首先是系統資訊
作業系統：win10
編譯環境：visual studio 2015
使用語言：visual C++
首先是安裝GLM，這是一個小小又簡單的library，只有使用std下的函數寫成，他用來作為openGL的矩陣表示非常方便，還有更多數學運算都很依賴他，也因為他足夠簡單，所以lib的建設方法也很快
網址https://github.com/g-truc/glm/tags
首先先去下載GLM解壓縮到D槽
只要在visual studio專案的屬性→VC++目錄→include目錄→新增D:\glm
即可
再來是simple OpenGL image library
網址http://www.lonesock.net/soil.html
這是用來讀取一般圖片轉成openGL可以使用的matrix type的lib，一樣很方便所以我們也加入他，一樣下載SOIL直接解壓縮到D槽
在visual studio專案的屬性→VC++目錄→include目錄→新增D:\Simple OpenGL Image Library\src
在visual studio專案的屬性→VC++目錄→程式庫目錄→新增D:\Simple OpenGL Image Library\lib
※這裡要注意一點SOIL並沒有幫我們編譯好可以直接使用的.lib檔，也就是說我們要自己編譯，使用SOIL資料夾裡的vs10的project打開並且並且直接執行，然後在debug資料夾裡找到編好的SOIL.lib把他丟到D:\Simple OpenGL Image Library\lib
再來安裝GLEW，這是用來使用shader language的library，一樣下載解壓縮到D槽
網址http://glew.sourceforge.net/
選擇win32版本，基本上所有lib都選擇32bit版本，64bit可能會有問題
在visual studio專案的屬性→VC++目錄→include目錄→新增D:\glew-2.0.0\include
在visual studio專案的屬性→VC++目錄→程式庫目錄→新增D:\glew-2.0.0\lib\Release\Win32
再來安裝GLFW，這是用來簡化openGL開啟視窗以及鍵盤滑鼠event的lib，加入它可以讓程式變得更精簡更好控制。
網址http://www.glfw.org/
一樣下載好到D槽，這裡注意一下版本都是選擇win32，64目前還不構穩定。
在visual studio專案的屬性→VC++目錄→include目錄→新增D:\glfw-3.2.1.bin.WIN32\include
在visual studio專案的屬性→VC++目錄→程式庫目錄→新增D:\glfw-3.2.1.bin.WIN32\lib-vc2015
最後就是在visual studio專案的屬性→連結器→輸入→其他相依性把下面這些lib加入
opengl32.lib
glfw3.lib
SOIL.lib
glew32s.lib
即可
接下來是一個範例程式只要能順利跑起來基本上openGLSL的環境就算架設好了
首先是main
--------------------------------------------------------------------------------------------------------
#include <iostream>
// GLEW
#define GLEW_STATIC
#include <GL/glew.h>
// GLFW
#include <GLFW/glfw3.h>
// Other includes
#include "Shader.h"
// Function prototypes
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
// Window dimensions
const GLuint WIDTH = 800, HEIGHT = 600;
// The MAIN function, from here we start the application and run the game loop
int main()
{
// Init GLFW
glfwInit();
// Set all the required options for GLFW
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
// Create a GLFWwindow object that we can use for GLFW's functions
GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
glfwMakeContextCurrent(window);
// Set the required callback functions
glfwSetKeyCallback(window, key_callback);
// Set this to true so GLEW knows to use a modern approach to retrieving function pointers and extensions
glewExperimental = GL_TRUE;
// Initialize GLEW to setup the OpenGL Function pointers
glewInit();
// Define the viewport dimensions
glViewport(0, 0, WIDTH, HEIGHT);
// Build and compile our shader program
Shader ourShader("vs.txt", "fs.txt");
// Set up vertex data (and buffer(s)) and attribute pointers
GLfloat vertices[] = {
// Positions // Colors
0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, // Bottom Right
-0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, // Bottom Left
0.0f, 0.5f, 0.0f, 0.0f, 0.0f, 1.0f // Top
};
GLuint VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
// Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
// Position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(0);
// Color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(1);
glBindVertexArray(0); // Unbind VAO
// Game loop
while (!glfwWindowShouldClose(window))
{
// Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
glfwPollEvents();
// Render
// Clear the colorbuffer
glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Draw the triangle
ourShader.Use();
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindVertexArray(0);
// Swap the screen buffers
glfwSwapBuffers(window);
}
// Properly de-allocate all resources once they've outlived their purpose
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
// Terminate GLFW, clearing any resources allocated by GLFW.
