SFML/include/SFML/Graphics/RenderTarget.hpp
2015-03-02 13:41:54 -05:00

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////////////////////////////////////////////////////////////
//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2015 Laurent Gomila (laurent@sfml-dev.org)
//
// This software is provided 'as-is', without any express or implied warranty.
// In no event will the authors be held liable for any damages arising from the use of this software.
//
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it freely,
// subject to the following restrictions:
//
// 1. The origin of this software must not be misrepresented;
// you must not claim that you wrote the original software.
// If you use this software in a product, an acknowledgment
// in the product documentation would be appreciated but is not required.
//
// 2. Altered source versions must be plainly marked as such,
// and must not be misrepresented as being the original software.
//
// 3. This notice may not be removed or altered from any source distribution.
//
////////////////////////////////////////////////////////////
#ifndef SFML_RENDERTARGET_HPP
#define SFML_RENDERTARGET_HPP
////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/Graphics/Export.hpp>
#include <SFML/Graphics/Color.hpp>
#include <SFML/Graphics/Rect.hpp>
#include <SFML/Graphics/View.hpp>
#include <SFML/Graphics/Transform.hpp>
#include <SFML/Graphics/BlendMode.hpp>
#include <SFML/Graphics/RenderStates.hpp>
#include <SFML/Graphics/PrimitiveType.hpp>
#include <SFML/Graphics/Vertex.hpp>
#include <SFML/System/NonCopyable.hpp>
namespace sf
{
class Drawable;
////////////////////////////////////////////////////////////
/// \brief Base class for all render targets (window, texture, ...)
///
////////////////////////////////////////////////////////////
class SFML_GRAPHICS_API RenderTarget : NonCopyable
{
public:
////////////////////////////////////////////////////////////
/// \brief Destructor
///
////////////////////////////////////////////////////////////
virtual ~RenderTarget();
////////////////////////////////////////////////////////////
/// \brief Clear the entire target with a single color
///
/// This function is usually called once every frame,
/// to clear the previous contents of the target.
///
/// \param color Fill color to use to clear the render target
///
////////////////////////////////////////////////////////////
void clear(const Color& color = Color(0, 0, 0, 255));
////////////////////////////////////////////////////////////
/// \brief Change the current active view
///
/// The view is like a 2D camera, it controls which part of
/// the 2D scene is visible, and how it is viewed in the
/// render target.
/// The new view will affect everything that is drawn, until
/// another view is set.
/// The render target keeps its own copy of the view object,
/// so it is not necessary to keep the original one alive
/// after calling this function.
/// To restore the original view of the target, you can pass
/// the result of getDefaultView() to this function.
///
/// \param view New view to use
///
/// \see getView, getDefaultView
///
////////////////////////////////////////////////////////////
void setView(const View& view);
////////////////////////////////////////////////////////////
/// \brief Get the view currently in use in the render target
///
/// \return The view object that is currently used
///
/// \see setView, getDefaultView
///
////////////////////////////////////////////////////////////
const View& getView() const;
////////////////////////////////////////////////////////////
/// \brief Get the default view of the render target
///
/// The default view has the initial size of the render target,
/// and never changes after the target has been created.
///
/// \return The default view of the render target
///
/// \see setView, getView
///
////////////////////////////////////////////////////////////
const View& getDefaultView() const;
////////////////////////////////////////////////////////////
/// \brief Get the viewport of a view, applied to this render target
///
/// The viewport is defined in the view as a ratio, this function
/// simply applies this ratio to the current dimensions of the
/// render target to calculate the pixels rectangle that the viewport
/// actually covers in the target.
///
/// \param view The view for which we want to compute the viewport
///
/// \return Viewport rectangle, expressed in pixels
///
////////////////////////////////////////////////////////////
IntRect getViewport(const View& view) const;
////////////////////////////////////////////////////////////
/// \brief Convert a point from target coordinates to world
/// coordinates, using the current view
///
/// This function is an overload of the mapPixelToCoords
/// function that implicitly uses the current view.
/// It is equivalent to:
/// \code
/// target.mapPixelToCoords(point, target.getView());
/// \endcode
///
/// \param point Pixel to convert
///
/// \return The converted point, in "world" coordinates
///
/// \see mapCoordsToPixel
///
////////////////////////////////////////////////////////////
Vector2f mapPixelToCoords(const Vector2i& point) const;
////////////////////////////////////////////////////////////
/// \brief Convert a point from target coordinates to world coordinates
///
/// This function finds the 2D position that matches the
/// given pixel of the render target. In other words, it does
/// the inverse of what the graphics card does, to find the
/// initial position of a rendered pixel.
