<?xml version="1.0" encoding="utf-8"?>

<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->

<!-- This component and the accompanying materials are made available under the terms of the License 

"Eclipse Public License v1.0" which accompanies this distribution, 

and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->

<!-- Initial Contributors:

    Nokia Corporation - initial contribution.

Contributors: 

-->

<!DOCTYPE concept

  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">

<concept id="GUID-DC3A8785-3ED3-5696-A5ED-AB66588A5C14" xml:lang="en"><title>EGL

Porting Guide</title><shortdesc>This is a guide for implementers of EGL working with the Symbian

platform. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>

<p> <b>Target audience</b>: Device creators. </p>

<section id="GUID-B4226103-3C9D-4E49-A447-45B057488305"><title>Required functionality </title> <p>The

implementation DLL must implement:</p><ul>

<li><p>All of the standard functions declared in the <xref href="GUID-A5914CFF-6F86-53E8-9928-36D3379835B1.dita">EGL

Interface component</xref>.</p></li>

<li><p>The <xref href="GUID-DEA883D0-7C53-407A-AC5D-0A3208E667C7.dita">EGL Reusable

Sync Extension</xref> if OpenWF Composition is in use.</p></li>

<li><p>The <xref href="GUID-8ED4E590-4FDC-4267-87D9-C7E5E57D6B7E.dita">EGL Resource

Profiling Extension</xref> which can be used to retrieve GPU

resource utilization information. </p></li>

</ul><p>Any implementation-specific functions can be included in the DLL or

placed into a separate DLL.</p> <p>Symbian implementations must use the following

native type interpretations for compatibility. Window and pixmap types are

actually defined as <codeph>void*</codeph> to avoid compilation problems for

C programs. However, the native types specified must be used, because pointers

are cast to these types within the implementation. </p> <table id="GUID-5F79DD06-1F95-5E36-B020-2141A672AE97">

<tgroup cols="3"><colspec colname="col0"/><colspec colname="col1"/><colspec colname="col2"/>

<thead>

<row>

<entry>OpenGL ES type</entry>

<entry>Native type</entry>

<entry>Defined type</entry>

</row>

</thead>

<tbody>

<row>

<entry><codeph>EGLNativeDisplayType</codeph> </entry>

<entry>int </entry>

<entry><codeph>int</codeph> </entry>

</row>

<row>

<entry><codeph>EGLNativeWindowType</codeph> </entry>

<entry><xref href="GUID-683603DD-F3D3-3193-BEB3-8236C7DE7F79.dita"><apiname>RWindow</apiname></xref> <codeph>*</codeph> </entry>

<entry><codeph>void*</codeph> </entry>

</row>

<row>

<entry><codeph>EGLNativePixmapType</codeph>  </entry>

<entry><xref href="GUID-683A1D42-2764-3EB7-BD19-9E12559199AB.dita"><apiname>CFbsBitmap</apiname></xref> <codeph>* </codeph> </entry>

<entry><codeph>void* </codeph> </entry>

</row>

</tbody>

</tgroup>

</table> <p>For information about implementing window surfaces and pixmaps,

see: </p> <ul>

<li id="GUID-3299A027-7B6F-54B2-9E22-28F233D7F2F1"> <xref href="GUID-0B2421FD-8431-5DDA-9FE3-046734AE495E.dita">Window

Surface Implementation</xref></li>

<li id="GUID-05B529F5-0B80-5A41-866C-4AEA2C9769E4"> <xref href="GUID-453CFE84-B2BA-56E6-BCB2-1162432B2358.dita">Pixmap

Implementation</xref></li>

</ul> <p><b>Warning </b> </p> <p>Implementations of the EGL APIs must not

open a session (<xref href="GUID-E5B29AC0-4953-385F-84C5-13EE6CB77D46.dita"><apiname>RFbsSession</apiname></xref>) with the <xref href="GUID-71DADA82-3ABC-52D2-8360-33FAEB2E5DE9.dita">Font

and Bitmap Server</xref> because this can lead to a deadlock caused by the

Font and Bitmap Server's dependence on EGL. Therefore within the implementation

of the EGL APIs: </p> <ul>

<li id="GUID-7BCFEA36-AAFC-5AEF-A9A7-D2B1927389AC"><p>Do not call <xref href="GUID-643DDA78-C7A7-386D-AB3F-8710141DDDA9.dita#GUID-643DDA78-C7A7-386D-AB3F-8710141DDDA9/GUID-6CA684BC-746E-3357-90A0-E5105DDC4E01"><apiname>RWsSession::Connect()</apiname></xref> to

create a session to the Window Server because this automatically creates an <xref href="GUID-E5B29AC0-4953-385F-84C5-13EE6CB77D46.dita"><apiname>RFbsSession</apiname></xref>. </p> </li>

