Opengl三维地形动态显示程序设计代码

下面是一个OpenGL三维地形动态显示程序的简单代码示例：

#include <GL/glut.h>
#include <cmath>

const int WIDTH = 800;
const int HEIGHT = 600;

// 地形高度图的宽度和高度
const int MAP_WIDTH = 256;
const int MAP_HEIGHT = 256;

// 地形高度图数据
unsigned char heightMap[MAP_WIDTH][MAP_HEIGHT];

// 地形顶点数组
float vertices[MAP_WIDTH][MAP_HEIGHT][3];

// 地形法向量数组
float normals[MAP_WIDTH][MAP_HEIGHT][3];

// 摄像机位置
float cameraX = 0.0f;
float cameraY = 0.0f;
float cameraZ = 0.0f;

// 摄像机方向
float pitch = 0.0f;
float yaw = 0.0f;

void generateHeightMap()
{
    // 生成随机高度图
    for (int i = 0; i < MAP_WIDTH; i++)
    {
        for (int j = 0; j < MAP_HEIGHT; j++)
        {
            heightMap[i][j] = rand() % 256;
        }
    }
}

void generateVertices()
{
    // 根据高度图生成顶点数组
    for (int i = 0; i < MAP_WIDTH; i++)
    {
        for (int j = 0; j < MAP_HEIGHT; j++)
        {
            vertices[i][j][0] = i - MAP_WIDTH / 2;
            vertices[i][j][1] = heightMap[i][j] / 10.0f;
            vertices[i][j][2] = j - MAP_HEIGHT / 2;
        }
    }
}

void generateNormals()
{
    // 根据顶点数组生成法向量数组
    for (int i = 0; i < MAP_WIDTH - 1; i++)
    {
        for (int j = 0; j < MAP_HEIGHT - 1; j++)
        {
            float x1 = vertices[i][j][0];
            float y1 = vertices[i][j][1];
            float z1 = vertices[i][j][2];

            float x2 = vertices[i+1][j][0];
            float y2 = vertices[i+1][j][1];
            float z2 = vertices[i+1][j][2];

            float x3 = vertices[i][j+1][0];
            float y3 = vertices[i][j+1][1];
            float z3 = vertices[i][j+1][2];

            float ax = x1 - x2;
            float ay = y1 - y2;
            float az = z1 - z2;

            float bx = x3 - x2;
            float by = y3 - y2;
            float bz = z3 - z2;

            float nx = ay * bz - az * by;
            float ny = az * bx - ax * bz;
            float nz = ax * by - ay * bx;

            float length = sqrt(nx * nx + ny * ny + nz * nz);

            normals[i][j][0] = nx / length;
            normals[i][j][1] = ny / length;
            normals[i][j][2] = nz / length;
        }
    }
}

void init()
{
    // 初始化OpenGL窗口
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(45.0, (double)WIDTH / (double)HEIGHT, 0.1, 1000.0);
    glEnable(GL_DEPTH_TEST);

    // 生成随机高度图和顶点数组
    generateHeightMap();
    generateVertices();
    generateNormals();
}

void display()
{
    // 清除屏幕和深度缓冲区
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // 设置摄像机位置和方向
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
    gluLookAt(cameraX, cameraY, cameraZ,
              cameraX + sin(yaw), cameraY - sin(pitch), cameraZ - cos(yaw),
              0.0f, 1.0f, 0.0f);

    // 绘制三角形网格
    glBegin(GL_TRIANGLES);
    for (int i = 0; i < MAP_WIDTH - 1; i++)
    {
        for (int j = 0; j < MAP_HEIGHT - 1; j++)
        {
            float x1 = vertices[i][j][0];
            float y1 = vertices[i][j][1];
            float z1 = vertices[i][j][2];

            float x2 = vertices[i+1][j][0];
            float y2 = vertices[i+1][j][1];
            float z2 = vertices[i+1][j][2];

            float x3 = vertices[i][j+1][0];
            float y3 = vertices[i][j+1][1];
            float z3 = vertices[i][j+1][2];

