// Link statically with GLEW #define GLEW_STATIC // Headers #include #include #include #include #include #include #include // Shader sources const GLchar* sceneVertexSource = "#version 150 core\n" "in vec3 position;" "in vec3 color;" "in vec2 texcoord;" "out vec3 Color;" "out vec2 Texcoord;" "uniform mat4 model;" "uniform mat4 view;" "uniform mat4 proj;" "uniform vec3 overrideColor;" "void main()" "{" " Color = overrideColor * color;" " Texcoord = texcoord;" " gl_Position = proj * view * model * vec4(position, 1.0);" "}"; const GLchar* sceneFragmentSource = "#version 150 core\n" "in vec3 Color;" "in vec2 Texcoord;" "out vec4 outColor;" "uniform sampler2D texKitten;" "uniform sampler2D texPuppy;" "void main()" "{" " outColor = vec4(Color, 1.0) * mix(texture(texKitten, Texcoord), texture(texPuppy, Texcoord), 0.5);" "}"; const GLchar* screenVertexSource = "#version 150 core\n" "in vec2 position;" "in vec2 texcoord;" "out vec2 Texcoord;" "void main()" "{" " Texcoord = texcoord;" " gl_Position = vec4(position, 0.0, 1.0);" "}"; const GLchar* screenFragmentSource = "#version 150 core\n" "in vec2 Texcoord;" "out vec4 outColor;" "uniform sampler2D texFramebuffer;" "void main()" "{" " outColor = texture(texFramebuffer, Texcoord);" "}"; // Cube vertices GLfloat cubeVertices[] = { -0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, -0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, -0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, -0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, -0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, -0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, -0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, -0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, -0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, -0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, -0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, -0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, 0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, -0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, -0.5f, -0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, -0.5f, -0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, -0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, 0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, 0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 1.0f, 0.0f, -0.5f, 0.5f, 0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 0.0f, -0.5f, 0.5f, -0.5f, 1.0f, 1.0f, 1.0f, 0.0f, 1.0f, -1.0f, -1.0f, -0.5f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, -1.0f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 1.0f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, -0.5f, 0.0f, 0.0f, 0.0f, 1.0f, 1.0f, -1.0f, 1.0f, -0.5f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, -1.0f, -1.0f, -0.5f, 0.0f, 0.0f, 0.0f, 0.0f, 0.0f }; // Quad vertices GLfloat quadVertices[] = { -1.0f, 1.0f, 0.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 0.0f, 1.0f, -1.0f, 1.0f, 0.0f, -1.0f, -1.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f, 1.0f }; // Create a texture from an image file GLuint loadTexture(const GLchar* path) { GLuint texture; glGenTextures(1, &texture); int width, height; unsigned char* image; glBindTexture(GL_TEXTURE_2D, texture); image = SOIL_load_image(path, &width, &height, 0, SOIL_LOAD_RGB); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image); SOIL_free_image_data(image); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); return texture; } void createShaderProgram(const GLchar* vertSrc, const GLchar* fragSrc, GLuint& vertexShader, GLuint& fragmentShader, GLuint& shaderProgram) { // Create and compile the vertex shader vertexShader = glCreateShader(GL_VERTEX_SHADER); glShaderSource(vertexShader, 