OpenGL学习笔记(一)

最新推荐文章于 2024-11-05 17:26:03 发布

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最新推荐文章于 2024-11-05 17:26:03 发布

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分类专栏： OpenGL 文章标签： opengl

本文链接：https://blog.youkuaiyun.com/u013871984/article/details/20321245

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#include <GLUT/GLUT.h>
#include <stdio.h>
//我使用的xcode vs下应该include gl.h glu.h

static GLfloat spin = 0.0;
void init(){
    glClearColor(0.0, 0.0, 0.0, 0.0);
    glShadeModel(GL_FLAT);
}

void display(){
    glClear(GL_COLOR_BUFFER_BIT);//清除颜色缓冲 参数还有GL_DEPTH_BUFFER_BIT 表示深度缓冲
    
    glPushMatrix();
    glRotatef(spin, 0.0, 0.0, 1.0);
    glColor3f(1.0, 1.0, 0.4);
    glRectf(-25.0, -25.0, 25.0, 25.0);
    glPopMatrix();
    
    glutSwapBuffers();//因为glutInitDisplayMode使用了双缓冲
    
}

void spinDisplay(){
    spin += 2.0;
    if (spin > 360.0) {
        spin -= 360.0;
    }
    glutPostRedisplay();
}

void reshape(int w, int v){
    glViewport(0, 0, (GLsizei) w, (GLsizei) v);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-50.0, 50.0, 50.0, -50.0, -1.0, 1.0);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}

void mouse(int button, int state, int x, int y){
    switch (button) {
        case GLUT_LEFT_BUTTON:
            if (state == GLUT_DOWN) {
                glutIdleFunc(spinDisplay);
            }
            break;
        case GLUT_RIGHT_BUTTON:
            if (state == GLUT_DOWN) {
                glutIdleFunc(NULL);
            }
            break;
        default:
            break;
    }
}

int main(int argc, char **argv){
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowSize(250, 250);
    glutInitWindowPosition(100, 100);
    glutCreateWindow(argv[0]);
    init();
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);
    glutMouseFunc(mouse);
    glutMainLoop();
    return 0;
}

关于glMatrixMode 可参考这篇文章 http://blog.youkuaiyun.com/jiangdf/article/details/8460012