OpenGL中GLSL渲染茶壶光照完整程序

顶点着色器VertexShader.txt：

uniform vec3 lightposition;//光源位置uniform vec3 eyeposition;//相机位置uniform vec4 ambient;//环境光颜色uniform vec4 lightcolor;//光源颜色uniform float Ns;//高光系数uniform float attenuation;//光线的衰减系数varying vec4 color;//向片段着色其传递的参数void main(){vec3 ECPosition = vec3(gl_ModelViewMatrix * gl_Vertex);vec3 N = normalize(gl_NormalMatrix * gl_Normal);vec3 L = normalize(lightposition - ECPosition);vec3 V = normalize(eyeposition - ECPosition);vec3 H = normalize(V + L);vec3 diffuse = lightcolor * max(dot(N , L) , 0);vec3 specular = lightcolor * pow(max(dot(N , H) , 0) , Ns) * attenuation;color = vec4(clamp((diffuse + specular) , 0.0 , 1.0) , 1.0);color = color + ambient;gl_Position = ftransform();}

片段着色器FragmentShader.txt：

varying vec4 color;void main(){gl_FragColor = color;}

完整程序：

#include <GL/glew.h>  #include <GL/freeglut.h>  #include <iostream>#include <stdio.h>  #include <stdlib.h>  #include <string.h>  #pragma comment(lib,"glew32.lib")    using namespace std;GLfloat lightPosition[3] = { 30.0,30.0,30.0 };GLfloat ambient[4] = { 0.0 , 0.0 , 1.0 , 1.0 };GLfloat lightcolor[4] = { 1.0 , 1.0 , 1.0 , 1.0 };GLfloat eyeposition[3] = { 0.0 , 10.0 , 30.0 };GLfloat Ns = 30;GLfloat attenuation = 0.01;GLfloat objectSize = 15.0;GLuint programHandle;GLuint vShader, fShader;//读入字符流  char *textFileRead(const char *fn){FILE *fp;char *content = NULL;int count = 0;if (fn != NULL){fp = fopen(fn, "rt");if (fp != NULL){fseek(fp, 0, SEEK_END);count = ftell(fp);rewind(fp);if (count > 0){content = (char *)malloc(sizeof(char) * (count + 1));count = fread(content, sizeof(char), count, fp);content[count] = '\0';}fclose(fp);}}return content;}void initShader(const char *VShaderFile, const char *FShaderFile){//1、查看显卡、GLSL和OpenGL的信息    const GLubyte *vendor = glGetString(GL_VENDOR);const GLubyte *renderer = glGetString(GL_RENDERER);const GLubyte *version = glGetString(GL_VERSION);const GLubyte *glslVersion = glGetString(GL_SHADING_LANGUAGE_VERSION);cout << "显卡供应商   : " << vendor << endl;cout << "显卡型号     : " << renderer << endl;cout << "OpenGL版本   : " << version << endl;cout << "GLSL版本     : " << glslVersion << endl;//2、编译着色器    //创建着色器对象：顶点着色器    vShader = glCreateShader(GL_VERTEX_SHADER);//错误检测    if (0 == vShader){cerr << "ERROR : Create vertex shader failed" << endl;exit(1);}//把着色器源代码和着色器对象相关联    const GLchar *vShaderCode = textFileRead(VShaderFile);const GLchar *vCodeArray[1] = { vShaderCode };//将字符数组绑定到对应的着色器对象上  glShaderSource(vShader, 1, vCodeArray, NULL);//编译着色器对象    glCompileShader(vShader);//检查编译是否成功    GLint compileResult;glGetShaderiv(vShader, GL_COMPILE_STATUS, &compileResult);if (GL_FALSE == compileResult){GLint logLen;//得到编译日志长度    glGetShaderiv(vShader, GL_INFO_LOG_LENGTH, &logLen);if (logLen > 0){char *log = (char *)malloc(logLen);GLsizei written;//得到日志信息并输出    glGetShaderInfoLog(vShader, logLen, &written, log);cerr << "vertex shader compile log : " << endl;cerr << log << endl;free(log);//释放空间    }}//创建着色器对象：片断着色器    fShader = glCreateShader(GL_FRAGMENT_SHADER);//错误检测    if (0 == fShader){cerr << "ERROR : Create fragment shader failed" << endl;exit(1);}//把着色器源代码和着色器对象相关联    const