godot-demo-projects/compute/post_shader/post_process_shader.gd

161 lines
4.8 KiB
GDScript

@tool
extends CompositorEffect
class_name PostProcessShader
const template_shader := """#version 450
// Invocations in the (x, y, z) dimension.
layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in;
layout(rgba16f, set = 0, binding = 0) uniform image2D color_image;
// Our push constant.
// Must be aligned to 16 bytes, just like the push constant we passed from the script.
layout(push_constant, std430) uniform Params {
vec2 raster_size;
vec2 pad;
} params;
// The code we want to execute in each invocation.
void main() {
ivec2 uv = ivec2(gl_GlobalInvocationID.xy);
ivec2 size = ivec2(params.raster_size);
if (uv.x >= size.x || uv.y >= size.y) {
return;
}
vec4 color = imageLoad(color_image, uv);
#COMPUTE_CODE
imageStore(color_image, uv, color);
}"""
@export_multiline var shader_code := "":
set(value):
mutex.lock()
shader_code = value
shader_is_dirty = true
mutex.unlock()
var rd: RenderingDevice
var shader: RID
var pipeline: RID
var mutex := Mutex.new()
var shader_is_dirty := true
func _init() -> void:
effect_callback_type = EFFECT_CALLBACK_TYPE_POST_TRANSPARENT
rd = RenderingServer.get_rendering_device()
# 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!
RenderingServer.free_rid(shader)
#region Code in this region runs on the rendering thread.
# Check if our shader has changed and needs to be recompiled.
func _check_shader() -> bool:
if not rd:
return false
var new_shader_code := ""
# Check if our shader is dirty.
mutex.lock()
if shader_is_dirty:
new_shader_code = shader_code
shader_is_dirty = false
mutex.unlock()
# We don't have a (new) shader?
if new_shader_code.is_empty():
return pipeline.is_valid()
# Apply template.
new_shader_code = template_shader.replace("#COMPUTE_CODE", new_shader_code);
# Out with the old.
if shader.is_valid():
rd.free_rid(shader)
shader = RID()
pipeline = RID()
# In with the new.
var shader_source := RDShaderSource.new()
shader_source.language = RenderingDevice.SHADER_LANGUAGE_GLSL
shader_source.source_compute = new_shader_code
var shader_spirv : RDShaderSPIRV = rd.shader_compile_spirv_from_source(shader_source)
if shader_spirv.compile_error_compute != "":
push_error(shader_spirv.compile_error_compute)
push_error("In: " + new_shader_code)
return false
shader = rd.shader_create_from_spirv(shader_spirv)
if not shader.is_valid():
return false
pipeline = rd.compute_pipeline_create(shader)
return pipeline.is_valid()
# 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 _check_shader():
# 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