1, &vertSrc, NULL); glCompileShader(vertexShader); // Create and compile the fragment shader fragmentShader = glCreateShader(GL_FRAGMENT_SHADER); glShaderSource(fragmentShader, 1, &fragSrc, NULL); glCompileShader(fragmentShader); // Link the vertex and fragment shader into a shader program shaderProgram = glCreateProgram(); glAttachShader(shaderProgram, vertexShader); glAttachShader(shaderProgram, fragmentShader); glBindFragDataLocation(shaderProgram, 0, "outColor"); glLinkProgram(shaderProgram); } void specifySceneVertexAttributes(GLuint shaderProgram) { GLint posAttrib = glGetAttribLocation(shaderProgram, "position"); glEnableVertexAttribArray(posAttrib); glVertexAttribPointer(posAttrib, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), 0); GLint colAttrib = glGetAttribLocation(shaderProgram, "color"); glEnableVertexAttribArray(colAttrib); glVertexAttribPointer(colAttrib, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void*)(3 * sizeof(GLfloat))); GLint texAttrib = glGetAttribLocation(shaderProgram, "texcoord"); glEnableVertexAttribArray(texAttrib); glVertexAttribPointer(texAttrib, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (void*)(6 * sizeof(GLfloat))); } void specifyScreenVertexAttributes(GLuint shaderProgram) { GLint posAttrib = glGetAttribLocation(shaderProgram, "position"); glEnableVertexAttribArray(posAttrib); glVertexAttribPointer(posAttrib, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), 0); GLint texAttrib = glGetAttribLocation(shaderProgram, "texcoord"); glEnableVertexAttribArray(texAttrib); glVertexAttribPointer(texAttrib, 2, GL_FLOAT, GL_FALSE, 4 * sizeof(GLfloat), (void*)(2 * sizeof(GLfloat))); } int main() { auto t_start = std::chrono::high_resolution_clock::now(); sf::ContextSettings settings; settings.depthBits = 24; settings.stencilBits = 8; sf::Window window(sf::VideoMode(800, 600, 32), "OpenGL", sf::Style::Titlebar | sf::Style::Close, settings); // Initialize GLEW glewExperimental = GL_TRUE; glewInit(); // Create VAOs GLuint vaoCube, vaoQuad; glGenVertexArrays(1, &vaoCube); glGenVertexArrays(1, &vaoQuad); // Load vertex data GLuint vboCube, vboQuad; glGenBuffers(1, &vboCube); glGenBuffers(1, &vboQuad); glBindBuffer(GL_ARRAY_BUFFER, vboCube); glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertices), cubeVertices, GL_STATIC_DRAW); glBindBuffer(GL_ARRAY_BUFFER, vboQuad); glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), quadVertices, GL_STATIC_DRAW); // Create shader programs GLuint sceneVertexShader, sceneFragmentShader, sceneShaderProgram; createShaderProgram(sceneVertexSource, sceneFragmentSource, sceneVertexShader, sceneFragmentShader, sceneShaderProgram); GLuint screenVertexShader, screenFragmentShader, screenShaderProgram; createShaderProgram(screenVertexSource, screenFragmentSource, screenVertexShader, screenFragmentShader, screenShaderProgram); // Specify the layout of the vertex data glBindVertexArray(vaoCube); glBindBuffer(GL_ARRAY_BUFFER, vboCube); specifySceneVertexAttributes(sceneShaderProgram); glBindVertexArray(vaoQuad); glBindBuffer(GL_ARRAY_BUFFER, vboQuad); specifyScreenVertexAttributes(screenShaderProgram); // Load textures GLuint texKitten = loadTexture("sample.png"); GLuint texPuppy = loadTexture("sample2.png"); glUseProgram(sceneShaderProgram); glUniform1i(glGetUniformLocation(sceneShaderProgram, "texKitten"), 0); glUniform1i(glGetUniformLocation(sceneShaderProgram, "texPuppy"), 1); glUseProgram(screenShaderProgram); glUniform1i(glGetUniformLocation(screenShaderProgram, "texFramebuffer"), 0); GLint uniModel = glGetUniformLocation(sceneShaderProgram, "model"); // Create framebuffer GLuint frameBuffer; glGenFramebuffers(1, &frameBuffer); glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer); // Create