openGL学习

由小到大绘制多个点，排成螺旋

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void RenderScene(void)
{
    GLfloat x, y, z, angle;
    z = -50.0f;
    GLfloat zStep = 0.5f;
    GLfloat sizes[2];
    GLfloat sizeStep;
    GLfloat curSize;
   
    glGetFloatv(GL_POINT_SIZE_RANGE, sizes);
    glGetFloatv(GL_POINT_SIZE_GRANULARITY, &sizeStep);

    curSize = sizes[0] + sizeStep;
   
    glClear(GL_COLOR_BUFFER_BIT);
    glPushMatrix();
    glRotatef(40.0f, 10.0f, -10.0f, 0.0f);
   
   

    for (angle = 0.0f; angle <= (2.0f * GL_PI) * 3.0f; angle += 0.1f)
    {
        x = 50.0f * sin(angle);
        y = 50.0f * cos(angle);
        z += zStep;
        glPointSize(curSize);
        glBegin(GL_POINTS);
        glVertex3f(x, y, z);
        glEnd();
        if (curSize < 10.0f) curSize += sizeStep;
       
    }
   
   
    glPopMatrix();
    glutSwapBuffers();
}

void ChangeSize(GLsizei w, GLsizei h)
{
    GLfloat nRange = 100.0f;
    if (h == 0) h = 1;
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
   
   
    if (w <= h)
    {
        glOrtho(-nRange, nRange, -nRange * h / w, nRange * h / w, -nRange, nRange);
    }
    else
    {
        glOrtho(-nRange * w / h, nRange * w / h, -nRange, nRange, -nRange, nRange);
    }
   
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

绘制直线、折线

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void RenderScene(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glPushMatrix();
    glRotatef(40.0f, 10.0f, -10.0f, 0.0f);
   
    GLfloat x, y, z, angle;

    glBegin(GL_LINE_STRIP); //如果用GL_LINE_LOOP,会自动加一条线，形成环，如果用GL_LINES，则只是画一条线
    glVertex3f(x, y, z);
    glVertex3f(x + 30, y + 30, z + 30);
    glVertex3f(x + 30, y + 60, z + 30);
    glVertex3f(x + 20, y + 40, z + 80);
    glEnd();

    glPopMatrix();
    glutSwapBuffers();
}

用折线画螺旋，并且用上下左右控制旋转

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/*
* File: main.c
* Author: root
*
* Created on August 30, 2013, 12:57 PM
*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <GL/glut.h>
#include <GL/gl.h>
#include <math.h>


#define GL_PI 3.1415f
#define KEY_UP 101
#define KEY_DOWN 103
#define KEY_LEFT 102
#define KEY_RIGHT 100

GLfloat rotateX = 0.0f;
GLfloat rotateY = 0.0f;

void RenderScene(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glPushMatrix();
    glRotatef(rotateX, 1.0f, 0.0f, 0.0f);
    glRotatef(rotateY, 0.0f, 1.0f, 0.0f);
   
   
    GLfloat x, y, z, angle;
    z = -50.0f;
    glBegin(GL_LINE_STRIP);
    for(angle = 0.0f; angle < (2.0f * GL_PI) * 4; angle += 0.1f)
    {
        x = 50.0f * sin(angle);
        y = 50.0f * cos(angle);
        z += 0.5f;
       
        glVertex3f(x, y, z);
        
    }
    glEnd();
   
   
   
    glPopMatrix();
    glutSwapBuffers();
}

void ChangeSize(GLsizei w, GLsizei h)
{
    GLfloat nRange = 100.0f;
    if (h == 0) h = 1;
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
   
   
    if (w <= h)
    {
        glOrtho(-nRange, nRange, -nRange * h / w, nRange * h / w, -nRange, nRange);
    }
    else
    {
        glOrtho(-nRange * w / h, nRange * w / h, -nRange, nRange, -nRange, nRange);
    }
   
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void SetupRC(void)
{
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glColor3f(0.0f, 1.0f, 0.0f);
}

void myTimer(int i)
{

}

void keyAction (int key, int x, int y)
{
    switch (key)
    {
        case KEY_UP:
            rotateX += 1.5f;
            break;
        case KEY_DOWN:
            rotateX -= 1.5f;
            break;
        case KEY_LEFT:
            rotateY -= 1.5f;
            break;
        case KEY_RIGHT:
            rotateY += 1.5f;
            break;
        default:
            break;
    }
    RenderScene();
}


/*
*
*/
int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitWindowPosition(100, 100);
    glutInitWindowSize(399, 400);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutCreateWindow("asd");
    SetupRC();
    glutDisplayFunc(RenderScene);
    glutReshapeFunc(ChangeSize);
    glutSpecialFunc(keyAction);
    glutMainLoop();
    return (EXIT_SUCCESS);
}

