计算机图形学实验二：画圆

贵州大学实验报告

学院：计算机科学与技术专业：计算机科学与技术班级：计科131

P i (x i

float d;

x = 0;

y = radius;

d = 5 - 4 * radius;

float deltaE = 12;

float deltaSE = 20 - 8 * radius;

glColor3f(0.0, 1.0, 0.0);

glVertex2i(x, y);

while (y>x)

{

if (d <= 0)

{

d += deltaE;

deltaSE += 8;

}

else

{

d += deltaSE;

deltaSE += 16;

y--;

}

deltaE += 8;

x++;

glColor3f(0.0, 1.0, 0.0);

glVertex2i(x, y);

glColor3f(0.5, 1.0, 0.0);

glVertex2i(x, -y);

glColor3f(1.0, 1.0, 0.0);

glVertex2i(-x, y);

glColor3f(1.0, 0.0, 0.0);

glVertex2i(-x, -y);

glColor3f(0.0, 1.0, 1.0);

glVertex2i(y, x);

glColor3f(0.0, 0.0, 1.0);

glVertex2i(y, -x);

glColor3f(1.0, 0.0, 1.0);

glVertex2i(-y, x);

glColor3f(0.0, 1.0, 0.5);

glVertex2i(-y, -x);

}

}

/*

画椭圆

*/

void myDisplayEllipse(void)

{

glClear(GL_COLOR_BUFFER_BIT);// 清除

glBegin(GL_LINES);

for (int i = 0; i < 360; i++)

{

//convert degrees into radians

float degInRad = i*DEG2RAD;

glVertex2f(cos(degInRad)*xradius, sin(degInRad)*yradius);

}

glEnd();

glFlush();//保证前面的OpenGL命令立即执行（而不是让它们在缓冲区中等待）}

void myDisplay(void)

{

glClear(GL_COLOR_BUFFER_BIT); //清屏

glBegin(GL_LINES);

for (int i = 0; i < 360; i++)

{

//convert degrees into radians

float degInRad = i*DEG2RAD;

glVertex2f(cos(degInRad)*xradius, sin(degInRad)*xradius);

}

glEnd();

glFlush();

}

int main(int argc, char *argv[])

{

glutInit(&argc, argv); //固定格式

glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);

glutInitWindowSize(500, 500); //显示框的大小

glutInitWindowPosition(400, 200); //确定显示框左上角的位置

printf("输入你想画的圆 0代表中点圆 1代表椭圆\n");

int choice;

while (1)

{

scanf("%d", &choice);

switch (choice)

{

case 0:

glutCreateWindow("画圆");

实验结

果