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<td align="center" valign="middle" width="75%"><font color="#ffccaa" size="+3"><b><i>第25课</i></b></font></td>
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<td width="72%"><p><font class="head">变形和从文件中加载3D物体:</font></p>
<p><font size="3">在这一课中,你将学会如何从文件加载3D模型,并且平滑的从一个模型变换为另一个模型。</font></p></td>
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<td valign="top" width="100%">欢迎来到这激动人心的一课,在这一课里,我们将介绍模型的变形。需要注意的是各个模型必须要有相同的顶点,才能一一对应,并应用变形。<br>
在这一课里,我们同样要教会你如何从一个文件中读取模型数据。<br>
文件开始的部分和前面一样,没有任何变化。</td>
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<font color="#aaffaa" size="3"> </font>
<table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">我们结下来添加几个旋转变量,用来记录旋转的信息。并使用cx,cy,cz设置物体在屏幕上的位置。<br>
变量key用来记录当前的模型,step用来设置相邻变形之间的中间步骤。如step为200,则需要200次,才能把一个物体变为另一个物体。<br>
最后我们用一个变量来设置是否使用变形。</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table><font color="#aaffaa" size="3">
<pre>GLfloat xrot,yrot,zrot, <font color="#ffffaa">// X, Y & Z 轴的旋转角度</font>
xspeed,yspeed,zspeed, <font color="#ffffaa">// X, Y & Z 轴的旋转速度</font>
cx,cy,cz=-15; <font color="#ffffaa">// 物体的位置</font>
int key=1; <font color="#ffffaa">// 物体的标识符</font>
int step=0,steps=200; <font color="#ffffaa">// 变换的步数</font>
bool morph=FALSE; <font color="#ffffaa">// 是否使用变形</font>
</pre>
</font><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">下面的结构定义一个三维顶点</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table><font color="#aaffaa" size="3">
<pre>typedef struct
{
float x, y, z;
} VERTEX; </pre>
</font><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">下面的结构使用顶点来描述一个三维物体</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table><font color="#aaffaa" size="3">
<pre>typedef struct <font color="#ffffaa">// 物体结构</font>
{
int verts; <font color="#ffffaa">// 物体中顶点的个数</font>
VERTEX *points; <font color="#ffffaa">// 包含顶点数据的指针</font>
} OBJECT; </pre>
</font><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">maxver用来记录各个物体中最大的顶点数,如一个物体使用5个顶点,另一个物体使用20个顶点,那么物体的顶点个数为20。<br>
结下来定义了四个我们使用的模型物体,并把相邻模型变形的中间状态保存在helper中,sour保存原模型物体,dest保存将要变形的模型物体。</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table><font color="#aaffaa" size="3">
<pre>int maxver; <font color="#ffffaa">// 最大的顶点数</font>
OBJECT morph1,morph2,morph3,morph4, <font color="#ffffaa">// 我们的四个物体</font>
helper,*sour,*dest; <font color="#ffffaa">// 帮助物体,原物体,目标物体</font>
</pre>
</font><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">WndProc()函数没有变化</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table>
<table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">下面的函数用来为模型分配保存顶点数据的内存空间</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table><font color="#aaffaa" size="3">
<pre>void objallocate(OBJECT *k,int n)
{
k->points=(VERTEX*)malloc(sizeof(VERTEX)*n); <font color="#ffffaa">// 分配n个顶点的内存空间</font>
} </pre>
</font><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">下面的函数用来释放为模型分配的内存空间</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table><font color="#aaffaa" size="3">
<pre>void objfree(OBJECT *k)
{
free(k->points);
}
</pre>
</font><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/tl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/tc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/tr.png" height="28" width="28"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td background="Tutorial_25_files/l.png"><img src="Tutorial_25_files/l.png"></td>
<td valign="top" width="100%">下面的代码用来读取文件中的一行。<br>
我们用一个循环来读取字符,最多读取255个字符,当遇到'\n'回车时,停止读取并立即返回。</td>
<td background="Tutorial_25_files/r.png"><img src="Tutorial_25_files/r.png"></td></tr></tbody></table><table border="0" cellpadding="0" cellspacing="0" width="100%"><tbody><tr><td><img src="Tutorial_25_files/bl.png" height="28" width="28"></td><td width="100%"><img src="Tutorial_25_files/bc.png" height="28" width="100%"></td><td><img src="Tutorial_25_files/br.png" height="28" width="28"></td></tr></tbody></table><font color="#aaffaa" size="3">
<pre>void readstr(FILE *f,char *string) <font color="#ffffaa">// 读取一行字符</font>
{
do
{
fgets(string, 255, f); <font color="#ffffaa">// 最多读取255个字符</font>
} while ((string[0] == '/') || (string[0] == '\n')); <font color="#ffffaa">// 遇到回车则停止读取</font>
return; <font color="#ffffaa">// 返回</font>
}
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