doc/reference/cogl-2.0-experimental/html/cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).html

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  24 <a href="#cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).synopsis" class="shortcut">Top</a>
  25                    |
  26                   <a href="#cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).description" class="shortcut">Description</a>
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  28 </table>
  29 <div class="refentry">
  30 <a name="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates)"></a><div class="titlepage"></div>
  31 <div class="refnamediv"><table width="100%"><tr>
  32 <td valign="top">
  33 <h2><span class="refentrytitle"><a name="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).top_of_page"></a>Rectangle textures (non-normalized coordinates)</span></h2>
  34 <p>Rectangle textures (non-normalized coordinates) — Functions for creating and manipulating rectangle
  35                     textures for use with non-normalized coordinates.</p>
  36 </td>
  37 <td valign="top" align="right"></td>
  38 </tr></table></div>
  39 <div class="refsynopsisdiv">
  40 <a name="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).synopsis"></a><h2>Synopsis</h2>
  41 <pre class="synopsis">                    <a class="link" href="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).html#CoglTextureRectangle" title="CoglTextureRectangle">CoglTextureRectangle</a>;
  42 #define             <a class="link" href="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).html#cogl-texture-rectangle-new-with-size" title="cogl_texture_rectangle_new_with_size">cogl_texture_rectangle_new_with_size</a>
  43 #define             <a class="link" href="cogl-2.0-experimental-2D-textures.html#cogl-is-texture-rectangle" title="cogl_is_texture_rectangle">cogl_is_texture_rectangle</a>
  44 </pre>
  45 </div>
  46 <div class="refsect1">
  47 <a name="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).description"></a><h2>Description</h2>
  48 <p>
  49 These functions allow low-level "rectangle" textures to be allocated.
  50 These textures are never constrained to power-of-two sizes but they
  51 also don't support having a mipmap and can only be wrapped with
  52 <code class="literal">COGL_PIPELINE_WRAP_MODE_CLAMP_TO_EDGE</code>.
  53 </p>
  54 <p>
  55 The most notable difference between rectangle textures and 2D
  56 textures is that rectangle textures are sampled using un-normalized
  57 texture coordinates, so instead of using coordinates (0,0) and
  58 (1,1) to map to the top-left and bottom right corners of the
  59 texture you would instead use (0,0) and (width,height).
  60 </p>
  61 <p>
  62 The use of non-normalized coordinates can be particularly
  63 convenient when writing glsl shaders that use a texture as a lookup
  64 table since you don't need to upload separate uniforms to map
  65 normalized coordinates to texels.
  66 </p>
  67 <p>
  68 If you want to sample from a rectangle texture from GLSL you should
  69 use the sampler2DRect sampler type.
  70 </p>
  71 <p>
  72 Applications wanting to use <a class="link" href="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).html#CoglTextureRectangle" title="CoglTextureRectangle"><span class="type">CoglTextureRectangle</span></a> should first check
  73 for the <a class="link" href="cogl-2.0-experimental-The-Top-Level-Context.html#COGL-FEATURE-ID-TEXTURE-RECTANGLE:CAPS"><code class="literal">COGL_FEATURE_ID_TEXTURE_RECTANGLE</code></a> feature using
  74 <a class="link" href="cogl-2.0-experimental-The-Top-Level-Context.html#cogl-has-feature" title="cogl_has_feature ()"><code class="function">cogl_has_feature()</code></a>.
  75 </p>
  76 </div>
  77 <div class="refsect1">
  78 <a name="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).details"></a><h2>Details</h2>
  79 <div class="refsect2">
  80 <a name="CoglTextureRectangle"></a><h3>CoglTextureRectangle</h3>
  81 <pre class="programlisting">typedef struct _CoglTextureRectangle CoglTextureRectangle;</pre>
  82 </div>
  83 <hr>
  84 <div class="refsect2">
  85 <a name="cogl-texture-rectangle-new-with-size"></a><h3>cogl_texture_rectangle_new_with_size</h3>
  86 <pre class="programlisting">#define             cogl_texture_rectangle_new_with_size</pre>
  87 <p>
  88 Allocates a new <span class="type">CoglRectangle</span> texture with a given <em class="parameter"><code>width</code></em>, <em class="parameter"><code>height</code></em>
  89 and <em class="parameter"><code>internal_format</code></em>. This texture is a low-level texture that
  90 the GPU can sample from directly unlike high-level textures such
  91 as <a class="link" href="cogl-2.0-experimental-Sliced-Textures.html#CoglTexture2DSliced" title="CoglTexture2DSliced"><span class="type">CoglTexture2DSliced</span></a> and <span class="type">CoglAtlasTexture</span>.
