- 6 * sizeof(float), (void*)0 The total length is 6 and the initial position is 0
- 6 * sizeof(float), (void*)(3 * sizeof(float)) total length 6, initial position 3
float vertices[] = {
// positions // colors
0.5 f.0.5 f.0.0 f.1.0 f.0.0 f.0.0 f.// bottom right
0.5 f.0.5 f.0.0 f.0.0 f.1.0 f.0.0 f.// bottom left
0.0 f.0.5 f.0.0 f.0.0 f.0.0 f.1.0 f // top
};
unsigned int VBO, VAO;
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
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(float), (void*)0);
glEnableVertexAttribArray(0);
// color attribute
glVertexAttribPointer(1.3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void(*)3 * sizeof(float)));
glEnableVertexAttribArray(1);
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The original
#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"
"layout (location = 1) in vec3 aColor; \n"
"out vec3 ourColor; \n"
"void main()\n"
"{\n"
"Gl_Position = vec4(aPos, 1.0); \n"
" ourColor = aColor; \n"
"} \ 0";
const char* fragmentShaderSource = "#version 330 core\n"
"out vec4 FragColor; \n"
"in vec3 ourColor; \n"
"void main()\n"
"{\n"
"FragColor = vec4(ourColor, 1.0f); \n"
"}\n\0";
int main(a)
{
// glfw: initialize and configure
// ------------------------------
glfwInit(a);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(a);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(a);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[] = {
// positions // colors
0.5 f.0.5 f.0.0 f.1.0 f.0.0 f.0.0 f.// bottom right
0.5 f.0.5 f.0.0 f.0.0 f.1.0 f.0.0 f.// bottom left
0.0 f.0.5 f.0.0 f.0.0 f.0.0 f.1.0 f // 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);
// position attribute
glVertexAttribPointer(0.3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// color attribute
glVertexAttribPointer(1.3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void(*)3 * sizeof(float)));
glEnableVertexAttribArray(1);
// 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);
// as we only have a single shader, we could also just activate our shader once beforehand if we want to
glUseProgram(shaderProgram);
// render loop
// -----------
while (!glfwWindowShouldClose(window))
{
// input
// -----
processInput(window);
// render
// ------
glClearColor(0.2 f.0.3 f.0.3 f.1.0 f);
glClear(GL_COLOR_BUFFER_BIT);
// render the triangle
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0.3);
// glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
// -------------------------------------------------------------------------------
glfwSwapBuffers(window);
glfwPollEvents(a); }// 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(a);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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