FGFS-4.1/simgear
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canvas::Element: floating point scissor coordinates.

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GL_SCISSOR itself only supports integer coordinates, but
with reference frames different from GLOBAL transforms
influence the position of the clipping frame, possibly
resulting in wrong positions due to too low precision.
This commit is contained in:
Thomas Geymayer 2014-07-19 20:52:17 +02:00
parent e415b08da4
commit f6b16e2ba8
1 changed files with 43 additions and 12 deletions
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55
simgear/canvas/elements/CanvasElement.cxx
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@ -26,7 +26,7 @@
#include <osg/Drawable>
#include <osg/Geode>
#include <osg/Scissor>
#include <osg/StateAttribute>
#include <boost/algorithm/string/predicate.hpp>
#include <boost/foreach.hpp>
@ -46,27 +46,34 @@ namespace canvas
* glScissor with coordinates relative to different reference frames.
*/
class Element::RelativeScissor:
public osg::Scissor
public osg::StateAttribute
{
public:
ReferenceFrame _coord_reference;
osg::observer_ptr<osg::Node> _node;
RelativeScissor(osg::Node* node = NULL):
explicit RelativeScissor(osg::Node* node = NULL):
_coord_reference(GLOBAL),
_node(node)
_node(node),
_x(0),
_y(0),
_width(0),
_height(0)
{
_width = 0;
_height = 0;
}
/** Copy constructor using CopyOp to manage deep vs shallow copy. */
RelativeScissor( const RelativeScissor& vp,
const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY ):
Scissor(vp, copyop),
StateAttribute(vp, copyop),
_coord_reference(vp._coord_reference),
_node(vp._node)
_node(vp._node),
_x(vp._x),
_y(vp._y),
_width(vp._width),
_height(vp._height)
{}
META_StateAttribute(simgear, RelativeScissor, SCISSOR);
@ -89,6 +96,24 @@ namespace canvas
return 0; // passed all the above comparison macros, must be equal.
}
virtual bool getModeUsage(StateAttribute::ModeUsage& usage) const
{
usage.usesMode(GL_SCISSOR_TEST);
return true;
}
inline float& x() { return _x; }
inline float x() const { return _x; }
inline float& y() { return _y; }
inline float y() const { return _y; }
inline float& width() { return _width; }
inline float width() const { return _width; }
inline float& height() { return _height; }
inline float height() const { return _height; }
virtual void apply(osg::State& state) const
{
if( _width <= 0 || _height <= 0 )
@ -163,6 +188,12 @@ namespace canvas
return false;
}
protected:
float _x,
_y,
_width,
_height;
};
//----------------------------------------------------------------------------
@ -576,10 +607,10 @@ namespace canvas
_scissor = new RelativeScissor(_transform.get());
// <top>, <right>, <bottom>, <left>
_scissor->x() = SGMiscf::roundToInt(values[3]);
_scissor->y() = SGMiscf::roundToInt(values[0]);
_scissor->width() = SGMiscf::roundToInt(width);
_scissor->height() = SGMiscf::roundToInt(height);
_scissor->x() = values[3];
_scissor->y() = values[0];
_scissor->width() = width;
_scissor->height() = height;
SGPropertyNode* clip_frame = _node->getChild("clip-frame", 0);
if( clip_frame )