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Implemented GPU Node requests
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@davids91
davids91 committed Nov 23, 2024
1 parent 4bd70ef commit 99f8ed3
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Showing 4 changed files with 273 additions and 178 deletions.
169 changes: 78 additions & 91 deletions assets/shaders/viewport_render.wgsl
View file
Original file line number Diff line number Diff line change
Expand Up @@ -275,8 +275,27 @@ fn set_brick_used(brick_index: u32) {
}
}

fn request_node(node: u32, child_octant: u32){

// Unique to this implementation, not adapted from rust code
/// Requests the child of the given node to be uploaded
fn request_node(node_meta_index: u32, child_octant: u32) -> bool {
let request_data = (
(node_meta_index & 0x00FFFFFFu)
| ((child_octant & 0x000000FF) << 24)
);
var request_index = 0u;
loop{
let exchange_result = atomicCompareExchangeWeak(
&node_requests[request_index], 0u, request_data
);
if(exchange_result.exchanged || exchange_result.old_value == request_data) {
break;
}
request_index += 1u;
if(request_index >= arrayLength(&node_requests)) {
return false;
}
}
return true;
}

//crate::spatial::math::step_octant
Expand Down Expand Up @@ -399,18 +418,7 @@ fn probe_brick(
) -> OctreeRayIntersection {
if(0 != ((0x01u << (8 + brick_octant)) & metadata[leaf_node_key])) { // brick is not empty
let brick_index = node_children[((leaf_node_key * 8) + brick_octant)];

// Brick not available in memory
if EMPTY_MARKER == brick_index {
return OctreeRayIntersection(true, vec4f(0.5,0.6,0.2,1.), 0, vec3f(0.), vec3f(0., 0., 1.));
}

// +++ DEBUG +++
//set_brick_used(brick_index);
if(0 == debug_interface){
set_brick_used(brick_index);
}
// --- DEBUG ---
set_brick_used(brick_index);
if(0 == ((0x01u << (16 + brick_octant)) & metadata[leaf_node_key])) { // brick is solid
// Whole brick is solid, ray hits it at first connection
return OctreeRayIntersection(
Expand All @@ -427,51 +435,7 @@ fn probe_brick(
brick_bounds, ray_scale_factors, direction_lut_index
);
if leaf_brick_hit.hit == true {

/// +++ DEBUG +++
/*// Color in bricks displayed
var result_rgb = color_palette[voxels[leaf_brick_hit.flat_index].albedo_index];
if 0 != ( metadata[brick_index / 8] & (0x01u << (24u + (brick_index % 8u))) ) {
result_rgb.r += 0.2;
}
return OctreeRayIntersection(
true,
result_rgb,
voxels[leaf_brick_hit.flat_index].content,
point_in_ray_at_distance(ray, *ray_current_distance),
cube_impact_normal(
Cube(
(*brick_bounds).min_position + (
vec3f(leaf_brick_hit.index)
* round((*brick_bounds).size / f32(octree_meta_data.voxel_brick_dim))
),
round((*brick_bounds).size / f32(octree_meta_data.voxel_brick_dim)),
),
point_in_ray_at_distance(ray, *ray_current_distance)
)
);*/

// Display marked bricks only
if 0 != ( metadata[brick_index / 8] & (0x01u << (24u + (brick_index % 8u))) ) {
return OctreeRayIntersection(
true,
color_palette[voxels[leaf_brick_hit.flat_index].albedo_index],
voxels[leaf_brick_hit.flat_index].content,
point_in_ray_at_distance(ray, *ray_current_distance),
cube_impact_normal(
Cube(
(*brick_bounds).min_position + (
vec3f(leaf_brick_hit.index)
* round((*brick_bounds).size / f32(octree_meta_data.voxel_brick_dim))
),
round((*brick_bounds).size / f32(octree_meta_data.voxel_brick_dim)),
),
point_in_ray_at_distance(ray, *ray_current_distance)
)
);
}

/*return OctreeRayIntersection(
true,
color_palette[voxels[leaf_brick_hit.flat_index].albedo_index],
voxels[leaf_brick_hit.flat_index].content,
Expand All @@ -487,21 +451,23 @@ fn probe_brick(
point_in_ray_at_distance(ray, *ray_current_distance)
)
);
*//// --- DEBUG ---
}
}
}

return OctreeRayIntersection(false, vec4f(0.), 0, vec3f(0.), vec3f(0., 0., 1.));
}