<li id="GUID-41A6C1CE-B87E-55CD-8EC2-A080303612A4"><p>Do not call any of the

Font and Bitmap Server APIs except on a <xref href="GUID-683A1D42-2764-3EB7-BD19-9E12559199AB.dita"><apiname>CFbsBitmap</apiname></xref> object

that has been passed into the function as an argument. </p> <p> </p> </li>

</ul> </section>

<section id="GUID-3EF15D30-E800-45C7-B1C5-74FD0EC7E3F0"><title>Library file</title> <p>The

EGL implementation must not deliver the <filepath>libEGL.lib</filepath> file,

because it is provided by the <xref href="GUID-A5914CFF-6F86-53E8-9928-36D3379835B1.dita">EGL

Interface component</xref>. To prevent a LIB file being automatically generated,

place the <codeph>NOEXPORTLIBRARY</codeph> directive in the MMP project file

that builds the implementation DLL. </p> <p>The LIB file delivered by the <xref href="GUID-A5914CFF-6F86-53E8-9928-36D3379835B1.dita">EGL Interface component</xref> has

only EGL standard functions and no implementation-specific functions. This

is to ensure that client programs do not link to implementation-specific functions

and so are portable across EGL implementations. </p> </section>

<section id="GUID-46E3542D-09D6-43E8-B8B4-B6081450DB8D"><title>EGL version

variability point</title> <p>The <xref href="GUID-A5914CFF-6F86-53E8-9928-36D3379835B1.dita">EGL

Interface component</xref> provides header files for EGL 1.2, 1.3 and 1.4.

The EGL 1.4 headers are used by default. However, there is a variability point

that can be used to change the header version. This allows a staged migration

from one version to the next. </p> <p>The variability point consists of adding

one of the following <codeph>#define</codeph> identifiers to the <filepath>eglheaders.mmh</filepath> file: </p> <ul>

<li id="GUID-D400FDC2-44DB-5D4E-8355-3DB34DAA6549"><codeph>SYMBIAN_EGLHEADERS_API_VERSION_1_4</codeph> </li>

<li id="GUID-E6CEFB0E-E60E-5B60-9085-83BC648B085C"><codeph>SYMBIAN_EGLHEADERS_API_VERSION_1_3</codeph> </li>

<li id="GUID-BC66DCE0-042E-577F-B1E0-45F72B8FDFC4"><codeph>SYMBIAN_EGLHEADERS_API_VERSION_1_2</codeph> </li>

</ul> <p>The <filepath>eglheaders.mmh</filepath> file is <codeph>#included</codeph> in

the EGL Interface component's <filepath>bld.inf</filepath> and <filepath>egllib.mmp</filepath> files. </p> </section>

<section id="GUID-A9195FBE-2418-5211-BD77-8DE3AFA5F1F4"><title>Ordinal reservation </title> <p>Symbian

has adopted an ordinal reservation scheme for EGL in order to maximize extensibility

while minimizing compatibility problems. The scheme is shown in the following

table. </p> <table id="GUID-827E458D-965F-5258-9DA1-FA0FCB2A9FAE">

<tgroup cols="3"><colspec colname="col0"/><colspec colname="col1"/><colspec colname="col2"/>

<thead>

<row>

<entry>Ordinals</entry>

<entry>Description</entry>

<entry>Owner</entry>

</row>

</thead>

<tbody>

<row>

<entry><p>1</p> </entry>

<entry><p>Reserved for use by implementations. </p> </entry>

<entry><p>EGL implementer </p> </entry>

</row>

<row>

<entry><p>2…249 </p> </entry>

<entry><p>Reserved for the EGL Interface component to use for the standard

functions that are defined in the EGL specification. In order to avoid future

binary compatibility issues, do not use these in your implementation. </p> </entry>

<entry><p>Symbian </p> </entry>

</row>

<row>

<entry><p>250…499 </p> </entry>

<entry><p>Reserved for use by implementations. </p> </entry>

<entry><p>EGL implementer </p> </entry>

</row>

</tbody>

</tgroup>

</table> <p>The following diagram illustrates a typical ordinal usage scenario. </p> <fig id="GUID-9EDB47A4-043E-52AE-A6F9-E449563B77B7">

<title>              Typical EGL ordinal usage scenario            </title>

<image href="GUID-03ED031D-65DB-51DE-8238-1F2ADF3BC936_d0e245515_href.png" placement="inline"/>

