OpenGl三维镂垫绘制

#include <iostream> #include<glew.h> #include<freeglut.h> #include<gl.h> #pragma comment(lib,"glew32.lib") #pragma comment(lib,"freeglut.lib") #pragma comment(lib,"glut32.lib") //#pragma comment(lib,"opengl.lib") /*/#define BUFFER_OFFSET(offset)((GLint *)NULL+offset)用这一个会变成奇怪的颜色*/ #define BUFFER_OFFSET(bytes)((GLvoid *)(bytes))/*/这个是在书上的，这种竟然没有在附录的代码里面*/ const int NumTimesToSubdivide = 5;/*/这里是递归的次数*/ const int NumTetrahedrons = 1024; /*4^5 tetrahedrons;根据上面递归五次,所以就是4的五次方个四面体*/ const int NumTriangles = 4 * NumTetrahedrons; /*/ 4 triangles / tetrahedron每个四面体有4各面*/ const int NumVertices = 3 * NumTriangles; /*/ 3 vertices / triangle 每个面有3个顶点*/ /*@注释 *这个看书上说是在vec.h的头文件里面，可是我电脑上没有， *我只知道，书上是说vec是甚么向量, *vec2是连续两个float， *vec3是连续三个float， *vec4是连续四个float， *我尝试自己弄这个结构体，并有构造函数初始化。 */ struct vec3 { GLfloat x, y, z; vec3(){} vec3(GLfloat hong, GLfloat lv, GLfloat lan) :x(hong), y(lv), z(lan) {} vec3 operator +(vec3 other)const { vec3 temp(x + other.x,y + other.y,z + other.z); return temp; } vec3 operator/(GLint t) { vec3 temp(x/t, y/t, z/t); return temp; } }; typedef ::vec3 point3; typedef ::vec3 color3;/*书上说甚么opengl习惯性这样，对于我来说，觉得这样很啰嗦，明明都是同一个类型*/ point3 points[NumVertices]; color3 YanSe[NumVertices]; color3 vertex_Yase[4] = { color3(0.6f, 0.7f, 0.0f), color3(0.0f, 1.0f, 0.0f), color3(0.0f, 0.5f, 0.2f), color3(0.4f, 0.0f, 0.0f) /*四面体有四个三角面，所以就设置了四种颜色*/ }; int Index = 0; //---------------------------------------------------------------------------- int colorIndex; /*@注释*对于由a、b、c确定的一个三角面，三个点设置同一个颜色才会是纯色的，否则是渐变的代码 */ void triangle(const vec3& a, const vec3& b, const vec3& c) { YanSe[Index] = vertex_Yase[colorIndex]; points[Index++] = a; YanSe[Index] = vertex_Yase[colorIndex]; points[Index++] = b; YanSe[Index] = vertex_Yase[colorIndex]; points[Index++] = c; /*@注释*下面是渐变代码 YanSe[Index] = vertex_Yase[0]; points[Index++] = a; YanSe[Index] = vertex_Yase[1]; points[Index++] = b; YanSe[Index] = vertex_Yase[2]; points[Index++] = c; */ } //---------------------------------------------------------------------------- /*@说明*下面的colorIndex用于给 *最终的每一个四面体的 *四个三角面triangle涂上不同的纯色， *如果要用渐变，可以去掉colorIndex */ void tetra(const vec3& a, const vec3& b, const vec3& c, const vec3& d) { colorIndex = 0; triangle(a, b, c); colorIndex = 1; triangle(a, c, d); colorIndex = 2; triangle(a, d, b); colorIndex = 3; triangle(b, d, c); } //---------------------------------------------------------------------------- /*@注释*递归划分*/ void divide_tetra(const vec3& a, const vec3& b, const vec3& c, const vec3& d, int count) { if (count > 0) { vec3 v0 =(a + b) / 2; vec3 v1 = (a + c) / 2; vec3 v2 = (a + d) / 2; vec3 v3 = (b + c) / 2; vec3 v4 = (c + d) / 2; vec3 v5 = (b + d) / 2; divide_tetra(a, v0, v1, v2, count - 1); divide_tetra(v0, b, v3, v5, count - 1); divide_tetra(v1, v3, c, v4, count - 1); divide_tetra(v2, v5, v4,d , count - 1); } else { tetra(a, b, c, d); // draw tetrahedron at end of recursion } } //---------------------------------------------------------------------------- /*@注释*读取文件，以字符串的形式返回*/ static char* readShaderSource(const char *file) { FILE *fp; if (file == NULL) return NULL; fopen_s(&fp,file, "rb"); /*@注释，我这里是用的vs2013，vs2013不让用fp=fopen(file, "rb");*/ if (fp == NULL)return NULL; fseek(fp, 0, SEEK_END);/*@注释：将fp所指向的文件位置指针移到以SEEK_END的基准位置，以0为位移量位置*/ GLsizei length = ftell(fp); rewind(fp);/*@注释：将fp指示文件中位置的的指针置于文件的开头位置，并清楚文件爱你结束标志和错误标志*/ GLchar * shaderChan =new GLchar[length + 1]; fread(shaderChan, sizeof(char), length, fp); shaderChan[length] = '\0'; if (shaderChan == NULL) { delete[]shaderChan;//删除着色器字符串 std::cerr << file << "error" << std::endl; exit(EXIT_FAILURE); } fclose(fp); return shaderChan; } /*@注释*创建并编译着色器*/ GLuint buildShader(const char* FileName, GLenum shaderType) { GLchar*shaderChan = readShaderSource(FileName);//以字符串的形式读取文件 GLuint shaderHandle = glCreateShader(shaderType); glShaderSource(shaderHandle, 1,&shaderChan, NULL); //(const GLchar**)把着色器对象与相应的着色器字符相关联 delete[]shaderChan;//删除着色器字符串 glCompileShader(shaderHandle); //编译着色器 GLint compileSuccess; glGetShaderiv(shaderHandle, GL_COMPILE_STATUS, &compileSuccess); if (compileSuccess == GL_FALSE) { // 若失败... std::cerr << FileName << "failed to compile:" << std::endl; GLint logsize; glGetShaderiv(shaderHandle, GL_INFO_LOG_LENGTH, &logsize); char*logMsg = new char[logsize+1]; glGetShaderInfoLog(shaderHandle, logsize, NULL, logMsg); std::cerr << logMsg << std::endl; delete[] logMsg; exit(EXIT_FAILURE); } return shaderHandle; } /*@注释*初始化着色器*/ GLuint InitShader(const char *vertexShaderFilename, const char *fragmentShaderFilename) { /*创建顶点着色器对象和片元着色器对象*/ GLuint vertexShaderHandle = buildShader(vertexShaderFilename, GL_VERTEX_SHADER); GLuint fragmentShaderHandle = buildShader(fragmentShaderFilename, GL_FRAGMENT_SHADER); GLuint programHandle = glCreateProgram(); glAttachShader(programHandle, vertexShaderHandle); glAttachShader(programHandle, fragmentShaderHandle); glLinkProgram(programHandle); GLint linkSuccess; glGetProgramiv(programHandle, GL_LINK_STATUS, &linkSuccess); if (linkSuccess == GL_FALSE) { // 判断连接是否成功... std::cerr << "shader program failed to link:" << std::endl; GLint logsize; glGetProgramiv(programHandle, GL_INFO_LOG_LENGTH, &logsize); char*logMsg = new char[logsize]; glGetProgramInfoLog(programHandle, logsize, NULL, logMsg); std::cerr << logMsg << std::endl; delete[]logMsg; exit(EXIT_FAILURE); } glUseProgram(programHandle); return programHandle; } /*@注释*初始化GLSL*/ void init(void) { /*@注释：初始化四个顶点*/ vec3 vertices[4] = { vec3(1.0, -1.0,0.0), vec3(-1.0,-1.0, 0.0), vec3(0.0,1.0, 0.0), vec3(0.0, 0.0, 0.6) }; /*@注释：调用递归划分Subdivide the original tetrahedron*/ divide_tetra(vertices[0], vertices[1], vertices[2], vertices[3], NumTimesToSubdivide); /*@注释： 创建一个顶点数组对象*/ GLuint vao; glGenVertexArrays(1, &vao);/*注释：顶点数组对象标识申请，管理着顶点属性的集合*/ glBindVertexArray(vao);/*@注释：在这里将做3个事情：1、如果参数是非0，并且是glGenvertexArrays()返回的新值，未经glBindVertexArray的 *那么他将创建一个新的顶点数组对象（这里才真正创建）,并且与其名称关联起来。 *2、如果绑定包已经创建过的顶点数组对象，那么该顶点数组对象将被激活。这便于帧间切换绘制数据 *3、如果输入参数是0那么OpenGL将不再使用程序所分配的任何顶点数组对象，并且将渲染状态重设为默认值。*/ /*@注释 创建并初始化一个缓冲区对象*/ GLuint buffer; glGenBuffers(1, &buffer);/*注释：申请顶点缓存对象标识。*/ glBindBuffer(GL_ARRAY_BUFFER, buffer); /*注释：申请顶点缓存对象标识。 *指定顶点缓存对象的用途，GL_ARRAY_BUFFER表示顶点数据。之力glBindBuffer同样完成了3项工作： *1、如果是第一次绑定对象(第二个参数)，他是一个非0的无符号整型，那么将创建一个与名称对应的（第一个参数）新的缓存对象 *2、如果绑定到一个已经创建的缓存对象，那么她将被激活为当前使用对象。 *3、如果第二个参数是0，那么OpenGL不再为当前名称（第一个参数）应用任何缓存对象。*/ glBufferData(GL_ARRAY_BUFFER, sizeof(points) + sizeof(YanSe), NULL, GL_STATIC_DRAW); /*注释：glBufferData( GLenum target, GLsizeiptr size, const GLvoid* data, GLenum usage ) *向缓存对象输入数