Initial Commit

README.md

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+# Introduction to PyOpenGL
+
+A basic introduction to PyOpenGL (using GLFW for GUI).
+
+## Requirements
+```
+pip install -r requirements.txt
+```
+
+## Tutorial 1
+Creating a GLFW Window.
+
+## Tutorial 2
+Drawing a static triangle in the GLFW Window.
+
+## Tutorial 3 
+Creating an animated cubical crate.

requirements.txt

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+pyopengl==3.1.6
+glfw==2.5.4
+pyrr==0.10.3
+pillow==8.4.0

tute1.py

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+import glfw
+
+# initializing glfw library
+if not glfw.init():
+    raise Exception("glfw can not be initialized!")
+
+# creating the window
+window = glfw.create_window(600, 600, "My OpenGL window", None, None)
+
+# check if window was created
+if not window:
+    glfw.terminate()
+    raise Exception("glfw window can not be created!")
+
+# set window's position
+glfw.set_window_pos(window, 650, 250)
+
+# make the context current
+glfw.make_context_current(window)
+
+# the main application loop
+while not glfw.window_should_close(window):
+    glfw.poll_events()
+    glfw.swap_buffers(window)
+
+# terminate glfw, free up allocated resources
+glfw.terminate()

tute2.py

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+import glfw
+from OpenGL.GL import *
+from OpenGL.GL.shaders import compileProgram, compileShader
+import numpy as np
+
+vertex_src = """
+# version 330
+
+in vec3 a_position;
+in vec3 a_color;
+
+out vec3 v_color;
+
+void main()
+{
+    gl_Position = vec4(a_position, 1.0);
+    v_color = a_color;
+}
+"""
+
+fragment_src = """
+# version 330
+
+in vec3 v_color;
+out vec4 out_color;
+
+void main()
+{
+    out_color = vec4(v_color, 1.0);
+}
+"""
+
+# initializing glfw library
+if not glfw.init():
+    raise Exception("glfw can not be initialized!")
+
+# creating the window
+window = glfw.create_window(600, 600, "My OpenGL window", None, None)
+
+# check if window was created
+if not window:
+    glfw.terminate()
+    raise Exception("glfw window can not be created!")
+
+# set window's position
+glfw.set_window_pos(window, 650, 250)
+
+# make the context current
+glfw.make_context_current(window)
+
+vertices = [-0.5, -0.5, 0.0, 1.0, 0.0, 0.0,
+             0.5, -0.5, 0.0, 0.0, 1.0, 0.0,
+             0.0,  0.5, 0.0, 0.0, 0.0, 1.0]
+
+vertices = np.array(vertices, dtype=np.float32)
+
+shader = compileProgram(compileShader(vertex_src, GL_VERTEX_SHADER), compileShader(fragment_src, GL_FRAGMENT_SHADER))
+
+VBO = glGenBuffers(1)
+glBindBuffer(GL_ARRAY_BUFFER, VBO)
+glBufferData(GL_ARRAY_BUFFER, vertices.nbytes, vertices, GL_STATIC_DRAW)
+
+position = glGetAttribLocation(shader, "a_position")
+glEnableVertexAttribArray(position)
+glVertexAttribPointer(position, 3, GL_FLOAT, GL_FALSE, 24, ctypes.c_void_p(0))
+
+color = glGetAttribLocation(shader, "a_color")
+glEnableVertexAttribArray(color)
+glVertexAttribPointer(color, 3, GL_FLOAT, GL_FALSE, 24, ctypes.c_void_p(12))
+
+glUseProgram(shader)
+glClearColor(0, 0.1, 0.1, 1)
+
+# the main application loop
+while not glfw.window_should_close(window):
+    glfw.poll_events()
+
+    glClear(GL_COLOR_BUFFER_BIT)
+
+    glDrawArrays(GL_TRIANGLES, 0, 3)
+
+    glfw.swap_buffers(window)
+
+# terminate glfw, free up allocated resources
+glfw.terminate()

