本週主題：
(1) OpenGL必背10函式
(2) 主題：打光Lighting
(3) glNormal3f(nx,ny,nz); 打光的向量
(4) 3D模型
教材地點：
https://jsyeh.org/3dcg10/
下載資料：
a. 05/04 Examples:[data]
b. 05/04 Examples:[win32]
c. 05/04 Examples:[source]
期中考試內容：
https://jsyeh.org/gl/
宣告
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 };
函式
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);
2. GLUT程式1：茶壺打光
將剛才找到的程式碼(綠色處)貼在原始10行程式碼的對應位置，並且改變光源位置(黃色處)，讓茶壺不要背光
#include <GL/glut.h>
void display(){
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glutSolidTeapot(0.5);
glutSwapBuffers();
}
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 };
int main(int argc, char *argv[]){
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);
glutCreateWindow("week06 lighting");
glutDisplayFunc(display);
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. 範例程式碼：將data資料夾拉進windows(不要解壓縮)
windows→Light & Material
windows→Light & Material
4. GLUT程式2：茶壺打光並繞y軸旋轉
#include <GL/glut.h>
float angle=0;
void display(){
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
glPushMatrix();
glRotated(angle++,0,1,0);
glBegin(GL_POLYGON);
glNormal3f(0,0,1); ///打光的法向量
glVertex2f(-1,-1);
glVertex2f(+1,-1);
glVertex2f(+1,+1);
glVertex2f(-1,+1);
glEnd();
glutSolidTeapot(0.5);
glPopMatrix();
glutSwapBuffers();
}
const GLfloat light_ambient[] = { 0.0f, 0.0f, 0.0f, 1.0f };
const GLfloat light_diffuse[] = { 0.6f, 1.0f, 1.0f, 1.0f }; ///顏色
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 };
int main(int argc, char *argv[]){
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);
glutCreateWindow("week06 lighting");
glutIdleFunc(display);
glutDisplayFunc(display);
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();
}
5. 範例程式碼：將data資料夾拉進windows(不要解壓縮)
source→glm.c、glm.h、transformation.c
source→glm.c、glm.h、transformation.c
a.研究transformation.c程式內容，找到下面幾行
a-1
#include "glm.h"
#include "glm.h"
a-2
GLMmodel* pmodel = NULL;
a-3
void drawmodel(void){
if (!pmodel) {
pmodel = glmReadOBJ("data/porsche.obj");
if (!pmodel) exit(0);
glmUnitize(pmodel);
glmFacetNormals(pmodel);
glmVertexNormals(pmodel, 90.0);
}
glmDraw(pmodel, GLM_SMOOTH | GLM_MATERIAL);
}
b.把 glm.h 放到 ...\week06-3_glm_obj_model 目錄中
把 glm.c 放到 ...\week06-3_glm_obj_model 目錄中，並改名glm.cpp
c.在專案裡右鍵Add Files, 加入glm.cpp檔
d.data資料夾放到...\freeglut\bin
6. GLUT程式3：根據上一點修改程式碼並調整相關設定
#include <GL/glut.h>
#include "glm.h"
GLMmodel* pmodel = NULL;
void drawmodel(void){
if (!pmodel){
pmodel = glmReadOBJ("data/porsche.obj");
if (!pmodel) exit(0);
glmUnitize(pmodel);
glmFacetNormals(pmodel);
glmVertexNormals(pmodel, 90.0);
}
glmDraw(pmodel, GLM_SMOOTH | GLM_MATERIAL);
}
void display(){
glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
drawmodel();//glutSolidTeapot(0.5);
glutSwapBuffers();
}
int main(int argc, char *argv[]){
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE|GLUT_DEPTH);
glutCreateWindow("week06 lighting");
glutDisplayFunc(display);
glutMainLoop();
}
Look now
I’m on the top of your world, top of your world
My darling
Here I come, I yell
And take a leap to Hell
Swirling wind sings for our reunion
And nine point eight is my acceleration
Take me to where our souls may live in peace
Our brand new commencement
----Nine Point Eight , Mili
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