Week06 打光

Week06:打光

1.期中考題:
glPushMatrix();//push備份矩陣
    glTranslatef(x, y, z);//移動
    glRotatef(角度, x, y, z)//旋轉
    glScalef(x, y, z);//縮放
    glBegin(GL_POLYGON);//開始畫
        glNormal3f(nx, ny, nz);//法向量
        glTexCoord2f(tx, ty);//貼圖座標
        glColor3f(r, g, b);//色彩
        glVertex3f(x, y, z);//頂點
    glEnd();
glPopMatrix();//pop還原矩陣

作業一:

下載jsyeh/3dcg10網頁裡的windows、data和glut32.dll，開啟Light Material.exe,試著改變裡面的值

開啟後試玩

作業二:

將上次用的茶壺程式碼，加入light的程式碼，產生結果如下

程式碼:

#include <GL/glut.h>
const GLfloat light_ambient[]  = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f };

const GLfloat mat_ambient[]    = { 0.7f, 0.7f, 0.7f, 1.0f };
const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };
const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat high_shininess[] = { 100.0f };
void display()
{
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    glutSolidTeapot(0.3);
    glutSwapBuffers();
}
int main(int argc, char**argv)
{
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);//設定視窗模式
    glutCreateWindow("hello 3D");//叫出顯示圖案的視窗""裡為視窗名

    glutDisplayFunc(display);//呼叫void裡的函釋
    glClearColor(1,1,1,1);
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);
    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);
    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    glutMainLoop();

}

作業三:

調整light程式碼裡面的參數值，觀看其變化:

結果如下↓↓↓

產生了顏色的變化，還有陰影也有些許不同

作業四: 加入motion，讓光可以隨者滑鼠移動

程式碼:

#include <GL/glut.h>
#include <stdio.h>
const GLfloat light_ambient[]  = { 0.6f, 0.5f, 0.0f, 0.5f };
const GLfloat light_diffuse[]  = { 5.0f, 5.0f, 5.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 1.0f, 1.0f, 1.0f };
GLfloat light_position[] = { 1.0f, 1.0f, -5.0f, 10.0f };

const GLfloat mat_ambient[]    = { 0.5f, 0.5f, 0.7f, 1.0f };
const GLfloat mat_diffuse[]    = { 0.8f, 0.8f, 0.8f, 1.0f };
const GLfloat mat_specular[]   = { 1.0f, 1.0f, 1.0f, 1.0f };
const GLfloat high_shininess[] = { 100.0f };
void display()
{
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    glPushMatrix();//備份Matrix (Matrix裡有translate, rotate, scale的量值)
        glColor3f(1,1,1);
        glutSolidTeapot(0.3);
    glPopMatrix();//還原Matrix(回到剛剛push的樣子)
    glutSwapBuffers();
}
void motion(int x,int y)
{
    light_position[0]=(x-150)/150.0;
    light_position[1]=-(y-150)/150.0;
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);//重設光位置
    glutPostRedisplay();//請glut送出Re display顯示
    printf("%f %f\n",light_position[0],light_position[1]);
}
int main(int argc, char**argv)
{
    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);//設定視窗模式
    glutCreateWindow("hello 3D");//叫出顯示圖案的視窗""裡為視窗名

    glutDisplayFunc(display);//呼叫void裡的函釋
    glutMotionFunc(motion);
    glClearColor(1,1,1,1);
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);

    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);
    glEnable(GL_LIGHTING);

    glLightfv(GL_LIGHT0, GL_AMBIENT,  light_ambient);
    glLightfv(GL_LIGHT0, GL_DIFFUSE,  light_diffuse);
    glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);

    glMaterialfv(GL_FRONT, GL_AMBIENT,   mat_ambient);
    glMaterialfv(GL_FRONT, GL_DIFFUSE,   mat_diffuse);
    glMaterialfv(GL_FRONT, GL_SPECULAR,  mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess);

    glutMainLoop();

}

結果↓↓↓