【图形学】OpenGL基本光照-CFANZ编程社区

【图形学】OpenGL基本光照

1.绘制目标
2.核心代码
3.运行结果

1.绘制目标

设置两个点光源，点光源的颜色属性及位置可以自由设置
立方体的材质属性：

shininess: 50
diffuse以及ambient都设为：0.5,0.5,0.5,1.0
specular设为: 1.0,1.0,1.0,1.0

支持键盘操作:

x:绕x轴旋转;
y:绕y轴旋转;
z:绕z轴旋转·
r:复位
设置按键分别响应对光源0和光源1的开启和关闭

2.核心代码

#define GLEW_STATIC
#define FREEGLUT_STATIC

#include <GL/glew.h>
#include <GL/freeglut.h>
#include <GL/glext.h>

#include <string>
#include <iostream>
using namespace std;

float XROT(0.f), YROT(0.f), ZROT(0.f); float view(60);
float nul(1.0);
//改变图形大小 
bool flag_0 = true, flag_1 = true;

//光源0属性 
float light_ambient_color0[] = { 0.f, 1.f, 0.f, 1.f };
float light_diffuse_and_specular0[] = { 1.f, 1.f, 1.f, 1.f };
float light_position0[] = { 600.f, 600.f, 600.f, 1.f };
//光源1属性 
float light_ambient_color1[] = { 1.f, 0.f, 0.f, 1.f };
float light_diffuse_and_specular1[] = { 1.f, 1.f, 1.f, 1.f };
float light_position1[] = { 0.f, 0.f, 600.f, 1.f };
//物体属性，要求的立方体材质属性 
float material_ambient_and_diffuse[] = { 0.5f, 0.5f, 0.5f, 1.f };
float material_specular[] = { 1.f, 1.f, 1.f, 1.f };
float material_shininess[] = { 50.f };

float global_ambient[] = { 0.25f, 0.25f, 0.25f, 1.f };


GLfloat CUBE_VERTICES1[8][3] = 
{
  100, 100, 100,
  -100, 100, 100,
  -100, -100, 100,
  100, -100, 100,
  100, -100, -100,
  100, 100, -100,
  -100, 100, -100,
  -100, 100, 100,
};

GLfloat CUBE_VERTICES2[8][3] = 
{
  -100, -100, -100,
  -100, -100, 100,
  100, -100, 100,
  100, -100, -100,
  100, 100, -100,
  -100, 100, -100,
  -100, 100, 100,
  -100, -100, 100
};

void init() 
{
  glClearColor(0.0, 0.0, 0.0, 0.0);

  glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);

  glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient_color0);
  glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse_and_specular0);
  glLightfv(GL_LIGHT0, GL_SPECULAR, light_diffuse_and_specular0);
  glLightfv(GL_LIGHT0, GL_POSITION, light_position0);

  glLightfv(GL_LIGHT1, GL_AMBIENT, light_ambient_color1);
  glLightfv(GL_LIGHT1, GL_DIFFUSE, light_diffuse_and_specular1);
  glLightfv(GL_LIGHT1, GL_SPECULAR, light_diffuse_and_specular1);
  glLightfv(GL_LIGHT1, GL_POSITION, light_position1);

  glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, material_ambient_and_diffuse);
  glMaterialfv(GL_FRONT, GL_SPECULAR, material_specular);
  glMaterialfv(GL_FRONT, GL_SHININESS, material_shininess);

  glLightModelfv(GL_LIGHT_MODEL_AMBIENT, global_ambient);
  glLightModeli(GL_LIGHT_MODEL_LOCAL_VIEWER, GL_TRUE);


  glEnable(GL_DEPTH_TEST);
  glEnable(GL_TEXTURE_2D);
  glEnable(GL_LIGHTING);
  glEnable(GL_LIGHT0);  glEnable(GL_LIGHT1);
  //glEnable(GL_COLOR_MATERIAL);//颜色追踪
}

void drawCube() 
{//绘制立方体 

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glPushMatrix();

