Week06

1.期中考題
   glPushMatrix(); //push備份矩陣
   glTranslatef(x, y, z);  //移動
   glRotatef(angle, 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

2.課堂教材LightMaterial.exe
   左上 model
   左下 material
   右 調整屬性
   
  實作: 將茶壺變3D

打開code blocks新增專案GLUT
#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);
    glutCreateWindow("hello 3D");
    glutDisplayFunc(display);
    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();
}

3.調整打光
   教材中的Illumination and Shading PDF檔可以做參考
   
   

4.可以調整光的方向
#include <GL/glut.h>
const GLfloat light_ambient[]  = { 0.0f, 1.0f, 0.0f, 0.0f };
const GLfloat light_diffuse[]  = { 1.0f, 1.0f, 0.0f, 1.0f };
const GLfloat light_specular[] = { 1.0f, 0.0f, 0.0f, 0.0f };
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, 0.85f, 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();
}
#include <stdio.h>
void motion(int x, int y)  ///滑鼠按下後的motion函式
{
    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重新 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);
    glutCreateWindow("hello 3D");
    glutDisplayFunc(display);
    glutMotionFunc(motion); ///加入motion函式

    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();

}