C++實現glut繪制點、直線、多邊形、圓

必備環境

• glut.h 頭文件
• glut32.lib 對象文件庫
• glut32.dll 動態連接庫

程序說明

C++實現了用glut畫點、畫直線、畫多邊形和畫圓形，并有一些清屏、重繪、清楚數據和窗口重繪的功能。

操作說明

• D：進入畫點模式
• L：進入畫直線模式
  • 第一次單擊確定直線起點
  • 第二次單擊繪出直線
• P：進入畫多邊形模式
  • 第一次單擊確定多邊形起點
  • 第n次單擊繪出多邊形的線
  • 右擊結束該多邊形的繪制
• O：進入畫圓模式
  • 第一次單擊決定圓心位置
  • 第二次單擊繪出圓
• C：清除屏幕
• X：消除全部數據
• R：重繪對象
• ` ：數字鍵調整畫筆顏色
  • 1~7對應紅橙黃綠藍靛紫
  • 8為默認黑色
• Q：退出程序

函數說明

void init( )
程序執行初用于告訴用戶的基本操作

void displayFunc( void )
glut窗口顯示和恢復顯示的時候調用的函數

void myKeyboard( unsigned char k, int x, int y )
鍵盤控制函數，用于綁定不同的畫圖函數到glut鼠標操作函數、改變畫筆顏色及其他一些功能

void drawDot( int x, in y )
在glut坐標軸(x, y)的位置根據畫筆設定繪制一個點

void Mouse_Dot( int button, int state, int x, int y )
鼠標控制畫點函數

void Mymouse_Line( int button, int state, int x, int y )
鼠標控制畫直線函數

void Mymouse_Polygon( int button, int state, int x, int y )
鼠標控制畫多邊形函數

void Mymouse_Circle( int button, int state, int x, int y )
鼠標控制畫圓函數

void drawLine1( int x0, int x1, int y0, int y1, bool xy_interchange )
直線繪制函數，負責區域1和區域5

void drawLine2( int x0, int x1, int y0, int y1, bool xy_interchange )
直線繪制函數，負責區域2和區域6

void drawLine3( int x0, int x1, int y0, int y1, bool xy_interchange )
直線繪制函數，負責區域3和區域7

void drawLine4( int x0, int x1, int y0, int y1, bool xy_interchange )
直線繪制函數，負責區域4和區域8

void DrawLine( int x0, int x1, int y0, int y1 )
直線繪制函數，自行添加，可全區域使用，目前暫給畫多邊形使用

void drawCircle( int radius, int center_x, int center_y )
圓繪制函數，負責畫出一個圓

void CirclePoints( int x, int y, int center_x, int center_y )
圓的八個點的繪制函數，每次畫出八個點

void redraw( )
重繪函數，把存儲的數據重繪出來

void clear( )
清空當前glut窗口的顯示

void erase( )
刪除所有保存的數據

重要函數說明

畫直線函數，把二維坐標區域分成8個區域，從第四象限靠近y軸的負半軸的區域開始算起為1號區域，逆時針計算。

注意的是，1號區域和5號區域是用同樣的函數控制的，唯一不同的是xy_interchange的值。1號區域的畫線方向是從原點畫到數字1的區域，5號區域的畫線是從數字5畫到原點。實質上畫線的方向是一致的。因此5~8號區域可以按照1~4號區域的相反來運算。

畫線的方法是中點二分法。取兩個像素點的中點，計算判斷鄰域像素點取哪一個。

// Draw line for dx>0 and dy>0 void drawLine1(int x0, int x1, int y0, int y1, bool xy_interchange){if (xy_interchange){int change = x0; x0 = x1; x1 = change;change = y0; y0 = y1; y1 = change;}int x = x1;int y = y1;int a = y1 - y0;int b = -(x1 - x0);int d = -a - 2 * b;int IncE = -2 * b;int IncNE = -2 * a - 2 * b;line_start[num_line] = line_data(x, y);lcp = &line_start[num_line];while (y >= y0){lcp->next = new line_data(x, y);lcp = lcp->next;drawDot(x, y);if (d <= 0){y--;d += IncE;}else{x--;y--;d += IncNE;}}glFlush();return; }

