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「gluLookAtを置き換える」(2014/04/16 (水) 18:48:58) の最新版変更点

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<p> <strong>gluLookAt　を置き換えてみます。</strong></p>
<p><strong><img alt="" src="http://www21.atwiki.jp/opengl?cmd=upload&amp;act=open&amp;pageid=133&amp;file=look.png" /></strong></p>
<table border="1" cellspacing="1" cellpadding="1" width="600"><tbody><tr><td>
<p>#pragma comment(linker, "/SUBSYSTEM:WINDOWS /ENTRY:mainCRTStartup")<br />
#include &lt;GL/freeglut/freeglut.h&gt;<br />
#include &lt;math.h&gt;</p>
<p>#define PI 3.1415926</p>
<p>#define WIDTH 320<br />
#define HEIGHT 240</p>
<p>//平行移動用<br />
float x = 0.0f;<br />
bool flag = false;<br />
//緑<br />
GLfloat green[] = { 0.0, 1.0, 0.0, 1.0 };<br />
//ライトの位置<br />
GLfloat lightpos[] = { 200.0, 150.0, -500.0, 1.0 };<br />
//単位行列<br />
GLfloat mat[]={<br />
 1,0,0,0,<br />
 0,1,0,0,<br />
 0,0,1,0,<br />
 0,0,0,1<br />
};<br />
//平行移動用<br />
GLfloat move[]={<br />
 1,0,0,0,<br />
 0,1,0,0,<br />
 0,0,1,0,<br />
 0,0,0,1<br />
};</p>
<p>GLfloat modelview[16];<br />
GLfloat multi[16];</p>
<p>//合成 glMultMatrixfの代わり<br />
void multiplication(GLfloat* src1,GLfloat* src2,GLfloat* dst)<br />
{<br />
 for(int y=0;y&lt;4;y++){<br />
  for(int x=0;x&lt;4;x++){<br />
  
dst[y*4+x]=src2[y*4]*src1[x]+src2[y*4+1]*src1[x+4]+src2[y*4+2]*src1[x+8]+src2[y*4+3]*src1[x+12];<br />
  }<br />
 }<br />
}<br />
//正規化<br />
void normalize(GLfloat* v){<br />
 float m=sqrt(v[0]*v[0]+v[1]*v[1]+v[2]*v[2]);<br />
 if(m &gt; 0.0f){m = 1.0f / m;}else{m = 0.0f;}<br />
 v[0]*=m;<br />
 v[1]*=m;<br />
 v[2]*=m;<br />
}<br />
//外積<br />
void cross( float* src1, float* src2 ,float* dst){<br />
dst[0] = src1[1]*src2[2] - src1[2]*src2[1];<br />
dst[1] = src1[2]*src2[0] - src1[0]*src2[2];<br />
dst[2] = src1[0]*src2[1] - src1[1]*src2[0];<br />
}</p>
<p>//gluLookAtと同じ<br />
void LookAt(GLfloat eyex, GLfloat eyey, GLfloat eyez, GLfloat centerx,<br />
GLfloat centery, GLfloat centerz, GLfloat upx, GLfloat upy,<br />
GLfloat upz)<br />
{<br />
float forward[3], side[3], up[3];</p>
<p>forward[0] = centerx - eyex;<br />
forward[1] = centery - eyey;<br />
forward[2] = centerz - eyez;</p>
<p>up[0] = upx;<br />
up[1] = upy;<br />
up[2] = upz;</p>
<p>normalize(forward);</p>
<p>cross(forward, up, side);<br />
normalize(side);</p>
<p>cross(side, forward, up);</p>
<p>GLfloat m[]={<br />
 side[0],up[0],-forward[0],0,<br />
 side[1],up[1],-forward[1],0,<br />
 side[2],up[2],-forward[2],0,<br />
