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OpenSceneGraph/include/osgText/Text

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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
*
* This library is open source and may be redistributed and/or modified under
* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
* (at your option) any later version. The full license is in LICENSE file
* included with this distribution, and on the openscenegraph.org website.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* OpenSceneGraph Public License for more details.
*/
#ifndef OSGTEXT_TEXT
#define OSGTEXT_TEXT 1
#include <osg/Drawable>
#include <osg/Quat>
#include <osgText/TextBase>
#include <osgText/Font>
namespace osgText {
class OSGTEXT_EXPORT Text : public osgText::TextBase
{
public:
Text();
Text(const Text& text,const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY);
virtual osg::Object* cloneType() const { return new Text(); }
virtual osg::Object* clone(const osg::CopyOp& copyop) const { return new Text(*this,copyop); }
virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const Text*>(obj)!=NULL; }
virtual const char* className() const { return "Text"; }
virtual const char* libraryName() const { return "osgText"; }
virtual void setFont(Font* font=0) { setFont(osg::ref_ptr<Font>(font)); };
/** Set the Font to use to render the text.*/
virtual void setFont(osg::ref_ptr<Font> font);
/** Set the font, loaded from the specified front file, to use to render the text,
* setFont("") sets the use of the default font.
* See the osgText::readFontFile function for how the font file will be located. */
virtual void setFont(const std::string& fontfile) { TextBase::setFont(fontfile); }
/**
* Turns off writing to the depth buffer when rendering text. This only affects text
* with no backdrop or text using the DELAYED_DEPTH_WRITES implementation, since
* the other backdrop implementations are really only useful for backwards
* compatibility and are not worth updating to utilize this flag.
*/
void setEnableDepthWrites(bool enable) { _enableDepthWrites = enable; }
bool getEnableDepthWrites() const { return _enableDepthWrites; }
enum BackdropType
{
DROP_SHADOW_BOTTOM_RIGHT = 0, // usually the type of shadow you see
DROP_SHADOW_CENTER_RIGHT,
DROP_SHADOW_TOP_RIGHT,
DROP_SHADOW_BOTTOM_CENTER,
DROP_SHADOW_TOP_CENTER,
DROP_SHADOW_BOTTOM_LEFT,
DROP_SHADOW_CENTER_LEFT,
DROP_SHADOW_TOP_LEFT,
OUTLINE,
NONE
};
enum BackdropImplementation
{
/* POLYGON_OFFSET:
* This uses glPolygonOffset to draw the text multiple times to
* create the drop-shadow and outline effects. glPolygonOffset
* is used to prevent z-fighting of the overlapping text.
* This probably should have been the best option, but all the ATI
* cards we have encountered so far have serious problems with this.
* We see little white holes/artifacts in the rendered glyph textures
* which move around depending on the viewing angle. For moving text,
* the moving holes give an extremely unpleasant flickering effect.
* Pumping up the "units" parameter in glPolygonOffset can minimize
* this problem, but two other bad side-effects occur if you do this.
* First, high values will cause problems with clipping, particularly
* when there are objects behind the text. The drop-shadows or outline
* may be culled because their computed offset is behind the object or
* z-far plane. Second, there is an additional problem associated with
* the Z-slope. High values can make large chunks of the backdrop
* suddenly disappear. This can be reduced by the "factor" parameter.
* Making the "factor" value small, can help, but experimentally, we've
* found that it creates a new, different kind of z-fighting problem.
* So there is no perfect solution. With units, you trade off the 'holes'
* for the large-section clipping.
* Experimentally, we have found units values from 150-512 to be tolerable
* to acceptable with respect to the 'holes'. A factor of .1 seems to
* bring down the large clipping problem without creating a new z-fighting
* problem.
* (You can experiment with these numbers by playing with the
* osg:PolygonOffset multipliers which this backend tries to respect.)
*
* If ATI ever fixes their cards/drivers, then this might become the
* best option.*/
POLYGON_OFFSET = 0,
/* NO_DEPTH_BUFFER
* Instead of using glPolygonOffset to prevent z-fighting, this mode
* just disables the depth buffer when rendering the text. This allows
* the text to be rendered without any z-fighting. The downside to this
* mode is that render order begins to matter and the text will not
* necessarily correctly appear above or behind other objects in the
* scene based on depth values.