</fig> <p>Note the following: </p> <ul>

<li id="GUID-050C3247-7462-52BB-A94D-01BC793761FB"><p>The DEF file for the

EGL Interface uses ordinal position entry points 2-249. </p> </li>

<li id="GUID-D9BD2169-A2ED-5C44-990C-7B705530E7FB"><p>The <codeph>TARGETTYPE</codeph> keyword

is set to <codeph>IMPLIB</codeph> in the EGL Interfaces's MMP file to indicate

that only a LIB file is to be generated. </p> </li>

<li id="GUID-0C96A6C4-6A2D-59AB-B026-8D55982D9485"><p>The DEF file for the

EGL implementation uses the full range of ordinal position entry points. </p> </li>

<li id="GUID-D822C741-2A75-590A-B519-246CE68D5D4D"><p>The <codeph>NOEXPORT</codeph> keyword

is used in the implementation's MMP file to suppress the generation of a LIB

file. </p> </li>

<li id="GUID-DC7B2260-FEE7-5E29-9CA9-1D9381D528B7"><p>The <codeph>TARGETTYPE</codeph> keyword

is set to <codeph>DLL</codeph> in the implementation's MMP file to indicate

that it is a DLL project. </p> </li>

</ul> </section>

<section id="GUID-7B4FCF2F-9130-405B-B0C0-F569A7052885"><title>Internal functions</title> <p>The

LIB file that the EGL Interface component produces is used to access the public

methods of <filepath>libEGL.dll</filepath>. However, the DLL also has private

methods. Sometimes internal access to these private methods is required—for

example, by the implementation of an EGL client rendering API, such as OpenVG. </p> <p>When

access to the private methods is required, it is recommended that the EGL

implementation provides a separate private LIB file containing the internal

API calls. This private LIB file works in a similar way to the public one

in that it does not create a DLL. Appropriate clients can then link to the

private LIB file when required. Applications should use the public LIB file

to access the public methods of the EGL DLL. </p> <p>This mechanism ensures

that normal clients never see the internal API calls and avoids tight coupling

with a specific implementation. </p> <fig id="GUID-BA940F99-A4A4-5DF4-88A3-32A500EC9AC1">

<title>              EGL implementation's private LIB file            </title>

<image href="GUID-FDDDF1F0-42D8-570E-AF06-620825FA1022_d0e245586_href.png" placement="inline"/>

</fig> <p>Note the following: </p> <ul>

<li id="GUID-C68A977A-0134-550D-8DAB-886B2E83F56E"><p>The DEF file for the

private interface uses ordinal position entry points 1 and 250-499. </p> </li>

<li id="GUID-61BA63E7-D0A3-531C-B378-7DF6890644CD"><p>The <codeph>TARGETTYPE</codeph> keyword

is set to <codeph>IMPLIB</codeph> in the private interface's MMP file to indicate

that only a LIB file is to be generated. </p> </li>

<li id="GUID-6A0E6E83-DF39-5243-8834-8CAA122A2C7D"><p>The <codeph>LINKAS</codeph> keyword

is used in the private interface's MMP file to indicate that it is to work

with <codeph>libEGL.dll</codeph>. </p> </li>

</ul> </section>

<section id="GUID-31B83800-5789-4029-84F4-BD4451C4FA3B"><title>Extension functions</title> <p>If

an EGL implementation provides an extension to EGL, clients must use the standard

EGL function <codeph>eglGetProcAddress()</codeph> to access that functionality.

This mechanism allows client programs to access the extension function without

the need to expose the function through the DEF file. </p> </section>

<section id="GUID-984B148D-C342-464A-B929-5AA2B8AE6A2E"><title>UIDs</title> <p>The

Symbian platform libraries are given unique identifiers when they are built.

The following UIDs have been allocated for EGL implementations: </p> <table id="GUID-20E5EE23-06A9-5565-8CF3-63A2CD8D8383">

<tgroup cols="3"><colspec colname="col0"/><colspec colname="col1"/><colspec colname="col2"/>

<thead>

<row>

<entry>Library</entry>

<entry> UID2</entry>

<entry>UID3</entry>

</row>

</thead>

<tbody>

<row>

<entry>EGL  </entry>

<entry><codeph>0x1000008d </codeph> </entry>

<entry><codeph>0x10281AB8 </codeph> </entry>

</row>

</tbody>

</tgroup>

</table> <p>The UIDs are provided in <filepath>egluids.hrh</filepath>, which

is provided in the <xref href="GUID-A5914CFF-6F86-53E8-9928-36D3379835B1.dita">EGL

Interface component</xref>. </p> </section>

<section id="GUID-8DF58D61-F0A2-4EFE-8DAD-CFE4117CDFE6"><title>Platform security </title> <p>From

Symbian OS v9.0 onwards, platform security must be considered. Essentially

this requires adding the following lines to the <filepath>MMP</filepath> file:

 </p> <codeblock id="GUID-B43D55E9-5F1D-52DB-9B2E-2059B7C8C15C" xml:space="preserve">CAPABILITY All –Tcb 

