演示如果通过glew使用opengl的新特性

1 安装msys：下载地址;在windows下提供类似linux的命令环境.

2 下载glew代码、解压到d:glew-xxx.

3 编译

1)启动msys.

2)进入d:glew-xxx.   使用命令：cd /d/glew-xxx

3)编译：（要求已预先安装了mingw或tdw-mingw64）

 make

4)得到编译后的.a文件和.dll文件.

4 将include下GL拷贝到(tdw-mingw64)include

将lib文件拷贝到(tdw-mingw64)lib

5 建立工作文件夹，如：d:workdir

6 拷贝4步中得到的dll到d:workdir

7 下载freeglut for mingw（freeglut-MinGW-3.0.0-1.mp）并安装include和lib文件，拷贝其目录下的freeglut.dll到d:workdir(注意不是freeglut32.dll).

8 编写测试程序，如vf_demo.cpp

9 编译c程序，命令：

 g++ -o vf_demo vf_demo.cpp -lglew32.dll -lopengl32 -lfreeglut -lglu32

10 运行程序：

 vf_demo

效果为：

附上三个程序文件：

vf_demo.cpp

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <gl/glew.h>

#include <gl/glut.h>

float window_width = 600;

float window_height = 600;

GLfloat xRot  =  0.0f;

GLfloat yRot  =  0.0f;

GLfloat xTrans  =  0;

GLfloat yTrans  =  0;

GLfloat zTrans  =  -32.0;

int ox;

int oy;

int buttonState;

GLfloat xRotLength  =  0.0f;

GLfloat yRotLength  =  0.0f;

GLfloat LightAmbient[] =  { 1.0f, 1.0f, 1.0f, 1.0f };

GLfloat LightDiffuse[] =  { 1.0f, 1.0f, 1.0f, 1.0f };

GLfloat LightPosition[] =  { 20.0f, 20.0f, 20.0f, 1.0f };

GLuint f;

GLuint v;

GLuint p;

void draw_box(float ox, float oy, float oz, float width, float height, float length)

{

   glLineWidth(1.0f);

   glBegin(GL_LINES);  

       glColor3f(1.0f, 0.0f, 0.0f);

//1

       glVertex3f(ox, oy, oz);

       glVertex3f(ox+width, oy, oz);

//2

       glVertex3f(ox, oy, oz);

       glVertex3f(ox, oy+height, oz);

//3

       glVertex3f(ox, oy, oz);

       glVertex3f(ox, oy, oz+length);

//4

       glVertex3f(ox+width, oy, oz);

       glVertex3f(ox+width, oy+height, oz);

//5

       glVertex3f(ox+width, oy+height, oz);

       glVertex3f(ox, oy+height, oz);

//6

       glVertex3f(ox, oy+height, oz+length);

       glVertex3f(ox, oy, oz+length);

//7

       glVertex3f(ox, oy+height, oz+length);

       glVertex3f(ox, oy+height, oz);

//8

       glVertex3f(ox+width, oy, oz);

       glVertex3f(ox+width, oy, oz+length);

//9

       glVertex3f(ox, oy, oz+length);

       glVertex3f(ox+width, oy, oz+length);

//10

       glVertex3f(ox+width, oy+height, oz);

       glVertex3f(ox+width, oy+height, oz+length);

//11

       glVertex3f(ox+width, oy+height, oz+length);

       glVertex3f(ox+width, oy, oz+length);

//12

       glVertex3f(ox, oy+height, oz+length);

       glVertex3f(ox+width, oy+height, oz+length);

   glEnd();

}

void set_shaders()

{

char *vs = NULL;

char *fs = NULL;

vs = (char *)malloc(sizeof(char)*10000);

fs = (char *)malloc(sizeof(char)*10000);

memset(vs, 0, sizeof(char)*10000);

memset(fs, 0, sizeof(char)*10000);

FILE *fp;

char c;

int count;

fp = fopen("checkerboard.vs", "r");

count = 0;

while((c = fgetc(fp)) !=  EOF)

