画家算法完整代码opengl

以下是一个使用OpenGL实现画家算法的示例代码，主要实现了画线、画圆、椭圆、矩形和填充矩形等基本图形的绘制：

#include <GL/glut.h>

int width = 800, height = 600; // 窗口宽高
int x1, y1, x2, y2; // 两个点的坐标
int radius, x, y; // 圆的半径和圆心坐标
int a, b; // 椭圆的长短半轴
bool fillRect = false; // 是否填充矩形

void init() {
    glClearColor(1.0, 1.0, 1.0, 0.0);
    glColor3f(0.0, 0.0, 0.0);
    glMatrixMode(GL_PROJECTION);
    gluOrtho2D(0.0, (GLdouble) width, 0.0, (GLdouble) height);
}

void drawPixel(int x, int y) {
    glBegin(GL_POINTS);
    glVertex2i(x, y);
    glEnd();
}

void drawLine(int x1, int y1, int x2, int y2) {
    int dx = x2 - x1, dy = y2 - y1;
    int steps = abs(dx) > abs(dy) ? abs(dx) : abs(dy);
    float xInc = dx / (float) steps, yInc = dy / (float) steps;
    float x = x1, y = y1;

    for (int i = 0; i <= steps; i++) {
        drawPixel((int) x, (int) y);
        x += xInc;
        y += yInc;
    }
}

void drawCircle(int radius, int x, int y) {
    int d = 3 - 2 * radius;
    int xc = 0, yc = radius;

    while (xc <= yc) {
        drawPixel(x + xc, y + yc);
        drawPixel(x + xc, y - yc);
        drawPixel(x - xc, y + yc);
        drawPixel(x - xc, y - yc);
        drawPixel(x + yc, y + xc);
        drawPixel(x + yc, y - xc);
        drawPixel(x - yc, y + xc);
        drawPixel(x - yc, y - xc);

        if (d < 0) {
            d = d + 4 * xc + 6;
        } else {
            d = d + 4 * (xc - yc) + 10;
            yc--;
        }

        xc++;
    }
}

void drawEllipse(int a, int b, int x, int y) {
    float d1 = b * b + a * a * (-b + 0.25);
    float dx = 2 * b * b * x, dy = 2 * a * a * y;
    float d2;

    while (dx < dy) {
        drawPixel(x, y);
        drawPixel(-x, y);
        drawPixel(x, -y);
        drawPixel(-x, -y);

        if (d1 < 0) {
            x++;
            dx += 2 * b * b;
            d1 += dx + b * b;
        } else {
            x++;
            y--;
            dx += 2 * b * b;
            dy -= 2 * a * a;
            d1 += dx - dy + b * b;
        }
    }

    d2 = b * b * (x + 0.5) * (x + 0.5) + a * a * (y - 1) * (y - 1) - a * a * b * b;

    while (y >= 0) {
        drawPixel(x, y);
        drawPixel(-x, y);
        drawPixel(x, -y);
        drawPixel(-x, -y);

        if (d2 > 0) {
            y--;
            dy -= 2 * a * a;
            d2 += a * a - dy;
        } else {
            y--;
            x++;
            dx += 2 * b * b;
            dy -= 2 * a * a;
            d2 += dx - dy + a * a;
        }
    }
}

void drawRectangle(int x1, int y1, int x2, int y2) {
    drawLine(x1, y1, x2, y1);
    drawLine(x2, y1, x2, y2);
    drawLine(x2, y2, x1, y2);
    drawLine(x1, y2, x1, y1);
}

void fillRectangle(int x1, int y1, int x2, int y2) {
    for (int i = x1; i <= x2; i++) {
        for (int j = y1; j <= y2; j++) {
            drawPixel(i, j);
        }
    }
}

void display() {
    glClear(GL_COLOR_BUFFER_BIT);

    if (fillRect) {
        fillRectangle(x1, y1, x2, y2);
    } else {
        drawRectangle(x1, y1, x2, y2);
    }

    drawCircle(radius, x, y);
    drawEllipse(a, b, x, y);

    glFlush();
}

void keyboard(unsigned char key, int x, int y) {
    switch (key) {
        case 'r':
            glColor3f(1.0, 0.0, 0.0); // 红色
            break;
        case 'g':
            glColor3f(0.0, 1.0, 0.0); // 绿色
            break;
        case 'b':
            glColor3f(0.0, 0.0, 1.0); // 蓝色
            break;
        case 'y':
            glColor3f(1.0, 1.0, 0.0); // 黄色
            break;
        case 'm':
            glColor3f(1.0, 0.0, 1.0); // 紫色
            break;
        case 'c':
            glColor3f(0.0, 1.0, 1.0); // 青色
            break;
        case 'w':
            glColor3f(1.0, 1.0, 1.0); // 白色
            break;
        case 'f':
            fillRect = !fillRect;
            break;
        case 27: // ESC键
            exit(0);
            break;
        default:
            break;
    }

    glutPostRedisplay();
}

void mouse(int button, int state, int x, int y) {
    if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
        x1 = x;
        y1 = height - y;
    } else if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
        x2 = x;
        y2 = height - y;
        glutPostRedisplay();
    } else if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN) {
        x = x;
        y = height - y;
        radius = 0;
    } else if (button == GLUT_RIGHT_BUTTON && state == GLUT_UP) {
        x = x;
        y = height - y;
        radius = (int) sqrt((x - x1) * (x - x1) + (y - y1) * (y - y1));
        glutPostRedisplay();
    } else if (button == GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) {
        x = x;
        y = height - y;
        a = abs(x - x1);
        b = abs(y - y1);
    } else if (button == GLUT_MIDDLE_BUTTON && state == GLUT_UP) {
        x = x;
        y = height - y;
        a = abs(x - x1);
        b = abs(y - y1);
        glutPostRedisplay();
    }
}

int main(int argc, char **argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(width, height);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Painter's Algorithm");
    init();
    glutDisplayFunc(display);
    glutKeyboardFunc(keyboard);
    glutMouseFunc(mouse);
    glutMainLoop();
    return 0;
}

注意：以上代码仅供参考，实际应用时需要根据具体的需求进行修改和调整。