[译]GLUT教程 - 整合代码2

最新推荐文章于 2013-10-30 01:59:00 发布

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最新推荐文章于 2013-10-30 01:59:00 发布

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原文链接：http://www.cnblogs.com/live41/p/3391950.html

本文介绍了一个使用GLUT库实现的3D场景绘制示例。该示例通过OpenGL库绘制了36个雪人，并实现了键盘和鼠标操作来控制相机视角。文章提供了完整的源代码，展示了如何设置投影矩阵、绘制雪人模型、处理用户输入等功能。

Lighthouse3d.com >> GLUT Tutorial >> Input >> The Code So Far II

以下是前面几节的完整整合代码:

#include <stdlib.h>
#include <math.h>

#ifdef __APPLE__
#include <GLUT/glut.h>
#else
#include <GL/glut.h>
#endif

// angle of rotation for the camera direction
float angle = 0.0f;

// actual vector representing the camera's direction
float lx=0.0f,lz=-1.0f;

// XZ position of the camera
float x=0.0f, z=5.0f;

// the key states. These variables will be zero
//when no key is being presses
float deltaAngle = 0.0f;
float deltaMove = 0;
int xOrigin = -1;

void changeSize(int w, int h) {

    // Prevent a divide by zero, when window is too short
    // (you cant make a window of zero width).
    if (h == 0)
        h = 1;

    float ratio =  w * 1.0 / h;

    // Use the Projection Matrix
    glMatrixMode(GL_PROJECTION);

    // Reset Matrix
    glLoadIdentity();

    // Set the viewport to be the entire window
    glViewport(0, 0, w, h);

    // Set the correct perspective.
    gluPerspective(45.0f, ratio, 0.1f, 100.0f);

    // Get Back to the Modelview
    glMatrixMode(GL_MODELVIEW);
}

void drawSnowMan() {

    glColor3f(1.0f, 1.0f, 1.0f);

// Draw Body
    glTranslatef(0.0f ,0.75f, 0.0f);
    glutSolidSphere(0.75f,20,20);

// Draw Head
    glTranslatef(0.0f, 1.0f, 0.0f);
    glutSolidSphere(0.25f,20,20);

// Draw Eyes
    glPushMatrix();
    glColor3f(0.0f,0.0f,0.0f);
    glTranslatef(0.05f, 0.10f, 0.18f);
    glutSolidSphere(0.05f,10,10);
    glTranslatef(-0.1f, 0.0f, 0.0f);
    glutSolidSphere(0.05f,10,10);
    glPopMatrix();

// Draw Nose
    glColor3f(1.0f, 0.5f , 0.5f);
    glRotatef(0.0f,1.0f, 0.0f, 0.0f);
    glutSolidCone(0.08f,0.5f,10,2);
}

void computePos(float deltaMove) {

    x += deltaMove * lx * 0.1f;
    z += deltaMove * lz * 0.1f;
}

void renderScene(void) {

    if (deltaMove)
        computePos(deltaMove);

    // Clear Color and Depth Buffers
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Reset transformations
    glLoadIdentity();
    // Set the camera
    gluLookAt(    x, 1.0f, z,
            x+lx, 1.0f,  z+lz,
            0.0f, 1.0f,  0.0f);

// Draw ground

    glColor3f(0.9f, 0.9f, 0.9f);
    glBegin(GL_QUADS);
        glVertex3f(-100.0f, 0.0f, -100.0f);
        glVertex3f(-100.0f, 0.0f,  100.0f);
        glVertex3f( 100.0f, 0.0f,  100.0f);
        glVertex3f( 100.0f, 0.0f, -100.0f);
    glEnd();

// Draw 36 SnowMen

    for(int i = -3; i < 3; i++)
        for(int j=-3; j < 3; j++) {
                     glPushMatrix();
                     glTranslatef(i*10.0,0,j * 10.0);
                     drawSnowMan();
                     glPopMatrix();
               }
        glutSwapBuffers();
} 

void processNormalKeys(unsigned char key, int xx, int yy) {     

        if (key == 27)
              exit(0);
} 

void pressKey(int key, int xx, int yy) {

       switch (key) {
             case GLUT_KEY_UP : deltaMove = 0.5f; break;
             case GLUT_KEY_DOWN : deltaMove = -0.5f; break;
       }
} 

void releaseKey(int key, int x, int y) {     

        switch (key) {
             case GLUT_KEY_UP :
             case GLUT_KEY_DOWN : deltaMove = 0;break;
        }
} 

void mouseMove(int x, int y) {     

         // this will only be true when the left button is down
         if (xOrigin >= 0) {

        // update deltaAngle
        deltaAngle = (x - xOrigin) * 0.001f;

        // update camera's direction
        lx = sin(angle + deltaAngle);
        lz = -cos(angle + deltaAngle);
    }
}

void mouseButton(int button, int state, int x, int y) {

    // only start motion if the left button is pressed
    if (button == GLUT_LEFT_BUTTON) {

        // when the button is released
        if (state == GLUT_UP) {
            angle += deltaAngle;
            xOrigin = -1;
        }
        else  {// state = GLUT_DOWN
            xOrigin = x;
        }
    }
}

int main(int argc, char **argv) {

    // init GLUT and create window
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGBA);
    glutInitWindowPosition(100,100);
    glutInitWindowSize(320,320);
    glutCreateWindow("Lighthouse3D - GLUT Tutorial");

    // register callbacks
    glutDisplayFunc(renderScene);
    glutReshapeFunc(changeSize);
    glutIdleFunc(renderScene);

    glutIgnoreKeyRepeat(1);
    glutKeyboardFunc(processNormalKeys);
    glutSpecialFunc(pressKey);
    glutSpecialUpFunc(releaseKey);

    // here are the two new functions
    glutMouseFunc(mouseButton);
    glutMotionFunc(mouseMove);

    // OpenGL init
    glEnable(GL_DEPTH_TEST);

    // enter GLUT event processing cycle
    glutMainLoop();

    return 1;
}