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Diffstat (limited to 'works/life/computer-graphics-experiment/4.cpp')
| -rw-r--r-- | works/life/computer-graphics-experiment/4.cpp | 192 |
1 files changed, 192 insertions, 0 deletions
diff --git a/works/life/computer-graphics-experiment/4.cpp b/works/life/computer-graphics-experiment/4.cpp new file mode 100644 index 0000000..9852844 --- /dev/null +++ b/works/life/computer-graphics-experiment/4.cpp @@ -0,0 +1,192 @@ +// Code from https://learnopengl.com/Getting-started/Hello-Triangle + +#include <glad/glad.h> + +#include <GLFW/glfw3.h> + +#include <iostream> + +void framebuffer_size_callback(GLFWwindow *window, int width, int height); +void processInput(GLFWwindow *window); + +// settings +const unsigned int SCR_WIDTH = 800; +const unsigned int SCR_HEIGHT = 600; + +const char *vertexShaderSource = + "#version 330 core\n" + "layout (location = 0) in vec3 aPos;\n" + "void main()\n" + "{\n" + " gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n" + "}\0"; +const char *fragmentShaderSource = + "#version 330 core\n" + "out vec4 FragColor;\n" + "void main()\n" + "{\n" + " FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n" + "}\n\0"; + +int main() { + // glfw: initialize and configure + // ------------------------------ + glfwInit(); + glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); + glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); + glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); + +#ifdef __APPLE__ + glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); +#endif + + // glfw window creation + // -------------------- + GLFWwindow *window = + glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL); + if (window == NULL) { + std::cout << "Failed to create GLFW window" << std::endl; + glfwTerminate(); + return -1; + } + glfwMakeContextCurrent(window); + glfwSetFramebufferSizeCallback(window, framebuffer_size_callback); + + // glad: load all OpenGL function pointers + // --------------------------------------- + if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) { + std::cout << "Failed to initialize GLAD" << std::endl; + return -1; + } + + // build and compile our shader program + // ------------------------------------ + // vertex shader + unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER); + glShaderSource(vertexShader, 1, &vertexShaderSource, NULL); + glCompileShader(vertexShader); + // check for shader compile errors + int success; + char infoLog[512]; + glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success); + if (!success) { + glGetShaderInfoLog(vertexShader, 512, NULL, infoLog); + std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" + << infoLog << std::endl; + } + // fragment shader + unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER); + glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL); + glCompileShader(fragmentShader); + // check for shader compile errors + glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success); + if (!success) { + glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog); + std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" + << infoLog << std::endl; + } + // link shaders + unsigned int shaderProgram = glCreateProgram(); + glAttachShader(shaderProgram, vertexShader); + glAttachShader(shaderProgram, fragmentShader); + glLinkProgram(shaderProgram); + // check for linking errors + glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success); + if (!success) { + glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog); + std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" + << infoLog << std::endl; + } + glDeleteShader(vertexShader); + glDeleteShader(fragmentShader); + + // set up vertex data (and buffer(s)) and configure vertex attributes + // ------------------------------------------------------------------ + float vertices[] = { + -0.5f, -0.5f, 0.0f, // left + 0.5f, -0.5f, 0.0f, // right + 0.0f, 0.5f, 0.0f // top + }; + + unsigned int VBO, VAO; + glGenVertexArrays(1, &VAO); + glGenBuffers(1, &VBO); + // bind the Vertex Array Object first, then bind and set vertex buffer(s), and + // then configure vertex attributes(s). + glBindVertexArray(VAO); + + glBindBuffer(GL_ARRAY_BUFFER, VBO); + glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); + + glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0); + glEnableVertexAttribArray(0); + + // note that this is allowed, the call to glVertexAttribPointer registered VBO + // as the vertex attribute's bound vertex buffer object so afterwards we can + // safely unbind + glBindBuffer(GL_ARRAY_BUFFER, 0); + + // You can unbind the VAO afterwards so other VAO calls won't accidentally + // modify this VAO, but this rarely happens. Modifying other VAOs requires a + // call to glBindVertexArray anyways so we generally don't unbind VAOs (nor + // VBOs) when it's not directly necessary. + glBindVertexArray(0); + + // uncomment this call to draw in wireframe polygons. + // glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); + + // render loop + // ----------- + while (!glfwWindowShouldClose(window)) { + // input + // ----- + processInput(window); + + // render + // ------ + glClearColor(0.2f, 0.3f, 0.3f, 1.0f); + glClear(GL_COLOR_BUFFER_BIT); + + // draw our first triangle + glUseProgram(shaderProgram); + glBindVertexArray( + VAO); // seeing as we only have a single VAO there's no need to bind it + // every time, but we'll do so to keep things a bit more organized + glDrawArrays(GL_TRIANGLES, 0, 3); + // glBindVertexArray(0); // no need to unbind it every time + + // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved + // etc.) + // ------------------------------------------------------------------------------- + glfwSwapBuffers(window); + glfwPollEvents(); + } + + // optional: de-allocate all resources once they've outlived their purpose: + // ------------------------------------------------------------------------ + glDeleteVertexArrays(1, &VAO); + glDeleteBuffers(1, &VBO); + glDeleteProgram(shaderProgram); + + // glfw: terminate, clearing all previously allocated GLFW resources. + // ------------------------------------------------------------------ + glfwTerminate(); + return 0; +} + +// process all input: query GLFW whether relevant keys are pressed/released this +// frame and react accordingly +// --------------------------------------------------------------------------------------------------------- +void processInput(GLFWwindow *window) { + if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) + glfwSetWindowShouldClose(window, true); +} + +// glfw: whenever the window size changed (by OS or user resize) this callback +// function executes +// --------------------------------------------------------------------------------------------- +void framebuffer_size_callback(GLFWwindow *window, int width, int height) { + // make sure the viewport matches the new window dimensions; note that width + // and height will be significantly larger than specified on retina displays. + glViewport(0, 0, width, height); +}
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