OpenGL——折线图柱状图饼图绘制
折线图绘制代码：
#include<iostream> //旧版本 固定管线 #include<Windows.h> #include <GL/glut.h> //新版本 可编程管线 /*#define GLEW_STATIC #include <GL/glew.h> #include<GLFW\glfw3.h> */ using namespace std; GLsizei winWidth = 610, winHeight = 500; GLint xRaster = 25, yRaster = 150; GLubyte label[36] = { 'J','a','n', 'F','e','b', 'M','a','r', 'A','p','r', 'M','a','y', 'J','u','n', 'J','u','l', 'A','u','g', 'S','e','p', 'O','c','t', 'N','o','v', 'D','e','c' }; GLint dataValue[12] = { 420,342,324,310,262,185,190,196,217,240,312,438 }; void init() { //窗口背景为白色 glClearColor(1, 1, 1, 1); glMatrixMode(GL_PROJECTION); gluOrtho2D(0.0, 610.0, 0.0, 500.0); } void lineGraph() { GLint month, k; GLint x = 30; glClear(GL_COLOR_BUFFER_BIT); //蓝色 glColor3f(0.0, 0.0, 1.0); glBegin(GL_LINE_STRIP); //画出折线段 for (k = 0; k < 12; k++) { glVertex2i(x + k * 50, dataValue[k]); } glEnd(); //红色 glColor3f(1.0, 0.0, 0.0); //标注各点 for (k = 0; k < 12; k++) { glRasterPos2i(xRaster + k * 50, dataValue[k] - 4); glutBitmapCharacter(GLUT_BITMAP_9_BY_15, '*'); } //黑色 glColor3f(0.0, 0.0, 0.0); //横坐标说明 xRaster = 20; for (month = 0; month < 12; month++) { glRasterPos2i(xRaster, yRaster); for (k = 3 * month;k < 3 * month + 3;k++) { glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, label[k]); xRaster += 17; } } glFlush(); } void winReshapeFcn(GLint newWidth, GLint newHeight) { glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0, GLdouble(newWidth), 0, GLdouble(newHeight)); glClear(GL_COLOR_BUFFER_BIT); } int main(int argc, char* argv[]) { //对GLUT进行初始化，并处理所有的命令行参数 glutInit(&argc, argv); //指定使用RGBA模式还是颜色索引模式，还可指定使用单缓冲还是双缓冲窗口 glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); //指定了窗口左上角在屏幕上的位置 glutInitWindowPosition(100, 100); //制定了窗口大小（以像素为单位） glutInitWindowSize(winWidth, winHeight); //创建支持opengl渲染的窗口，在调用glutMainLoop函数前，窗口没有显示 glutCreateWindow("折线图"); init(); //显示回调函数 //每当GLUT确定一个窗口的内容需要重新显示时，通过glutDisplayFunc()注册的那个回调函数就会被执行 glutDisplayFunc(lineGraph); glutReshapeFunc(winReshapeFcn); //启动程序，所有窗口这时显示 glutMainLoop(); system("pause"); return 0; }
运行结果：
柱状图代码：
void barChart() { GLint month, k; glClear(GL_COLOR_BUFFER_BIT); //红色 glColor3f(1.0, 0.0, 0.0); for (k = 0; k < 12; k++) { glRecti(20 + k * 50, 165, 40 + k * 50, dataValue[k]); } //黑色 glColor3f(0.0, 0.0, 0.0); //横坐标说明 xRaster = 20; for (month = 0; month < 12; month++) { glRasterPos2i(xRaster, yRaster); for (k = 3 * month;k < 3 * month + 3;k++) { glutBitmapCharacter(GLUT_BITMAP_HELVETICA_12, label[k]); xRaster += 17; } } glFlush(); }
运行结果：
饼图代码：
#include<iostream> #include <math.h> //旧版本 固定管线 #include<Windows.h> #include <GL/glut.h> //新版本 可编程管线 /*#define GLEW_STATIC #include <GL/glew.h> #include<GLFW\glfw3.h> */ using namespace std; const GLdouble twoPi = 6.283185; class scrPt { public: scrPt() { x = y = 0; } GLint x, y; void setCoords(GLint xCoordValue, GLint yCorrdValue) { x = xCoordValue; y = yCorrdValue; } GLint getx() const { return x; } GLint gety() const { return y; } void incrementx() { x++; } void incrementy() { y--; } }; GLsizei winWidth = 400, winHeight = 300; void init() { //窗口背景为白色 glClearColor(1, 1, 1, 1); glMatrixMode(GL_PROJECTION); gluOrtho2D(0.0, 200.0, 0.0, 150.0); } void setPixel(GLint xCoord, GLint yCoord) { glBegin(GL_POINTS); glVertex2i(xCoord, yCoord); glEnd(); } void circlePlotPoints(GLint xc, GLint yc, scrPt circPt) { setPixel(xc + circPt.getx(), yc + circPt.gety()); setPixel(xc - circPt.getx(), yc + circPt.gety()); setPixel(xc + circPt.getx(), yc - circPt.gety()); setPixel(xc - circPt.getx(), yc - circPt.gety()); setPixel(xc + circPt.gety(), yc + circPt.getx()); setPixel(xc - circPt.gety(), yc + circPt.getx()); setPixel(xc + circPt.gety(), yc - circPt.getx()); setPixel(xc - circPt.gety(), yc - circPt.getx()); } //中心画圆算法 void circleMidpoint(GLint xc, GLint yc, GLint radius) { scrPt circPt; GLint p = 1 - radius;//中点参数初值 circPt.setCoords(0, radius); circlePlotPoints(xc, yc, circPt); while (circPt.getx() < circPt.gety()) { circPt.incrementx(); if (p < 0) p += 2 * circPt.getx() + 1; else { circPt.incrementy(); p += 2 * (circPt.getx() - circPt.gety()) + 1; } circlePlotPoints(xc, yc, circPt); } } void pieChart() { scrPt circCtr, piePt; GLint radius = winWidth / 4; GLdouble sliceAngle, previousSliceAngle = 0.0; GLint k, nSlices = 12; 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; circCtr.y = winHeight / 2; circleMidpoint(circCtr.x,circCtr.y, radius); for (k = 0;k < nSlices;k++) { dataSum += dataValues[k]; } for (k = 0; k < 12; 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() { glClear(GL_COLOR_BUFFER_BIT); glColor3f(0.0, 0.0, 1.0); pieChart(); glFlush(); } void winReshapeFcn(GLint newWidth, GLint newHeight) { glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(0.0, GLdouble(newWidth), 0.0, GLdouble(newHeight)); glClear(GL_COLOR_BUFFER_BIT); winWidth = newWidth; winHeight = newHeight; } int main(int argc, char* argv[]) { //对GLUT进行初始化，并处理所有的命令行参数 glutInit(&argc, argv); //指定使用RGBA模式还是颜色索引模式，还可指定使用单缓冲还是双缓冲窗口 glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE); //指定了窗口左上角在屏幕上的位置 glutInitWindowPosition(100, 100); //制定了窗口大小（以像素为单位） glutInitWindowSize(winWidth, winHeight); //创建支持opengl渲染的窗口，在调用glutMainLoop函数前，窗口没有显示 glutCreateWindow("Pie"); init(); //显示回调函数 //每当GLUT确定一个窗口的内容需要重新显示时，通过glutDisplayFunc()注册的那个回调函数就会被执行 glutDisplayFunc(displayFcn); glutReshapeFunc(winReshapeFcn); //启动程序，所有窗口这时显示 glutMainLoop(); system("pause"); return 0; }
运行结果：