{

vs[count] = c;

count++;

}

fclose(fp);

fp = fopen("checkerboard.fs", "r");

count = 0;

while((c = fgetc(fp)) !=  EOF)

{

fs[count] = c;

count++;

}

fclose(fp);

printf("Shaders loaded...n");

v = glCreateShader(GL_VERTEX_SHADER);

f = glCreateShader(GL_FRAGMENT_SHADER);

const char *vv;

const char *ff;

vv = vs;

ff = fs;

glShaderSource(v, 1, &vv, NULL);

glShaderSource(f, 1, &ff, NULL);

int success;

glCompileShader(v);

glGetShaderiv(v, GL_COMPILE_STATUS, &success);

if(!success)

{

char info_log[5000];

glGetShaderInfoLog(v, 5000, NULL, info_log);

printf("Error in vertex shader compilation!n");

//printf("Info Log: %sn", info_log);

}

glCompileShader(f);

glGetShaderiv(f, GL_COMPILE_STATUS, &success);

if(!success)

{

char info_log[5000];

glGetShaderInfoLog(f, 5000, NULL, info_log);

printf("Error in fragment shader compilation!n");

//printf("Info Log: %sn", info_log);

}

p = glCreateProgram();

glAttachShader(p, v);

glAttachShader(p, f);

glLinkProgram(p);

glUseProgram(p);

free(vs);

free(fs);

}

void init()

{

glShadeModel(GL_SMOOTH);

glEnable(GL_LIGHTING);

glewInit();   //glew init

set_shaders();

}

void display_func()

{

glEnable(GL_DEPTH_TEST);

glClearColor(0, 0, 0, 0.25); //0.75f, 0.75f, 0.75f, 0.25f);

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

   glPushMatrix();

if(buttonState  ==  1)

{

xRot+= (xRotLength-xRot)*0.1f;

yRot+= (yRotLength-yRot)*0.1f;

}

glTranslatef(xTrans, yTrans, zTrans);

   glRotatef(xRot, 1.0f, 0.0f, 0.0f);

   glRotatef(yRot, 0.0f, 1.0f, 0.0f);

glLightfv(GL_LIGHT1, GL_AMBIENT, LightAmbient);

glLightfv(GL_LIGHT1, GL_DIFFUSE, LightDiffuse);

glLightfv(GL_LIGHT1, GL_POSITION,LightPosition);

glEnable(GL_LIGHT1);

draw_box(-10.0f, -10.0f, -10.0f, 20.0f, 20.0f, 20.0f);

glColor3f(1.0f, 0.0f, 0.0f);

GLint uniformLoc  =  glGetUniformLocation(p, "lightPos");

   if (uniformLoc !=  -1)

   {

       glUniform3fv(uniformLoc, 1, LightPosition);

   }

glutSolidSphere(8.0, 300, 300);

glPopMatrix();

   glutSwapBuffers();

}

void idle_func()

{

glutPostRedisplay();

}

void reshape_func(GLint width, GLint height)

{

glViewport(0, 0, width, height);

glMatrixMode(GL_PROJECTION);

glLoadIdentity();

gluPerspective(45.0, (float)width/height, 0.001, 100.0);

glMatrixMode(GL_MODELVIEW);

glLoadIdentity();

glTranslatef(0.0f, 0.0f, -3.0f);

}

void keyboard_func(unsigned char key, int x, int y)

{

switch(key) {

case 'w': zTrans +=  2.0f; break;

case 's': zTrans -=  2.0f; break;

case 'a': xTrans +=  2.0f; break;

case 'd': xTrans -=  2.0f; break;

case 'q': yTrans +=  2.0f; break;

case 'e': yTrans -=  2.0f; break;

default:

break;

}

glutPostRedisplay();

}

void specialkey_func(int key, int x, int y)

{

if(key  ==  GLUT_KEY_UP)

{

zTrans +=  2.0f;

}

if(key  ==  GLUT_KEY_DOWN)

