OpenGL with Python 5: Loading Obj Models

In this tutorial, we will learn how to load Obj models in OpenGL using Python. Obj models are a popular file format for representing 3D models with vertices, texture coordinates, and normals.

First, we need to install the required libraries for this tutorial. We will use PyOpenGL, PyOpenGL-accelerate, and PyObj for loading and rendering the Obj models. You can install these libraries using pip:


pip install PyOpenGL PyOpenGL-accelerate PyObj


Once you have installed the necessary libraries, let’s move on to loading the Obj models in our OpenGL program. We will use the below code snippet to load an Obj model:


import objloader

obj = objloader.OBJ("model.obj")
vertices, normals, texcoords, faces = obj.unpack('T2', 'N3', 'VT2', faces=True)


With the above code snippet, we have loaded the Obj model and extracted its vertices, normals, texture coordinates, and faces. Now, we can render this model in our OpenGL program.

Below is a simple code snippet to render the loaded Obj model:


import OpenGL.GL as gl

def render():
gl.glBegin(gl.GL_TRIANGLES)
for face in faces:
for i in range(3):
vertex_index, texture_index, normal_index = face[i]
gl.glVertex3fv(vertices[vertex_index])
gl.glNormal3fv(normals[normal_index])
gl.glTexCoord2fv(texcoords[texture_index])
gl.glEnd()


Finally, we need to call the render function in our OpenGL program to display the loaded Obj model on the screen. You can combine this code with other OpenGL features like lighting, shading, textures, etc., to create a visually appealing 3D rendering.

That’s it! You have now learned how to load Obj models in OpenGL using Python. Feel free to experiment with different Obj models and OpenGL functionalities to create stunning 3D visuals in your applications. Happy coding!