个人可以做网站导航,模板网站劣势,百度免费广告发布平台,wordpress主题 书以下是完整的例子。在第四版 《计算机图形学 with openGL》第四章的例子中#xff0c;竟然只调用了circleMidpoint(scrPt c, GLint r) #xff0c;没有实现#xff0c;我认为是系统方法#xff0c;怎么找都找不到。openGL 官方文档也没找到#xff0c;这不会是自定义… 以下是完整的例子。在第四版 《计算机图形学 with openGL》第四章的例子中竟然只调用了circleMidpoint(scrPt c, GLint r) 没有实现我认为是系统方法怎么找都找不到。openGL 官方文档也没找到这不会是自定义的吧。我在同类文章中发现 有人写了 circleMidpoint(scrPt c, GLint r) 和里面嵌套的void putpixel(GLint x0, GLint y0, GLint x, GLint y)竟然跑起来了。
为啥没有人提到这个事情是本道长太菜了还是这事太简单了不值一提 #include stdafx.h
#include GL/glut.h
#include stdlib.h
#include math.h using namespace std;const GLdouble twoPi 6.283185;class scrPt {
public:GLint x, y;
};GLsizei winWidth 400, winHeight 300; // Initial display window size.void init(void)
{glClearColor(1.0, 1.0, 1.0, 1.0);glMatrixMode(GL_PROJECTION);gluOrtho2D(0.0, 200.0, 0.0, 150.0);
}
//书上的代码里没有自己后补的。2-1
void putpixel(GLint x0, GLint y0, GLint x, GLint y)
{glBegin(GL_POINTS);glVertex2f(x0 x, y0 y);glVertex2f(x0 x, y0 - y);glVertex2f(x0 - x, y0 y);glVertex2f(x0 - x, y0 - y);glVertex2f(x0 y, y0 x);glVertex2f(x0 y, y0 - x);glVertex2f(x0 - y, y0 x);glVertex2f(x0 - y, y0 - x);glEnd();}// Midpoint routines for displaying a circle.//书上的代码里没有自己后补的。2-2
void circleMidpoint(scrPt c, GLint r) //中点画圆函数
{int x, y, p;x 0; y r; p 1 - r;while (x y) {putpixel(c.x, c.y, x, y);if (p 0) {p 2 * x 1;}else {p 2 * (x - y) 1;y--;}x;}
}
void pieChart(void)
{scrPt circCtr, piePt;GLint radius winWidth / 4; // Circle radius.GLdouble sliceAngle, previousSliceAngle 0.0;GLint k, nSlices 12; // Number of slices.GLfloat dataValues[12] { 10.0, 7.0, 13.0, 5.0, 13.0, 14.0, 3.0, 16.0, 5.0, 3.0, 17.0, 8.0 };GLfloat dataSum 0.0;circCtr.x winWidth / 2; // Circle center position.circCtr.y winHeight / 2;circleMidpoint(circCtr, radius); // Call a midpoint circle-plot routine.for (k 0; k nSlices; k)dataSum dataValues[k];for (k 0; k nSlices; k) {sliceAngle twoPi * dataValues[k] / dataSum previousSliceAngle;piePt.x circCtr.x radius * cos(sliceAngle);piePt.y circCtr.y radius * sin(sliceAngle);glBegin(GL_LINES);glVertex2i(circCtr.x, circCtr.y);glVertex2i(piePt.x, piePt.y);glEnd();previousSliceAngle sliceAngle;}
}void displayFcn(void)
{glClear(GL_COLOR_BUFFER_BIT); // Clear display window.glColor3f(0.0, 0.0, 1.0); // Set circle color to blue.pieChart();glFlush();
}void winReshpeFcn(GLint newWidth, GLint newHeight)
{glMatrixMode(GL_PROJECTION);glLoadIdentity();gluOrtho2D(0.0, GLdouble(newWidth), 0.0, GLdouble(newHeight));glClear(GL_COLOR_BUFFER_BIT);/* Reset display-window size parameters. */winWidth newWidth;winHeight newHeight;
}void main(int argc, char** argv)
{glutInit(argc, argv);glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);glutInitWindowPosition(100, 100);glutInitWindowSize(winWidth,winHeight);glutCreateWindow(Pie Chart);init();glutDisplayFunc(displayFcn);glutReshapeFunc(winReshpeFcn);glutMainLoop();
}
