Created
January 19, 2024 05:28
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OpenGL triangle interpolated colors code
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#include <spdlog/spdlog.h> | |
#include <glad/glad.h> | |
#include <GLFW/glfw3.h> | |
const char* vertShaderSource = R"( | |
#version 330 core | |
layout(location = 0) in vec3 aPos; | |
layout(location = 1) in vec3 aColor; | |
out vec3 vertexColor; | |
void main() { | |
gl_Position = vec4(aPos, 1.0); | |
vertexColor = aColor; | |
})"; | |
const char* fragShaderSource = R"( | |
#version 330 core | |
in vec3 vertexColor; | |
out vec4 FragColor; | |
void main() { | |
FragColor = vec4(vertexColor, 1.0); | |
})"; | |
void window_resize_callback(GLFWwindow* window, int width, int height) { | |
glViewport(0, 0, width, height); | |
spdlog::info("Window resized to dimensions: {:d}x{:d}", width, height); | |
} | |
int main() { | |
spdlog::info("Initialize GLFW"); | |
if (!glfwInit()) { | |
spdlog::error("Failed to initialize GLFW"); | |
return EXIT_FAILURE; | |
} | |
spdlog::info("Set OpenGL 3.3 core profile"); | |
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3); | |
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3); | |
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); | |
spdlog::info("Create window: 640x480"); | |
GLFWwindow* window = glfwCreateWindow(640, 480, "OpenGL Playground", nullptr, nullptr); | |
if (!window) { | |
spdlog::error("Failed to create window"); | |
spdlog::info("Initiate cleanup"); | |
glfwTerminate(); | |
return EXIT_FAILURE; | |
} | |
glfwSetWindowSizeCallback(window, window_resize_callback); | |
glfwMakeContextCurrent(window); | |
spdlog::info("Load OpenGL function pointers"); | |
if (!gladLoadGL()) { | |
spdlog::error("Failed to load OpenGL function pointers"); | |
spdlog::info("Initiate cleanup"); | |
glfwDestroyWindow(window); | |
glfwTerminate(); | |
return EXIT_FAILURE; | |
} | |
GLfloat vertices[] = { | |
-0.5f, -0.433f, 0.0f, | |
1.0f, 0.0f, 0.0f, | |
0.5f, -0.433f, 0.0f, | |
0.0f, 1.0f, 0.0f, | |
0.0f, 0.433f, 0.0f, | |
0.0f, 0.0f, 1.0f, | |
}; | |
GLuint indices[] = { | |
0, 1, 2 | |
}; | |
spdlog::info("Setup graphics pipeline"); | |
spdlog::info("Process vertex and fragment shaders"); | |
GLuint vertShader, fragShader, shaderProg; | |
vertShader = glCreateShader(GL_VERTEX_SHADER); | |
glShaderSource(vertShader, 1, &vertShaderSource, nullptr); | |
glCompileShader(vertShader); | |
fragShader = glCreateShader(GL_FRAGMENT_SHADER); | |
glShaderSource(fragShader, 1, &fragShaderSource, nullptr); | |
glCompileShader(fragShader); | |
shaderProg = glCreateProgram(); | |
glAttachShader(shaderProg, vertShader); | |
glAttachShader(shaderProg, fragShader); | |
glLinkProgram(shaderProg); | |
glDeleteShader(vertShader); | |
glDeleteShader(fragShader); | |
spdlog::info("Setup VAO, VBO, and IBO"); | |
GLuint VAO, VBO, IBO; | |
glGenVertexArrays(1, &VAO); | |
glGenBuffers(1, &VBO); | |
glGenBuffers(1, &IBO); | |
glBindVertexArray(VAO); | |
glBindBuffer(GL_ARRAY_BUFFER, VBO); | |
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW); | |
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, IBO); | |
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW); | |
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), nullptr); | |
glEnableVertexAttribArray(0); | |
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (void*)(3 * sizeof(GLfloat))); | |
glEnableVertexAttribArray(1); | |
spdlog::info("Start window event loop"); | |
while (!glfwWindowShouldClose(window)) { | |
glClearColor(0.0f, 0.0f, 0.0f, 1.0f); | |
glClear(GL_COLOR_BUFFER_BIT); | |
glUseProgram(shaderProg); | |
glDrawElements(GL_TRIANGLES, 3, GL_UNSIGNED_INT, 0); | |
glfwSwapBuffers(window); | |
glfwPollEvents(); | |
} | |
spdlog::info("Initiate cleanup"); | |
glDeleteBuffers(1, &VBO); | |
glDeleteBuffers(1, &IBO); | |
glDeleteVertexArrays(1, &VAO); | |
glfwDestroyWindow(window); | |
glfwTerminate(); | |
return EXIT_SUCCESS; | |
} |
glfwPollEvents()
is used here to capture window events (maximize, minimize, etc).
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glfwPollEvents() ? i usually do: first input handling and update, then draw the current/updated.
clear + draw + swap is fine as sequence.