VENDORID &lt;your vendor id in hex&gt; </codeblock> </section>

<section id="GUID-5DE89FBE-FBD7-4304-A453-32A55E3DAA5E"><title>ROM building </title> <p>Building

a ROM image for a target platform involves using IBY files. There is a generic

IBY file called <filepath>egl.iby</filepath> for the EGL implementation. This

must not be replaced. However, you can create an implementation-specific IBY

file. This should have a unique name with the format <filepath>egl_adaptation.iby</filepath>,

where <filepath>adaptation</filepath> is replaced by the vendor's name. For

example: </p> <codeblock id="GUID-0787AB13-84BD-5CCB-9001-4C4DAF0684CF" xml:space="preserve">// EGL_VENDOR.IBY

#ifndef __EGL_VENDOR_IBY__

#define __EGL_VENDOR_IBY__

REM EGL Vendor implementation

file=ABI_DIR/BUILD_DIR/libegl_vendor.dll                 /sys/bin/libEGL.dll

#endif</codeblock> <p>This IBY file must be exported by the <filepath>bld.inf</filepath> file

to the <filepath>/epoc32/rom/include/</filepath> folder. </p> <p>You can include

this implementation-specific IBY file in a device ROM configuration file by

adding the following line to a top-level OBY file like this: </p> <codeblock id="GUID-E51D16DC-0059-58D2-A3E4-866E34BFB15E" xml:space="preserve">#define EGL_DRV &lt;egl_vendor.iby&gt;</codeblock> <p>This

is the preferred method. However, an alternative is to specify the IBY on

the BUILDROM command line like this: </p> <codeblock id="GUID-9C5B7F9E-AA57-5694-A4DB-9E4ED500FA98" xml:space="preserve">BUILDROM ... –DEGL_DRV="^&lt;"EGL_vendor.iby"^&gt;" ... </codeblock> <p>Notice that the ^ character is used as an escape character for the &lt;

and &gt; characters. </p> <p>See <xref href="GUID-946E64D6-3E5D-5264-AD5D-29D3AD296543.dita">Selection

of Adaptations</xref> for more information. </p> </section>

<section id="GUID-BD4C33B6-EBBA-44DE-86BB-1896D1E74F79"><title>Project files</title> <p>Here

is an example MMP file: </p> <codeblock id="GUID-9F08315E-DB1C-52C9-B777-6FD265EFF1CB" xml:space="preserve">#include "/epoc32/include/platform/egl/egluids.hrh" // For UIDs

// These statements are always required: 

target          libEGL.dll             // Destination filename

targettype      dll                    // Binary build type

uid             KUidSharedDllUidValue KUidEGLDllUidValue       // File UIDs

capability      All –Tcb               // Platform Security requirement

vendorid        <Your vendor ID in hex>

NOEXPORTLIBRARY                        // Suppress generation of LIB/DSO file

DEFFILE         libegl13.def

// These statements are examples and may vary:

userinclude     ../include             // Local include files

systeminclude   /epoc32/include        // Symbian include files

sourcepath      ../egl                 // Relative path to source files

source          context.cpp            // Source files

source          display.cpp

source          egl.cpp

source          surface.cpp

library         euser.lib              // For the user library.

library         fbscli.lib             // For CFbsBitmap, etc.

library         bitgdi.lib             // For CFbsBitmapDevice, CFbsBitGc, etc.

library         ws32.lib               // For RWindow, Direct Screen Access, etc.</codeblock> </section>

<section id="GUID-8B5874FB-7367-484E-90B2-2AD9C2F522AB"><title>Example bld.inf</title> <p>A <filepath>bld.inf</filepath> file

is also required: </p> <codeblock id="GUID-42A0C512-1685-5A1A-9687-851BF431BC00" xml:space="preserve">PRJ_PLATFORMS

DEFAULT      

PRJ_EXPORTS

egl_vendor.iby       /epoc32/rom/include/egl_vendor.iby

PRJ_MMPFILES

./egl.mmp</codeblock> </section>

</conbody><related-links>

<link href="GUID-0B2421FD-8431-5DDA-9FE3-046734AE495E.dita"><linktext>Window Surface

Implementation</linktext></link>

<link href="GUID-453CFE84-B2BA-56E6-BCB2-1162432B2358.dita"><linktext>Pixmap Implementation</linktext>

</link>

<link href="GUID-D252E75C-C8CA-5C51-8DA3-95B937A1295C.dita"><linktext>EGL Interface

Component</linktext></link>

<link href="GUID-DC8BFEF5-DA50-52DA-8CE2-5729A4A005F6.dita"><linktext>EGL Collection

Overview</linktext></link>

<link href="http://www.khronos.org/egl/" scope="external"><linktext>http://www.khronos.org/egl/</linktext>

</link>

</related-links></concept>