Week05打光

#include <GL/glut.h>

///打光0 : 宣告陣列,裡面是光的屬性值
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();
}
void motion(int x, int y)
{
    GLfloat light_position[] = {2.0f , 5.0f, -5.0f ,0.0f};
    light_position[0] = (x-150)/150.0 * 10;
    light_position[1] = -(y-150)/150.0 * 10;
    glLightfv(GL_LIGHT0, GL_POSITION, light_position);
    glutPostRedisplay();
}
static void resize(int width, int height)
{
    const float ar = (float) width/ (float)height;
    glViewport(0,0,width,height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(-ar,ar,-1,+1,-1,+1);
    glMatrixMode(GL_MODELVIEW);
    glLoadIdentity();
}
int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutCreateWindow("GLUT Shapes");
    glutDisplayFunc(display);
    glutMotionFunc(motion);
    glutReshapeFunc(resize);

    ///打光要3D的depth test
    glEnable(GL_DEPTH_TEST);

    ///打光1 : 開啟光線
    glEnable(GL_LIGHT0);
    glEnable(GL_NORMALIZE);
    glEnable(GL_COLOR_MATERIAL);
    glEnable(GL_LIGHTING);

    ///打光2 : 設定light值 (拿前面的陣列來用)
    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);

    ///打光 2-2 : 設定物體material
    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;
}




 const GLfloat light_position[] = { 2.0f, 5.0f, 5.0f, 0.0f }; 」
才不會背光