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		<title>shot and diagonal movents</title>
		<link>http://www.allegro.cc/forums/view/607104</link>
		<description>Allegro.cc Forum Thread</description>
		<webMaster>matthew@allegro.cc (Matthew Leverton)</webMaster>
		<lastBuildDate>Tue, 26 Apr 2011 22:53:05 +0000</lastBuildDate>
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		<description><![CDATA[<div class="mockup v2"><p>hi ,i dont speak very well english(i speak spanish) so i will try be very puntual in the things that i need help.<br />I need to do sometime like the game geometry wars.<br />The first problem is that i have adaptet de diagonal movent but i can&#39;t adapt the movent to diagonal imagenes, i dont know how do it, the second problem is that i need that when the users press the arrow keys, a shot go in the direction of the arrow key, the problem is that i dont know how make that the shot continue in the direction that the arrow key indicates, i think that i need like use the timer but i haven´t seen a example for that, please help, and sorry for my english;D
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		<author>no-reply@allegro.cc (dengue)</author>
		<pubDate>Sun, 24 Apr 2011 10:13:38 +0000</pubDate>
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		<description><![CDATA[<div class="mockup v2"><div class="quote_container"><div class="title">Dengue said:</div><div class="quote"><p>
The first problem is that i have adaptet de diagonal movent but i can&#39;t adapt the movent to diagonal imagenes, i dont know how do it,
</p></div></div><p>

You need to keep track of position, speed, and the angle of your object :
</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;math.h&gt;</span>
<span class="number">  2</span>
<span class="number">  3</span><span class="k1">typedef</span> <span class="k1">struct</span> Moveable <span class="k2">{</span>
<span class="number">  4</span>   <span class="k1">float</span> x<span class="k2">;</span>     <span class="c">// x position</span>
<span class="number">  5</span>   <span class="k1">float</span> y<span class="k2">;</span>     <span class="c">// y position</span>
<span class="number">  6</span>   <span class="k1">float</span> xvel<span class="k2">;</span>  <span class="c">// x velocity</span>
<span class="number">  7</span>   <span class="k1">float</span> yvel<span class="k2">;</span>  <span class="c">// y velocity</span>
<span class="number">  8</span>   <span class="k1">float</span> speed<span class="k2">;</span> <span class="c">// total speed</span>
<span class="number">  9</span>   <span class="k1">float</span> angle<span class="k2">;</span> <span class="c">// angle in degrees</span>
<span class="number"> 10</span><span class="k2">}</span><span class="k2">;</span>
<span class="number"> 11</span>
<span class="number"> 12</span>Moveable NewMoveable<span class="k2">(</span><span class="k1">int</span> x , <span class="k1">int</span> y , <span class="k1">float</span> speed , <span class="k1">float</span> angle<span class="k2">)</span> <span class="k2">{</span>
<span class="number"> 13</span>   Moveable m<span class="k2">;</span>
<span class="number"> 14</span>   m.x <span class="k3">=</span> x<span class="k2">;</span>
<span class="number"> 15</span>   m.y <span class="k3">=</span> y<span class="k2">;</span>
<span class="number"> 16</span>   SetSpeedAndAngle<span class="k2">(</span><span class="k3">&amp;</span>m , speed , angle<span class="k2">)</span><span class="k2">;</span>
<span class="number"> 17</span>   <span class="k1">return</span> m<span class="k2">;</span>
<span class="number"> 18</span><span class="k2">}</span>
<span class="number"> 19</span>
<span class="number"> 20</span><span class="k1">void</span> SetSpeedAndAngle<span class="k2">(</span>Moveable<span class="k3">*</span> m , <span class="k1">float</span> speed , <span class="k1">float</span> angle<span class="k2">)</span> <span class="k2">{</span>
<span class="number"> 21</span>   m-&gt;speed <span class="k3">=</span> speed<span class="k2">;</span>
<span class="number"> 22</span>   m-&gt;angle <span class="k3">=</span> angle<span class="k2">;</span>
<span class="number"> 23</span>   m-&gt;xvel <span class="k3">=</span> speed<span class="k3">*</span><a href="http://www.delorie.com/djgpp/doc/libc/libc_113.html" target="_blank">cos</a><span class="k2">(</span>angle<span class="k3">*</span><span class="k2">(</span><span class="k2">(</span><span class="n">2</span>.<span class="n">0f</span><span class="k3">*</span>M_PI<span class="k2">)</span><span class="k3">/</span><span class="n">360</span>.<span class="n">0f</span><span class="k2">)</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 24</span>   m-&gt;yvel <span class="k3">=</span> speed<span class="k3">*</span><a href="http://www.delorie.com/djgpp/doc/libc/libc_728.html" target="_blank">sin</a><span class="k2">(</span>angle<span class="k3">*</span><span class="k2">(</span><span class="k2">(</span><span class="n">2</span>.<span class="n">0f</span><span class="k3">*</span>M_PI<span class="k2">)</span><span class="k3">/</span><span class="n">360</span>.<span class="n">0f</span><span class="k2">)</span><span class="k2">)</span><span class="k2">;</span>
<span class="number"> 25</span><span class="k2">}</span>
<span class="number"> 26</span>
<span class="number"> 27</span><span class="k1">void</span> Move<span class="k2">(</span>Moveable<span class="k3">*</span> m<span class="k2">)</span> <span class="k2">{</span>
<span class="number"> 28</span>   m-&gt;x <span class="k3">+</span><span class="k3">=</span> m-&gt;xvel<span class="k2">;</span>
<span class="number"> 29</span>   m-&gt;y <span class="k3">+</span><span class="k3">=</span> m-&gt;yvel<span class="k2">;</span>
<span class="number"> 30</span><span class="k2">}</span>
</div></div><p>

