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14<TITLE>Hardware Buffers In OGRE: Textures</TITLE>
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37<H3> 2.8.1 Textures </H3>
38<!--docid::SEC23::-->
39<P>
40
41A texture is an image that can be applied onto the surface of a three dimensional model. In Ogre, textures are represented by the Texture resource class.
42</P><P>
43
44<A NAME="SEC24"></A>
45<H3> Creating a texture </H3>
46<!--docid::SEC24::-->
47<P>
48
49Textures are created through the TextureManager. In most cases they are created from image files directly by the
50Ogre resource system. If you are reading this, you most probably want to create a texture manually so that you can provide it with image data yourself. This is done through TextureManager::createManual:
51</P><P>
52
53<TABLE><tr><td>&nbsp;</td><td class=example><pre>ptex = TextureManager::getSingleton().createManual(
54    "MyManualTexture", // Name of texture
55    "General", // Name of resource group in which the texture should be created
56    TEX_TYPE_2D, // Texture type
57    256, // Width
58    256, // Height
59    1, // Depth (Must be 1 for two dimensional textures)
60    0, // Number of mipmaps
61    PF_A8R8G8B8, // Pixel format
62    TU_DYNAMIC_WRITE_ONLY // usage
63);
64</pre></td></tr></table></P><P>
65
66This example creates a texture named <EM>MyManualTexture</EM> in resource group <EM>General</EM>. It is a
67square <EM>two dimensional</EM> texture, with width 256 and height 256. It has <EM>no mipmaps</EM>, internal
68format <EM>PF_A8R8G8B8</EM> and usage <EM>TU_DYNAMIC_WRITE_ONLY</EM>.
69</P><P>
70
71The different texture types will be discussed in <A HREF="vbo-update_20.html#SEC30">2.8.3 Texture Types</A>. Pixel formats are summarised in
72<A HREF="vbo-update_21.html#SEC32">2.8.4 Pixel Formats</A>.
73</P><P>
74
75<A NAME="SEC25"></A>
76<H3> Texture usages </H3>
77<!--docid::SEC25::-->
78<P>
79
80In addition to the hardware buffer usages as described in See section <A HREF="vbo-update_5.html#SEC5">2.2 Buffer Usage</A> there are some usage flags specific to textures:
81<DL COMPACT>
82<DT>TU_AUTOMIPMAP
83<DD>Mipmaps for this texture will be automatically generated by the graphics hardware. The exact algorithm used is not
84defined, but you can assume it to be a 2x2 box filter.
85<DT>TU_RENDERTARGET
86<DD>This texture will be a render target, ie. used as a target for render to texture. Setting this flag will ignore all other texture usages except TU_AUTOMIPMAP.
87<DT>TU_DEFAULT
88<DD>This is actualy a combination of usage flags, and is equivalent to TU_AUTOMIPMAP | TU_STATIC_WRITE_ONLY. The resource
89system uses these flags for textures that are loaded from images.
90<P>
91
92</DL>
93<P>
94
95<A NAME="SEC26"></A>
96<H3> Getting a PixelBuffer </H3>
97<!--docid::SEC26::-->
98<P>
99
100A Texture can consist of multiple PixelBuffers, one for each combo if mipmap level and face number. To get a PixelBuffer from a Texture object the method Texture::getBuffer(face, mipmap) is used:
101</P><P>
102
103<EM>face</EM> should be zero for non-cubemap textures. For cubemap textures it identifies the face to use, which is one of the cube faces described in See section <A HREF="vbo-update_20.html#SEC30">2.8.3 Texture Types</A>.
104</P><P>
105
106<EM>mipmap</EM> is zero for the zeroth mipmap level, one for the first mipmap level, and so on. On textures that have automatic mipmap generation (TU_AUTOMIPMAP) only level 0 should be accessed, the rest will be taken care of by the rendering API.
107</P><P>
108
109A simple example of using getBuffer is
110<TABLE><tr><td>&nbsp;</td><td class=example><pre>// Get the PixelBuffer for face 0, mipmap 0.
111HardwarePixelBufferSharedPtr ptr = tex-&#62;getBuffer(0,0);
112</pre></td></tr></table></P><P>
113
114<A NAME="Updating Pixel Buffers"></A>
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