GLchar *fShaderCode = textFileRead(FShaderFile);const GLchar *fCodeArray[1] = { fShaderCode };glShaderSource(fShader, 1, fCodeArray, NULL);//编译着色器对象    glCompileShader(fShader);//检查编译是否成功    glGetShaderiv(fShader, GL_COMPILE_STATUS, &compileResult);if (GL_FALSE == compileResult){GLint logLen;//得到编译日志长度    glGetShaderiv(fShader, GL_INFO_LOG_LENGTH, &logLen);if (logLen > 0){char *log = (char *)malloc(logLen);GLsizei written;//得到日志信息并输出    glGetShaderInfoLog(fShader, logLen, &written, log);cerr << "fragment shader compile log : " << endl;cerr << log << endl;free(log);//释放空间    }}//3、链接着色器对象    //创建着色器程序    programHandle = glCreateProgram();if (!programHandle){cerr << "ERROR : create program failed" << endl;exit(1);}//将着色器程序链接到所创建的程序中    glAttachShader(programHandle, vShader);glAttachShader(programHandle, fShader);//将这些对象链接成一个可执行程序    glLinkProgram(programHandle);//查询链接的结果    GLint linkStatus;glGetProgramiv(programHandle, GL_LINK_STATUS, &linkStatus);if (GL_FALSE == linkStatus){cerr << "ERROR : link shader program failed" << endl;GLint logLen;glGetProgramiv(programHandle, GL_INFO_LOG_LENGTH,&logLen);if (logLen > 0){char *log = (char *)malloc(logLen);GLsizei written;glGetProgramInfoLog(programHandle, logLen,&written, log);cerr << "Program log : " << endl;cerr << log << endl;}}}//完成glew初始化和加载顶点、片段着色器void init(){//初始化glew扩展库    GLenum err = glewInit();if (GLEW_OK != err){cout << "Error initializing GLEW: " << glewGetErrorString(err) << endl;}glEnable(GL_DEPTH_TEST);//加载顶点和片段着色器对象并链接到一个程序对象上  initShader("VertexShader.txt", "FragmentShader.txt");glClearColor(0.0, 0.0, 0.0, 0.0);}void Reshape(int w, int h){glViewport(0, 0, (GLsizei)w, (GLsizei)h);glMatrixMode(GL_PROJECTION);glLoadIdentity();gluPerspective(90, 1, 0.1, 1000.0);glMatrixMode(GL_MODELVIEW);glLoadIdentity();gluLookAt(eyeposition[0], eyeposition[1], eyeposition[2], 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);}void display(){glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);glColor3f(1.0, 1.0, 1.0);glUseProgram(programHandle);glUniform3f(glGetUniformLocation(programHandle, "lightposition"), lightPosition[0], lightPosition[1], lightPosition[2]);glUniform3f(glGetUniformLocation(programHandle, "eyeposition"), eyeposition[0], eyeposition[1], eyeposition[2]);glUniform4f(glGetUniformLocation(programHandle, "ambient"), ambient[0], ambient[1], ambient[2], ambient[3]);glUniform4f(glGetUniformLocation(programHandle, "lightcolor"), lightcolor[0], lightcolor[1], lightcolor[2], lightcolor[3]);glUniform1f(glGetUniformLocation(programHandle, "Ns"), Ns);glUniform1f(glGetUniformLocation(programHandle, "attenuation"), attenuation);glutSolidTeapot(objectSize);//glutSolidSphere(objectSize-3, 100, 100);glutSwapBuffers();}void SpecialKey(GLint key, GLint x, GLint y){if (key == GLUT_KEY_UP){//do something}display();}int main(int argc, char** argv){glutInit(&argc, argv);glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);glutInitWindowSize(600, 600);glutInitWindowPosition(100, 100);glutCreateWindow("Hello GLSL");init();glutReshapeFunc(Reshape);glutDisplayFunc(display);glutSpecialFunc(SpecialKey);glutMainLoop();return 0;}

执行效果：

再绘制一个实心球体：