OpenGL之路（四）自制图形函数（正方体、圆柱、圆锥）

#include <gl/glut.h>
#include <gl/GLU.h>
#include <gl/GL.h>
#pragma comment(lib, "opengl32.lib")
#pragma comment(lib, "glut32.lib")
#pragma comment(lib, "glu32.lib")
#pragma comment(lib, "glut.lib")

#include <math.h>
void Cube()
{
glBegin(GL_QUAD_STRIP);//填充凸多边形
glVertex3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.0f, 1.0f, 0.0f);
glVertex3f(1.0f, 0.0f, 0.0f);
glVertex3f(1.0f, 1.0f, 0.0f);
glVertex3f(1.0f, 0.0f, -1.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glVertex3f(0.0f, 0.0f, -1.0f);
glVertex3f(0.0f, 1.0f, -1.0f);
glVertex3f(0.0f, 0.0f, 0.0f);
glVertex3f(0.0f, 1.0f, 0.0f);
glEnd();
glBegin(GL_QUAD_STRIP);
glVertex3f(0.0f, 0.0f, 0.0f);
glVertex3f(1.0f, 0.0f, 0.0f);
glVertex3f(0.0f, 0.0f, -1.0f);
glVertex3f(1.0f, 0.0f, -1.0f);
glVertex3f(0.0f, 1.0f, 0.0f);
glVertex3f(1.0f, 1.0f, 0.0f);
glVertex3f(0.0f, 1.0f, -1.0f);
glVertex3f(1.0f, 1.0f, -1.0f);
glEnd();
}
void Circle()
{
glBegin(GL_TRIANGLE_FAN);//扇形连续填充三角形串
glVertex3f(0.0f, 0.0f, 0.0f);
int i = 0;
for (i = 0; i <= 390; i += 15)
{
float p = i * 3.14 / 180;
glVertex3f(sin(p), cos(p), 0.0f);
}
glEnd();
}
void Cylinder()
{
glBegin(GL_QUAD_STRIP);//连续填充四边形串
int i = 0;
for (i = 0; i <= 390; i += 15)
{
float p = i * 3.14 / 180;
glVertex3f(sin(p), cos(p), 1.0f);
glVertex3f(sin(p), cos(p), 0.0f);
}
glEnd();
Circle();
glTranslatef(0, 0, 1);
Circle();
}
void Cone()
{
glBegin(GL_QUAD_STRIP);//连续填充四边形串
int i = 0;
for (i = 0; i <= 390; i += 15)
{
float p = i * 3.14 / 180;
glVertex3f(0, 0, 1.0f);
glVertex3f(sin(p), cos(p), 0.0f);
}
glEnd();
Circle();
}
void renderScene(void)
{
static float i = 0;
i += 0.1;
if (i > 360)
i = 0;
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glLoadIdentity();

glPushMatrix();
glColor3f(0, 1, 0);
glTranslatef(-2, 2.0, -12);
glRotatef(i, 1, 1 ,1);
Cylinder();
glPopMatrix();

glPushMatrix();
glColor3f(1, 0, 0);
glTranslatef(2, 2, -12);
glRotatef(i, 1, 1, 1);
Circle();
glPopMatrix();

glPushMatrix();
glColor3f(0, 1, 1);
glTranslatef(-2, -2, -12);
glRotatef(i, 1, 1, 1);
Cube();
glPopMatrix();

glPushMatrix();
glColor3f(1, 1, 0);
glTranslatef(2, -2, -12);
glRotatef(i, 1, 1, 1);
Cone();
glPopMatrix();
glutSwapBuffers();
}
void changeSize(int w, int h) {

// 防止除数即高度为0
// (你可以设置窗口宽度为0).
if (h == 0)
h = 1;
float ratio = 1.0* w / h;

// 单位化投影矩阵。
glMatrixMode(GL_PROJECTION);
glLoadIdentity();

// 设置视口大小为整个窗口大小
glViewport(0, 0, w, h);

// 设置正确的投影矩阵
gluPerspective(45, ratio, 1, 1000);
//下面是设置模型视图矩阵
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0.0, 0.0, 5.0, 0.0, 0.0, -1.0, 0.0f, 1.0f, 0.0f);//设置观测点
}
int main(int argc, char * argv[])
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
glutInitWindowPosition(100, 100);
glutInitWindowSize(320, 320);
glutCreateWindow("Hello OpenGL");
glutDisplayFunc(renderScene);
glutIdleFunc(renderScene); //指定程序空闲时调用函数
glutReshapeFunc(changeSize); //指定窗口形状变化时的回调函数
glEnable(GL_DEPTH_TEST);
glutMainLoop();
return 0;
}