OpenGL用户自定义几何变换

最新推荐文章于 2024-10-04 13:09:52 发布

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最新推荐文章于 2024-10-04 13:09:52 发布

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CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/xiacl/archive/2012/04/06/2434990.html

本文介绍了一个使用OpenGL实现的用户自定义几何变换实例，包括旋转和平移操作，并展示了如何设置光照效果来增强3D模型的真实感。代码中详细演示了如何通过GLUT库创建窗口、设置显示模式和投影方式等。

效果图：

代码：

#define GLUT_DISABLE_ATEXIT_HACK
#include "gl/glut.h"

void OnDisplay(void);
void OnReShape(int,int);
void SetupLights();

void main(int argc,char* argv[])
{
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(600,480);
    glutCreateWindow("OpenGL用户自定义几何变换");

    glutReshapeFunc(OnReShape);
    glutDisplayFunc(OnDisplay);



    SetupLights();

    glutMainLoop();
}

void OnDisplay(void)
{
    GLfloat mat[]={1.0f,0.0f,0.0f,0.0f,
0.0f,-1.0f,0.0f,0.0f,
0.0f,0.0f,1.0f,0.0f,
0.0f,0.0f,0.0f,1.0f

    };
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glEnable(GL_DEPTH_TEST);

    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();

    glRotatef(30.0f,1.0f,0.0f,0.0f);
    glRotatef(15.0f,0.0f,1.0f,0.0f);


    glColor3f(1.0f,0.0f,1.0f);
    glBegin(GL_QUADS);
        glVertex3i(0,-30,-30);
        glVertex3i(0,30,-30);
        glVertex3i(0,30,30);
        glVertex3i(0,-30,30);
    glEnd();

    glPushMatrix();
    glTranslatef(30.0f,0.0f,0.0f);
    glColor3f(1.0f,1.0f,0.0f);
    glutSolidCube(50.0f);
    glPopMatrix();

    glMultMatrixf(mat);
    glTranslatef(-30.0f,0.0f,0.0f);
    glColor3f(1.0f,0.0f,0.0f);
    glutSolidCube(50.0f);



    glutSwapBuffers();

}

void OnReShape(int w,int h)
{
    GLfloat aspect =(GLfloat)w/(GLfloat)h;
    GLfloat nRange=100.0f;

    glViewport(0,0,w,h);

    glMatrixMode(GL_PROJECTION);     //将当前矩阵指定为投影模式
    glLoadIdentity();

//设置三维投影区
    
if (w<=h)
    {
        glOrtho(-nRange,nRange,-nRange*aspect,nRange*aspect,-nRange,nRange);
    } 
else
    {
        glOrtho(-nRange,nRange,-nRange/aspect,nRange/aspect,-nRange,nRange);
    }

}


void SetupLights()
{
    GLfloat ambientLight[]={0.2f,0.2f,0.2f,1.0f};//环境光
    GLfloat diffuseLight[]={0.9f,0.9f,0.9f,1.0f};//漫反射
    GLfloat specularLight[]={1.0f,1.0f,1.0f,1.0f};//镜面光
    GLfloat lightPos[]={50.0f,80.0f,60.0f,1.0f};//光源位置
    
    glEnable(GL_LIGHTING);                      //启用光照
    glLightfv(GL_LIGHT0,GL_AMBIENT,ambientLight);//设置环境光源
    glLightfv(GL_LIGHT0,GL_DIFFUSE,diffuseLight);//设置漫反射光源
    glLightfv(GL_LIGHT0,GL_SPECULAR,specularLight);//设置镜面光源
    glLightfv(GL_LIGHT0,GL_POSITION,lightPos);//设置灯光位置
    glEnable(GL_LIGHT0);                              //打开第一个灯光
    
    glEnable(GL_COLOR_MATERIAL);                      //启用材质的颜色跟踪
    glColorMaterial(GL_FRONT,GL_AMBIENT_AND_DIFFUSE); //指定材料着色的面
    glMaterialfv(GL_FRONT,GL_SPECULAR,specularLight); //指定材料对镜面光的反应
    glMateriali(GL_FRONT,GL_SHININESS,100);           //指定反射系数
    

 }