CODEWITHSUNDEEP
pythonopenglpygletrender-to-texture
timfoden
timfoden

Reputation: 443

Pyglet render into texture

I'm writing a drawing program using pyglet, and I want to be able to have the image being created as separate from the window's buffer (for instance, the image could be larger than the window, or may want to draw to this image at a different rate than the main window is being re-drawn). I want to be able to draw into this off-screen image, then display it in the window, but pyglet doesn't allow drawing to anything else than a window. Is there any simple way I can do this?

I've tried creating a second hidden pyglet window, but this gets rendered at the same rate as the main window which I definitely don't want.

The closest I found was Pyglet draw text into texture, but the code there isn't complete, and also no longer works as the opengl version used by pyglet has moved on.

Upvotes: 0

Views: 598

Answers (1)

timfoden
timfoden

Reputation: 443

The following code works for me, perhaps someone else can improve on my answer:

import pyglet
from pyglet.gl import *
from ctypes import byref

W, H = 800, 600

image   = pyglet.image.create(W, H)
texture = image.get_texture()
window  = pyglet.window.Window(width=W, height=H)

fbo_id = gl.GLuint(0)
glGenFramebuffers(1, byref(fbo_id))
glBindFramebuffer(GL_FRAMEBUFFER, fbo_id)

glBindTexture(GL_TEXTURE_2D, texture.id)

glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture.id, 0)

rect1 = pyglet.shapes.Rectangle(0, 0, W, H, (255, 0, 0) )
rect2 = pyglet.shapes.Rectangle(W//4, H//4, W//2, H//2, (0, 0, 255) )
label = pyglet.text.Label("Hello World", font_name="Times New Roman", font_size=36,
                          x=W//2, y=H//2, anchor_x="center", anchor_y="center")
rect1.draw()
rect2.draw()
label.draw()

@window.event
def on_mouse_drag(x, y, dx, dy, xxx, modifiers):
    glBindFramebuffer(GL_FRAMEBUFFER, fbo_id)
    line = pyglet.shapes.Line(x-dx, y-dy, x, y, 3, (0, 255, 255))
    line.draw()

@window.event
def on_draw():
    glBindFramebuffer(GL_FRAMEBUFFER, 0)
    window.clear()
    texture.blit(0, 0)
    
pyglet.app.run()

Upvotes: 0

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