  92 </p>
  93 <p>
  94 </p>
  95 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
  96 <h3 class="title">Note</h3>If you want to sample from a rectangle texture from GLSL you
  97 should use the sampler2DRect sampler type.</div>
  98 <p>
  99 </p>
 100 <p>
 101 </p>
 102 <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
 103 <h3 class="title">Note</h3>Applications wanting to use <a class="link" href="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).html#CoglTextureRectangle" title="CoglTextureRectangle"><span class="type">CoglTextureRectangle</span></a> should
 104 first check for the <a class="link" href="cogl-2.0-experimental-The-Top-Level-Context.html#COGL-FEATURE-ID-TEXTURE-RECTANGLE:CAPS"><code class="literal">COGL_FEATURE_ID_TEXTURE_RECTANGLE</code></a> feature
 105 using <a class="link" href="cogl-2.0-experimental-The-Top-Level-Context.html#cogl-has-feature" title="cogl_has_feature ()"><code class="function">cogl_has_feature()</code></a>.</div>
 106 <p>
 107 </p>
 108 <div class="variablelist"><table border="0">
 109 <col align="left" valign="top">
 110 <tbody>
 111 <tr>
 112 <td><p><span class="term"><em class="parameter"><code>context</code></em> :</span></p></td>
 113 <td>A <span class="type">CoglContext</span> pointer</td>
 114 </tr>
 115 <tr>
 116 <td><p><span class="term"><em class="parameter"><code>width</code></em> :</span></p></td>
 117 <td>The texture width to allocate</td>
 118 </tr>
 119 <tr>
 120 <td><p><span class="term"><em class="parameter"><code>height</code></em> :</span></p></td>
 121 <td>The texture height to allocate</td>
 122 </tr>
 123 <tr>
 124 <td><p><span class="term"><em class="parameter"><code>internal_format</code></em> :</span></p></td>
 125 <td>The desired internal texture format</td>
 126 </tr>
 127 <tr>
 128 <td><p><span class="term"><em class="parameter"><code>error</code></em> :</span></p></td>
 129 <td>An optional GError pointer for reporting exceptions</td>
 130 </tr>
 131 <tr>
 132 <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
 133 <td>A pointer to a newly allocated <span class="type">CoglRectangle</span> texture
 134 or if the size was too large or there wasn't enough memory
 135 <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> is returned and <em class="parameter"><code>error</code></em> set.</td>
 136 </tr>
 137 </tbody>
 138 </table></div>
 139 <p class="since">Since 1.10</p>
 140 <p class="stability">Stability Level: Unstable</p>
 141 </div>
 142 <hr>
 143 <div class="refsect2">
 144 <a name="cogl-is-texture-rectangle"></a><h3>cogl_is_texture_rectangle</h3>
 145 <pre class="programlisting">#define cogl_is_texture_rectangle cogl_is_texture_rectangle_EXP
 146 </pre>
 147 <p>
 148 Gets whether the given object references an existing
 149 <a class="link" href="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).html#CoglTextureRectangle" title="CoglTextureRectangle"><span class="type">CoglTextureRectangle</span></a> object.
 150 </p>
 151 <div class="variablelist"><table border="0">
 152 <col align="left" valign="top">
 153 <tbody>
 154 <tr>
 155 <td><p><span class="term"><em class="parameter"><code>object</code></em> :</span></p></td>
 156 <td>A <a class="link" href="cogl-2.0-experimental-The-Object-Interface.html#CoglObject" title="CoglObject"><span class="type">CoglObject</span></a>
 157 </td>
 158 </tr>
 159 <tr>
 160 <td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
 161 <td>
 162 <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the object references a
 163 <a class="link" href="cogl-2.0-experimental-Rectangle-textures-(non-normalized-coordinates).html#CoglTextureRectangle" title="CoglTextureRectangle"><span class="type">CoglTextureRectangle</span></a>, <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#FALSE:CAPS"><code class="literal">FALSE</code></a> otherwise.</td>
 164 </tr>
 165 </tbody>
 166 </table></div>
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