lab2.cpp

#include <stdio.h>
#include <stdlib.h>
#include <GL/freeglut.h>
#include <math.h>
#include <vector>

// 定義維度選項
#define DIM_10 123
#define DIM_13 124
#define DIM_15 125

// 全域變數
int coordRange = 10; // 預設座標範圍為(-10,10)
std::vector<std::pair<int, int> > filledCells; // 儲存已填充的格子座標
const float LINE_WIDTH = 1.0f; // 線寬
const float TOTAL_WIDTH = 20.0f; // 總寬度固定為20

// 繪製網格
void drawGrid() {
    glLineWidth(LINE_WIDTH);
    glColor3f(1.0, 0.0, 0.0); // 紅色線

    // 計算網格間距
    float gridSpacing = TOTAL_WIDTH / (coordRange * 2 + 1); // 總寬度20除以格子數
    float margin = LINE_WIDTH/2;

    // 繪製垂直線
    glBegin(GL_LINES);
    for(int x = -coordRange; x <= coordRange + 1; x++) {
        float xPos = x * gridSpacing;
        glVertex2f(xPos, -coordRange * gridSpacing);
        glVertex2f(xPos, (coordRange + 1) * gridSpacing);
    }
    glEnd();

    // 繪製水平線
    glBegin(GL_LINES);
    for(int y = -coordRange; y <= coordRange + 1; y++) {
        float yPos = y * gridSpacing;
        glVertex2f(-coordRange * gridSpacing, yPos);
        glVertex2f((coordRange + 1) * gridSpacing, yPos);
    }
    glEnd();
    
    // 繪製原點標記和周圍格子
    glColor3f(0.0, 1.0, 0.0); // 綠色原點
    glPointSize(5.0);
    glBegin(GL_POINTS);
    // 原點(0,0)
    glVertex2f(0.0, 0.0);
    // 上方格子(0,1)
    glVertex2f(0.0, gridSpacing);
    // 右方格子(1,0)
    glVertex2f(gridSpacing, 0.0);
    // 右上方格子(1,1)
    glVertex2f(gridSpacing, gridSpacing);
    glEnd();
}

// 填充格子
void fillCell(int x, int y) {
    float gridSpacing = TOTAL_WIDTH / (coordRange * 2 + 1);
    float xPos = x * gridSpacing;
    float yPos = y * gridSpacing;
    
    glColor3f(1.0, 0.0, 0.0); // 紅色填充
    glBegin(GL_QUADS);
    glVertex2f(xPos, yPos);
    glVertex2f(xPos + gridSpacing, yPos);
    glVertex2f(xPos + gridSpacing, yPos + gridSpacing);
    glVertex2f(xPos, yPos + gridSpacing);
    glEnd();
}

// 繪製已填充的格子
void drawFilledCells() {
    for(const auto& cell : filledCells) {
        fillCell(cell.first, cell.second);
    }
}

// 右鍵選單回調函數
void processMenu(int value) {
    switch(value) {
        case DIM_10:
            coordRange = 10;
            break;
        case DIM_13:
            coordRange = 13;
            break;
        case DIM_15:
            coordRange = 15;
            break;
    }
    filledCells.clear(); // 清空已填充的格子
    printf("座標系範圍已更改為: (-%d, %d)\n", coordRange, coordRange);
    glutPostRedisplay();
}

// 滑鼠點擊回調函數
void mouse(int button, int state, int x, int y) {
    if(button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
        int windowWidth = glutGet(GLUT_WINDOW_WIDTH);
        int windowHeight = glutGet(GLUT_WINDOW_HEIGHT);
        
        // 計算網格間距和邊距
        float gridSpacing = TOTAL_WIDTH / (coordRange * 2 + 1);
        float margin = LINE_WIDTH/2;
        float totalWidth = TOTAL_WIDTH + 2 * margin;
        
        // 將視窗座標轉換為OpenGL座標，考慮margin的影響
        float glX = (2.0f * x / windowWidth - 1.0f) * (totalWidth / 2.0f) - margin;
        float glY = -(2.0f * y / windowHeight - 1.0f) * (totalWidth / 2.0f) - margin;
        
        // 將座標轉換為網格座標
        int gridX = round(glX / gridSpacing);
        int gridY = round(glY / gridSpacing);
        
        // 檢查是否在有效範圍內
        if(gridX >= -coordRange && gridX <= coordRange && 
           gridY >= -coordRange && gridY <= coordRange) {
            // 添加到已填充格子列表
            filledCells.push_back(std::make_pair(gridX, gridY));
            printf("點擊的格子座標: (%d, %d)\n", gridX, gridY);
            glutPostRedisplay();
        }
    }
}

void RenderScene(void) {
    glClear(GL_COLOR_BUFFER_BIT);
    glLoadIdentity();
    
    drawGrid();
    drawFilledCells();
    
    glutSwapBuffers();
}

void init() {
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f); // 黑色背景
}

void ChangeSize(int w, int h) {
    glViewport(0, 0, w, h);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    float gridSpacing = TOTAL_WIDTH / (coordRange * 2 + 1);
    float margin = LINE_WIDTH/2; // 添加邊距以顯示最外層的線
    float halfWidth = TOTAL_WIDTH / 2.0f + margin;
    glOrtho(-halfWidth, halfWidth, -halfWidth, halfWidth, -1.0, 1.0);
    glMatrixMode(GL_MODELVIEW);
}

int main(int argc, char** argv) {
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
    glutInitWindowSize(600, 600);
    glutInitWindowPosition(100, 100);
    glutCreateWindow("Grid System");

    // 創建右鍵選單
    int menu = glutCreateMenu(processMenu);
    glutAddMenuEntry("10 x 10", DIM_10);
    glutAddMenuEntry("13 x 13", DIM_13);
    glutAddMenuEntry("15 x 15", DIM_15);
    glutAttachMenu(GLUT_RIGHT_BUTTON);

    init();
    glutReshapeFunc(ChangeSize);
    glutDisplayFunc(RenderScene);
    glutMouseFunc(mouse);
    glutMainLoop();
    return 0;
}