* This mode is best for text that only needs to be ontop and
* not obscured by any objects.*/
NO_DEPTH_BUFFER,
/* DEPTH_RANGE
* This mode is inspired by Paul Martz's OpenGL FAQ, item 13.050.
* This uses glDepthRange as a substitute for glPolygonOffset.
* Strangely, experiments on ATI cards seem to produce cleaner results
* than when using glPolygonOffset. The trade-off for this is that the
* backdrop still may be placed too far back and might be culled by objects
* directly behind the object or by the far z-plane. If ATI ever fixes
* the glPolygonOffset problem, polygon offset is probably a slightly
* better solution because you can use smaller offsets. But with the
* current ATI problem, this option may be preferable.*/
DEPTH_RANGE,
/* STENCIL_BUFFER
* (Assuming the backend is written correctly,) the Stencil Buffer is
* the most "correct" and reliable way of producing backdrop text.
* The stencil buffer is a multipass system that allows writing to the
* same z-values without needing to resort to offsets. This implementation
* should not have any of the problems associated with the 3 previous
* implementations. But the trade-off for this mode is that without
* hardware acceleration for the stencil buffer, rendering will be
* extremely slow. (There is also potentially more overhead for this
* algorithm so it could be slower than the other implementations.
* Benchmarking would be required to determine if the speed differences
* are significant on your particular hardware.) This mode is best for
* when quality is important and stencil buffer hardware acceleration
* is available.*/
STENCIL_BUFFER,
/* DELAYED_DEPTH_WRITES
* This mode renders all text with depth writes turned off, then
* again with depth writes on, but with the color buffer disabled.
* This should render text accurately for all graphics cards. The
* only downside is the additional pass to render to the depth
* buffer. But if you don't need the depth buffer updated for
* your, this extra pass can be disabled by calling
* enableDepthWrites(false).*/
DELAYED_DEPTH_WRITES
};
/**
* BackdropType gives you a background shadow text behind your regular
* text. This helps give text extra contrast which can be useful when
* placing text against noisy backgrounds.
* The color of the background shadow text is specified by setBackdropColor().
* DROP_SHADOW_BOTTOM_RIGHT will draw backdrop text to the right and down of
* the normal text. Other DROW_SHADOW_* modes do the same for their repective directions.
* OUTLINE will draw backdrop text so that it appears the text has an outline
* or border around the normal text. This mode is particularly useful against
* really noisy backgrounds that may put text on top of things that have
* all types of colors which you don't have control over.
* Some real world examples of this general technique in use that I know of
* are Google Earth, Sid Meier's Pirates (2004 Remake), and Star Control 2 (PC 1993).
* The default is NONE.
*/
void setBackdropType(BackdropType type);
BackdropType getBackdropType() const { return _backdropType; }
/**
* Sets the amount text is offset to create the backdrop/shadow effect.
* Set the value too high and for example, in OUTLINE mode you will get a "Brady Bunch"
* effect where you see duplicates of the text in a 3x3 grid.
* Set the value too small and you won't see anything.
* The values represent percentages. 1.0 means 100% so a value of 1.0
* in DROW_SHADOW_LEFT_CENTER mode would cause each glyph to be echoed
* next to it self. So the letter 'e' might look like 'ee'.
* Good values tend to be in the 0.03 to 0.10 range (but will be subject
* to your specific font and display characteristics).
* Note that the text bounding boxes are updated to include backdrop offsets.
* However, other metric information such as getCharacterHeight() are unaffected
* by this. This means that individual glyph spacing (kerning?) are unchanged
* even when this mode is used.
* The default is 0.07 (7% offset).
*/
void setBackdropOffset(float offset = 0.07f);
/**
* This overloaded version lets you specify the offset for the horizontal
* and vertical components separately.
*/
void setBackdropOffset(float horizontal, float vertical);
float getBackdropHorizontalOffset() const { return _backdropHorizontalOffset; }
float getBackdropVerticalOffset() const { return _backdropVerticalOffset; }
/**
* This specifies the color of the backdrop text.
* The default is black.
*/
void setBackdropColor(const osg::Vec4& color);
const osg::Vec4& getBackdropColor() const { return _backdropColor; }
/**
* This specifies the underlying backdrop rendering implementation.
