Merge branch 'master' of git.shadowcat.co.uk:SDL-Site

[sdlgit/SDL-Site.git] / pages / SDL-Cookbook-OpenGL.html-inc

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<!-- INDEX START -->
<h3 id="TOP">Index</h3>

<ul><li><a href="#NAME">NAME</a></li>
<li><a href="#CATEGORY">CATEGORY</a></li>
<li><a href="#DESCRIPTION">DESCRIPTION</a>
<ul><li><a href="#EXAMPLE">EXAMPLE</a></li>
</ul>
</li>
<li><a href="#SEE_ALSO">SEE ALSO</a></li>
<li><a href="#AUTHORS">AUTHORS</a>
</li>
</ul><hr />
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<h1 id="NAME">NAME</h1><p><a href="#TOP" class="toplink">Top</a></p>
<div id="NAME_CONTENT">
<p>SDL::Cookbook::OpenGL - Using SDL with OpenGL</p>

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<h1 id="CATEGORY">CATEGORY</h1><p><a href="#TOP" class="toplink">Top</a></p>
<div id="CATEGORY_CONTENT">
<p>Cookbook</p>

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<h1 id="DESCRIPTION">DESCRIPTION</h1><p><a href="#TOP" class="toplink">Top</a></p>
<div id="DESCRIPTION_CONTENT">
<p>As of release 2.5 SDL no longer maintains it's own bindings of openGL. Support for openGL has been moved over to a more mature implementation. </p>
<p>This implementation is the POGL project. <a href="http://search.cpan.org/perldoc?OpenGL">OpenGL</a> is faster and more complete; and works with SDL seemlessly.</p>

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<h2 id="EXAMPLE">EXAMPLE</h2>
<div id="EXAMPLE_CONTENT">
<p>Expanded from Floyd-ATC's OpenGL example.</p>
<pre>


	use strict;
	use warnings;
	use SDL;
	use SDLx::App;
	use SDL::Mouse;
	use SDL::Video;
	use SDL::Events;
	use SDL::Event;
	use OpenGL qw(:all);

</pre>
<p>You can use OpenGL as needed here.</p>
<pre>	my ($SDLAPP, $WIDTH, $HEIGHT, $SDLEVENT);

	$| = 1;
	$WIDTH = 1024;
	$HEIGHT = 768;
	$SDLAPP = SDLx::App-&gt;new(title =&gt; &quot;Opengl App&quot;, width =&gt; $WIDTH, height =&gt; $HEIGHT, gl =&gt; 1);
	$SDLEVENT = SDL::Event-&gt;new;

</pre>
<p>SDLx::App can start an OpenGL application with the parameter gl =&gt; 1.</p>
<pre>	glEnable(GL_DEPTH_TEST);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity;
	gluPerspective(60, $WIDTH / $HEIGHT, 1, 1000);
	glTranslatef(0, 0, -20);

</pre>
<p>Above we enable GL and set the correct prespective</p>
<pre>	while (1) {
	  &amp;handlepolls;
	  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
	  glRotatef(.1, 1, 1, 1);
	  &amp;drawscene;
	  $SDLAPP-&gt;sync;
	}

</pre>
<p>For SDLx::App sync handles the GL buffer clean.</p>
<pre>	sub drawscene {
	  my ($color, $x, $y, $z);

	  for (-2 .. 2) {
	    glPushMatrix;
	    glTranslatef($_ * 3, 0, 0);
	    glColor3d(1, 0, 0);
	    &amp;draw_cube;
	    glPopMatrix;
	  }

	  return &quot;&quot;;
	}




	sub draw_cube {
	  my (@indices, @vertices, $face, $vertex, $index, $coords);

	  @indices = qw(4 5 6 7   1 2 6 5   0 1 5 4
			0 3 2 1   0 4 7 3   2 3 7 6);
	  @vertices = ([-1, -1, -1], [ 1, -1, -1],
		       [ 1,  1, -1], [-1,  1, -1],
		       [-1, -1,  1], [ 1, -1,  1],
		       [ 1,  1,  1], [-1,  1,  1]);

	  glBegin(GL_QUADS);

	  foreach my $face (0..5) {
	    foreach my $vertex (0..3) {
	      $index  = $indices[4 * $face + $vertex];
	      $coords = $vertices[$index];

	      glVertex3d(@$coords);
	    }
	  }

	  glEnd;

	  return &quot;&quot;;
	}

</pre>
<p>Below we can use SDL::Events as normal:</p>
<pre>	sub handlepolls {
	  my ($type, $key);

	  SDL::Events::pump_events();

	  while (SDL::Events::poll_event($SDLEVENT)) {
	    $type = $SDLEVENT-&gt;type();
	    $key = ($type == 2 or $type == 3) ? $SDLEVENT-&gt;key_sym : &quot;&quot;;

	    if ($type == 4) { printf(&quot;You moved the mouse! x=%s y=%s xrel=%s yrel=%s\n&quot;, $SDLEVENT-&gt;motion_x, $SDLEVENT-&gt;motion_y, $SDLEVENT-&gt;motion_xrel, $SDLEVENT-&gt;motion_yrel) }
	    elsif ($type == 2) { print &quot;You are pressing $key\n&quot; }
	    elsif ($type == 3) { print &quot;You released $key\n&quot; }
	    elsif ($type == 12) { exit }
	    else { print &quot;TYPE $type UNKNOWN!\n&quot; }

	    if ($type == 2) {
	      if ($key eq &quot;q&quot; or $key eq &quot;escape&quot;) { exit }
	    }
	  }

	  return &quot;&quot;;
	}

</pre>

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<h1 id="SEE_ALSO">SEE ALSO</h1><p><a href="#TOP" class="toplink">Top</a></p>
<div id="SEE_ALSO_CONTENT">
<p><a href="http://search.cpan.org/perldoc?perl">perl</a> <a href="SDLx-App.html">SDLx::App</a> <a href="http://search.cpan.org/perldoc?OpenGL">OpenGL</a> </p>

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<h1 id="AUTHORS">AUTHORS</h1><p><a href="#TOP" class="toplink">Top</a></p>
<div id="AUTHORS_CONTENT">
<p>See <a href="/SDL.html#AUTHORS">/SDL.html#AUTHORS</a>.</p>





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