///
/// Initially, both coordinate systems (world units and target pixels)
/// match perfectly. But if you define a custom view or resize your
/// render target, this assertion is not true anymore, i.e. a point
/// located at (10, 50) in your render target may map to the point
/// (150, 75) in your 2D world -- if the view is translated by (140, 25).
///
/// For render-windows, this function is typically used to find
/// which point (or object) is located below the mouse cursor.
///
/// This version uses a custom view for calculations, see the other
/// overload of the function if you want to use the current view of the
/// render target.
///
/// \param point Pixel to convert
/// \param view The view to use for converting the point
///
/// \return The converted point, in "world" units
///
/// \see mapCoordsToPixel
///
////////////////////////////////////////////////////////////
Vector2f mapPixelToCoords(const Vector2i& point, const View& view) const;
////////////////////////////////////////////////////////////
/// \brief Convert a point from world coordinates to target
/// coordinates, using the current view
///
/// This function is an overload of the mapCoordsToPixel
/// function that implicitly uses the current view.
/// It is equivalent to:
/// \code
/// target.mapCoordsToPixel(point, target.getView());
/// \endcode
///
/// \param point Point to convert
///
/// \return The converted point, in target coordinates (pixels)
///
/// \see mapPixelToCoords
///
////////////////////////////////////////////////////////////
Vector2i mapCoordsToPixel(const Vector2f& point) const;
////////////////////////////////////////////////////////////
/// \brief Convert a point from world coordinates to target coordinates
///
/// This function finds the pixel of the render target that matches
/// the given 2D point. In other words, it goes through the same process
/// as the graphics card, to compute the final position of a rendered point.
///
/// Initially, both coordinate systems (world units and target pixels)
/// match perfectly. But if you define a custom view or resize your
/// render target, this assertion is not true anymore, i.e. a point
/// located at (150, 75) in your 2D world may map to the pixel
/// (10, 50) of your render target -- if the view is translated by (140, 25).
///
/// This version uses a custom view for calculations, see the other
/// overload of the function if you want to use the current view of the
/// render target.
///
/// \param point Point to convert
/// \param view The view to use for converting the point
///
/// \return The converted point, in target coordinates (pixels)
///
/// \see mapPixelToCoords
///
////////////////////////////////////////////////////////////
Vector2i mapCoordsToPixel(const Vector2f& point, const View& view) const;
////////////////////////////////////////////////////////////
/// \brief Draw a drawable object to the render target
///
/// \param drawable Object to draw
/// \param states Render states to use for drawing
///
////////////////////////////////////////////////////////////
void draw(const Drawable& drawable, const RenderStates& states = RenderStates::Default);
////////////////////////////////////////////////////////////
/// \brief Draw primitives defined by an array of vertices
///
/// \param vertices Pointer to the vertices
/// \param vertexCount Number of vertices in the array
/// \param type Type of primitives to draw
/// \param states Render states to use for drawing
///
////////////////////////////////////////////////////////////
void draw(const Vertex* vertices, std::size_t vertexCount,
PrimitiveType type, const RenderStates& states = RenderStates::Default);
////////////////////////////////////////////////////////////
/// \brief Return the size of the rendering region of the target
///
/// \return Size in pixels
///
////////////////////////////////////////////////////////////
virtual Vector2u getSize() const = 0;
////////////////////////////////////////////////////////////
/// \brief Save the current OpenGL render states and matrices
///
/// This function can be used when you mix SFML drawing
/// and direct OpenGL rendering. Combined with popGLStates,
/// it ensures that:
/// \li SFML's internal states are not messed up by your OpenGL code
/// \li your OpenGL states are not modified by a call to a SFML function
///
/// More specifically, it must be used around code that
/// calls Draw functions. Example:
/// \code
/// // OpenGL code here...
/// window.pushGLStates();
/// window.draw(...);
/// window.draw(...);
/// window.popGLStates();
/// // OpenGL code here...
/// \endcode
///
/// Note that this function is quite expensive: it saves all the
/// possible OpenGL states and matrices, even the ones you
/// don't care about. Therefore it should be used wisely.
/// It is provided for convenience, but the best results will
/// be achieved if you handle OpenGL states yourself (because
/// you know which states have really changed, and need to be
/// saved and restored). Take a look at the resetGLStates
/// function if you do so.