 0,0,0,1<br />
};</p>
<p>GLfloat mov[]={<br />
 1,0,0,0,<br />
 0,1,0,0,<br />
 0,0,1,0,<br />
 -eyex,-eyey,-eyez,1<br />
};</p>
<p>multiplication(m,mov,multi);<br />
glLoadMatrixf(multi);<br />
}</p>
<p>//gluPerspectiveと同じ<br />
void perspective(float fovy,float aspect,float znear,float zfar)<br />
{<br />
 float radian=2*PI*fovy/360.0;<br />
 float t = (float)(1.0 / tan(radian/2));<br />
 GLfloat m[]={<br />
 t / aspect,0,0,0,<br />
 0,t,0,0,<br />
 0,0,(zfar + znear) / (znear - zfar),-1,<br />
 0,0,(2 * zfar * znear) / (znear - zfar),0<br />
 };<br />
 glLoadMatrixf(m);<br />
}</p>
<p>void display(void)<br />
{</p>
<p> glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);<br />
 glViewport(0, 0, WIDTH, HEIGHT);<br />
 glMatrixMode(GL_PROJECTION);</p>
<p> //glLoadIdentity();と同じ↓<br />
 glLoadMatrixf(mat);</p>
<p> //視野角,アスペクト比(ウィンドウの幅/高さ),描画する範囲(最も近い距離,最も遠い距離)<br />
 //gluPerspective(30.0, (double)WIDTH / (double)HEIGHT, 1.0, 1000.0);と同じ↓<br />
 perspective(30.0, (double)WIDTH / (double)HEIGHT, 1.0, 1000.0);<br />
 glMatrixMode(GL_MODELVIEW);</p>
<p> //glLoadIdentity();と同じ↓<br />
 glLoadMatrixf(mat);</p>
<p> //視点の設定<br />
 //gluLookAt(150.0,100.0,-200.0,0.0,0.0,0.0,0.0,1.0,0.0);と同じ↓<br />
 LookAt(150.0,100.0,-200.0, //カメラの座標<br />
      0.0,0.0,0.0, // 注視点の座標<br />
     0.0,1.0,0.0); // 画面の上方向を指すベクトル<br />
 //ライトの設定<br />
 glLightfv(GL_LIGHT0, GL_POSITION, lightpos);<br />
 //マテリアルの設定<br />
 glMaterialfv(GL_FRONT, GL_DIFFUSE, green);<br />
 //平行移動<br />
 //glTranslatef(x,0.0f,0.0f);と同じ↓<br />
 move[12]=x; //X軸の平行移動成分を設定<br />
 //glMultMatrixf(move);と同じ↓<br />
 glGetFloatv(GL_MODELVIEW_MATRIX,modelview);<br />
 multiplication(modelview,move,multi);<br />
 glLoadMatrixf(multi);</p>
<p> glutSolidSphere(40.0,16,16);</p>
<p> glutSwapBuffers();<br />
}<br />
void idle(void)<br />
{<br />
 if(flag){x-=0.05f;}else{x+=0.05f;}<br />
 if(x&gt;50.0f)flag=true;<br />
 if(x&lt;-50.0f)flag=false;<br />
 glutPostRedisplay();<br />
}<br />
void Init(){<br />
 glClearColor(0.3f, 0.3f, 0.3f, 1.0f);<br />
 glEnable(GL_DEPTH_TEST);<br />
 glEnable(GL_LIGHTING);<br />
 glEnable(GL_LIGHT0);<br />
}<br />
int main(int argc, char *argv[])<br />
{<br />
 glutInitWindowPosition(100, 100);<br />
 glutInitWindowSize(WIDTH, HEIGHT);<br />
 glutInit(&amp;argc, argv);<br />
 glutCreateWindow("gluLookAtを置き換える");<br />
 glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);<br />
 glutDisplayFunc(display);<br />
 glutIdleFunc(idle);<br />
 Init();<br />
 glutMainLoop();<br />
