Scope¶
-
class
moderngl.
Scope
¶ This class represents a Scope object.
Responsibilities on enter:
- Set the enable flags.
- Bind the framebuffer.
- Assing textures to texture locations.
- Assing buffers to uniform buffers.
- Assing buffers to shader storage buffers.
Responsibilities on exit:
- Restore the enable flags.
- Restore the framebuffer.
Create¶
-
Context.
scope
(framebuffer, enable_only=None, textures=(), uniform_buffers=(), storage_buffers=()) → Scope Create a
Scope
object.Parameters: - framebuffer (Framebuffer) – The framebuffer to use when entering.
- enable_only (int) – The enable_only flags to set when entering.
Keyword Arguments: - textures (list) – List of (texture, binding) tuples.
- uniform_buffers (list) – List of (buffer, binding) tuples.
- storage_buffers (list) – List of (buffer, binding) tuples.
Examples¶
Simple scope example
scope1 = ctx.scope(fbo1, moderngl.BLEND)
scope2 = ctx.scope(fbo2, moderngl.DEPTH_TEST | moderngl.CULL_FACE)
with scope1:
# do some rendering
with scope2:
# do some rendering
Scope for querying
query = ctx.query(samples=True)
scope = ctx.scope(ctx.screen, moderngl.DEPTH_TEST | moderngl.RASTERIZER_DISCARD)
with scope, query:
# do some rendering
print(query.samples)
Understanding what scope objects do
scope = ctx.scope(
framebuffer=framebuffer1,
enable_flags=moderngl.BLEND,
textures=[
(texture1, 4),
(texture2, 3),
],
uniform_buffers=[
(buffer1, 6),
(buffer2, 5),
],
storage_buffers=[
(buffer3, 8),
],
)
# Let's assume we have some state before entering the scope
some_random_framebuffer.use()
some_random_texture.use(3)
some_random_buffer.bind_to_uniform_block(5)
some_random_buffer.bind_to_storage_buffer(8)
ctx.enable_only(moderngl.DEPTH_TEST)
with scope:
# on __enter__
# framebuffer1.use()
# ctx.enable_only(moderngl.BLEND)
# texture1.use(4)
# texture2.use(3)
# buffer1.bind_to_uniform_block(6)
# buffer2.bind_to_uniform_block(5)
# buffer3.bind_to_storage_buffer(8)
# do some rendering
# on __exit__
# some_random_framebuffer.use()
# ctx.enable_only(moderngl.DEPTH_TEST)
# Originally we had the following, let's see what was changed
some_random_framebuffer.use() # This was restored hurray!
some_random_texture.use(3) # Have to restore it manually.
some_random_buffer.bind_to_uniform_block(5) # Have to restore it manually.
some_random_buffer.bind_to_storage_buffer(8) # Have to restore it manually.
ctx.enable_only(moderngl.DEPTH_TEST) # This was restored too.
# Scope objects only do as much as neccessary.
# Restoring the framebuffer and enable flags are lowcost operations and
# without them you could get a hard time debugging the application.