用三角形画圆锥

两个扇面组成封口的锥形

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 void RenderScene(void)
 {
     glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
     glPushMatrix();

     glRotatef(rotateX, 10.0f, 0.0f, 0.0f);
     glRotatef(rotateY, 0.0f, 10.0f, 0.0f);

     char p0[3] = {0.0f, 50.0f, 0.0f};
     char p1[3] = {20.0f, 0.0, 20.0f};
     GLfloat angle;
     glShadeModel(GL_SMOOTH);
     glEnable(GL_CULL_FACE); //开启多边形剔除，不渲染多边形的背面，这样如果要显示一个正面朝外的封闭多边形，则背面超前的地方根本就不渲染。如果是创建不发呢关闭的集合形体，如纸，就不能打开这个选项。
     glEnable(GL_DEPTH_TEST); // 开启深度测试，可以避免晚描绘的像素错误遮挡之前描绘的Z坐标靠前的像素

     glPolygonMode(GL_BACK, GL_FILL); // 显示填充好的多边形，如果选GL_LINE，则只显示每个多边形的轮廓。

     glBegin(GL_TRIANGLE_FAN);
     glVertex3f(p0[0], p0[1], p0[2]);
     for (angle = 0; angle <= 2*GL_PI + 0.1f; angle += 0.1f)
     {
         glColor3f(sin(angle), 0.0f, 0.5f);
         glVertex3f(p1[0] * sin(angle), p1[1], p1[2] * cos(angle));
     }
     glEnd();

     glBegin(GL_TRIANGLE_FAN);
     glColor3f(1.0f, 1.0f, 1.0f);
     glVertex3f(p0[0], p1[1], p0[2]);
     for (angle = 0; angle <= 2*GL_PI + 0.1f; angle += 0.1f)
     {
         glVertex3f(p1[0] * cos(angle), p1[1], p1[2] * sin(angle));
     }
     glEnd();

     glPopMatrix();
     glutSwapBuffers();
 }

用GL_QUAD_STRIP绘制连续的四边形。提供顶点的方向是折线形的

提供顶点的顺序逆时针，则为正面。

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void RenderScene(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glRotatef(rotateX, 1.0f, 0.0f, 0.0f);
    glRotatef(rotateY, 0.0f, 1.0f, 0.0f);
    glEnable(GL_CULL_FACE);
    glEnable(GL_DEPTH_TEST);
    glPolygonMode(GL_BACK, GL_FILL);

    GLfloat r = 2.0f;
   
    glPushMatrix();
   
    glBegin(GL_QUAD_STRIP);
    glColor3f(1.0, 0.0f, 0.0f);
   
    glVertex3f(r, -r, -r);
    glVertex3f(r, -r, r);
    glVertex3f(-r, -r, -r);
    glVertex3f(-r, -r, r);
   
    glColor3f(0.0, 1.0f, 0.0f);
    glVertex3f(-r, r, -r);
    glVertex3f(-r, r, r);

    glColor3f(0.0, 0.0f, 1.0f);
    glVertex3f(r, r, -r);
    glVertex3f(r, r, r);

    glColor3f(0.0, 1.0f, 1.0f);
    glVertex3f(r, -r, -r);
    glVertex3f(r, -r, r);
    glEnd();
   
    glBegin(GL_QUADS);
    glColor3f(1.0, 1.0f, 1.0f);
    glVertex3f(-r, -r, r);
    glVertex3f(r, -r, r);
    glVertex3f(r, r, r);
    glVertex3f(-r, r, r);
   
    glEnd();
   
    glBegin(GL_QUADS);
    glColor3f(1.0, 0.0f, 1.0f);
    glVertex3f(r, -r, -r);
    glVertex3f(-r, -r, -r);
    glVertex3f(-r, r, -r);
    glVertex3f(r, r, -r);
   
   
    glEnd();
   
    glPopMatrix();
    glutSwapBuffers();
}

透视效果

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void ChangeSize(GLsizei w, GLsizei h)
{
    if (h == 0) h = 1;
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
   
    gluPerspective(80.0f, (GLfloat)w/(GLfloat)h, 11.0, 30.0);
   
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    glTranslatef(0.0f, 0.0f, -15.0f); 把坐标向x轴负方向推，使得图像装到gluPerspective的后两个参数范围里
}

方块回弹

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/*
* File: main.c
* Author: root
*
* Created on August 30, 2013, 12:57 PM
*/

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <GL/glut.h>
#include <GL/gl.h>


GLfloat rsize = 25.0f;
GLfloat x = 200.0f;
GLfloat y = 25.0f;

GLfloat xStep = 5.0f;
GLfloat yStep = 5.0f;

GLfloat windowWidth;
GLfloat windowHight;

void RenderScene(void)
{
   
    glClear(GL_COLOR_BUFFER_BIT);
    glColor3f(1.0f, 0.0f, 0.0f);
    glRectf(x , y , x + rsize, y - rsize);
   
   
    glutSwapBuffers();
}

void ChangeSize(GLsizei w, GLsizei h)
{
    windowWidth = w;
    windowHight = h;
    glViewport(0, 0, windowWidth, windowHight);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0, windowWidth, 0, windowHight, 20.0, -20.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void SetupRC(void)
{
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
// glColor3f(0.0f, 1.0f, 0.0f);
}

void myTimer(int i)
{
    if (x > windowWidth - rsize || x < 0) xStep *= -1;
    if (y > windowHight || y < rsize) yStep *= -1;
    x += xStep;
    y += yStep;
   
    glutPostRedisplay();
   
    glutTimerFunc(30, myTimer, i);
}

/*
*
*/
int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitWindowPosition(100, 100);
    glutInitWindowSize(399, 400);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutCreateWindow("asd");
// glEnable(GL_LIGHTING);
    glutDisplayFunc(RenderScene);
    glutReshapeFunc(ChangeSize);
    glutTimerFunc(30, myTimer, 1);
    SetupRC();
    glutMainLoop();
    return (EXIT_SUCCESS);
}

来自 “ ITPUB博客 ” ，链接：http://blog.itpub.net/26239116/viewspace-2125609/，如需转载，请注明出处，否则将追究法律责任。

转载于:http://blog.itpub.net/26239116/viewspace-2125609/