  //绘制坐标系  
  glColor3f(1.0, 0.0, 1.0);

  glBegin(GL_TRIANGLE_FAN);
  glNormal3f(1.f, 1.f, 1.f); glVertex3fv(CUBE_VERTICES1[0]);
  glNormal3f(-1.f, 1.f, 1.f); glVertex3fv(CUBE_VERTICES1[1]);
  glNormal3f(-1.f, -1.f, 1.f); glVertex3fv(CUBE_VERTICES1[2]);
  glNormal3f(1.f, -1.f, 1.f); glVertex3fv(CUBE_VERTICES1[3]);
  glNormal3f(1.f, -1.f, -1.f); glVertex3fv(CUBE_VERTICES1[4]);
  glNormal3f(1.f, 1.f, -1.f); glVertex3fv(CUBE_VERTICES1[5]);
  glNormal3f(-1.f, 1.f, -1.f); glVertex3fv(CUBE_VERTICES1[6]);
  glNormal3f(-1.f, 1.f, 1.f); glVertex3fv(CUBE_VERTICES1[7]);
  glEnd();

  glBegin(GL_TRIANGLE_FAN);
  glNormal3f(-1.f, -1.f, -1.f); glVertex3fv(CUBE_VERTICES2[0]);
  glNormal3f(-1.f, -1.f, 1.f); glVertex3fv(CUBE_VERTICES2[1]);
  glNormal3f(1.f, -1.f, 1.f); glVertex3fv(CUBE_VERTICES2[2]);
  glNormal3f(1.f, -1.f, -1.f); glVertex3fv(CUBE_VERTICES2[3]);
  glNormal3f(1.f, 1.f, -1.f); glVertex3fv(CUBE_VERTICES2[4]);
  glNormal3f(-1.f, 1.f, -1.f); glVertex3fv(CUBE_VERTICES2[5]);
  glNormal3f(-1.f, 1.f, 1.f); glVertex3fv(CUBE_VERTICES2[6]);
  glNormal3f(-1.f, -1.f, 1.f); glVertex3fv(CUBE_VERTICES2[7]);
  glEnd();

}

void display() 
{
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();

  gluLookAt(0.0, 0.0, 600.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);

  glRotatef(ZROT, 0.f, 0.f, 1.f);
  glRotatef(YROT, 0.f, 1.f, 0.f);
  glRotatef(XROT, 1.f, 0.f, 0.f);

  glScalef(nul, nul, nul);

  drawCube();

  glutSwapBuffers();
  glFlush();
}


void keyboard(unsigned char key, int x, int y) 
{
  switch (key) {
  case 'x':
    XROT += 1;
    glutPostRedisplay();
    break;
  case 'y':
    YROT += 1;
    glutPostRedisplay();
    break;
  case 'z':
    ZROT += 1;
    glutPostRedisplay();
    break;
  case 'r':
    XROT = 0;
    YROT = 0;
    ZROT = 0;
    glutPostRedisplay();
    break;
  case 'a':
    nul += 0.2;
    glutPostRedisplay();
    break;
  case 'd':
    nul -= 0.2;
    glutPostRedisplay();
    break;
  case '0':
    //控制光源0是否存在   
    if (flag_0)
    {
      glDisable(GL_LIGHT0);
      flag_0 = false;
    }
    else
    {
      flag_0 = true;
      glEnable(GL_LIGHT0);
    }
    glutPostRedisplay();
    break;
  case '1':
    //控制光源1是否存在  
    if (flag_1)
    {
      flag_1 = false;
      glDisable(GL_LIGHT1);
    }
    else
    {
      flag_1 = true;
      glEnable(GL_LIGHT1);
    }
    glutPostRedisplay();
    break;
  default:
    break;
  }
}

void reshape(int w, int h)
{
  glViewport(0, 0, w, h);
  glMatrixMode(GL_PROJECTION);
  //加载投影矩阵  
  glLoadIdentity();
  gluPerspective(view, float(w) / float(h), 10.0, 1000.0);

}

int main(int argc, char** argv)
{
  glutInit(&argc, argv);

  glutInitContextVersion(3, 2);
  glutInitContextProfile(GLUT_COMPATIBILITY_PROFILE);

  glutInitDisplayMode(GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH);
  glutInitWindowPosition(100, 100);
  glutInitWindowSize(800, 600);
  glutCreateWindow("LiCube");

  glutDisplayFunc(display);
  glutReshapeFunc(reshape);
  glutKeyboardFunc(keyboard);

  init();

  glutMainLoop();

  return 0;
}