五角星自由變換和移動 & 結構體數組初始化 & DIRECTION

• 圖形學課堂作業

// 五角星運動方向
#include <GL/glut.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>
#include <time.h>
#include <iostream>
using namespace std;
int wWidth, wHeight;
int rtheta, movex = 0, movey = 0;
int len_star = 100;
float scale = 1, dscale = 0.1;
const double PI = acos(-1.0);
typedef struct tagDIRECTION
{
    int x_offset;
    int y_offset;
} DIRECTION;
// DIRECTION direction_8[] = { { -10, 0}, { -10, 10}, {0, 10}, {10, 10}, {10, 0}, {10, -10}, {0, -10}, { -10, -10} };
DIRECTION direction_8[] = { { -10, 0}, {10, 10}, { -10, -10}, {10, 0}, { -10, 10}, {0, -10}, {0, 10}, {10, -10}};
int idx_dir = 0;
int idx_circle = 3;
int R = 25;
int circle_x = 0, circle_y = 0;
typedef struct
{
    int x;
    int y;
} Point;
typedef struct
{
    float R;
    float G;
    float B;
} RGB; // glColor3f();
// RGB *rgb = new RGB;
void myDraw(Point point, RGB rgb, float Length, float theta)
{
    // glColor3ub(255, 0, 0);
    glColor3f(rgb.R, rgb.G, rgb.B);
    glBegin(GL_LINE_LOOP);
    float Short = Length * sin(0.1 * PI) / sin(0.7 * PI);
    float beta = 18 + theta; //五角星NE的長半徑和x軸的夾角
    float p1[2];
    glColor3f(1.0, 0.0, 0.0);
    for (int i = 0; i < 5; i++) //從最右邊的那個長邊頂點開始畫
    {
        p1[0] = Length * cos(i * 2 * 0.2 * PI + beta * 3.1415926 / 180.0) + point.x; //x座標 18 * 3.1415926 = 56.55
        p1[1] = Length * sin(i * 2 * 0.2 * PI + beta * 3.1415926 / 180.0) + point.y; //y座標
        glVertex2fv(p1);
        p1[0] = Short * cos((i * 2 + 1) * 0.2 * PI + beta * 3.1415926 / 180.0) + point.x;
        p1[1] = Short * sin((i * 2 + 1) * 0.2 * PI + beta * 3.1415926 / 180.0) + point.y;
        glVertex2fv(p1);
    }
    glEnd();

    // glPushMatrix();
    // glLoadIdentity();
    // // 繪製座標系
    // glBegin(GL_LINES);
    // glVertex2i(0, -wHeight / 2 + 5);
    // glVertex2i(0, wHeight / 2 - 5);
    // glVertex2i(wWidth / 2 - 5, 0);
    // glVertex2i(-wWidth / 2 + 5, 0);
    // glEnd();
    // glPopMatrix();
}
void drawCircle()
{
    glBegin(GL_POLYGON);
    glColor3f(0, 1, 0);
    for (float i = 0; i < 360; i += 0.1) {
        glVertex2f(R * cos(i * PI / 180), R * sin(i * PI / 180));
    }
    glEnd();
}
void display()
{
    glClearColor(0, 1, 1, 0);
    glClear(GL_COLOR_BUFFER_BIT);
    Point point = {0, 0};
    RGB rgb = {1, 0, 0};
    myDraw(point, rgb, len_star, 0);


    //題目要求畫一個小圓，沿任意方向運動
    glPushMatrix();
    glLoadIdentity();

    circle_x += direction_8[idx_circle].x_offset;
    circle_y += direction_8[idx_circle].y_offset;
    if (circle_x + R > wWidth / 2 || circle_x - R < (-wWidth / 2) || circle_y + R > wHeight / 2 || circle_y - R < (-wHeight / 2)) {
        circle_x -= direction_8[idx_circle].x_offset;
        circle_y -= direction_8[idx_circle].y_offset;
        int ii = rand() % 8;
        idx_circle = ii;
    }
    cout << circle_x << " " << circle_y << endl;
    glTranslatef(circle_x, circle_y, 0);
    drawCircle();
    glPopMatrix();

    glFlush();
    glutSwapBuffers();
}
void change() {
    // 改變方向
    movex += direction_8[idx_dir].x_offset;
    movey += direction_8[idx_dir].y_offset;
    if ((movex + len_star) > (wWidth / 2) || (movex - len_star) < (-(wWidth / 2)) || (movey + len_star) > (wHeight / 2) || (movey - len_star) < (-(wHeight / 2))) {
        movex -= direction_8[idx_dir].x_offset;
        movey -= direction_8[idx_dir].y_offset;
        idx_dir += 1;
        idx_dir %= 8;
        // return;
    }
    // cout << idx_dir << endl;

    // 改變旋轉方向
    rtheta += 10;
    rtheta %= 360;

    // 改變大小
    scale += dscale;
    if (scale > 2 || scale < 0.5)
        dscale = -dscale;
    // cout << movex << " " << movey << endl;
    // cout << wWidth << " " << wHeight << endl;
    glTranslatef (movex, movey, 0.0);
    glRotatef (rtheta, 0.0, 0.0, 1.0);
    glScalef(scale, scale, 0);
    display();

    usleep(100000);
    glLoadIdentity();
}
void myReshape(GLsizei w, GLsizei h)
{
    wWidth = w; wHeight = h;
    glMatrixMode (GL_PROJECTION);
    glLoadIdentity (); // cout << w << " " << h << " " << endl;
    gluOrtho2D(-w / 2, w / 2, -h / 2, h / 2); // gluOrtho2D(-w / 2, w / 2, -h / 2, h / 2);
    glMatrixMode (GL_MODELVIEW);
    glLoadIdentity ();
    glViewport (0, 0, w, h);
}
int main(int argc, char* argv[]) //main(int argc, char **argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowPosition(300, 300);
    glutInitWindowSize(900, 900);
    glutCreateWindow("example");
    srand(time(NULL));
    glutDisplayFunc(display);
    glutReshapeFunc(myReshape);
    glutIdleFunc(change);
    glutMainLoop();
    return 0;
}