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Next: <a href="Viewports.html" accesskey="n" rel="next">Viewports</a>, Previous: <a href="Shaders.html" accesskey="p" rel="prev">Shaders</a>, Up: <a href="Graphics.html" accesskey="u" rel="up">Graphics</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p>
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<span id="Framebuffers-1"></span><h4 class="subsection">5.3.14 Framebuffers</h4>
<p>A framebuffer is a chunk of memory that the GPU can render things
onto. By default, the framebuffer that is used for rendering is the
one belonging to the game window, but custom framebuffers can be used
as well. A common use-case for custom framebuffers is applying
post-processing effects: The entire scene is rendered to a
framebuffer, and then the contents of that framebuffer are applied to
a post-processing shader and rendered to the game window. The
post-processing shader could do any number of things: scaling,
antialiasing, motion blur, etc.
</p>
<dl>
<dt id="index-make_002dframebuffer">Procedure: <strong>make-framebuffer</strong> <em>width height [#:min-filter <code>linear</code>] [#:mag-filter <code>linear</code>] [#:wrap-s <code>repeat</code>] [#:wrap-t <code>repeat</code>]</em></dt>
<dd>
<p>Create a new framebuffer that is <var>width</var> pixels wide and <var>height</var> pixels high.
</p>
<p><var>min-filter</var> and <var>mag-filter</var> determine the scaling algorithm
applied to the framebuffer when rendering. By default, linear scaling
is used in both cases. To perform no smoothing at all, use
<code>nearest</code> for simple nearest neighbor scaling. This is typically
the best choice for pixel art games.
</p></dd></dl>
<dl>
<dt id="index-framebuffer_003f">Procedure: <strong>framebuffer?</strong> <em>obj</em></dt>
<dd><p>Return <code>#t</code> if <var>obj</var> is a framebuffer.
</p></dd></dl>
<dl>
<dt id="index-framebuffer_002dtexture">Procedure: <strong>framebuffer-texture</strong> <em>fb</em></dt>
<dd><p>Return the texture backing the framebuffer <var>fb</var>.
</p></dd></dl>
<dl>
<dt id="index-framebuffer_002dviewport">Procedure: <strong>framebuffer-viewport</strong> <em>fb</em></dt>
<dd><p>Return the default viewport (see <a href="Viewports.html">Viewports</a>) used by the
framebuffer <var>fb</var>.
</p></dd></dl>
<dl>
<dt id="index-null_002dframebuffer">Procedure: <strong>null-framebuffer</strong></dt>
<dd><p>The default framebuffer.
</p></dd></dl>
<dl>
<dt id="index-current_002dframebuffer">Procedure: <strong>current-framebuffer</strong></dt>
<dd><p>Return the current framebuffer.
</p></dd></dl>
<dl>
<dt id="index-g_003aframebuffer">Variable: <strong>g:framebuffer</strong></dt>
<dd><p>Render state for framebuffers (see <a href="Rendering-Engine.html">Rendering Engine</a>.)
</p></dd></dl>
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