{

zTrans -=  2.0f;

}

if(key  ==  GLUT_KEY_LEFT)

{

xTrans -=  2.0f;

}

if(key  ==  GLUT_KEY_RIGHT)

{

xTrans +=  2.0f;

}

glutPostRedisplay();

}

void mouse_func(int button, int state, int x, int y)

{

if (state  ==  GLUT_DOWN)

{

buttonState  =  1;

}

   else if (state  ==  GLUT_UP)

{

buttonState  =  0;

}

   ox  =  x; oy  =  y;

   glutPostRedisplay();

}

void motion_func(int x, int y)

{

   float dx, dy;

   dx  =  (float)(x - ox);

   dy  =  (float)(y - oy);

if (buttonState  ==  1)

{

xRotLength +=  dy / 5.0f;

yRotLength +=  dx / 5.0f;

}

ox  =  x; oy  =  y;

glutPostRedisplay();

}

int main(int argc, char **argv)

{

   glutInit(&argc, argv);

   glutInitDisplayMode(GLUT_DEPTH  | GLUT_RGBA | GLUT_DOUBLE);

   glutInitWindowPosition(0, 0);

   glutInitWindowSize(window_width, window_height);

   glutCreateWindow("Sphere demo");

init();

   glutDisplayFunc(display_func);

glutReshapeFunc(reshape_func);

glutSpecialFunc(specialkey_func);

glutKeyboardFunc(keyboard_func);

glutMouseFunc(mouse_func);

glutMotionFunc(motion_func);

glutIdleFunc(idle_func);

glEnable(GL_DEPTH_TEST);

   glutMainLoop();

   return 0;

}

顶点着色文件checkerboard.vs(保存在workdir下)

uniform vec3 lightPos;

varying vec3 N, L, V;

void main(void)

{

   // normal MVP transform

   gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;

   // map object-space position onto unit sphere

   V = gl_Vertex.xyz;

   // eye-space normal

   N = gl_NormalMatrix * gl_Normal;

   // eye-space light vector

   vec4 Veye = gl_ModelViewMatrix * gl_Vertex;

   L = lightPos - Veye.xyz;

}

面源着色文件checkerboard.fs

// 3D solid checker grid

varying vec3 V; // object-space position

varying vec3 N; // eye-space normal

varying vec3 L; // eye-space light vector

const vec3 onColor = vec3(1.0, 1.0, 1.0);

const vec3 offColor = vec3(0.0, 0.0, 0.0);

const float ambientLighting = 0.2;

const float specularExp = 60.0;

const float specularIntensity = 0.75;

const int numSquaresPerSide = 8;

void main (void)

{

   // Normalize vectors

   vec3 NN = normalize(N);

   vec3 NL = normalize(L);

   vec3 NV = normalize(V);

   vec3 NH = normalize(NL + vec3(0.0, 0.0, 1.0));

   // Map -1,1 to 0,numSquaresPerSide

   vec3 onOrOff = ((NV + 1.0) * float(numSquaresPerSide)) / 2.0;

   // mod 2 >= 1

   onOrOff = step(1.0, mod(onOrOff, 2.0));

   // 3-way xor

   onOrOff.x = step(0.5,

       mod(onOrOff.x + onOrOff.y + onOrOff.z, 2.0));

   // checkerboard grid

   vec3 surfColor = mix(offColor, onColor, onOrOff.x);

   // calculate diffuse lighting + 20% ambient

   surfColor *= (ambientLighting + vec3(max(0.0, dot(NN, NL))));

   // calculate specular lighting w/ 75% intensity

   surfColor += (specularIntensity *

       vec3(pow(max(0.0, dot(NN, NH)), specularExp)));

   gl_FragColor = vec4(surfColor, 1.0);

}

编译后，程序正常工作。

只是奇怪的是，freeglut.dll是64位的，glew32.dll是32位的，编译运行没有问题；但如果freeglut32.dll被使用的话，程序运行就出错。