1<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 2<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US" lang="en-US"> 3<!-- InstanceBegin template="/Templates/default_template.dwt" codeOutsideHTMLIsLocked="false" --> 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 6<meta http-equiv="Content-Style-Type" content="text/css" /> 7<!-- InstanceBeginEditable name="CSS の相対パス指定" --> 8<link href="../../../common/manual.css" rel="stylesheet" type="text/css" /> 9<!-- InstanceEndEditable --> <!-- InstanceBeginEditable name="ページのタイトル" --> 10<title>Mipmap</title> 11<!-- InstanceEndEditable --> 12</head> 13<body> 14<div> 15 <div class="body"> <!-- InstanceBeginEditable name="本文のタイトル" --> 16 <h1>Mipmap</h1> 17 <!-- InstanceEndEditable --> <!-- InstanceBeginEditable name="本文" --> 18 <p>This page describes mipmaps.</p> 19 <p>A mipmap is a technique of applying a low-resolution texture prepared ahead of time when displaying a texture at a reduced size.</p> 20 <p>For details on mipmaps, see the separate document Introduction to CTR Graphics.</p> 21 <p class="new_hint"><B>Note:</B> Use the Photoshop Plug-in to create the mipmap texture.<BR> For details on the Photoshop Plug-in, see the following documentation:<br /> %NW4C_ROOT%/documents/DccPlugin/Photoshop/PhotoshopPlugin.html</p> 22 <h2>Creating a Mipmapped Texture</h2> 23 <p>You must create a mipmapped texture from a square image whose dimensions are <a href="../../../glossary/index.html#power_method">powers of two</a>.</p> 24 <p>Figure 1 Mipmap Texture</p> 25 <img class="user_guide_chart" src="assets/mipmapping_making.png" alt="Creating a Mipmapped Texture"/> 26 <p>The figure above depicts an example of a four-level mipmap with a maximum texture size of 128 x 128.</p> 27 <p>In this case, we create a texture that leaves the right-most unused portion empty, and specify the number of mipmap levels in the plug-in settings when outputting the texture data.</p> 28 <h3>Mipmap Level</h3> 29 <p>Mipmapped textures have levels. Level 0 is the original image at the original size. Each successive level is then the preceding level image cut to half the length and width.</p> 30 <p>A mipmaps can be prepared with up to eight levels before the image reaches its smallest size either vertically or horizontally in a given texture format.</p> 31 <!-- ★テクススチャフォーマットへリンク --> 32 <p>Figure 2 Relationship Between Mipmap Levels and Resolution</p> 33 <img class="user_guide_chart" src="assets/mipmapping_level.png" alt="Mipmap Level"/> 34 <p>The mipmap level or resolution used is determined by the <I>mipmap level of detail (LOD)</I>.</p> 35 <h3>LOD bias</h3> 36 <!-- #BeginLibraryItem "/Library/glossary_mipmaplodbias.lbi" --> <!-- ミップマップ LOD バイアス( mipmap lod bias ) --> 37 <p><I>Mipmap LOD bias</I> refers to a feature that adjusts the mipmap level that is applied by shifting the mipmap LOD level when the a level with something other than the desired resolution is referenced.</p> 38 <!-- #EndLibraryItem --> 39 <p>Figure 3 Example of Adjusting LOD Bias</p> 40 <img class="user_guide_chart" src="assets/mipmapping_bias.png" alt="Mipmap LOD Bias"/> 41 <h2>Mipmap Characteristics</h2> 42 <p>This section describes the characteristics of using mipmaps.</p> 43 <h3>Processor Load Reduction</h3> 44 <p>When using mipmaps, textures are displayed at the resolution best suited for the area displayed on the screen.</p> 45 <p>The load from the texel process can be reduced by applying a large size texture to a small area screen.</p> 46 <p class="new_hint"><B>Note:</B> There is still a load incurred even when using mipmaps when the mipmap level filtering method is configured for smooth interpolation.</p> 47 <!-- ★マテリアルパイプラインへリンク --> 48 <h3>Moiré Reduction</h3> 49 <p>You can reduce visual artifacts caused by moiré patterns when using mipmaps.</p> 50 <p>Figure 4 Comparison Using Mipmaps</p> 51 <img class="user_guide_chart" src="assets/mipmapping_comparing.png" alt="Comparing Mipmapped Textures With and Without Moiré Reduction"/> 52 53 <!-- #BeginLibraryItem "/Library/glossary_moire.lbi" --> <!-- モアレ( moire ) --> 54 <p><I>Moiré patterns</I> are interference patterns that occur when regular patterns are reduced in size.<br /> Moiré patterns occur when a texture with relatively high resolution is mapped to an on-screen area with relatively low resolution, causing the texture not to fit neatly within a single pixel. This causes the texture to appear to flicker.</p> 55 <!-- #EndLibraryItem --> 56 57 <!-- InstanceEndEditable --> </div> 58 <div class="footer" /> 59</div> 60<hr><p>CONFIDENTIAL</p></body> 61<!-- InstanceEnd --> 62</html>
