 vertex_model4) \n"
"{ \n"
" const float epsilon = 0.0001; \n"
" vec4 center = vec4(oe_polyline_center, 1.0); \n"
" vec3 vector = vertex_model4.xyz - center.xyz; \n"
" float r = length(vector); \n"
" float activate = step(epsilon, r*oe_polyline_min_pixels);\n"
" float pixelSize = max(epsilon, 2.0*abs(r/dot(center, oe_PixelSizeVector))); \n"
" float min_scale = max(oe_polyline_min_pixels/pixelSize, 1.0); \n"
" float scale = mix(1.0, max(oe_polyline_scale, min_scale), activate); \n"
" vertex_model4.xyz = center.xyz + vector*scale; \n"
"} \n";
vp->setFunction( "oe_polyline_scalelines", vs, ShaderComp::LOCATION_VERTEX_MODEL, 0.5f );
vp->addBindAttribLocation( "oe_polyline_center", ATTR_LOCATION );
// add the default scaling uniform.
// good way to test:
// osgearth_viewer earthfile --uniform oe_polyline_scale 1.0 10.0
osg::Uniform* scaleU = new osg::Uniform(osg::Uniform::FLOAT, "oe_polyline_scale");
scaleU->set( 1.0f );
stateset->addUniform( scaleU, 1 );
// the default "min pixels" uniform.
osg::Uniform* minPixelsU = new osg::Uniform(osg::Uniform::FLOAT, "oe_polyline_min_pixels");
minPixelsU->set( minPixels );
stateset->addUniform( minPixelsU, 1 );
// this will install and update the oe_PixelSizeVector uniform.
node->addCullCallback( new PixelSizeVectorCullCallback(stateset) );
}
