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		<title>GL Target Bitmaps Don&#39;t like Mipmap Flag But D3D is fine</title>
		<link>http://www.allegro.cc/forums/view/613196</link>
		<description>Allegro.cc Forum Thread</description>
		<webMaster>matthew@allegro.cc (Matthew Leverton)</webMaster>
		<lastBuildDate>Fri, 30 Aug 2013 04:08:21 +0000</lastBuildDate>
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		<description><![CDATA[<div class="mockup v2"><p>There was a bug in my game since upgrading to I think 5.1.5 or 5.1.6</p><p>Any target bitmap I made, using GL, would render pure white.</p><p>In D3D all was fine.</p><p>I tracked it down to the fact that all my bitmaps are created with the mipmap flag on.</p><p>I turned it off and it fixed it.</p><p>Here is a minimum example of the problem:
</p><div class="source-code"><div class="toolbar"><span class="button numbers"><b>#</b></span><span class="button select">Select</span><span class="button expand">Expand</span></div><div class="inner"><span class="number">  1</span><span class="p">#include &lt;allegro5/allegro.h&gt;</span>
<span class="number">  2</span><span class="p">#include &lt;allegro5/allegro_font.h&gt;</span>
<span class="number">  3</span><span class="p">#include &lt;allegro5/allegro_image.h&gt;</span>
<span class="number">  4</span><span class="p">#include &lt;allegro5/allegro_primitives.h&gt;</span>
<span class="number">  5</span><span class="p">#include &lt;stdio.h&gt;</span>
<span class="number">  6</span><span class="p">#include &lt;stdarg.h&gt;</span>
<span class="number">  7</span><span class="p">#include &lt;math.h&gt;</span>
<span class="number">  8</span>
<span class="number">  9</span>
<span class="number"> 10</span><span class="k1">const</span> <span class="k1">int</span> W <span class="k3">=</span> <span class="n">300</span>, H <span class="k3">=</span> <span class="n">300</span><span class="k2">;</span> <span class="c">/* Size of target bitmap. */</span>
<span class="number"> 11</span><span class="k1">const</span> <span class="k1">int</span> RW <span class="k3">=</span> <span class="n">50</span>, RH <span class="k3">=</span> <span class="n">50</span><span class="k2">;</span> <span class="c">/* Size of rectangle we draw to it. */</span>
<span class="number"> 12</span><a href="http://www.allegro.cc/manual/ALLEGRO_DISPLAY"><span class="a">ALLEGRO_DISPLAY</span></a> <span class="k3">*</span>display<span class="k2">;</span>
<span class="number"> 13</span><a href="http://www.allegro.cc/manual/ALLEGRO_BITMAP"><span class="a">ALLEGRO_BITMAP</span></a> <span class="k3">*</span>target<span class="k2">;</span> <span class="c">/* The target bitmap. */</span>
<span class="number"> 14</span><span class="k1">float</span> x, y, dx, dy<span class="k2">;</span> <span class="c">/* Position and velocity of moving rectangle. */</span>
<span class="number"> 15</span><span class="k1">double</span> last_time<span class="k2">;</span> <span class="c">/* For controling speed. */</span>
<span class="number"> 16</span><span class="k1">bool</span> quit<span class="k2">;</span> <span class="c">/* Flag to record Esc key or X button. */</span>
<span class="number"> 17</span><a href="http://www.allegro.cc/manual/ALLEGRO_FONT"><span class="a">ALLEGRO_FONT</span></a> <span class="k3">*</span>myfont<span class="k2">;</span> <span class="c">/* Our font. */</span>
<span class="number"> 18</span><a href="http://www.allegro.cc/manual/ALLEGRO_EVENT_QUEUE"><span class="a">ALLEGRO_EVENT_QUEUE</span></a> <span class="k3">*</span>queue<span class="k2">;</span> <span class="c">/* Our events queue. */</span>
<span class="number"> 19</span>
<span class="number"> 20</span><span class="k1">int</span> main<span class="k2">(</span><span class="k1">void</span><span class="k2">)</span>
<span class="number"> 21</span><span class="k2">{</span>
<span class="number"> 22</span>
<span class="number"> 23</span><a href="http://www.allegro.cc/manual/al_init"><span class="a">al_init</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 24</span>   <a href="http://www.allegro.cc/manual/al_init_primitives_addon"><span class="a">al_init_primitives_addon</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 25</span>   <a href="http://www.allegro.cc/manual/al_install_keyboard"><span class="a">al_install_keyboard</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 26</span>   <a href="http://www.allegro.cc/manual/al_init_image_addon"><span class="a">al_init_image_addon</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 27</span>   <a href="http://www.allegro.cc/manual/al_init_font_addon"><span class="a">al_init_font_addon</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 28</span>   <a href="http://www.allegro.cc/manual/al_set_new_display_flags"><span class="a">al_set_new_display_flags</span></a><span class="k2">(</span>ALLEGRO_RESIZABLE <span class="k3">|</span> ALLEGRO_OPENGL<span class="k2">)</span><span class="k2">;</span>
