OpenGL学习十四：光照1

环境光：那些在环境中进行了充分的散射，无法辨别其方向的光，它似乎来自所有方向 散射光：来自某个方向。因此从它正面照射的表面，看起来更明亮以下。 镜面光：来自特定的方向，并且倾向于从表面的某个特定的方向放射 右图1:环境光 右图2：散射光 右图3：环境光与散射光的混合

创建光源 GLAPI void GLAPIENTRY glLightfv (GLenum light, GLenum pname, const GLfloat *params); light:对应光源，一般支持0~7号光源 pname:光照信息参数 GL_AMBIENT                    环境光 GL_DIFFUSE                    散射光 GL_SPECULAR                   镜面光 GL_POSITION                   光源位置 GL_CONSTANT_ATTENUATION       常量衰减因子 GL_LINEAR_ATTENUATION         线性衰减因子 GL_QUADRATIC_ATTENUATION      二次衰减因子 params：参数 对于GL_LIGHT0与其他光源默认值不一致GL_LIGHT0的环境光和散射光的默认值是（1,1,1,1）

光源位置 GLfloat light_position[] = { x,y,z,w}; glLightfv(GL_LIGHT2, GL_POSITION, light_position); w=0 为方向性光源 w!=0 为位置性光源 右图1：方向性光源（1,1,1，0） 右图2：位置性光源（1,1,1，1） 右图3：位置性光源（1,1,5，1）

光的衰减 衰减因子=1/k1+k2d+k3d*d d=光源与顶点之间的距离 k1=GL_CONSTANT_ATTENUATION k2=GL_LINEAR_ATTENUATION k3=GL_QUADRATIC_ATTENUATION 说明光的衰减特效要求光源位位置性光源 右图1：光源位置z=5,k1=1 右图2：光源位置z=5,k1=3

材料属性 GLAPI void GLAPIENTRY glMaterialfv (GLenum face, GLenum pname, const GLfloat *params); face:GL_FRONT,GL_BACK,GL_FRONT_AND_BACK pname:GL_AMBIENT                    材料的环境颜色       GL_DIFFUSE                    材料的散射颜色       GL_SPECULAR                   材料的镜面颜色       GL_SHININESS                  镜面指数       GL_AMBIENT_AND_DIFFUSE        材料的环境和散射颜色       GL_EMSSION                    材料的发射颜色       GL_COLOR_INDEXS               颜色索引 球1：   GLfloat mat_diffuse[] = { 0.1, 0.5, 0.8, 1.0 }; glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); 球2：    GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 };    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);    glMaterialfv(GL_FRONT, GL_SHININESS, 5); 球3：    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);    glMaterialfv(GL_FRONT, GL_SHININESS, 180) 球4：    GLfloat mat_emission[] = {0.3, 0.2, 0.2, 0.0};    glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse);    glMaterialfv(GL_FRONT, GL_EMISSION, mat_emission);

镜面反射 OPENGL允许我们在不存在反射光的情况下通过设置反射材料达到效果，并控制亮点的大小和亮点（GL_SHININESS）其实范围在【0~128】值越小亮度越大 亮点越小

