代码
#include <iostream>
#include <gl/glew.h>
#include <SFML/Graphics.hpp>
#include <windows.h>int main()
{auto getInstance = [](){return (HINSTANCE)GetModuleHandle(nullptr);};auto debug = [](GLenum source, GLenum type, GLuint id, GLenum severity, GLsizei length, const GLchar* message, const void* userParam){std::cout << message << std::endl;};const char* vsource ="#version 330 core\n""layout(location=0)in vec3 a_position;""void main()""{gl_Position = vec4(a_position,1.0);}";const char* fsource ="#version 330 core\n""out vec4 o_color;""void main()""{o_color = vec4(0.0,0.0,1.0,1.0);}";const float ver[] ={0.0f,0.5f,0.0f,-0.5f,-0.5f,0.0f,0.5f,-0.5f,0.0,};sf::RenderWindow main_window(sf::VideoMode(640,480),"Multi Contexts");sf::Event main_event;sf::WindowHandle main_handle = main_window.getSystemHandle();HWND sub_window_handle_1 = CreateWindowEx(WS_EX_WINDOWEDGE,TEXT("static"),TEXT(""),WS_VISIBLE|WS_CHILD,0,0,320,480,main_handle,nullptr,getInstance(),nullptr);sf::RenderWindow sub_window_1(sub_window_handle_1);sf::ContextSettings cs(8,8,8,3,3,sf::ContextSettings::Attribute::Core|sf::ContextSettings::Attribute::Debug);HWND sub_window_handle_2 = CreateWindowEx(WS_EX_WINDOWEDGE,TEXT("static"),TEXT(""),WS_VISIBLE|WS_CHILD,320,0,320,480,main_handle,nullptr,getInstance(),nullptr);sf::RenderWindow sub_window_2(sub_window_handle_2,cs);sub_window_2.setActive(true);std::cout << (glewInit() == GLEW_OK) << std::endl;glDebugMessageCallback(debug,nullptr);GLuint vs = glCreateShader(GL_VERTEX_SHADER);GLuint fs = glCreateShader(GL_FRAGMENT_SHADER);glShaderSource(vs,1,&vsource,nullptr);glShaderSource(fs,1,&fsource,nullptr);glCompileShader(vs);glCompileShader(fs);GLuint program = glCreateProgram();glAttachShader(program,vs);glAttachShader(program,fs);glLinkProgram(program);glDeleteShader(vs);glDeleteShader(fs);GLuint vao;glGenVertexArrays(1,&vao);glBindVertexArray(vao);GLuint vbo;glGenBuffers(1,&vbo);glBindBuffer(GL_ARRAY_BUFFER,vbo);glBufferData(GL_ARRAY_BUFFER,sizeof(ver),ver,GL_STATIC_DRAW);glEnableVertexAttribArray(0);glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,3 * sizeof(float),nullptr);glBindVertexArray(0);glBindBuffer(GL_ARRAY_BUFFER,0);glDeleteBuffers(1,&vbo);//sub_window_2.setActive(false);sf::RectangleShape rect(sf::Vector2f(160,240));rect.setFillColor(sf::Color::Red);rect.setPosition(sf::Vector2f(80,120));while(main_window.isOpen()){while (main_window.pollEvent(main_event)){if(main_event.type == sf::Event::Closed){main_window.close();}else if(main_event.type == sf::Event::KeyPressed){if(main_event.key.code == sf::Keyboard::Key::Escape){main_window.close();}}}/*main_window.clear();main_window.display();*/sub_window_1.clear();sub_window_1.draw(rect);sub_window_1.display();sub_window_2.setActive(true);glClear(GL_COLOR_BUFFER_BIT);glUseProgram(program);glBindVertexArray(vao);glDrawArrays(GL_TRIANGLES,0,3);glBindVertexArray(0);sub_window_2.setActive(false);sub_window_2.display();}sub_window_2.setActive(true);glDeleteVertexArrays(1,&vao);glDeleteProgram(program);sub_window_2.setActive(false);return 0;
}
稍微讲一下
这里创建了一个主窗口(main_window),之后再主窗口内创建了两个小窗口(sub_window),一个是用默认上下文的,另一个是OpenGL3.3的上下文。
窗口创建可以看[C++] [SFML] 基于Win32的SFML程序。
效果
但是最后出现了奇怪的日志,表示没法启用上下文,让人困惑
Failed to activate OpenGL context:
Failed to activate the window’s context
Failed to activate OpenGL context:
Failed to activate the window’s context
Failed to activate OpenGL context:
Failed to activate the window’s context
Failed to activate OpenGL context:
Failed to activate the window’s context
Failed to activate OpenGL context:
Failed to activate the window’s context
Failed to activate OpenGL context:
Failed to activate OpenGL context: