[轉]OpenGL 通過VBO實現頂點數組繪製頂點

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#include "stdlib.h"  #include <OpenGL/glext.h>  #include <GLUT/GLUT.h>    #define BUFFER_OFFSET(bytes) ((GLubyte*) NULL + (bytes))  #define VERTICES 0  #define INDICES 1  #define NUM_BUFFERS 6  GLuint buffers[NUM_BUFFERS];    GLfloat vertices[][3] = {      {-1.0f,-1.0f,-1.0f},      {1.0f,-1.0f,-1.0f},      {1.0f,1.0f,-1.0f},      {-1.0f,1.0f,-1.0f},      {-1.0f,-1.0f,1.0f},      {1.0f,-1.0f,1.0f},      {1.0f,1.0f,1.0f},      {-1.0f,1.0f,1.0f}  };  GLubyte indices[][4] = {      {0,1,2,3},      {4,7,6,5},      {0,4,5,1},      {3,2,6,7},      {0,3,7,4},      {1,5,6,2}  };    GLfloat* bdata;    void changeSize(int w, int h)  {      glViewport(0,0,(GLsizei)w,(GLsizei)h);      glMatrixMode(GL_PROJECTION);      glLoadIdentity();      gluPerspective(45.0,(double)w/(double)h,0.01,30);      glMatrixMode(GL_MODELVIEW);      glLoadIdentity();  }    void keyDown(unsigned char key, int x, int y)  {      switch (key)      {          case‘b‘:              bdata = (GLfloat*)glMapBuffer(GL_ARRAY_BUFFER,GL_READ_WRITE);              for (int i =0; i <24; i ++)              {                  *(bdata + i) *=1.1f;              }              glUnmapBuffer(GL_ARRAY_BUFFER);              glutPostRedisplay();              break;      }  }    void mouse(int button, int state, int x, int y)  {        }  void display(void)  {      glLoadIdentity();      glTranslatef(0.0f,0.0f,-5.0f);      glRotatef(30.0f,1.0f,1.0f,0.0f);       // 6. 繪製， 這個地方注意的是最後一個參數，這個與普通的非VBO最大的不同就在這裡      glDrawElements(GL_QUADS,24,GL_UNSIGNED_BYTE,BUFFER_OFFSET(0));      //glDrawArrays(GL_TRIANGLE_FAN, 0, 8);      glutSwapBuffers();  }    void init(void)  {      glClearColor(0.0f,0.0f,0.0f,0.0f);      glShadeModel(GL_FLAT);      glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);        //1.  建立緩衝區對象，系統會自動建立緩動區標示符放入到buffers中，可以使用glIsBuffer()函數，判斷一個標示符是否被使用      glGenBuffers(NUM_BUFFERS ,buffers);      //2.  啟用緩衝區對象，綁定緩衝區對象表示未來選擇的操作將影響哪個緩衝區。 如果要金融緩衝區對象，可以用0來作為緩衝區對象的標示符， 第一個參數target可以為GL_ARRAY_BUFFER,GL_ELEMENT_ARRAY_FUFFER      glBindBuffer(GL_ARRAY_BUFFER,buffers[VERTICES]);      //3. 用資料分配和初始化緩衝區對象      glBufferData(GL_ARRAY_BUFFER,sizeof(vertices),vertices,GL_DYNAMIC_DRAW);      //4. 指定相對於緩衝區起始位置的位移量      glVertexPointer(3,GL_FLOAT,0,BUFFER_OFFSET(0));      //5.一定不要忘記啟動      glEnableClientState(GL_VERTEX_ARRAY);            glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,buffers[INDICES]);      glBufferData(GL_ELEMENT_ARRAY_BUFFER,sizeof(indices),indices,GL_STATIC_DRAW);  }    int main(int argc, char* argv[])  {      glutInit(&argc, argv);      glutInitDisplayMode(GL_DOUBLE | GLUT_RGBA | GLUT_DEPTH);      glutInitWindowSize(512, 512);      glutCreateWindow("Buffer Demo");       init();      glutReshapeFunc(changeSize);      glutMouseFunc(mouse);      glutKeyboardFunc(keyDown);      glutDisplayFunc(display);           glutMainLoop();      return 0;  } 

原文連結：OpenGL 通過VBO實現頂點數組繪製頂點

[轉]OpenGL 通過VBO實現頂點數組繪製頂點