各方向均ok的畫線函數，由于需要每一步都使用乘法和除法，相比上一個畫線函數時間復雜一些，但是各方向均可繪圖，而且單純繪制一條直線在人腦反應時間上是無差別的。

void DrawLine(int x0, int x1, int y0, int y1) {//polygon_start[num_polygon] = line_data(x0, y0);int max_dis = abs(x1 - x0);max_dis = max_dis > abs(y0 - y1) ? max_dis : abs(y0 - y1);//lcp = &polygon_start[num_polygon];lcp = temp;if (max_dis != 0) {for (int i = 0; i < max_dis; ++i) {lcp->next = new line_data(x0 + i * (x1 - x0) / max_dis, y0 + i * (y1 - y0) / max_dis);lcp = lcp->next;}}lcp = temp;while (lcp != NULL) {drawDot(lcp->x, lcp->y);temp = lcp;lcp = lcp->next;}glFlush();return; }

繪制圓形，將一個圓分成1/8個圓，如圖所示

可以通過8個點之間相互關系，繪制出整個圓
（x, y） -> （y, x）->（x, -y）->（y, -x）->（-x, -y）->（-y, -x）->（-x, y）->（-y, x）
假設圓的半徑為R，只需要計算（0, R）->（R/2, R/2）即可

void CirclePoints(int x, int y, int center_x, int center_y){drawDot(center_x + x, center_y + y);drawDot(center_x + y, center_y + x);drawDot(center_x + x, center_y - y);drawDot(center_x + y, center_y - x);drawDot(center_x - x, center_y - y);drawDot(center_x - y, center_y - x);drawDot(center_x - x, center_y + y);drawDot(center_x - y, center_y + x);glFlush();return; }