tute3.py

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+import glfw
+from OpenGL.GL import *
+from OpenGL.GL.shaders import compileProgram, compileShader
+import numpy as np
+import pyrr
+from PIL import Image
+
+vertex_src = """
+# version 330
+
+layout(location = 0) in vec3 a_position;
+layout(location = 1) in vec3 a_color;
+layout(location = 2) in vec2 a_texture;
+
+uniform mat4 rotation;
+
+out vec3 v_color;
+out vec2 v_texture;
+
+void main()
+{
+    gl_Position = rotation * vec4(a_position, 1.0);
+    v_color = a_color;
+    v_texture = a_texture;
+    
+    //v_texture = 1 - a_texture;                      // Flips the texture vertically and horizontally
+    //v_texture = vec2(a_texture.s, 1 - a_texture.t); // Flips the texture vertically
+}
+"""
+
+fragment_src = """
+# version 330
+
+in vec3 v_color;
+in vec2 v_texture;
+
+out vec4 out_color;
+
+uniform sampler2D s_texture;
+
+void main()
+{
+    out_color = texture(s_texture, v_texture); // * vec4(v_color, 1.0f);
+}
+"""
+
+# glfw callback functions
+def window_resize(window, width, height):
+    glViewport(0, 0, width, height)
+
+# initializing glfw library
+if not glfw.init():
+    raise Exception("glfw can not be initialized!")
+
+# creating the window
+window = glfw.create_window(600, 600, "My OpenGL window", None, None)
+
+# check if window was created
+if not window:
+    glfw.terminate()
+    raise Exception("glfw window can not be created!")
+
+# set window's position
+glfw.set_window_pos(window, 650, 250)
+
+# set the callback function for window resize
+glfw.set_window_size_callback(window, window_resize)
+
+# make the context current
+glfw.make_context_current(window)
+
+vertices = [-0.5, -0.5,  0.5,  1.0, 0.0, 0.0,  0.0, 0.0,
+             0.5, -0.5,  0.5,  0.0, 1.0, 0.0,  1.0, 0.0,
+             0.5,  0.5,  0.5,  0.0, 0.0, 1.0,  1.0, 1.0,
+            -0.5,  0.5,  0.5,  1.0, 1.0, 1.0,  0.0, 1.0,
+
+            -0.5, -0.5, -0.5,  1.0, 0.0, 0.0,  0.0, 0.0,
+             0.5, -0.5, -0.5,  0.0, 1.0, 0.0,  1.0, 0.0,
+             0.5,  0.5, -0.5,  0.0, 0.0, 1.0,  1.0, 1.0,
+            -0.5,  0.5, -0.5,  1.0, 1.0, 1.0,  0.0, 1.0,
+
+             0.5, -0.5, -0.5,  1.0, 0.0, 0.0,  0.0, 0.0,
+             0.5,  0.5, -0.5,  0.0, 1.0, 0.0,  1.0, 0.0,
+             0.5,  0.5,  0.5,  0.0, 0.0, 1.0,  1.0, 1.0,
+             0.5, -0.5,  0.5,  1.0, 1.0, 1.0,  0.0, 1.0,
+
+            -0.5,  0.5, -0.5,  1.0, 0.0, 0.0,  0.0, 0.0,
+            -0.5, -0.5, -0.5,  0.0, 1.0, 0.0,  1.0, 0.0,
+            -0.5, -0.5,  0.5,  0.0, 0.0, 1.0,  1.0, 1.0,
+            -0.5,  0.5,  0.5,  1.0, 1.0, 1.0,  0.0, 1.0,
+
+            -0.5, -0.5, -0.5,  1.0, 0.0, 0.0,  0.0, 0.0,
+             0.5, -0.5, -0.5,  0.0, 1.0, 0.0,  1.0, 0.0,
+             0.5, -0.5,  0.5,  0.0, 0.0, 1.0,  1.0, 1.0,
+            -0.5, -0.5,  0.5,  1.0, 1.0, 1.0,  0.0, 1.0,
+
+             0.5,  0.5, -0.5,  1.0, 0.0, 0.0,  0.0, 0.0,
+            -0.5,  0.5, -0.5,  0.0, 1.0, 0.0,  1.0, 0.0,
+            -0.5,  0.5,  0.5,  0.0, 0.0, 1.0,  1.0, 1.0,
+             0.5,  0.5,  0.5,  1.0, 1.0, 1.0,  0.0, 1.0]
+
+indices = [0,  1,  2,  2,  3,  0,
+           4,  5,  6,  6,  7,  4,
+           8,  9, 10, 10, 11,  8,
+          12, 13, 14, 14, 15, 12,
+          16, 17, 18, 18, 19, 16,
+          20, 21, 22, 22, 23, 20]
+
+vertices = np.array(vertices, dtype=np.float32)
+indices = np.array(indices, dtype=np.uint32)
+
+shader = compileProgram(compileShader(vertex_src, GL_VERTEX_SHADER), compileShader(fragment_src, GL_FRAGMENT_SHADER))
+
+# Vertex Buffer Object
+VBO = glGenBuffers(1)
+glBindBuffer(GL_ARRAY_BUFFER, VBO)
+glBufferData(GL_ARRAY_BUFFER, vertices.nbytes, vertices, GL_STATIC_DRAW)
+
+# Element Buffer Object
+EBO = glGenBuffers(1)
+glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO)
+glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.nbytes, indices, GL_STATIC_DRAW)
+
+glEnableVertexAttribArray(0)
+glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, vertices.itemsize * 8, ctypes.c_void_p(0))
+
+glEnableVertexAttribArray(1)
+glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, vertices.itemsize * 8, ctypes.c_void_p(12))
+
+glEnableVertexAttribArray(2)
+glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, vertices.itemsize * 8, ctypes.c_void_p(24))
+
+texture = glGenTextures(1)
+glBindTexture(GL_TEXTURE_2D, texture)
+
+# Set the texture wrapping parameters
+glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
+glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
+# Set texture filtering parameters
+glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
+glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
+
+# load image
+image = Image.open("images/crate.jpg")
+image = image.transpose(Image.FLIP_TOP_BOTTOM)
+img_data = image.convert("RGBA").tobytes()
+# img_data = np.array(image.getdata(), np.uint8) # second way of getting the raw image data
+glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width, image.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, img_data)
+
+glUseProgram(shader)
+glClearColor(0, 0.1, 0.1, 1)
+glEnable(GL_DEPTH_TEST)
+glEnable(GL_BLEND)
+glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
+
+rotation_loc = glGetUniformLocation(shader, "rotation")
+
+# the main application loop
+while not glfw.window_should_close(window):
+    glfw.poll_events()
+
+    glClear(GL_COLOR_BUFFER_BIT|GL_DEPTH_BUFFER_BIT)
+
+    rot_x = pyrr.Matrix44.from_x_rotation(0.5 * glfw.get_time())
+    rot_y = pyrr.Matrix44.from_y_rotation(0.8 * glfw.get_time())
+
+    glUniformMatrix4fv(rotation_loc, 1, GL_FALSE, pyrr.matrix44.multiply(rot_x, rot_y))
+
+    glDrawElements(GL_TRIANGLES, len(indices), GL_UNSIGNED_INT, None)
+
+    glfw.swap_buffers(window)
+
+# terminate glfw, free up allocated resources
+glfw.terminate()