OpenGL de プログラミング

glEvalMesh2関数を用いて、(0,0)〜(1,1)の範囲にメッシュを描画せよ。
その他条件：

キーボード「↑」「↓」でメッシュの細かさを変えられる。
マウスで視点が変えられる。

#include <cstdio>
#include <GL/glut.h>
#include <GL/glu.h>
#include <GL/gl.h>

void display();
void reshape(int w, int h);


void myMouseFunc(int button,int state,int x,int y);
void myMouseMotion(int x,int y);
void SpecialKey(int key, int x, int y);

void DRAW_XYZ();
void DRAW_TRI();

using namespace std;


GLdouble points[2][2][3]=
{
{{0,0,0},{1,0,0}},
{{0,1,0},{1,1,0}}
};


inline void GLUT_INIT()
{
glutInitDisplayMode(GLUT_RGBA| GLUT_DOUBLE | GLUT_DEPTH);
glutInitWindowSize(200,200);
}

inline void GLUT_CALL_FUNC()
{
glutDisplayFunc(display);
glutReshapeFunc(reshape);
glutMouseFunc(myMouseFunc);
glutMotionFunc(myMouseMotion);
glutSpecialFunc(SpecialKey);
}

inline void MY_INIT()
{
glClearColor(1.0, 1.0, 1.0, 1.0);
glEnable(GL_MAP2_VERTEX_3);
}


int main(int argc, char **argv)
{
glutInit(&argc,argv);
GLUT_INIT();
glutCreateWindow("window name");
GLUT_CALL_FUNC();
MY_INIT();
glutMainLoop();

return 0;
}

/********[ここからコールバック]****************************************/
double xAngle = 0.0, yAngle = 0.0;
int num = 10;
void display()
{

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();
gluLookAt(3.0, 4.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

glRotated(xAngle,1,0,0);
glRotated(yAngle,0,1,0);

glEnable(GL_DEPTH_TEST);

DRAW_XYZ();

glPushMatrix();
glMap2d(GL_MAP2_VERTEX_3, 0.0, 1.0, 3, 2, 0.0, 1.0, 6, 2,&points[0][0][0]);
glMapGrid2d(num, 0.0, 1.0, num, 0.0, 1.0);
glEvalMesh2(GL_LINE, 0, num, 0, num);
glPopMatrix();


glDisable(GL_DEPTH_TEST);

glutSwapBuffers();


}


void reshape(int w, int h)
{
glViewport(0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(30.0, (double)w / (double)h, 1.0, 100.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}



int xStart,yStart;
bool mouseFlag = GL_FALSE;
void myMouseFunc(int button,int state,int x,int y)
{
if(button == GLUT_LEFT_BUTTON &&state == GLUT_DOWN)
{
xStart = x;
yStart = y;
mouseFlag = GL_TRUE;
}
else
{
mouseFlag = GL_FALSE;

}

}

void myMouseMotion(int x,int y)
{
int xdis,ydis;
double a = 0.5;

if(mouseFlag == GL_FALSE)return;

xdis = x - xStart;
ydis = y - yStart;

xAngle += (double)ydis * a;
yAngle += (double)xdis * a;

xStart = x;
yStart = y;
glutPostRedisplay();
}



void SpecialKey(int key, int x, int y)
{
switch (key) {
case GLUT_KEY_UP:
num += 1;
break;

case GLUT_KEY_DOWN:
num -= 1;
break;

}

glutPostRedisplay();
}


/**********[ここから各種関数]***********************/
void DRAW_XYZ()
{
glBegin(GL_LINES);

glColor3d(0,1,0);//x
glVertex2d(-100,0);
glVertex2d(100, 0);

glColor3d(1,0,0);//y
glVertex2d(0,0);
glVertex2d(0,100);

glColor3d(0,0,1);//z
glVertex3d(0,0,-100);
glVertex3d(0,0, 100);
glEnd();

}

void DRAW_TRI()
{
glBegin(GL_TRIANGLES);

glVertex2d(0,1);
glVertex2d(-0.5, 0);
glVertex2d(0.5, 0);
glEnd();
}