texture to hold color buffer GLuint texColorBuffer; glGenTextures(1, &texColorBuffer); glBindTexture(GL_TEXTURE_2D, texColorBuffer); glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 800, 600, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texColorBuffer, 0); // Create Renderbuffer Object to hold depth and stencil buffers GLuint rboDepthStencil; glGenRenderbuffers(1, &rboDepthStencil); glBindRenderbuffer(GL_RENDERBUFFER, rboDepthStencil); glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, 800, 600); glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_RENDERBUFFER, rboDepthStencil); // Set up projection glm::mat4 view = glm::lookAt( glm::vec3(2.5f, 2.5f, 2.0f), glm::vec3(0.0f, 0.0f, 0.0f), glm::vec3(0.0f, 0.0f, 1.0f) ); glUseProgram(sceneShaderProgram); GLint uniView = glGetUniformLocation(sceneShaderProgram, "view"); glUniformMatrix4fv(uniView, 1, GL_FALSE, glm::value_ptr(view)); glm::mat4 proj = glm::perspective(glm::radians(45.0f), 800.0f / 600.0f, 1.0f, 10.0f); GLint uniProj = glGetUniformLocation(sceneShaderProgram, "proj"); glUniformMatrix4fv(uniProj, 1, GL_FALSE, glm::value_ptr(proj)); GLint uniColor = glGetUniformLocation(sceneShaderProgram, "overrideColor"); bool running = true; while (running) { sf::Event windowEvent; while (window.pollEvent(windowEvent)) { switch (windowEvent.type) { case sf::Event::Closed: running = false; break; } } // Bind our framebuffer and draw 3D scene (spinning cube) glBindFramebuffer(GL_FRAMEBUFFER, frameBuffer); glBindVertexArray(vaoCube); glEnable(GL_DEPTH_TEST); glUseProgram(sceneShaderProgram); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texKitten); glActiveTexture(GL_TEXTURE1); glBindTexture(GL_TEXTURE_2D, texPuppy); // Clear the screen to white glClearColor(1.0f, 1.0f, 1.0f, 1.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Calculate transformation auto t_now = std::chrono::high_resolution_clock::now(); float time = std::chrono::duration_cast>(t_now - t_start).count(); glm::mat4 model; model = glm::rotate( model, time * glm::radians(180.0f), glm::vec3(0.0f, 0.0f, 1.0f) ); glUniformMatrix4fv(uniModel, 1, GL_FALSE, glm::value_ptr(model)); // Draw cube glDrawArrays(GL_TRIANGLES, 0, 36); glEnable(GL_STENCIL_TEST); // Draw floor glStencilFunc(GL_ALWAYS, 1, 0xFF); glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE); glStencilMask(0xFF); glDepthMask(GL_FALSE); glClear(GL_STENCIL_BUFFER_BIT); glDrawArrays(GL_TRIANGLES, 36, 6); // Draw cube reflection glStencilFunc(GL_EQUAL, 1, 0xFF); glStencilMask(0x00); glDepthMask(GL_TRUE); model = glm::scale(glm::translate(model, glm::vec3(0, 0, -1)), glm::vec3(1, 1, -1)); glUniformMatrix4fv(uniModel, 1, GL_FALSE, glm::value_ptr(model)); glUniform3f(uniColor, 0.3f, 0.3f, 0.3f); glDrawArrays(GL_TRIANGLES, 0, 36); glUniform3f(uniColor, 1.0f, 1.0f, 1.0f); glDisable(GL_STENCIL_TEST); // Bind default framebuffer and draw contents of our framebuffer glBindFramebuffer(GL_FRAMEBUFFER, 0); glBindVertexArray(vaoQuad); glDisable(GL_DEPTH_TEST); glUseProgram(screenShaderProgram); glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D, texColorBuffer); glDrawArrays(GL_TRIANGLES, 0, 6); // Swap buffers window.display(); } glDeleteRenderbuffers(1, &rboDepthStencil); glDeleteTextures(1, &texColorBuffer); glDeleteFramebuffers(1, &frameBuffer); glDeleteTextures(1, &texKitten); glDeleteTextures(1, &texPuppy); glDeleteProgram(screenShaderProgram); glDeleteShader(screenFragmentShader); glDeleteShader(screenVertexShader); glDeleteProgram(sceneShaderProgram); glDeleteShader(sceneFragmentShader); glDeleteShader(sceneVertexShader); glDeleteBuffers(1, &vboCube); glDeleteBuffers(1, &vboQuad); glDeleteVertexArrays(1, &vaoCube); glDeleteVertexArrays(1, &vaoQuad); window.close(); return 0; }