发射颜色光 通过GL_EMISSION参数指定RGBA颜色值，可以使物体看上去好像发射这种颜色的光

材料颜色模式 glEnable(GL_COLOR_METERIAL) glcolor3f(0.5,0.2,0.6); glColorMeterial(GL_FRONT,GL_AMBIENT)     环境散射衰减光： #include "header.h" float roar=0.0f; GLfloat attentation[]={1.0}; GLfloat light_position[] = { 1.0, 1.0,1, 0}; void init(void) { GLfloat ambient[] = { 0.5, 0.5, 0.5, 0.0 }; GLfloat diffuse[] = { 1.0, 0.0, 0.0, 0.0 }; glClearColor (0.0, 0.0, 0.0, 0.0); glLightfv(GL_LIGHT1, GL_POSITION, light_position); glLightfv(GL_LIGHT1,GL_AMBIENT,ambient); glLightfv(GL_LIGHT2, GL_POSITION, light_position); glLightfv(GL_LIGHT2,GL_DIFFUSE,diffuse); glLightfv(GL_LIGHT3, GL_POSITION, light_position); glLightfv(GL_LIGHT3,GL_DIFFUSE,diffuse); glLightfv(GL_LIGHT3,GL_AMBIENT,ambient); glLightfv(GL_LIGHT1,GL_CONSTANT_ATTENUATION,attentation); glLightfv(GL_LIGHT2,GL_CONSTANT_ATTENUATION,attentation); glLightfv(GL_LIGHT3,GL_CONSTANT_ATTENUATION,attentation); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_DEPTH_TEST); } void display(void) { glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); glutSolidSphere(1.0, 16, 16); glFlush (); } void reshape (int w, int h) { glViewport (0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode (GL_PROJECTION); glLoadIdentity(); if (w <= h) glOrtho (-2.5, 2.5, -2.5*(GLfloat)h/(GLfloat)w, 2.5*(GLfloat)h/(GLfloat)w, -10.0, 10.0); else glOrtho (-2.5*(GLfloat)w/(GLfloat)h, 2.5*(GLfloat)w/(GLfloat)h, -2.5, 2.5, -10.0, 10.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void keyboard(unsigned char key, int x, int y) { switch (key) { case '1': glEnable(GL_LIGHTING); glEnable(GL_LIGHT1); glDisable(GL_LIGHT0); glDisable(GL_LIGHT2); glDisable(GL_LIGHT3); break; case '2': glEnable(GL_LIGHTING); glEnable(GL_LIGHT2); glDisable(GL_LIGHT0); glDisable(GL_LIGHT1); glDisable(GL_LIGHT3); break; case '3': glEnable(GL_LIGHTING); glEnable(GL_LIGHT3); glDisable(GL_LIGHT0); glDisable(GL_LIGHT2); glDisable(GL_LIGHT1); break; case '0': glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glDisable(GL_LIGHT1); glDisable(GL_LIGHT2); glDisable(GL_LIGHT3); break; case 'A': light_position[0]=1; light_position[1]=1; light_position[2]=1; light_position[3]=0; glLightfv(GL_LIGHT1, GL_POSITION, light_position); glLightfv(GL_LIGHT2, GL_POSITION, light_position); glLightfv(GL_LIGHT3, GL_POSITION, light_position); break; case 'S': light_position[0]=1; light_position[1]=1; light_position[2]=1; light_position[3]=1; glLightfv(GL_LIGHT1, GL_POSITION, light_position); glLightfv(GL_LIGHT2, GL_POSITION, light_position); glLightfv(GL_LIGHT3, GL_POSITION, light_position); break; case 'D': light_position[0]=1; light_position[1]=1; light_position[2]=5; light_position[3]=1; glLightfv(GL_LIGHT1, GL_POSITION, light_position); glLightfv(GL_LIGHT2, GL_POSITION, light_position); glLightfv(GL_LIGHT3, GL_POSITION, light_position); break; case 'Z': light_position[0]=1; light_position[1]=1; light_position[2]=5; light_position[3]=1; glLightfv(GL_LIGHT1, GL_POSITION, light_position); glLightfv(GL_LIGHT2, GL_POSITION, light_position); glLightfv(GL_LIGHT3, GL_POSITION, light_position); attentation[0]=1; glLightfv(GL_LIGHT1,GL_CONSTANT_ATTENUATION,attentation); glLightfv(GL_LIGHT2,GL_CONSTANT_ATTENUATION,attentation); glLightfv(GL_LIGHT3,GL_CONSTANT_ATTENUATION,attentation); break; case 'X': light_position[0]=1; light_position[1]=1; light_position[2]=5; light_position[3]=1; attentation[0]=3; glLightfv(GL_LIGHT1, GL_POSITION, light_position); glLightfv(GL_LIGHT2, GL_POSITION, light_position); glLightfv(GL_LIGHT3, GL_POSITION, light_position); glLightfv(GL_LIGHT1,GL_CONSTANT_ATTENUATION,attentation); glLightfv(GL_LIGHT2,GL_CONSTANT_ATTENUATION,attentation); glLightfv(GL_LIGHT3,GL_CONSTANT_ATTENUATION,attentation); break; } glutPostRedisplay(); } void rotate() { roar+=0.0001f; glutPostRedisplay(); } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowSize (500, 500); glutInitWindowPosition (100, 100); glutCreateWindow (argv[0]); init (); glutDisplayFunc(display); glutReshapeFunc(reshape); glutKeyboardFunc(keyboard); glutMainLoop(); return 0; }  移动光源 #include "header.h" static int spin = 0; void init(void) { glClearColor (0.0, 0.0, 0.0, 0.0); glShadeModel (GL_SMOOTH); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glEnable(GL_DEPTH_TEST); } void display(void) { GLfloat position[] = { 0.0, 0.0, 1.5, 1.0 }; glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix (); gluLookAt (0.0, 0.0, 5.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0); glPushMatrix (); glRotated ((GLdouble) spin, 1.0, 0.0, 0.0); glLightfv (GL_LIGHT0, GL_POSITION, position); glTranslated (0.0, 0.0, 1.5); glDisable (GL_LIGHTING); glColor3f (0.0, 1.0, 1.0); glutWireCube (0.1); glEnable (GL_LIGHTING); glPopMatrix (); glutSolidTorus (0.275, 0.85, 8, 15); glPopMatrix (); glFlush (); } void reshape (int w, int h) { glViewport (0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode (GL_PROJECTION); glLoadIdentity(); gluPerspective(40.0, (GLfloat) w/(GLfloat) h, 1.0, 20.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void mouse(int button, int state, int x, int y) { switch (button) { case GLUT_LEFT_BUTTON: if (state == GLUT_DOWN) { spin = (spin + 30) % 360; glutPostRedisplay(); } break; default: break; } } void keyboard(unsigned char key, int x, int y) { switch (key) { case 27: exit(0); break; } } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowSize (500, 500); glutInitWindowPosition (100, 100); glutCreateWindow (argv[0]); init (); glutDisplayFunc(display); glutReshapeFunc(reshape); glutMouseFunc(mouse); glutKeyboardFunc(keyboard); glutMainLoop(); return 0; }    光源材料 #include "header.h" void init(void) { GLfloat ambient[] = { 0.0, 0.0, 0.0, 1.0 }; GLfloat diffuse[] = { 1.0, 1.0, 1.0, 1.0 }; GLfloat position[] = { 0.0, 3.0, 2.0, 0.0 }; GLfloat lmodel_ambient[] = { 0.4, 0.4, 0.4, 1.0 }; GLfloat local_view[] = { 0.0 }; glClearColor(0.0, 0.1, 0.1, 0.0); glEnable(GL_DEPTH_TEST); glShadeModel(GL_SMOOTH); glLightfv(GL_LIGHT0, GL_AMBIENT, ambient); glLightfv(GL_LIGHT0, GL_DIFFUSE, diffuse); glLightfv(GL_LIGHT0, GL_POSITION, position); glLightModelfv(GL_LIGHT_MODEL_AMBIENT, lmodel_ambient); glLightModelfv(GL_LIGHT_MODEL_LOCAL_VIEWER, local_view); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); } void display(void) { GLfloat no_mat[] = { 0.0, 0.0, 0.0, 1.0 }; GLfloat mat_ambient[] = { 0.7, 0.7, 0.7, 1.0 }; GLfloat mat_ambient_color[] = { 0.8, 0.8, 0.2, 1.0 }; GLfloat mat_diffuse[] = { 0.1, 0.5, 0.8, 1.0 }; GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 }; GLfloat no_shininess[] = { 0.0 }; GLfloat low_shininess[] = { 5.0 }; GLfloat high_shininess[] = { 100.0 }; GLfloat mat_emission[] = {0.3, 0.2, 0.2, 0.0}; glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); glTranslatef (-3.75, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (-1.25, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, low_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (1.25, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (3.75, 3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, no_mat); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, mat_emission); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (-3.75, 0.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (-1.25, 0.0, 0.0); 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, low_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (1.25, 0.0, 0.0); 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); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (3.75, 0.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, mat_emission); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (-3.75, -3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient_color); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (-1.25, -3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient_color); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, low_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (1.25, -3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient_color); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialfv(GL_FRONT, GL_SHININESS, high_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, no_mat); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glPushMatrix(); glTranslatef (3.75, -3.0, 0.0); glMaterialfv(GL_FRONT, GL_AMBIENT, mat_ambient_color); glMaterialfv(GL_FRONT, GL_DIFFUSE, mat_diffuse); glMaterialfv(GL_FRONT, GL_SPECULAR, no_mat); glMaterialfv(GL_FRONT, GL_SHININESS, no_shininess); glMaterialfv(GL_FRONT, GL_EMISSION, mat_emission); glutSolidSphere(1.0, 16, 16); glPopMatrix(); glFlush(); } void reshape(int w, int h) { glViewport(0, 0, w, h); glMatrixMode(GL_PROJECTION); glLoadIdentity(); if (w <= (h * 2)) glOrtho (-6.0, 6.0, -3.0*((GLfloat)h*2)/(GLfloat)w, 3.0*((GLfloat)h*2)/(GLfloat)w, -10.0, 10.0); else glOrtho (-6.0*(GLfloat)w/((GLfloat)h*2), 6.0*(GLfloat)w/((GLfloat)h*2), -3.0, 3.0, -10.0, 10.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void keyboard(unsigned char key, int x, int y) { switch (key) { case 27: exit(0); break; } } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowSize (600, 450); glutCreateWindow(argv[0]); init(); glutReshapeFunc(reshape); glutDisplayFunc(display); glutKeyboardFunc (keyboard); glutMainLoop(); return 0; }  材料颜色模式 #include "header.h" GLfloat diffuseMaterial[4] = { 0.5, 0.5, 0.5, 1.0 }; void init(void) { GLfloat mat_specular[] = { 1.0, 1.0, 1.0, 1.0 }; GLfloat light_position[] = { 1.0, 1.0, 1.0, 0.0 }; glClearColor (0.0, 0.0, 0.0, 0.0); glShadeModel (GL_SMOOTH); glEnable(GL_DEPTH_TEST); glMaterialfv(GL_FRONT, GL_DIFFUSE, diffuseMaterial); glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular); glMaterialf(GL_FRONT, GL_SHININESS, 25.0); glLightfv(GL_LIGHT0, GL_POSITION, light_position); glEnable(GL_LIGHTING); glEnable(GL_LIGHT0); glColorMaterial(GL_FRONT, GL_DIFFUSE); glEnable(GL_COLOR_MATERIAL); } void display(void) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glutSolidSphere(1.0, 20, 16); glFlush (); } void reshape (int w, int h) { glViewport (0, 0, (GLsizei) w, (GLsizei) h); glMatrixMode (GL_PROJECTION); glLoadIdentity(); if (w <= h) glOrtho (-1.5, 1.5, -1.5*(GLfloat)h/(GLfloat)w, 1.5*(GLfloat)h/(GLfloat)w, -10.0, 10.0); else glOrtho (-1.5*(GLfloat)w/(GLfloat)h, 1.5*(GLfloat)w/(GLfloat)h, -1.5, 1.5, -10.0, 10.0); glMatrixMode(GL_MODELVIEW); glLoadIdentity(); } void mouse(int button, int state, int x, int y) { switch (button) { case GLUT_LEFT_BUTTON: if (state == GLUT_DOWN) { diffuseMaterial[0] += 0.1; if (diffuseMaterial[0] > 1.0) diffuseMaterial[0] = 0.0; glColor4fv(diffuseMaterial); glutPostRedisplay(); } break; case GLUT_MIDDLE_BUTTON: if (state == GLUT_DOWN) { diffuseMaterial[1] += 0.1; if (diffuseMaterial[1] > 1.0) diffuseMaterial[1] = 0.0; glColor4fv(diffuseMaterial); glutPostRedisplay(); } break; case GLUT_RIGHT_BUTTON: if (state == GLUT_DOWN) { diffuseMaterial[2] += 0.1; if (diffuseMaterial[2] > 1.0) diffuseMaterial[2] = 0.0; glColor4fv(diffuseMaterial); glutPostRedisplay(); } break; default: break; } } void keyboard(unsigned char key, int x, int y) { switch (key) { case 27: exit(0); break; } } int main(int argc, char** argv) { glutInit(&argc, argv); glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB | GLUT_DEPTH); glutInitWindowSize (500, 500); glutInitWindowPosition (100, 100); glutCreateWindow (argv[0]); init (); glutDisplayFunc(display); glutReshapeFunc(reshape); glutMouseFunc(mouse); glutKeyboardFunc(keyboard); glutMainLoop(); return 0; }