2024年4月11日 星期四

week08電腦圖學

本週主題: OBJ模型 

課本範例
1.課本範例https://jsyeh.org/3dcg10/ 
2.下載source、data、win32=>解壓縮
3.分析data裡的檔案AI.mtl
   =>用Notepad++打開
   =>裡面Ka、Kd
   =>AI.obj 裡面很多內容,#代表註解
   =>v代表頂點,後面有座標x, y, z
   =>f代表面face或facet後面有頂點的編號
   =>g代表group


week08-1_glm_gundam
1.建立新專案week08-1_glm_gundam
2.要把source.zip裡面的glm.h、glm.c都copy到week08-1_glm_gundam專案資料夾,把glm.c改名成glm.cpp
3.在week08-1_glm_gundam專案裡,按右鍵 Add Files把glm.cpp加入專案
4.把main.cpp裡,改成11行程式
5.新增資料夾data,把Gundam模型(Gundam.mtl、Gundam.obj)加入專案目錄裡的data資料夾
6.不能讀=>要把專案的工作執行目錄換成小數點=>專案按右鍵,選properties,出現下圖後選Build targets,把Execution working dir改成小數點
7.main.cpp再加入讀模型的程式碼

程式碼:
```cpp
#include <GL/glut.h>
#include "glm.h"
GLMmodel * pmodel = NULL;
void drawmodel(void)
{
    if (!pmodel) {
pmodel = glmReadOBJ("data/Gundam.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();
    glutSwapBuffers();
}
int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);
    glutCreateWindow("week08 gundam");
    glutDisplayFunc(display);

    glutMainLoop();
}
```

執行畫面:


week08-2_glm_gundam_opencv_texture
1.安裝OpenCV 2.1 記得要Add PATH,不要改目錄
2.關閉重開CodeBlocks(才會把PATH設定好)
3.建立專案week08-2_glm_gundam_opencv_texture
4.重做剛剛的 glm.h、glm.cpp放到目錄裡,把Gundam.obj、Gundam.mtl及新的Diffuse.jpg都放到專案的data目錄裡
5.在專案裡,按右鍵Add file把glm.cpp加入專案
6.不能讀=>要把專案的工作執行目錄換成小數點
7.把桌面\freeglut\bin\freeglut.dll複製到專案目錄裡
8.貼上week08-1_glm_gundam,再加新程式
9.Setting-Compiler要加入OpenCV相關的3個設定
     =>compiler的include要加入C:\OpenCV2.1\include
     =>linker的lib要加入cv210、cxcore210、highgui210
10.改程式碼glmDraw(pmodel, GLM_SMOOTH | GLM_MATERIAL);加上|GLM_TEXTURE
     =>glmDraw(pmodel, GLM_SMOOTH | GLM_MATERIAL|GLM_TEXTURE);

程式碼:
```cpp
#include <opencv/highgui.h> 
#include <opencv/cv.h>
#include <GL/glut.h>
int myTexture(char * filename)
{
    IplImage * img = cvLoadImage(filename);
    cvCvtColor(img,img, CV_BGR2RGB); 
    glEnable(GL_TEXTURE_2D);
    GLuint id; 
    glGenTextures(1, &id);
    glBindTexture(GL_TEXTURE_2D, id);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); 
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); 
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img->width, img->height, 0, GL_RGB, GL_UNSIGNED_BYTE, img->imageData);
    return id;
}
#include <GL/glut.h>
#include "glm.h"
GLMmodel * pmodel = NULL;
void drawmodel(void)
{
    if (!pmodel) {
pmodel = glmReadOBJ("data/Gundam.obj");
if (!pmodel) exit(0);
glmUnitize(pmodel);
glmFacetNormals(pmodel);
glmVertexNormals(pmodel, 90.0);
    }
    glmDraw(pmodel, GLM_SMOOTH | GLM_MATERIAL|GLM_TEXTURE);
}
void display()
{
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    drawmodel();
    glutSwapBuffers();
}
int main(int argc, char *argv[])
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_DOUBLE | GLUT_DEPTH);
    glutCreateWindow("week08 gundam");
    glutDisplayFunc(display);
    myTexture("data/Diffuse.jpg");
    glutMainLoop();
}
```

執行畫面:


week08-3_glm_gundam_opencv_texture_lighting
1.建立新專案week08-3_glm_gundam_opencv_texture_lighting
2.在專案目錄裡,加入data目錄,裡面有Gundam.obj、Gundam.mtl、Diffuse.jpg三個檔案
3.在專案目錄裡,加入glm.h、glm.cpp、freeglut.dll三個檔案
4.專案設定,把專案的工作執行目錄換成小數點
5.在main.cpp裡,貼入week08-2_glm_gundam_opencv_texture程式碼
6.再加入打光lighting程式碼8行陣列及12+2行的函式呼叫

程式碼:
```cpp
///先把 week08-1_glm_gundam 的程式貼上來
///等一下, 要再加貼圖的 18行程式
#include <opencv/highgui.h> ///使用 OpenCV 2.1 比較簡單, 只要用 High GUI 即可
#include <opencv/cv.h>
#include <GL/glut.h>
int myTexture(char * filename)
{
    IplImage * img = cvLoadImage(filename); ///OpenCV讀圖
    cvCvtColor(img,img, CV_BGR2RGB); ///OpenCV轉色彩 (需要cv.h)
    glEnable(GL_TEXTURE_2D); ///1. 開啟貼圖功能
    GLuint id; ///準備一個 unsigned int 整數, 叫 貼圖ID
    glGenTextures(1, &id); /// 產生Generate 貼圖ID
    glBindTexture(GL_TEXTURE_2D, id); ///綁定bind 貼圖ID
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); /// 貼圖參數, 超過包裝的範圖T, 就重覆貼圖
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); /// 貼圖參數, 超過包裝的範圖S, 就重覆貼圖
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); /// 貼圖參數, 放大時的內插, 用最近點
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); /// 貼圖參數, 縮小時的內插, 用最近點
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img->width, img->height, 0, GL_RGB, GL_UNSIGNED_BYTE, img->imageData);
    return id;
}
#include <GL/glut.h>
#include "glm.h"
GLMmodel * pmodel = NULL;
void drawmodel(void)
{
    if (!pmodel) {
pmodel = glmReadOBJ("data/Gundam.obj");
if (!pmodel) exit(0);
glmUnitize(pmodel);
glmFacetNormals(pmodel);
glmVertexNormals(pmodel, 90.0);
    }

    glmDraw(pmodel, GLM_SMOOTH | GLM_TEXTURE);
}
float angle = 0; ///加這行, 讓它轉動
void display()
{
    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT);
    glPushMatrix(); ///加這行, 讓它轉動
        glRotatef(angle++, 0, 1, 0); ///加這行, 讓它轉動
        drawmodel(); //glutSolidTeapot( 0.3 );
    glPopMatrix(); ///加這行, 讓它轉動
    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 };///加這行, 讓它轉動

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("week08 Gundam");
    glutDisplayFunc(display);
    glutIdleFunc(display); ///加這行, 讓它轉動

    myTexture("data/Diffuse.jpg");

    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();
}
```

執行畫面:(會轉圈)



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