            float nx1 = normals[i][j][0];
            float ny1 = normals[i][j][1];
            float nz1 = normals[i][j][2];

            float nx2 = normals[i+1][j][0];
            float ny2 = normals[i+1][j][1];
            float nz2 = normals[i+1][j][2];

            float nx3 = normals[i][j+1][0];
            float ny3 = normals[i][j+1][1];
            float nz3 = normals[i][j+1][2];

            glNormal3f(nx1, ny1, nz1);
            glVertex3f(x1, y1, z1);
            glNormal3f(nx2, ny2, nz2);
            glVertex3f(x2, y2, z2);
            glNormal3f(nx3, ny3, nz3);
            glVertex3f(x3, y3, z3);

            x1 = vertices[i+1][j][0];
            y1 = vertices[i+1][j][1];
            z1 = vertices[i+1][j][2];

            x2 = vertices[i+1][j+1][0];
            y2 = vertices[i+1][j+1][1];
            z2 = vertices[i+1][j+1][2];

            x3 = vertices[i][j+1][0];
            y3 = vertices[i][j+1][1];
            z3 = vertices[i][j+1][2];

            nx1 = normals[i+1][j][0];
            ny1 = normals[i+1][j][1];
            nz1 = normals[i+1][j][2];

            nx2 = normals[i+1][j+1][0];
            ny2 = normals[i+1][j+1][1];
            nz2 = normals[i+1][j+1][2];

            nx3 = normals[i][j+1][0];
            ny3 = normals[i][j+1][1];
            nz3 = normals[i][j+1][2];

            glNormal3f(nx1, ny1, nz1);
            glVertex3f(x1, y1, z1);
            glNormal3f(nx2, ny2, nz2);
            glVertex3f(x2, y2, z2);
            glNormal3f(nx3, ny3, nz3);
            glVertex3f(x3, y3, z3);
        }
    }
    glEnd();

    // 刷新屏幕
    glutSwapBuffers();
}

void keyboard(unsigned char key, int x, int y)
{
    // 处理键盘输入
    switch (key)
    {
    case 'w':
        cameraX += sin(yaw);
        cameraZ -= cos(yaw);
        break;
    case 's':
        cameraX -= sin(yaw);
        cameraZ += cos(yaw);
        break;
    case 'a':
        cameraX += sin(yaw - M_PI / 2);
        cameraZ -= cos(yaw - M_PI / 2);
        break;
    case 'd':
        cameraX += sin(yaw + M_PI / 2);
        cameraZ -= cos(yaw + M_PI / 2);
        break;
    case 'q':
        cameraY += 0.1f;
        break;
    case 'e':
        cameraY -= 0.1f;
        break;
    }
}

void mouse(int x, int y)
{
    // 处理鼠标输入
    static int lastX = 0;
    static int lastY = 0;

    if (lastX != 0 || lastY != 0)
    {
        yaw += (x - lastX) * 0.01f;
        pitch += (y - lastY) * 0.01f;

        if (pitch > M_PI / 2)
        {
            pitch = M_PI / 2;
        }
        else if (pitch < -M_PI / 2)
        {
            pitch = -M_PI / 2;
        }
    }

    lastX = x;
    lastY = y;
}

int main(int argc, char** argv)
{
    // 初始化OpenGL窗口和GLEW库
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
    glutInitWindowSize(WIDTH, HEIGHT);
    glutCreateWindow("Dynamic Terrain");
    glewInit();

    // 初始化OpenGL状态和数据
    init();

    // 注册回调函数
    glutDisplayFunc(display);
    glutKeyboardFunc(keyboard);
    glutPassiveMotionFunc(mouse);

    // 进入主循环
    glutMainLoop();

    return 0;
}

这个程序使用OpenGL绘制了一个随机生成的三维地形，并且可以使用键盘和鼠标控制摄像机位置和方向。它使用了一个高度图来生成地形，并且计算了每个顶点的法向量，以便在光照计算中使用。