程序添加了顏色管理，清屏等操作。

實現效果

求輕噴~

完整代碼

#include <iostream> #include <stdlib.h> #include <cmath> #include "glut.h" using namespace std;int height, width; static int xOrg = 0, yOrg = 0; #define MAX_LINE 100 // Max number of lines for drawing: 100 #define MAX_POLYGON 20 // Max number of polygons for drawing: 20 #define MAX_CIRCLE 20 // Max number of circles for drawing: 20struct line_structure{int x0, x1, y0, y1; };struct line_data{int x, y;line_data* next;line_data(int _x = -1, int _y = -1){x = _x;y = _y;next = NULL;} };struct center_data{int c_x, c_y;center_data(int cx = -1, int cy = -1){c_x = cx;c_y = cy;} };line_structure line[MAX_LINE]; line_data line_start[MAX_LINE]; line_data polygon_start[MAX_POLYGON]; line_data circle_start[MAX_CIRCLE]; center_data center[MAX_CIRCLE]; line_data* lcp; line_data* temp;int num_line = 0; int num_polygon = 0; int num_circle = 0; int key_line = 1; bool first_point = true;const float default_r = 255.0; const float default_g = 255.0; const float default_b = 255.0; float r = 0.0; float g = 0.0; float b = 0.0; float alpha = 0.0;void init(); void drawDot(int x, int y); void Mymouse_Dot(int button, int state, int x, int y); void Mymouse_Line(int button, int state, int x, int y); void Mymouse_Polygon(int button, int state, int x, int y); void Mymouse_Circle(int button, int state, int x, int y); void drawLine1(int x0, int x1, int y0, int y1, bool xy_interchange); void drawLine2(int x0, int x1, int y0, int y1, bool xy_interchange); void drawLine3(int x0, int x1, int y0, int y1, bool xy_interchange); void drawLine4(int x0, int x1, int y0, int y1, bool xy_interchange); void DrawLine(int x0, int x1, int y0, int y1); void drawCircle(int radius, int center_x, int center_y); void CirclePoints(int x, int y, int center_x, int center_y); void redraw(); void myKeyboard(unsigned char key, int x, int y); void clear(); void erase(); void displayFunc(void);void init(){cout << "Welcome GLUT painter" << endl;cout << "Here are command key: (case insensitive)" << endl;cout << "\tD - Dot Mode" << endl;cout << "\tL - Line Mode" << endl;cout << "\tP - Polygon Mode" << endl;cout << "\tO - Circle Mode" << endl;cout << "\tC - Clear Screen" << endl;cout << "\tX - Clear all objects" << endl;cout << "\tR - Redraw Objects" << endl;cout << "\t` - Number to set color" << endl;cout << "\tQ - Quit" << endl; }// Draw 8 points void CirclePoints(int x, int y, int center_x, int center_y){drawDot(center_x + x, center_y + y);drawDot(center_x + y, center_y + x);drawDot(center_x + x, center_y - y);drawDot(center_x + y, center_y - x);drawDot(center_x - x, center_y - y);drawDot(center_x - y, center_y - x);drawDot(center_x - x, center_y + y);drawDot(center_x - y, center_y + x);glFlush();return; }// Draw a circle void drawCircle(int radius, int center_x, int center_y){int x = 0;int y = radius;int d = 1 - radius;int IncE = 3;int IncSE = -2 * radius + 5;while (x <= y){if (d <= 0){x++;d += IncE;IncE += 2;IncSE += 2;}else{x++;y--;d += IncSE;IncE += 2;IncSE += 4;}lcp->next = new line_data(x, y);lcp = lcp->next;CirclePoints(x, y, center_x, center_y);}return; }// Mouse control for circle drawing void Mymouse_Circle(int button, int state, int x, int y){if (state == GLUT_DOWN && first_point == true){cout << "\tcircle center" << endl;cout << "\t\ton location (" << x << ", " << y << ")" << endl;center[num_circle] = center_data(x, y);first_point = false;}else if (state == GLUT_DOWN && first_point == false){cout << "\tmouse clicks" << endl;cout << "\t\ton location (" << x << ", " << y << ")" << endl;int radius = (int)sqrt(pow(x - center[num_circle].c_x, 2) + pow(y - center[num_circle].c_y, 2));circle_start[num_circle] = line_data(center[num_circle].c_x + 0, center[num_circle].c_y + radius);lcp = &circle_start[num_circle];drawCircle(radius, center[num_circle].c_x, center[num_circle].c_y);num_circle++;first_point = true;}return; }// Clear screen void clear(){glClearColor(default_r, default_g, default_b, alpha);glClear(GL_COLOR_BUFFER_BIT);glFlush(); }// Clear objects void erase(){for (int i = 0; i < num_line; i++){if (line_start[i].next != NULL){lcp = line_start[i].next;while (lcp != NULL){temp = lcp;lcp = lcp->next;delete(temp);}}}num_line = 0;for (int i = 0; i < num_polygon; i++){if (polygon_start[i].next != NULL){lcp = polygon_start[i].next;while (lcp != NULL){temp = lcp;lcp = lcp->next;delete(temp);}}}num_polygon = 0;for (int i = 0; i < num_circle; i++){if (circle_start[i].next != NULL){lcp = circle_start[i].next;while (lcp != NULL){temp = lcp;lcp = lcp->next;delete(temp);}}}num_circle = 0; }// Mouse control for polygon drawing void Mymouse_Polygon(int button, int state, int x, int y){if (button == GLUT_LEFT_BUTTON){if (state == GLUT_DOWN && first_point == true){cout << "\tpolygon starts" << endl;cout << "\t\ton location (" << x << ", " << y << ")" << endl;polygon_start[num_polygon] = line_data(x, y);temp = lcp = &polygon_start[num_polygon];first_point = false;num_polygon++;}else if (state == GLUT_DOWN && first_point == false){cout << "\tpolygon clicks" << endl;cout << "\t\ton location (" << x << ", " << y << ")" << endl;DrawLine(temp->x, x, temp->y, y);}}else if (button == GLUT_RIGHT_BUTTON){if (state == GLUT_DOWN){first_point = true;}}return; }void DrawLine(int x0, int x1, int y0, int y1) {//polygon_start[num_polygon] = line_data(x0, y0);int max_dis = abs(x1 - x0);max_dis = max_dis > abs(y0 - y1) ? max_dis : abs(y0 - y1);//lcp = &polygon_start[num_polygon];lcp = temp;if (max_dis != 0) {for (int i = 0; i < max_dis; ++i) {lcp->next = new line_data(x0 + i * (x1 - x0) / max_dis, y0 + i * (y1 - y0) / max_dis);lcp = lcp->next;}}lcp = temp;while (lcp != NULL) {drawDot(lcp->x, lcp->y);temp = lcp;lcp = lcp->next;}glFlush();return; }// Redraw all objects stored void redraw(){int i;line_data* rd_line;line_data* rd_polygon;line_data* rd_circle;for (i = 0; i<num_line; i++){rd_line = &line_start[i];while (rd_line != NULL){drawDot(rd_line->x, rd_line->y);rd_line = rd_line->next;}}for (i = 0; i<num_polygon; i++){rd_polygon = &polygon_start[i];while (rd_polygon != NULL){drawDot(rd_polygon->x, rd_polygon->y);rd_polygon = rd_polygon->next;}}for (i = 0; i<num_circle; i++){rd_circle = &circle_start[i];while (rd_circle != NULL){CirclePoints(rd_circle->x, rd_circle->y, center[i].c_x, center[i].c_y);rd_circle = rd_circle->next;}}glFlush(); }// draw a dot at location with integer coordinates (x,y) void drawDot(int x, int y){glBegin(GL_POINTS);// set the color of dotglColor3f(r, g, b);// invert height because the opengl origin is at top-left instead of bottom-leftglVertex2i(x, height - y);glEnd(); }// Mouse callback function void Mymouse_Dot(int button, int state, int x, int y){if (state == GLUT_DOWN) {cout << "\tdot clicks" << endl;cout << "\t\ton location (" << x << ", " << y << ")" << endl;drawDot(x, y);glFlush();} }#pragma region Drawline// Mouse control for line drawing void Mymouse_Line(int button, int state, int x, int y){if (state == GLUT_DOWN && first_point == true){cout << "\tline starts" << endl;cout << "\t\ton location (" << x << ", " << y << ")" << endl;line[num_line].x0 = x;line[num_line].y0 = y;first_point = false;}else if (state == GLUT_DOWN && first_point == false){cout << "\tline ends" << endl;cout << "\t\ton location (" << x << ", " << y << ")" << endl;line[num_line].x1 = x;line[num_line].y1 = y;first_point = true;int dx = line[num_line].x1 - line[num_line].x0;int dy = line[num_line].y1 - line[num_line].y0;if (dx >= 0 && dy > 0 && abs(dx) < abs(dy)){drawLine1(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, false);}else if (dx > 0 && dy >= 0 && abs(dx) >= abs(dy)){drawLine2(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, false);}else if (dx > 0 && dy <= 0 && abs(dx) > abs(dy)){drawLine3(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, false);}else if (dx >= 0 && dy < 0 && abs(dx) <= abs(dy)){drawLine4(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, false);}else if (dx <= 0 && dy < 0 && abs(dx) < abs(dy)){drawLine1(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, true);}else if (dx < 0 && dy <= 0 && abs(dx) >= abs(dy)){drawLine2(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, true);}else if (dx < 0 && dy >= 0 && abs(dx) > abs(dy)){drawLine3(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, true);}else{drawLine4(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1, true);}//DrawLine(line[num_line].x0, line[num_line].x1, line[num_line].y0, line[num_line].y1);num_line++;}return; }// Draw line for dx>0 and dy>0 void drawLine1(int x0, int x1, int y0, int y1, bool xy_interchange){if (xy_interchange){int change = x0; x0 = x1; x1 = change;change = y0; y0 = y1; y1 = change;}int x = x1;int y = y1;int a = y1 - y0;int b = -(x1 - x0);int d = -a - 2 * b;int IncE = -2 * b;int IncNE = -2 * a - 2 * b;line_start[num_line] = line_data(x, y);lcp = &line_start[num_line];while (y >= y0){lcp->next = new line_data(x, y);lcp = lcp->next;drawDot(x, y);if (d <= 0){y--;d += IncE;}else{x--;y--;d += IncNE;}}glFlush();return; }// Draw line for dx>0 and dy<0 void drawLine2(int