* Unfortunately, at this time, there is no "perfect" rendering solution
* so this function is provided to let you 'pick your poison'. Each
* implementation has trade-offs. See BackdropImplementation enum
* docs for details.*/
void setBackdropImplementation(BackdropImplementation implementation);
BackdropImplementation getBackdropImplementation() const { return _backdropImplementation; }
enum ColorGradientMode
{
SOLID = 0, // a.k.a. ColorGradients off
PER_CHARACTER,
OVERALL
};
/**
* This sets different types of text coloring modes.
* When the coloring mode is not set to SOLID, the
* colors specified in setColorGradientCorners() determine
* the colors for the text.
* When the gradient mode is OVERALL, the coloring scheme
* attempts to approximate the effect as if the entire text box/region
* were a single polygon and you had applied colors to each of the four
* corners with GL_SMOOTH enabled. In this mode, OpenGL interpolates
* the colors across the polygon, and this is what OVERALL tries to
* emulate. This can be used to give nice embellishments on things
* like logos and names.
* PER_CHARACTER is similar to OVERALL except that it applies the
* color interpolation to the four corners of each character instead
* of across the overall text box.
* The default is SOLID (a.k.a. off).
*/
void setColorGradientMode(ColorGradientMode mode);
ColorGradientMode getColorGradientMode() const { return _colorGradientMode; }
/**
* Used only for gradient mode, let's you specify the colors of the 4 corners.
* If ColorGradients are off, these values are ignored (and the value from setColor()
* is the only one that is relevant.
*/
void setColorGradientCorners(const osg::Vec4& topLeft, const osg::Vec4& bottomLeft, const osg::Vec4& bottomRight, const osg::Vec4& topRight);
const osg::Vec4& getColorGradientTopLeft() const { return _colorGradientTopLeft; }
const osg::Vec4& getColorGradientBottomLeft() const { return _colorGradientBottomLeft; }
const osg::Vec4& getColorGradientBottomRight() const { return _colorGradientBottomRight; }
const osg::Vec4& getColorGradientTopRight() const { return _colorGradientTopRight; }
/** Draw the text.*/
virtual void drawImplementation(osg::RenderInfo& renderInfo) const;
/** return false, osgText::Text does not support accept(AttributeFunctor&).*/
virtual bool supports(const osg::Drawable::AttributeFunctor&) const { return false; }
/** return true, osgText::Text does support accept(ConstAttributeFunctor&).*/
virtual bool supports(const osg::Drawable::ConstAttributeFunctor&) const { return true; }
/** accept an ConstAttributeFunctor and call its methods to tell it about the internal attributes that this Drawable has.*/
virtual void accept(osg::Drawable::ConstAttributeFunctor& af) const;
/** return true, osgText::Text does support accept(PrimitiveFunctor&) .*/
virtual bool supports(const osg::PrimitiveFunctor&) const { return true; }
/** accept a PrimtiveFunctor and call its methods to tell it about the internal primitives that this Drawable has.*/
virtual void accept(osg::PrimitiveFunctor& pf) const;
/** Set whether to use a mutex to ensure ref() and unref() are thread safe.*/
virtual void setThreadSafeRefUnref(bool threadSafe);
/** Resize any per context GLObject buffers to specified size. */
virtual void resizeGLObjectBuffers(unsigned int maxSize);
/** If State is non-zero, this function releases OpenGL objects for
* the specified graphics context. Otherwise, releases OpenGL objexts
* for all graphics contexts. */
virtual void releaseGLObjects(osg::State* state=0) const;
public:
// internal structures, variable and methods used for rendering of characters.