Example usage :
</p><div class="source-code snippet"><div class="inner"><pre>Moveable m <span class="k3">=</span> NewMoveable<span class="k2">(</span>x , y , <span class="n">25</span>.<span class="n">0f</span><span class="k3">/</span><span class="n">60</span>.<span class="n">0f</span> , <span class="n">45</span>.<span class="n">0</span><span class="k2">)</span><span class="k2">;</span><span class="c">// Moves 25 pixels per second down and right</span>
</pre></div></div><p>
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		<author>no-reply@allegro.cc (Edgar Reynaldo)</author>
		<pubDate>Sun, 24 Apr 2011 10:57:05 +0000</pubDate>
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		<description><![CDATA[<div class="mockup v2"><p>I can&#39;t really figure out what you are doing at the moment, but it seems you use a fixed set of bitmaps. And you seem to have player input combined with updating the ship.<br />What you&#39;ll want to do is something like:<br />detect input;<br />update world (use input; move according to time passed; handle collisions/other game events);<br />blit to screen;<br />repeat;</p><p>You might want to look into storing the player&#39;s (and bullet&#39;s) directions <a href="http://www.helixsoft.nl/articles/circle/sincos.htm">as an angle</a> and using <span class="source-code"><a href="http://www.allegro.cc/manual/rotate_sprite"><span class="a">rotate_sprite</span></a></span>. Then it will also get a speed. (And only in the &#39;update&#39; part of the program, the speed will have effect.)</p><p>Some other remarks.<br /><span class="source-code"><span class="k1">if</span><span class="k2">(</span>x<span class="k3">=</span><span class="k3">=</span><span class="n">0</span><span class="k2">)</span><span class="k2">{</span><a href="http://www.allegro.cc/manual/rest"><span class="a">rest</span></a><span class="k2">(</span><span class="n">50</span><span class="k2">)</span><span class="k2">;</span><span class="k2">}</span></span><br />Very bad way to handle boundaries, at a very bad place in your code (player input != collision detection). Also don&#39;t use rest...<br />[edit]Beaten by 20 minutes WTF I didn&#39;t use so much time writing this.<br />There are enough examples of timers. Search for &#39;timer&#39; &amp; &#39;speed&#39;, or &#39;game loop&#39;.
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		<author>no-reply@allegro.cc (weapon_S)</author>
		<pubDate>Sun, 24 Apr 2011 11:17:15 +0000</pubDate>
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		<description><![CDATA[<div class="mockup v2"><p>I didn&#39;t see the attached file before, but after looking at it I have a few comments :</p><div class="quote_container"><div class="title">main.cpp said:</div><div class="quote"><p>
</p><div class="source-code snippet"><div class="inner"><pre><span class="k1">class</span> Nave <span class="k2">{</span>
<span class="c">//...</span>
        <a href="http://www.allegro.cc/manual/BITMAP"><span class="a">BITMAP</span></a> <span class="k3">*</span>imagenes<span class="k2">[</span><span class="n">9</span><span class="k2">]</span><span class="k2">;</span>
<span class="k2">}</span><span class="k2">;</span>
<span class="c">//...</span>
Nave::~Nave<span class="k2">(</span><span class="k2">)</span><span class="k2">{</span>
    <span class="k1">delete</span> <span class="k2">[</span><span class="k2">]</span> imagenes<span class="k2">;</span>
<span class="k2">}</span><span class="k2">;</span>
</pre></div></div><p>
</p></div></div><p>

Don&#39;t use delete on a pointer that you didn&#39;t use new to create. Use <span class="source-code"><a href="http://www.allegro.cc/manual/destroy_bitmap"><span class="a">destroy_bitmap</span></a></span> on imagenes[0] thru imagenes[8] instead.</p><p>Your MoverX and MoverY functions should not draw anything to the screen, they should only change the position of your objects.</p><p>Separate logic and drawing.</p><p>You don&#39;t <span class="source-code"><a href="http://www.allegro.cc/manual/clear_to_color"><span class="a">clear_to_color</span></a></span> on your buffer, so your program must look pretty messy right now.</p><p>You use draw_sprite to draw the buffer, but you should use <span class="source-code"><a href="http://www.allegro.cc/manual/blit"><span class="a">blit</span></a></span> instead.
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		<author>no-reply@allegro.cc (Edgar Reynaldo)</author>
		<pubDate>Sun, 24 Apr 2011 11:56:17 +0000</pubDate>
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		<description><![CDATA[<div class="mockup v2"><p>Thanks Edgar Reynaldo, That code that you posted helped me <img src="http://www.allegro.cc/forums/smileys/smiley.gif" alt=":)" /> I was trying to do this too but as normal I use Search and Recent on these boards to see if it&#39;s been covered else I was just about to post <img src="http://www.allegro.cc/forums/smileys/tongue.gif" alt=":P" /></p><p>Thanks again
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		<author>no-reply@allegro.cc (Desmond Taylor)</author>
		<pubDate>Sun, 24 Apr 2011 12:07:02 +0000</pubDate>
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		<description><![CDATA[<div class="mockup v2"><p>thanks Edgar Reynaldo and weapon_S, i am reading the articles of the angles and i am editing my code, thanks a lot <img src="http://www.allegro.cc/forums/smileys/grin.gif" alt=";D" />
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		<author>no-reply@allegro.cc (dengue)</author>
		<pubDate>Tue, 26 Apr 2011 22:53:05 +0000</pubDate>
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