x0, int x1, int y0, int y1, bool xy_interchange){if (xy_interchange){int change = x0; x0 = x1; x1 = change;change = y0; y0 = y1; y1 = change;}int x = x0;int y = y0;int a = y1 - y0;int b = -(x1 - x0);int d = 2 * a + b;int IncE = 2 * a;int IncNE = 2 * a + 2 * b;line_start[num_line] = line_data(x, y);lcp = &line_start[num_line];while (x <= x1){lcp->next = new line_data(x, y);lcp = lcp->next;drawDot(x, y);if (d <= 0){x++;d += IncE;}else{x++;y++;d += IncNE;}}glFlush();return; }// Draw line for dx<0 and dy>0 void drawLine3(int x0, int x1, int y0, int y1, bool xy_interchange){if (xy_interchange){int change = x0; x0 = x1; x1 = change;change = y0; y0 = y1; y1 = change;}int x = x0;int y = y0;int a = y0 - y1;int b = -(x1 - x0);int d = 2 * a + b;int IncE = 2 * a;int IncNE = 2 * a + 2 * b;line_start[num_line] = line_data(x, y);lcp = &line_start[num_line];while (x <= x1){lcp->next = new line_data(x, y);lcp = lcp->next;drawDot(x, y);if (d <= 0){x++;d += IncE;}else{x++;y--;d += IncNE;}}glFlush();return; }// Draw line for dx<0 and dy<0 void drawLine4(int x0, int x1, int y0, int y1, bool xy_interchange){if (xy_interchange){int change = x0; x0 = x1; x1 = change;change = y0; y0 = y1; y1 = change;}int x = x0;int y = y0;int a = y1 - y0;int b = -(x1 - x0);int d = a - 2 * b;int IncE = -2 * b;int IncNE = 2 * a - 2 * b;line_start[num_line] = line_data(x, y);lcp = &line_start[num_line];while (y >= y1){lcp->next = new line_data(x, y);lcp = lcp->next;drawDot(x, y);if (d <= 0){y--;d += IncE;}else{x++;y--;d += IncNE;}}glFlush();return; } #pragma endregion// Keyboard callback function void myKeyboard(unsigned char key, int x, int y) {switch (key) {// Draw dots with 'd' or 'D'case 'd':case 'D':cout << "\nchoose the Dot mode" << endl;glutMouseFunc(Mymouse_Dot);break;// Draw lines with 'l' or 'L'case 'l':case 'L':cout << "\nchoose the Line mode" << endl;first_point = true;glutMouseFunc(Mymouse_Line);break;// Draw polygons with 'p' or 'P'case 'p':case 'P':cout << "\nchoose the Polygon mode" << endl;first_point = true;glutMouseFunc(Mymouse_Polygon);break;// Draw circle with 'c' or 'C'case 'o':case 'O':cout << "\nchoose the Circle mode" << endl;first_point = true;glutMouseFunc(Mymouse_Circle);break;// Redraw all with 'r' or 'R'case 'r':case 'R':cout << "\nnow redraw all" << endl;redraw();break;// Clear screen with 'c' or 'C'case 'c':case 'C':cout << "\nclear the screen" << endl;clear();break;case 'x':case 'X':cout << "\nclear all the objects" << endl;erase();break;// Quit with 'q' or 'Q'case 'q':case 'Q':cout << "\napplication exit successfully" << endl;exit(0);break;case '1':r = 1.0; g = 0; b = 0;break;case '2':r = 1.0; g = 0.5; b = 0;break;case '3':r = 1.0; g = 1.0; b = 0;break;case '4':r = 0; g = 1.0; b = 0;break;case '5':r = 0; g = 0; b = 1.0;break;case '6':r = 0; g = 1.0; b = 1.0;break;case '7':r = 1.0; g = 0; b = 1.0;break;case '8':r = 0; g = 0; b = 0;break;default:break;} }// Display function void displayFunc(void){// clear the entire window to the background colorglClear(GL_COLOR_BUFFER_BIT);glClearColor(default_r, default_g, default_b, alpha);// draw the contents!!! Iterate your object's data structure!redraw();// flush the queue to actually paint the dots on the opengl windowglFlush(); }// Main int main(int argc, char** argv) {int winSizeX, winSizeY;//set the window sizeif (argc == 3) {winSizeX = atoi(argv[1]);winSizeY = atoi(argv[2]);}else { // default window sizewinSizeX = 800;winSizeY = 600;}width = winSizeX;height = winSizeY;init();// initialize OpenGL utility toolkit (glut)glutInit(&argc, argv);// single disply and RGB color mappingglutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display modeglutInitWindowSize(winSizeX, winSizeY); // set window sizeglutInitWindowPosition(500, 100); // set window position on screenglutCreateWindow("Lab1 Window"); // set window title// set up the mouse and keyboard callback functionsglutKeyboardFunc(myKeyboard); // register the keyboard action function// displayFunc is called whenever there is a need to redisplay the windowglutDisplayFunc(displayFunc); // register the redraw function// set background colorglClearColor(default_r, default_g, default_b, alpha); // set the background to whiteglClear(GL_COLOR_BUFFER_BIT); // clear the buffer// misc setupglMatrixMode(GL_PROJECTION); // setup coordinate systemglLoadIdentity();gluOrtho2D(0, winSizeX, 0, winSizeY);glShadeModel(GL_FLAT);glFlush();glutMainLoop();return 0; }

轉載于:https://www.cnblogs.com/wsine/p/4639050.html

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