 return 0;<br />
}</p>
</td>
</tr></tbody></table><p> </p>

<p> <strong>gluLookAt　を置き換えてみます。</strong></p>
<p><strong><img alt="" src="http://cdn21.atwikiimg.com/opengl?cmd=upload&amp;act=open&amp;pageid=133&amp;file=look.png" /></strong></p>
<table border="1" cellpadding="1" cellspacing="1" width="600"><tbody><tr><td>
<p>#pragma comment(linker, "/SUBSYSTEM:WINDOWS /ENTRY:mainCRTStartup")<br />
#include &lt;GL/freeglut/freeglut.h&gt;<br />
#include &lt;math.h&gt;</p>
<p>#define PI 3.1415926</p>
<p>#define WIDTH 320<br />
#define HEIGHT 240</p>
<p>//平行移動用<br />
float x = 0.0f;<br />
bool flag = false;<br />
//緑<br />
GLfloat green[] = { 0.0, 1.0, 0.0, 1.0 };<br />
//ライトの位置<br />
GLfloat lightpos[] = { 200.0, 150.0, -500.0, 1.0 };<br />
//単位行列<br />
GLfloat mat[]={<br />
 1,0,0,0,<br />
 0,1,0,0,<br />
 0,0,1,0,<br />
 0,0,0,1<br />
};<br />
//平行移動用<br />
GLfloat move[]={<br />
 1,0,0,0,<br />
 0,1,0,0,<br />
 0,0,1,0,<br />
 0,0,0,1<br />
};</p>
<p>GLfloat modelview[16];<br />
GLfloat multi[16];</p>
<p>//合成 glMultMatrixfの代わり<br />
void multiplication(GLfloat* src1,GLfloat* src2,GLfloat* dst)<br />
{<br />
 for(int y=0;y&lt;4;y++){<br />
  for(int x=0;x&lt;4;x++){<br />
 
 dst[y*4+x]=src2[y*4]*src1[x]+src2[y*4+1]*src1[x+4]+src2[y*4+2]*src1[x+8]+src2[y*4+3]*src1[x+12];<br />
  }<br />
 }<br />
}<br />
//正規化<br />
void normalize(GLfloat* v){<br />
 float m=sqrt(v[0]*v[0]+v[1]*v[1]+v[2]*v[2]);<br />
 if(m &gt; 0.0f){m = 1.0f / m;}else{m = 0.0f;}<br />
 v[0]*=m;<br />
 v[1]*=m;<br />
 v[2]*=m;<br />
}<br />
//外積<br />
void cross( float* src1, float* src2 ,float* dst){<br />
dst[0] = src1[1]*src2[2] - src1[2]*src2[1];<br />
dst[1] = src1[2]*src2[0] - src1[0]*src2[2];<br />
dst[2] = src1[0]*src2[1] - src1[1]*src2[0];<br />
}</p>
<p>//gluLookAtと同じ<br />
void LookAt(GLfloat eyex, GLfloat eyey, GLfloat eyez, GLfloat centerx,<br />
GLfloat centery, GLfloat centerz, GLfloat upx, GLfloat upy,<br />
GLfloat upz)<br />
{<br />
float forward[3], side[3], up[3];</p>
<p>forward[0] = centerx - eyex;<br />
forward[1] = centery - eyey;<br />
forward[2] = centerz - eyez;</p>
<p>up[0] = upx;<br />
up[1] = upy;<br />
up[2] = upz;</p>
<p>normalize(forward);</p>
<p>cross(forward, up, side);<br />
normalize(side);</p>
<p>cross(side, forward, up);</p>
<p>GLfloat m[]={<br />
 side[0],up[0],-forward[0],0,<br />
 side[1],up[1],-forward[1],0,<br />
 side[2],up[2],-forward[2],0,<br />
 0,0,0,1<br />
};</p>
<p>GLfloat mov[]={<br />
 1,0,0,0,<br />
 0,1,0,0,<br />
