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10<title>Framebuffer</title>
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16    <h1>Framebuffer</h1>
17    <!-- InstanceEndEditable --> <!-- InstanceBeginEditable name="本文" -->
18    <p>This document describes the framebuffer.</p>
19    <h2>Framebuffer Configuration</h2>
20    <!-- #BeginLibraryItem "/Library/glossary_frame_buffer.lbi" --> <!-- フレームバッファ ( frame_buffer ) -->
21    <p>The <I>framebuffer</I> is a memory region for temporarily storing data output from the fragment shader.<br /> Values for fragments for which processing by fragment using the blender has ended are stored here.</p>
22    <p>The table below gives an overview of the three <I>buffers</I> that collectively make up the framebuffer.</p>
23    <table>
24      <thead>
25        <tr>
26          <th>Buffer Type</th>
27          <th>Usage</th>
28        </tr>
29      </thead>
30      <tbody>
31        <tr>
32          <th>Color Buffer</th>
33          <td>Renders fragment values that contain color and alpha values.</td>
34        </tr>
35        <tr>
36          <th>Stencil Buffer</th>
37          <td>Stores information that limits the area being rendered. This is used during stencil tests.</td>
38        </tr>
39        <tr>
40          <th>Depth Buffer</th>
41          <td>Stores information about the depth from the camera. This is used during depth tests.</td>
42        </tr>
43      </tbody>
44    </table>
45    <!-- #EndLibraryItem -->
46    <h3>Buffer Format</h3>
47    <p>Several different data recording <em>formats</em> can be specified for each buffer when storing data.</p>
48    <p>The following figure shows the formats for the color buffer, stencil buffer, and depth buffer.</p>
49    <img class="user_guide_chart" src="assets/frame_buffer_format.png" alt="Buffer Formats"/> <!-- #BeginLibraryItem "/Library/performance_frame_buffer.lbi" --> <!-- フレームバッファのフォーマットによるデータサイズ ( performance_frame_buffer ) -->
50    <p>The number of bits per pixel differs for the format of each buffer making up the framebuffer. For buffers with few bits, the on-screen display system degrades in proportion to how small the buffer allocated in recording memory is.</p>
51    <!-- #EndLibraryItem -->
52    <p class="hint_warn"><B>Note:</B> A format having a total of 32 bits results when using an 8-bit stencil buffer combined with a 24-bit depth buffer.</p>
53    <h2><B>Anti-aliasing</B></h2>
54    <p>This section describes anti-aliasing when rendering to the screen.</p>
55    <!-- #BeginLibraryItem "/Library/glossary_frame_buffer_antialiasing.lbi" --> <!-- アンチエイリアス ( frame_buffer_antialiasing ) -->
56    <p><I>Anti-aliasing </I>is a method for smoothing outlines when drawing polygons.<br /> You can apply anti-aliasing by having a larger image scale in the frame buffer than in the display buffer and reducing the image when sending it from the frame buffer to the display buffer.</p>
57    <!-- #EndLibraryItem --><!-- #BeginLibraryItem "/Library/glossary_display_buffer.lbi" --> <!-- ディスプレイバッファ ( display_buffer ) -->
58    <p>The <I>display buffer</I> is the region of memory where the image output from the framebuffer is stored after the image data have been converted to an actual picture for display on the screen.<br /> It can be secured in VRAM and in device memory.</p>
59    <!-- #EndLibraryItem -->
60    <p>The table below lists the two available anti-aliasing methods.</p>
61    <table>
62      <thead>
63        <tr>
64          <th>Types of Rendering Scaling Factors</th>
65          <th>Direction anti-aliasing is applied</th>
66          <th>Required framebuffer size.</th>
67        </tr>
68      </thead>
69      <tbody>
70        <tr>
71          <th>2 &times; 1</th>
72          <td>Vertical direction of screen.</td>
73          <td>Results in two times the display buffer.</td>
74        </tr>
75        <tr>
76          <th>2 &times; 2</th>
77          <td>Vertical and horizontal direction of screen.</td>
78          <td>Results in four times the display buffer.</td>
79        </tr>
80      </tbody>
81    </table>
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