struct OSGTEXT_EXPORT GlyphQuads
{
typedef std::vector<Glyph*> Glyphs;
typedef std::vector<unsigned int> LineNumbers;
typedef osg::ref_ptr<osg::Vec2Array> Coords2;
typedef osg::ref_ptr<osg::Vec3Array> Coords3;
typedef osg::ref_ptr<osg::Vec2Array> TexCoords;
typedef osg::ref_ptr<osg::Vec4Array> ColorCoords;
Glyphs _glyphs;
Coords2 _coords;
osg::buffered_object<Coords3> _transformedCoords;
TexCoords _texcoords;
LineNumbers _lineNumbers;
osg::buffered_object<Coords3> _transformedBackdropCoords[8];
ColorCoords _colorCoords;
osg::ref_ptr<osg::DrawElementsUInt> _quadIndices;
void updateQuadIndices();
GlyphQuads();
GlyphQuads(const GlyphQuads& gq);
void initGlyphQuads();
void initGPUBufferObjects();
Glyphs& getGlyphs() { return _glyphs; }
const Glyphs& getGlyphs() const { return _glyphs; }
Coords2& getCoords() { return _coords; }
const Coords2& getCoords() const { return _coords; }
Coords3& getTransformedCoords(unsigned int contexID) { return _transformedCoords[contexID]; }
const Coords3& getTransformedCoords(unsigned int contexID) const { return _transformedCoords[contexID]; }
TexCoords& getTexCoords() { return _texcoords; }
const TexCoords& getTexCoords() const { return _texcoords; }
LineNumbers& getLineNumbers() { return _lineNumbers; }
const LineNumbers& getLineNumbers() const { return _lineNumbers; }
/** Resize any per context GLObject buffers to specified size. */
virtual void resizeGLObjectBuffers(unsigned int maxSize);
/** If State is non-zero, this function releases OpenGL objects for
* the specified graphics context. Otherwise, releases OpenGL objexts
* for all graphics contexts. */
virtual void releaseGLObjects(osg::State* state=0) const;
private:
GlyphQuads& operator = (const GlyphQuads&) { return *this; }
};
typedef std::map<osg::ref_ptr<GlyphTexture>,GlyphQuads> TextureGlyphQuadMap;
/** Direct Access to GlyphQuads */
const GlyphQuads* getGlyphQuads(GlyphTexture* texture) const
{
TextureGlyphQuadMap::iterator itGlyphQuad = _textureGlyphQuadMap.find(texture);
if (itGlyphQuad == _textureGlyphQuadMap.end()) return NULL;
return &itGlyphQuad->second;
}
const TextureGlyphQuadMap& getTextureGlyphQuadMap() const
{
return _textureGlyphQuadMap;
}
protected:
virtual ~Text();
Font* getActiveFont();
const Font* getActiveFont() const;
String::iterator computeLastCharacterOnLine(osg::Vec2& cursor, String::iterator first,String::iterator last);
// members which have public access.
// iternal map used for rendering. Set up by the computeGlyphRepresentation() method.
mutable TextureGlyphQuadMap _textureGlyphQuadMap;
void computeGlyphRepresentation();
// internal caches of the positioning of the text.
bool computeAverageGlyphWidthAndHeight(float& avg_width, float& avg_height) const;
virtual void computePositions(unsigned int contextID) const;
void computeBackdropPositions(unsigned int contextID) const;
void computeBackdropBoundingBox() const;
void computeBoundingBoxMargin() const;
void computeColorGradients() const;
void computeColorGradientsOverall() const;
void computeColorGradientsPerCharacter() const;
void drawImplementation(osg::State& state, const osg::Vec4& colorMultiplier) const;
void drawForegroundText(osg::State& state, const GlyphQuads& glyphquad, const osg::Vec4& colorMultiplier) const;
void drawTextWithBackdrop(osg::State& state, const osg::Vec4& colorMultiplier) const;
void renderOnlyForegroundText(osg::State& state, const osg::Vec4& colorMultiplier) const;
void renderWithPolygonOffset(osg::State& state, const osg::Vec4& colorMultiplier) const;
void renderWithNoDepthBuffer(osg::State& state, const osg::Vec4& colorMultiplier) const;
void renderWithDepthRange(osg::State& state, const osg::Vec4& colorMultiplier) const;
void renderWithStencilBuffer(osg::State& state, const osg::Vec4& colorMultiplier) const;
void renderWithDelayedDepthWrites(osg::State& state, const osg::Vec4& colorMultiplier) const;
bool _enableDepthWrites;
BackdropType _backdropType;
BackdropImplementation _backdropImplementation;
float _backdropHorizontalOffset;
float _backdropVerticalOffset;
osg::Vec4 _backdropColor;
ColorGradientMode _colorGradientMode;
osg::Vec4 _colorGradientTopLeft;
osg::Vec4 _colorGradientBottomLeft;
osg::Vec4 _colorGradientBottomRight;
osg::Vec4 _colorGradientTopRight;
// Helper function for color interpolation
float bilinearInterpolate(float x1, float x2, float y1, float y2, float x, float y, float q11, float q12, float q21, float q22) const;
};
}
#endif
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