 0,0,1,0,<br />
 -eyex,-eyey,-eyez,1<br />
};</p>
<p>multiplication(m,mov,multi);<br />
glLoadMatrixf(multi);<br />
}</p>
<p>//gluPerspectiveと同じ<br />
void perspective(float fovy,float aspect,float znear,float zfar)<br />
{<br />
 float radian=2*PI*fovy/360.0;<br />
 float t = (float)(1.0 / tan(radian/2));<br />
 GLfloat m[]={<br />
 t / aspect,0,0,0,<br />
 0,t,0,0,<br />
 0,0,(zfar + znear) / (znear - zfar),-1,<br />
 0,0,(2 * zfar * znear) / (znear - zfar),0<br />
 };<br />
 glLoadMatrixf(m);<br />
}</p>
<p>void display(void)<br />
{</p>
<p> glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);<br />
 glViewport(0, 0, WIDTH, HEIGHT);<br />
 glMatrixMode(GL_PROJECTION);</p>
<p> //glLoadIdentity();と同じ↓<br />
 glLoadMatrixf(mat);</p>
<p> //視野角,アスペクト比(ウィンドウの幅/高さ),描画する範囲(最も近い距離,最も遠い距離)<br />
 //gluPerspective(30.0, (double)WIDTH / (double)HEIGHT, 1.0, 1000.0);と同じ↓<br />
 perspective(30.0, (double)WIDTH / (double)HEIGHT, 1.0, 1000.0);<br />
 glMatrixMode(GL_MODELVIEW);</p>
<p> //glLoadIdentity();と同じ↓<br />
 glLoadMatrixf(mat);</p>
<p> //視点の設定<br />
 //gluLookAt(150.0,100.0,-200.0,0.0,0.0,0.0,0.0,1.0,0.0);と同じ↓<br />
 LookAt(150.0,100.0,-200.0, //カメラの座標<br />
      0.0,0.0,0.0, // 注視点の座標<br />
     0.0,1.0,0.0); // 画面の上方向を指すベクトル<br />
 //ライトの設定<br />
 glLightfv(GL_LIGHT0, GL_POSITION, lightpos);<br />
 //マテリアルの設定<br />
 glMaterialfv(GL_FRONT, GL_DIFFUSE, green);<br />
 //平行移動<br />
 //glTranslatef(x,0.0f,0.0f);と同じ↓<br />
 move[12]=x; //X軸の平行移動成分を設定<br />
 //glMultMatrixf(move);と同じ↓<br />
 glGetFloatv(GL_MODELVIEW_MATRIX,modelview);<br />
 multiplication(modelview,move,multi);<br />
 glLoadMatrixf(multi);</p>
<p> glutSolidSphere(40.0,16,16);</p>
<p> glutSwapBuffers();<br />
}<br />
void idle(void)<br />
{<br />
 if(flag){x-=1.0f;}else{x+=1.0f;}<br />
 if(x&gt;50.0f)flag=true;<br />
 if(x&lt;-50.0f)flag=false;<br />
 Sleep(1);<br />
 glutPostRedisplay();<br />
}<br />
void Init(){<br />
 glClearColor(0.3f, 0.3f, 0.3f, 1.0f);<br />
 glEnable(GL_DEPTH_TEST);<br />
 glEnable(GL_LIGHTING);<br />
 glEnable(GL_LIGHT0);<br />
}<br />
int main(int argc, char *argv[])<br />
{<br />
 glutInitWindowPosition(100, 100);<br />
 glutInitWindowSize(WIDTH, HEIGHT);<br />
 glutInit(&amp;argc, argv);<br />
 glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE);<br />
 glutCreateWindow("gluLookAtを置き換える");<br />
 glutDisplayFunc(display);<br />
 glutIdleFunc(idle);<br />
 Init();<br />
 glutMainLoop();<br />
 return 0;<br />
}</p>
</td>
</tr></tbody></table><p> </p>