///
/// \see popGLStates
///
////////////////////////////////////////////////////////////
void pushGLStates();
////////////////////////////////////////////////////////////
/// \brief Restore the previously saved OpenGL render states and matrices
///
/// See the description of pushGLStates to get a detailed
/// description of these functions.
///
/// \see pushGLStates
///
////////////////////////////////////////////////////////////
void popGLStates();
////////////////////////////////////////////////////////////
/// \brief Reset the internal OpenGL states so that the target is ready for drawing
///
/// This function can be used when you mix SFML drawing
/// and direct OpenGL rendering, if you choose not to use
/// pushGLStates/popGLStates. It makes sure that all OpenGL
/// states needed by SFML are set, so that subsequent draw()
/// calls will work as expected.
///
/// Example:
/// \code
/// // OpenGL code here...
/// glPushAttrib(...);
/// window.resetGLStates();
/// window.draw(...);
/// window.draw(...);
/// glPopAttrib(...);
/// // OpenGL code here...
/// \endcode
///
////////////////////////////////////////////////////////////
void resetGLStates();
protected:
////////////////////////////////////////////////////////////
/// \brief Default constructor
///
////////////////////////////////////////////////////////////
RenderTarget();
////////////////////////////////////////////////////////////
/// \brief Performs the common initialization step after creation
///
/// The derived classes must call this function after the
/// target is created and ready for drawing.
///
////////////////////////////////////////////////////////////
void initialize();
private:
////////////////////////////////////////////////////////////
/// \brief Apply the current view
///
////////////////////////////////////////////////////////////
void applyCurrentView();
////////////////////////////////////////////////////////////
/// \brief Apply a new blending mode
///
/// \param mode Blending mode to apply
///
////////////////////////////////////////////////////////////
void applyBlendMode(const BlendMode& mode);
////////////////////////////////////////////////////////////
/// \brief Apply a new transform
///
/// \param transform Transform to apply
///
////////////////////////////////////////////////////////////
void applyTransform(const Transform& transform);
////////////////////////////////////////////////////////////
/// \brief Apply a new texture
///
/// \param texture Texture to apply
///
////////////////////////////////////////////////////////////
void applyTexture(const Texture* texture);
////////////////////////////////////////////////////////////
/// \brief Apply a new shader
///
/// \param shader Shader to apply
///
////////////////////////////////////////////////////////////
void applyShader(const Shader* shader);
////////////////////////////////////////////////////////////
/// \brief Activate the target for rendering
///
/// This function must be implemented by derived classes to make
/// their OpenGL context current; it is called by the base class
/// everytime it's going to use OpenGL calls.
///
/// \param active True to make the target active, false to deactivate it
///
/// \return True if the function succeeded
///
////////////////////////////////////////////////////////////
virtual bool activate(bool active) = 0;
////////////////////////////////////////////////////////////
/// \brief Render states cache
///
////////////////////////////////////////////////////////////
struct StatesCache
{
enum {VertexCacheSize = 4};
bool glStatesSet; ///< Are our internal GL states set yet?
bool viewChanged; ///< Has the current view changed since last draw?
BlendMode lastBlendMode; ///< Cached blending mode
Uint64 lastTextureId; ///< Cached texture
bool useVertexCache; ///< Did we previously use the vertex cache?
Vertex vertexCache[VertexCacheSize]; ///< Pre-transformed vertices cache
};
////////////////////////////////////////////////////////////
// Member data
////////////////////////////////////////////////////////////
View m_defaultView; ///< Default view
View m_view; ///< Current view
StatesCache m_cache; ///< Render states cache
};
} // namespace sf
#endif // SFML_RENDERTARGET_HPP
////////////////////////////////////////////////////////////
/// \class sf::RenderTarget
/// \ingroup graphics
///
/// sf::RenderTarget defines the common behavior of all the
/// 2D render targets usable in the graphics module. It makes
/// it possible to draw 2D entities like sprites, shapes, text
/// without using any OpenGL command directly.
///
/// A sf::RenderTarget is also able to use views (sf::View),
/// which are a kind of 2D cameras. With views you can globally
/// scroll, rotate or zoom everything that is drawn,
/// without having to transform every single entity. See the
/// documentation of sf::View for more details and sample pieces of
/// code about this class.
///
/// On top of that, render targets are still able to render direct
/// OpenGL stuff. It is even possible to mix together OpenGL calls
/// and regular SFML drawing commands. When doing so, make sure that
/// OpenGL states are not messed up by calling the
/// pushGLStates/popGLStates functions.
///
/// \see sf::RenderWindow, sf::RenderTexture, sf::View
///
////////////////////////////////////////////////////////////