glfwTerminate();
return 0;
}
// Is called whenever a key is pressed/released via GLFW
void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
{
if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
glfwSetWindowShouldClose(window, GL_TRUE);
}
-------------------------------------------------------------------------------------------------------------
再來是Shader class，我們用它來作為shader之間溝通的媒介
Shader.h
-------------------------------------------------------------------------------------------------------------
#ifndef SHADER_H
#define SHADER_H
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <GL/glew.h> // Include glew to get all the required OpenGL headers
class Shader
{
public:
// The program ID
GLuint Program;
// Constructor reads and builds the shader
Shader(const GLchar* vertexPath, const GLchar* fragmentPath);
// Use the program
void Use();
};
#endif
Shader.cpp
-------------------------------------------------------------------------------------------------------------
#include <string>
#include <fstream>
#include <sstream>
#include <iostream>
#include <GL/glew.h>
#include "Shader.h"
Shader::Shader(const GLchar* vertexPath, const GLchar* fragmentPath)
{
// 1. Retrieve the vertex/fragment source code from filePath
std::string vertexCode;
std::string fragmentCode;
std::ifstream vShaderFile;
std::ifstream fShaderFile;
// ensures ifstream objects can throw exceptions:
vShaderFile.exceptions(std::ifstream::badbit);
fShaderFile.exceptions(std::ifstream::badbit);
try
{
// Open files
vShaderFile.open(vertexPath);
fShaderFile.open(fragmentPath);
std::stringstream vShaderStream, fShaderStream;
// Read file's buffer contents into streams
vShaderStream << vShaderFile.rdbuf();
fShaderStream << fShaderFile.rdbuf();
// close file handlers
vShaderFile.close();
fShaderFile.close();
// Convert stream into string
vertexCode = vShaderStream.str();
fragmentCode = fShaderStream.str();
}
catch (std::ifstream::failure e)
{
std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ" << std::endl;
}
const GLchar* vShaderCode = vertexCode.c_str();
const GLchar * fShaderCode = fragmentCode.c_str();
// 2. Compile shaders
GLuint vertex, fragment;
GLint success;
GLchar infoLog[512];
// Vertex Shader
vertex = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertex, 1, &vShaderCode, NULL);
glCompileShader(vertex);
// Print compile errors if any
glGetShaderiv(vertex, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(vertex, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Fragment Shader
fragment = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragment, 1, &fShaderCode, NULL);
glCompileShader(fragment);
// Print compile errors if any
glGetShaderiv(fragment, GL_COMPILE_STATUS, &success);
if (!success)
{
glGetShaderInfoLog(fragment, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
}
// Shader Program
this->Program = glCreateProgram();
glAttachShader(this->Program, vertex);
glAttachShader(this->Program, fragment);
glLinkProgram(this->Program);
// Print linking errors if any
glGetProgramiv(this->Program, GL_LINK_STATUS, &success);
if (!success)
{
glGetProgramInfoLog(this->Program, 512, NULL, infoLog);
std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
}
// Delete the shaders as they're linked into our program now and no longer necessery
glDeleteShader(vertex);
glDeleteShader(fragment);
}
// Uses the current shader
void Shader::Use()
{
glUseProgram(this->Program);
}
-----------------------------------------------------------------------------------------------------------------
最後就是創建fs.txt跟vs.txt注意路徑資料夾要在main同一個理
vs.txt
------------------------------------------------------------------------------------------------------------------
#version 330 core
in vec3 ourColor;
out vec4 color;
void main()
{
color = vec4(ourColor, 1.0f);
}
-------------------------------------------------------------------------------------------------------------------
fs.txt
------------------------------------------------------------------------------------------------------------------
#version 330 core
in vec3 ourColor;
out vec4 color;
void main()
{
color = vec4(ourColor, 1.0f);
}
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