<span class="number"> 29</span>   <a href="http://www.allegro.cc/manual/al_set_new_bitmap_flags"><span class="a">al_set_new_bitmap_flags</span></a><span class="k2">(</span>ALLEGRO_VIDEO_BITMAP <span class="k3">|</span> ALLEGRO_MIPMAP<span class="k2">)</span><span class="k2">;</span>
<span class="number"> 30</span>   display <span class="k3">=</span> <a href="http://www.allegro.cc/manual/al_create_display"><span class="a">al_create_display</span></a><span class="k2">(</span><span class="n">640</span>, <span class="n">480</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 31</span>
<span class="number"> 32</span>
<span class="number"> 33</span>   queue <span class="k3">=</span> <a href="http://www.allegro.cc/manual/al_create_event_queue"><span class="a">al_create_event_queue</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 34</span>   <a href="http://www.allegro.cc/manual/al_register_event_source"><span class="a">al_register_event_source</span></a><span class="k2">(</span>queue, <a href="http://www.allegro.cc/manual/al_get_keyboard_event_source"><span class="a">al_get_keyboard_event_source</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 35</span>   <a href="http://www.allegro.cc/manual/al_register_event_source"><span class="a">al_register_event_source</span></a><span class="k2">(</span>queue, <a href="http://www.allegro.cc/manual/al_get_display_event_source"><span class="a">al_get_display_event_source</span></a><span class="k2">(</span>display<span class="k2">)</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 36</span>
<span class="number"> 37</span>target <span class="k3">=</span> <a href="http://www.allegro.cc/manual/al_create_bitmap"><span class="a">al_create_bitmap</span></a><span class="k2">(</span><span class="n">300</span>,<span class="n">300</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 38</span>
<span class="number"> 39</span>   <span class="k1">while</span> <span class="k2">(</span><span class="k3">!</span>quit<span class="k2">)</span> <span class="k2">{</span>
<span class="number"> 40</span><a href="http://www.allegro.cc/manual/al_clear_to_color"><span class="a">al_clear_to_color</span></a><span class="k2">(</span><a href="http://www.allegro.cc/manual/al_map_rgb"><span class="a">al_map_rgb</span></a><span class="k2">(</span><span class="n">0</span>,<span class="n">0</span>,<span class="n">0</span><span class="k2">)</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 41</span><a href="http://www.allegro.cc/manual/al_set_target_bitmap"><span class="a">al_set_target_bitmap</span></a><span class="k2">(</span>target<span class="k2">)</span><span class="k2">;</span>
<span class="number"> 42</span><a href="http://www.allegro.cc/manual/al_draw_filled_circle"><span class="a">al_draw_filled_circle</span></a><span class="k2">(</span><span class="n">0</span>,<span class="n">0</span>,<span class="n">90</span>,<a href="http://www.allegro.cc/manual/al_map_rgb"><span class="a">al_map_rgb</span></a><span class="k2">(</span><span class="n">0</span>,<span class="n">0</span>,<span class="n">255</span><span class="k2">)</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 43</span><a href="http://www.allegro.cc/manual/al_set_target_bitmap"><span class="a">al_set_target_bitmap</span></a><span class="k2">(</span><a href="http://www.allegro.cc/manual/al_get_backbuffer"><span class="a">al_get_backbuffer</span></a><span class="k2">(</span>display<span class="k2">)</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 44</span><a href="http://www.allegro.cc/manual/al_draw_bitmap"><span class="a">al_draw_bitmap</span></a><span class="k2">(</span>target,<span class="n">0</span>,<span class="n">0</span>,<span class="n">0</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 45</span><a href="http://www.allegro.cc/manual/al_flip_display"><span class="a">al_flip_display</span></a><span class="k2">(</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 46</span>   <span class="k2">}</span>
<span class="number"> 47</span>
<span class="number"> 48</span>   <a href="http://www.allegro.cc/manual/al_destroy_event_queue"><span class="a">al_destroy_event_queue</span></a><span class="k2">(</span>queue<span class="k2">)</span><span class="k2">;</span>  
<span class="number"> 49</span>   
<span class="number"> 50</span>   <span class="k1">return</span> <span class="n">0</span><span class="k2">;</span>
<span class="number"> 51</span><span class="k2">}</span>
</div></div><p>

I think this is a bug. Unless there is something I have overlooked in the changes.</p><p>Thanks
</p></div>]]>
		</description>
		<author>no-reply@allegro.cc (jmasterx)</author>
		<pubDate>Fri, 30 Aug 2013 04:08:21 +0000</pubDate>
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