新建ios 及win32 opengl工程

新建ios 及win32 opengl工程

ios上新建opengl工程很简单，打开xcode->选择opengl模板，然后运行。就可以看到三个立方体了。

win32上比较复杂。不过我们可以通过使用glfw来简化流程。打开vs2012->新建win32 application->在main 中调用 glfw。代码如下：

#include "stdafx.h"
#include <stdio.h>
#include "vector"
#include "string"
#include <fstream>

#include "glew.h"
#include <glfw3.h>


GLuint LoadShaders(const char* vertex_file_path,const char* fragment_file_path)
{
	//Create the shaders
	GLuint VertexShaderID = glCreateShader(GL_VERTEX_SHADER);
	GLuint FragmentShaderID = glCreateShader(GL_FRAGMENT_SHADER);

	//Read the Vertex Shader code from the file
	std::string VertexShaderCode;
	std::ifstream VertexShaderStream(vertex_file_path,std::ios::in);
	if (VertexShaderStream.is_open())
	{
		std::string Line = "";
		while (getline(VertexShaderStream,Line))
		{
			VertexShaderCode += "\n" + Line;
		}

		VertexShaderStream.close();
	}


	//Read the Fragment Shader code from the file
	std::string FragmentShaderCode;
	std::ifstream FragmentShaderStream(fragment_file_path,std::ios::in);
	if (FragmentShaderStream.is_open())
	{
		std::string Line = "";
		while (getline(FragmentShaderStream,Line))
		{
			FragmentShaderCode += "\n" + Line;
		}

		FragmentShaderStream.close();
	}

	GLint Result = GL_FALSE;
	int InfoLogLength;

	//compile Vertex Shader
	printf("Compiling shader : %s\n",vertex_file_path);
	char const * VertexSourcePointer = VertexShaderCode.c_str();
	glShaderSource(VertexShaderID,1,&VertexSourcePointer,NULL);
	glCompileShader(VertexShaderID);

	// Check vertex Shader
	glGetShaderiv(VertexShaderID,GL_COMPILE_STATUS,&Result);
	glGetShaderiv(VertexShaderID,GL_INFO_LOG_LENGTH,&InfoLogLength);
	std::vector<char> VerTexShaderErrorMessage(InfoLogLength); 
	glGetShaderInfoLog(VertexShaderID,InfoLogLength,NULL,&VerTexShaderErrorMessage[0]);
	fprintf(stdout,"%s\n",&VerTexShaderErrorMessage[0]);

	//compile Fragment Shader
	printf("Compiling shader : %s\n",vertex_file_path);
	char const * FragmentSourcePointer = FragmentShaderCode.c_str();
	glShaderSource(FragmentShaderID,1,&FragmentSourcePointer,NULL);
	glCompileShader(FragmentShaderID);

	// Check vertex Shader
	glGetShaderiv(FragmentShaderID,GL_COMPILE_STATUS,&Result);
	glGetShaderiv(FragmentShaderID,GL_INFO_LOG_LENGTH,&InfoLogLength);
	std::vector<char> FragmentShaderErrorMessage(InfoLogLength); 
	glGetShaderInfoLog(FragmentShaderID,InfoLogLength,NULL,&FragmentShaderErrorMessage[0]);
	fprintf(stdout,"%s\n",&FragmentShaderErrorMessage[0]);

	//Link the program
	fprintf(stdout,"Linking programn");
	GLuint ProgramID = glCreateProgram();
	glAttachShader(ProgramID,VertexShaderID);
	glAttachShader(ProgramID,FragmentShaderID);
	glLinkProgram(ProgramID);

	//Check the program
	glGetProgramiv(ProgramID,GL_LINK_STATUS,&Result);
	glGetProgramiv(ProgramID,GL_INFO_LOG_LENGTH,&InfoLogLength);
	std::vector<char> ProgramErrorMessage(InfoLogLength);
	glGetProgramInfoLog(ProgramID,InfoLogLength,NULL,&ProgramErrorMessage[0]);
	fprintf(stdout,"%s\n",&ProgramErrorMessage[0]);

	glDeleteShader(VertexShaderID);
	glDeleteShader(FragmentShaderID);

	return ProgramID;
}


int APIENTRY _tWinMain(_In_ HINSTANCE hInstance,
					   _In_opt_ HINSTANCE hPrevInstance,
					   _In_ LPTSTR    lpCmdLine,
					   _In_ int       nCmdShow)
{
	UNREFERENCED_PARAMETER(hPrevInstance);
	UNREFERENCED_PARAMETER(lpCmdLine);

	GLFWwindow* window;

	/* Initialize the library */ 
	if (!glfwInit())
		return -1;

	/* Create a windowed mode window and its OpenGL context */
	window = glfwCreateWindow(480, 320, "Hello World", NULL, NULL);
	if (!window)
	{
		glfwTerminate();
		return -1;
	}

	/* Make the window's context current */
	glfwMakeContextCurrent(window);

	// Needed in core profile
	if( glewInit() != GLEW_OK)
	{
		glfwTerminate();
		return -1;
	}

	// An array of 3 vectors which represents 3 vertices
	static const GLfloat g_vertex_buffer_data[] = {
		-1.0f,-1.0f,0.0f,
		1.0f,-1.0f,0.0f,
		0.0f,1.0f,0.0f,
	};


	//This will identify our vertex buffer
	GLuint vertexbuffer;


	//Generate 1 buffer,put the resulting identifier in vertexbuffer
	glGenBuffers(1,&vertexbuffer);		

	//The following commands will talk about our 'vertexbuffer' buffer
	glBindBuffer(GL_ARRAY_BUFFER,vertexbuffer);

	//Give our vertices to OpenGL.
	glBufferData(GL_ARRAY_BUFFER,sizeof(g_vertex_buffer_data),g_vertex_buffer_data,GL_STATIC_DRAW);
	GLuint programID = LoadShaders("vertex.shader","fragment.shader");
	glUseProgram(programID);

	glClearColor(0.0f, 0.0f, 0.4f, 0.0f);
	/* Loop until the user closes the window */
	while (!glfwWindowShouldClose(window))
	{
		glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		

		glEnableVertexAttribArray(0);	



		glVertexAttribPointer(
			0,			// attribute 0. No particular reason for 0, but must match the layout in the shader.
			3,			// size
			GL_FLOAT,	// type
			GL_FALSE,	// normalized?
			0,			// stride
			(void*)0	// array buffer offset
			);

		glDrawArrays(GL_TRIANGLES,0,3);// Starting from vertex 0; 3 vertices total -> 1 triangle
		glDisableVertexAttribArray(0);

		/* Swap front and back buffers */
		glfwSwapBuffers(window);

		/* Poll for and process events */
		glfwPollEvents();
	}

	glfwTerminate();

	return true;

}

这样我们就在win32上绘制了一个三角形。注意要导入相应的.h,lib和dll文件。glew,glfw。