week15

glFrestum 是gl 系列

gluPerspective 是glu系列

static void resize(int width, int height)
{
    const float ar = (float) width / (float) height;
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    ///glFrustum(-ar, ar, -1.0, 1.0, 2.0, 100.0);
    gluPerspective(60,ar,2,100); ///TODO改用gluPerspective
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ;
}

太大了 所以將 glOrtho都乘上 2

static void resize(int width, int height)
{
    const float ar = (float) width / (float) height;
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    ///glFrustum(-ar, ar, -1.0, 1.0, 2.0, 100.0);
    ///gluPerspective(60,ar,2,100);///TODO改用gluPerspective
    glOrtho(-2.4*2,+2.4*2,-1.2*2,+1.2*2,-6*2,+6*2);
    ///依照剛剛放東西的範圍,大一點,不要用預設的-1,+1 
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ;
}

///我們要大改程式!!
#include <GL/glut.h>
static void resize(int width, int height) ///留下resize()
{
    const float ar = (float) width / (float) height;
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(60, ar, 0.01, 1000); ///我們改了它!!!
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ; ///原本只有2行, 沒有運鏡
    ///需要運鏡時, 要加上第3行 gluLookAt()
}
static void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glutSolidTeapot(0.3);
    glutSwapBuffers();
}
#include <math.h>
float eyeX=0, eyeY=0, eyeZ=1;///TODO
float angle=0;
static void idle(void)
{
    eyeX=sin(angle);
    eyeZ=cos(angle);
    angle+=0.01;
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity() ; ///原本只有2行, 沒有運鏡
    gluLookAt(eyeX, eyeY, eyeZ, 0,0,0, 0,1,0); ///需要運鏡時, 要加上第3行 gluLookAt()
    glutPostRedisplay();
}
void motion(int x, int y)
{
    eyeY = (y-240)/240.0;
}
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 };
/* Program entry point */
int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitWindowSize(640,480);
    glutInitWindowPosition(10,10);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutCreateWindow("GLUT Shapes");
    glutReshapeFunc(resize);
    glutDisplayFunc(display);
    glutIdleFunc(idle);
    glutMotionFunc(motion); ///TODO 控制 eyeY
    glClearColor(1,1,1,1);
    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();
    return EXIT_SUCCESS;
}