ep21_texturing_from_framebuffers.py

import glfw
from OpenGL.GL import *
from OpenGL.GL.shaders import compileProgram, compileShader
import pyrr
from TextureLoader import load_texture
from ObjLoader import ObjLoader
import numpy as np

from camera import Camera

cam = Camera()
WIDTH, HEIGHT = 1280, 720
lastX, lastY = WIDTH / 2, HEIGHT / 2
first_mouse = True
left, right, forward, backward = False, False, False, False


# the keyboard input callback
def key_input_clb(window, key, scancode, action, mode):
    global left, right, forward, backward
    if key == glfw.KEY_ESCAPE and action == glfw.PRESS:
        glfw.set_window_should_close(window, True)

    if key == glfw.KEY_W and action == glfw.PRESS:
        forward = True
    elif key == glfw.KEY_W and action == glfw.RELEASE:
        forward = False
    if key == glfw.KEY_S and action == glfw.PRESS:
        backward = True
    elif key == glfw.KEY_S and action == glfw.RELEASE:
        backward = False
    if key == glfw.KEY_A and action == glfw.PRESS:
        left = True
    elif key == glfw.KEY_A and action == glfw.RELEASE:
        left = False
    if key == glfw.KEY_D and action == glfw.PRESS:
        right = True
    elif key == glfw.KEY_D and action == glfw.RELEASE:
        right = False


# do the movement, call this function in the main loop
def do_movement():
    if left:
        cam.process_keyboard("LEFT", 0.1)
    if right:
        cam.process_keyboard("RIGHT", 0.1)
    if forward:
        cam.process_keyboard("FORWARD", 0.1)
    if backward:
        cam.process_keyboard("BACKWARD", 0.1)


# the mouse position callback function
def mouse_look_clb(window, xpos, ypos):
    global first_mouse, lastX, lastY

    if first_mouse:
        lastX = xpos
        lastY = ypos
        first_mouse = False

    xoffset = xpos - lastX
    yoffset = lastY - ypos

    lastX = xpos
    lastY = ypos

    cam.process_mouse_movement(xoffset, yoffset)


vertex_src = """
# version 330

layout(location = 0) in vec3 a_position;
layout(location = 1) in vec2 a_texture;
layout(location = 2) in vec3 a_normal;

uniform mat4 model;
uniform mat4 projection;
uniform mat4 view;

out vec2 v_texture;

void main()
{
    gl_Position = projection * view * model * vec4(a_position, 1.0);
    v_texture = a_texture;
}
"""

fragment_src = """
# version 330

in vec2 v_texture;

out vec4 out_color;

uniform sampler2D s_texture;

void main()
{
    out_color = texture(s_texture, v_texture);
}
"""


# glfw callback functions
def window_resize(window, width, height):
    glViewport(0, 0, width, height)
    projection = pyrr.matrix44.create_perspective_projection_matrix(45, width / height, 0.1, 100)
    glUniformMatrix4fv(proj_loc, 1, GL_FALSE, projection)


# initializing glfw library
if not glfw.init():
    raise Exception("glfw can not be initialized!")

# creating the window
window = glfw.create_window(1280, 720, "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, 400, 200)

# set the callback function for window resize
glfw.set_window_size_callback(window, window_resize)
# set the mouse position callback
glfw.set_cursor_pos_callback(window, mouse_look_clb)
# set the keyboard input callback
glfw.set_key_callback(window, key_input_clb)
# capture the mouse cursor
glfw.set_input_mode(window, glfw.CURSOR, glfw.CURSOR_DISABLED)
# make the context current
glfw.make_context_current(window)

# load here the 3d meshes
chibi_indices, chibi_buffer = ObjLoader.load_model("meshes/chibi.obj")


plane_buffer = [0.0, 0.0, 0.0, 0.0, 0.0,
                10.0, 0.0, 0.0, 1.0, 0.0,
                10.0, 10.0, 0.0, 1.0, 1.0,
                0.0, 10.0, 0.0, 0.0, 1.0]

plane_buffer = np.array(plane_buffer, dtype=np.float32)

plane_indices = [0, 1, 2, 2, 3, 0]
plane_indices = np.array(plane_indices, dtype=np.uint32)

shader = compileProgram(compileShader(vertex_src, GL_VERTEX_SHADER), compileShader(fragment_src, GL_FRAGMENT_SHADER))

