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module SF::RenderTarget #

Base module for all render targets (window, texture, ...)

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 module.

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 push_gl_states/pop_gl_states functions.

See also: SF::RenderWindow, SF::RenderTexture, SF::View

Included modules

SF::NonCopyable

Direct including types

SF::RenderTexture SF::RenderWindow

Methods#

#active=(active : Bool = true) : Bool#

Activate or deactivate the render target for rendering

This function makes the render target's context current for future OpenGL rendering operations (so you shouldn't care about it if you're not doing direct OpenGL stuff). A render target's context is active only on the current thread, if you want to make it active on another thread you have to deactivate it on the previous thread first if it was active. Only one context can be current in a thread, so if you want to draw OpenGL geometry to another render target don't forget to activate it again. Activating a render target will automatically deactivate the previously active context (if any).

  • active - True to activate, false to deactivate

Returns: True if operation was successful, false otherwise

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#clear(color : Color = Color.new(0, 0, 0, 255))#

Clear the entire target with a single color

This function is usually called once every frame, to clear the previous contents of the target.

  • color - Fill color to use to clear the render target
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#default_view : View#

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.

Returns: The default view of the render target

See also: view=, view

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#draw(vertices : Array(Vertex) | Slice(Vertex), type : PrimitiveType, states : RenderStates = RenderStates::Default)#

Draw primitives defined by an array of vertices

  • vertices - Pointer to the vertices
  • vertex_count - Number of vertices in the array
  • type - Type of primitives to draw
  • states - Render states to use for drawing
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#draw(vertex_buffer : VertexBuffer, first_vertex : Int, vertex_count : Int, states : RenderStates = RenderStates::Default)#

Draw primitives defined by a vertex buffer

  • vertex_buffer - Vertex buffer
  • first_vertex - Index of the first vertex to render
  • vertex_count - Number of vertices to render
  • states - Render states to use for drawing
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#draw(vertex_buffer : VertexBuffer, states : RenderStates = RenderStates::Default)#

Draw primitives defined by a vertex buffer

  • vertex_buffer - Vertex buffer
  • states - Render states to use for drawing
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#draw(drawable : Drawable, states : RenderStates = RenderStates::Default)#

Draw a drawable object to the render target.

Shorthand for Drawable#draw(self, states)

  • drawable - Object to draw
  • states - Render states to use for drawing
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#get_viewport(view : View) : IntRect#

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.

  • view - The view for which we want to compute the viewport

Returns: Viewport rectangle, expressed in pixels

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#map_coords_to_pixel(point : Vector2 | Tuple, view : View) : Vector2i#

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.

  • point - Point to convert
  • view - The view to use for converting the point

Returns: The converted point, in target coordinates (pixels)

See also: map_pixel_to_coords

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#map_coords_to_pixel(point : Vector2 | Tuple) : Vector2i#

Convert a point from world coordinates to target coordinates, using the current view

This function is an overload of the map_coords_to_pixel function that implicitly uses the current view. It is equivalent to: 

target.map_coords_to_pixel(point, target.view)

  • point - Point to convert

Returns: The converted point, in target coordinates (pixels)

See also: map_pixel_to_coords

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#map_pixel_to_coords(point : Vector2 | Tuple, view : View) : Vector2f#

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.

  • point - Pixel to convert
  • view - The view to use for converting the point

Returns: The converted point, in "world" units

See also: map_coords_to_pixel

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#map_pixel_to_coords(point : Vector2 | Tuple) : Vector2f#

Convert a point from target coordinates to world coordinates, using the current view

This function is an overload of the map_pixel_to_coords function that implicitly uses the current view. It is equivalent to: 

target.map_pixel_to_coords(point, target.view)

  • point - Pixel to convert

Returns: The converted point, in "world" coordinates

See also: map_coords_to_pixel

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#pop_gl_states#

Restore the previously saved OpenGL render states and matrices

See the description of push_gl_states to get a detailed description of these functions.

See also: push_gl_states

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#push_gl_states#

Save the current OpenGL render states and matrices

This function can be used when you mix SFML drawing and direct OpenGL rendering. Combined with pop_gl_states, it ensures that:

  • SFML's internal states are not messed up by your OpenGL code
  • 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: 

# OpenGL code here...
window.push_gl_states
window.draw(...)
window.draw(...)
window.pop_gl_states
# OpenGL code here...

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 reset_gl_states function if you do so.

See also: pop_gl_states

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#reset_gl_states#

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 push_gl_states/pop_gl_states. It makes sure that all OpenGL states needed by SFML are set, so that subsequent draw() calls will work as expected.

Example: 

# OpenGL code here...
glPushAttrib(...)
window.reset_gl_states
window.draw(...)
window.draw(...)
glPopAttrib(...)
# OpenGL code here...

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abstract #size : Vector2u#

Return the size of the rendering region of the target

Returns: Size in pixels

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#srgb? : Bool#

Tell if the render target will use sRGB encoding when drawing on it

Returns: True if the render target use sRGB encoding, false otherwise

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#view : View#

Get the view currently in use in the render target

Returns: The view object that is currently used

See also: view=, default_view

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#view=(view : View)#

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 default_view() to this function.

  • view - New view to use

See also: view, default_view

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