Files
godot-demo-projects/compute/post_shader/post_process_grayscale.gd

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3.2 KiB
GDScript

@tool
class_name PostProcessGrayScale
extends CompositorEffect
var rd: RenderingDevice
var shader: RID
var pipeline: RID
func _init() -> void:
effect_callback_type = EFFECT_CALLBACK_TYPE_POST_TRANSPARENT
rd = RenderingServer.get_rendering_device()
RenderingServer.call_on_render_thread(_initialize_compute)
# System notifications, we want to react on the notification that
# alerts us we are about to be destroyed.
func _notification(what: int) -> void:
if what == NOTIFICATION_PREDELETE:
if shader.is_valid():
# Freeing our shader will also free any dependents such as the pipeline!
rd.free_rid(shader)
#region Code in this region runs on the rendering thread.
# Compile our shader at initialization.
func _initialize_compute() -> void:
rd = RenderingServer.get_rendering_device()
if not rd:
return
# Compile our shader.
var shader_file := load("res://post_process_grayscale.glsl")
var shader_spirv: RDShaderSPIRV = shader_file.get_spirv()
shader = rd.shader_create_from_spirv(shader_spirv)
if shader.is_valid():
pipeline = rd.compute_pipeline_create(shader)
# Called by the rendering thread every frame.
func _render_callback(p_effect_callback_type: EffectCallbackType, p_render_data: RenderData) -> void:
if rd and p_effect_callback_type == EFFECT_CALLBACK_TYPE_POST_TRANSPARENT and pipeline.is_valid():
# Get our render scene buffers object, this gives us access to our render buffers.
# Note that implementation differs per renderer hence the need for the cast.
var render_scene_buffers := p_render_data.get_render_scene_buffers()
if render_scene_buffers:
# Get our render size, this is the 3D render resolution!
var size: Vector2i = render_scene_buffers.get_internal_size()
if size.x == 0 and size.y == 0:
return
# We can use a compute shader here.
@warning_ignore("integer_division")
var x_groups := (size.x - 1) / 8 + 1
@warning_ignore("integer_division")
var y_groups := (size.y - 1) / 8 + 1
var z_groups := 1
# Create push constant.
# Must be aligned to 16 bytes and be in the same order as defined in the shader.
var push_constant := PackedFloat32Array([
size.x,
size.y,
0.0,
0.0,
])
# Loop through views just in case we're doing stereo rendering. No extra cost if this is mono.
var view_count: int = render_scene_buffers.get_view_count()
for view in view_count:
# Get the RID for our color image, we will be reading from and writing to it.
var input_image: RID = render_scene_buffers.get_color_layer(view)
# Create a uniform set, this will be cached, the cache will be cleared if our viewports configuration is changed.
var uniform := RDUniform.new()
uniform.uniform_type = RenderingDevice.UNIFORM_TYPE_IMAGE
uniform.binding = 0
uniform.add_id(input_image)
var uniform_set := UniformSetCacheRD.get_cache(shader, 0, [uniform])
# Run our compute shader.
var compute_list := rd.compute_list_begin()
rd.compute_list_bind_compute_pipeline(compute_list, pipeline)
rd.compute_list_bind_uniform_set(compute_list, uniform_set, 0)
rd.compute_list_set_push_constant(compute_list, push_constant.to_byte_array(), push_constant.size() * 4)
rd.compute_list_dispatch(compute_list, x_groups, y_groups, z_groups)
rd.compute_list_end()
#endregion