# VAO and VBO
VAO = glGenVertexArrays(2)
VBO = glGenBuffers(2)
EBO = glGenBuffers(1)

# Chibi VAO
glBindVertexArray(VAO[0])
# Chibi Vertex Buffer Object
glBindBuffer(GL_ARRAY_BUFFER, VBO[0])
glBufferData(GL_ARRAY_BUFFER, chibi_buffer.nbytes, chibi_buffer, GL_STATIC_DRAW)

# chibi vertices
glEnableVertexAttribArray(0)
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, chibi_buffer.itemsize * 8, ctypes.c_void_p(0))
# chibi textures
glEnableVertexAttribArray(1)
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, chibi_buffer.itemsize * 8, ctypes.c_void_p(12))
# chibi normals
glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, chibi_buffer.itemsize * 8, ctypes.c_void_p(20))
glEnableVertexAttribArray(2)

# Plane VAO
glBindVertexArray(VAO[1])
# Plane Vertex Buffer Object
glBindBuffer(GL_ARRAY_BUFFER, VBO[1])
glBufferData(GL_ARRAY_BUFFER, plane_buffer.nbytes, plane_buffer, GL_STATIC_DRAW)

glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO)
glBufferData(GL_ELEMENT_ARRAY_BUFFER, plane_indices.nbytes, plane_indices, GL_STATIC_DRAW)

# plane vertices
glEnableVertexAttribArray(0)
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, plane_buffer.itemsize * 5, ctypes.c_void_p(0))
# plane textures
glEnableVertexAttribArray(1)
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, plane_buffer.itemsize * 5, ctypes.c_void_p(12))

textures = glGenTextures(2)
load_texture("meshes/chibi.png", textures[0])

# create texture for the plane
glBindTexture(GL_TEXTURE_2D, textures[1])
# texture wrapping params
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
# texture filtering params
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR)
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 1280, 720, 0, GL_RGBA, GL_UNSIGNED_BYTE, None)
glBindTexture(GL_TEXTURE_2D, 0)

depth_buff = glGenRenderbuffers(1)
glBindRenderbuffer(GL_RENDERBUFFER, depth_buff)
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, 1280, 720)

FBO = glGenFramebuffers(1)
glBindFramebuffer(GL_FRAMEBUFFER, FBO)
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, textures[1], 0)
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depth_buff)
glBindFramebuffer(GL_FRAMEBUFFER, 0)

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)

projection = pyrr.matrix44.create_perspective_projection_matrix(45, 1280 / 720, 0.1, 100)
chibi_pos_main = pyrr.matrix44.create_from_translation(pyrr.Vector3([0, 0, -5]))
plane_pos = pyrr.matrix44.create_from_translation(pyrr.Vector3([-20, -3, -10]))

model_loc = glGetUniformLocation(shader, "model")
proj_loc = glGetUniformLocation(shader, "projection")
view_loc = glGetUniformLocation(shader, "view")

glUniformMatrix4fv(proj_loc, 1, GL_FALSE, projection)

# the main application loop
while not glfw.window_should_close(window):
    glfw.poll_events()
    do_movement()

    glClearColor(0, 0.1, 0.1, 1)
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)

    view = cam.get_view_matrix()
    glUniformMatrix4fv(view_loc, 1, GL_FALSE, view)

    rot_y = pyrr.Matrix44.from_y_rotation(0.8 * glfw.get_time())
    model = pyrr.matrix44.multiply(rot_y, chibi_pos_main)

    # draw the chibi character
    glBindVertexArray(VAO[0])
    glBindTexture(GL_TEXTURE_2D, textures[0])
    glUniformMatrix4fv(model_loc, 1, GL_FALSE, model)
    glDrawArrays(GL_TRIANGLES, 0, len(chibi_indices))

    # draw the chibi to the custom frame buffer
    glBindFramebuffer(GL_FRAMEBUFFER, FBO)
    glClearColor(0.0, 0.0, 0.0, 1.0)
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT)
    glDrawArrays(GL_TRIANGLES, 0, len(chibi_indices))
    glBindVertexArray(0)
    glBindFramebuffer(GL_FRAMEBUFFER, 0)

    # draw the plane
    glBindVertexArray(VAO[1])
    glBindTexture(GL_TEXTURE_2D, textures[1])
    glUniformMatrix4fv(model_loc, 1, GL_FALSE, plane_pos)
    glDrawElements(GL_TRIANGLES, len(plane_indices), GL_UNSIGNED_INT, None)

    glfw.swap_buffers(window)

# terminate glfw, free up allocated resources
glfw.terminate()