// Unique to this implementation, not adapted from rust code
/// Traverses the node to provide information about how the occupied bits of the node
/// and the given ray collides. The higher the number, the closer the hit is.
fn traverse_node_for_ocbits(
ray: ptr<function, Line>,
ray_current_distance: ptr<function,f32>,
node_key: u32,
node_bounds: ptr<function, Cube>,
ray_scale_factors: ptr<function, vec3f>,
) -> vec3f {
) -> f32 {
let original_distance = *ray_current_distance;

var position = vec3f(
Expand All @@ -524,7 +490,7 @@ fn traverse_node_for_ocbits(
);

var safety = 0u;
var rgb_result = vec3f(0.);
var result = 0.;
loop {
if safety > 10 || current_index.x < 0 || current_index.x >= 4
|| current_index.y < 0 || current_index.y >= 4
Expand All @@ -539,22 +505,15 @@ fn traverse_node_for_ocbits(
if (
(
(bitmap_index < 32)
&& (
0u != (node_occupied_bits[node_key * 2]
&& (0u != (node_occupied_bits[node_key * 2]
& (0x01u << bitmap_index) ))
)||(
(bitmap_index >= 32)
&& (
0u != (node_occupied_bits[node_key * 2 + 1]
& (0x01u << (bitmap_index - 32))
))
&& (0u != (node_occupied_bits[node_key * 2 + 1]
& (0x01u << (bitmap_index - 32)) ))
)
){
rgb_result = vec3f(
1. - (f32(safety) * 0.25),
1. - (f32(safety) * 0.25),
1. - (f32(safety) * 0.25)
);
result = 1. - (f32(safety) * 0.25);
break;
}

Expand All @@ -570,7 +529,7 @@ fn traverse_node_for_ocbits(
}

*ray_current_distance = original_distance;
return rgb_result;
return result;
}

fn get_by_ray(ray: ptr<function, Line>) -> OctreeRayIntersection {
Expand Down Expand Up @@ -638,7 +597,7 @@ fn get_by_ray(ray: ptr<function, Line>) -> OctreeRayIntersection {
);

if(
// In case node doesn't yet have the relevant child node uploaded to GPU
// In case node doesn't yet have the target child node uploaded to GPU
(0 == (0x00000004 & current_node_meta)) // node is not a leaf
&& target_octant != OOB_OCTANT
&& target_child_key == EMPTY_MARKER // target child key is invalid
Expand All @@ -653,16 +612,29 @@ fn get_by_ray(ray: ptr<function, Line>) -> OctreeRayIntersection {
)
)
){
missing_data_color += (
vec3f(0.5,0.3,0.0) *
traverse_node_for_ocbits(
ray,
&ray_current_distance,
current_node_key,
&current_bounds,
&ray_scale_factors
)
);
if request_node(current_node_key, target_octant) {
missing_data_color += (
vec3f(0.5,0.3,0.0) *
vec3f(traverse_node_for_ocbits(
ray,
&ray_current_distance,
current_node_key,
&current_bounds,
&ray_scale_factors
))
);
} else {
missing_data_color += (
vec3f(0.7,0.2,0.0) *
vec3f(traverse_node_for_ocbits(
ray,
&ray_current_distance,
current_node_key,
&current_bounds,
&ray_scale_factors
))
);
}
}

if (target_octant != OOB_OCTANT) {
Expand All @@ -676,13 +648,25 @@ fn get_by_ray(ray: ptr<function, Line>) -> OctreeRayIntersection {
);
do_backtrack_after_leaf_miss = true;
} else { // node is a non-uniform leaf
target_bounds = child_bounds_for(&current_bounds, target_octant);
hit = probe_brick(
ray, &ray_current_distance,
current_node_key, target_octant,
&target_bounds,
&ray_scale_factors, direction_lut_index
);
if // node not empty at target octant, while the brick is marked unavailable
(0 != ((0x01u << (8 + target_octant)) & current_node_meta))
&& EMPTY_MARKER == node_children[(current_node_key * 8) + target_octant]
{
// child brick is not yet uploaded to GPU
if request_node(current_node_key, target_octant) {
missing_data_color += vec3f(0.3,0.1,0.0);
} else {
missing_data_color += vec3f(0.7,0.0,0.0);
}
} else {
target_bounds = child_bounds_for(&current_bounds, target_octant);
hit = probe_brick(
ray, &ray_current_distance,
current_node_key, target_octant,
&target_bounds,
&ray_scale_factors, direction_lut_index
);
}
}
if hit.hit == true {
hit.albedo += vec4f(missing_data_color, 0.);
Expand Down Expand Up @@ -893,6 +877,9 @@ var output_texture: texture_storage_2d<rgba8unorm, read_write>;
@group(0) @binding(1)
var<uniform> viewport: Viewport;

@group(0) @binding(2)
var<storage, read_write> node_requests: array<atomic<u32>>;

@group(1) @binding(0)
var<uniform> octree_meta_data: OctreeMetaData;

Expand Down
53 changes: 38 additions & 15 deletions src/octree/raytracing/bevy/data.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,7 @@ where
do_the_thing: false,
data_handler: Arc::new(Mutex::new(gpu_data_handler)),
spyglass: OctreeSpyGlass {
node_requests: vec![0; 4],
output_texture: output_texture.clone(),
viewport: viewport,
},
Expand Down Expand Up @@ -175,23 +176,49 @@ pub(crate) fn sync_with_main_world(// tree_view: Option<ResMut<OctreeGPUView>>,
// █████ █████ ██████████ █████ █████ ██████████
// ░░░░░ ░░░░░ ░░░░░░░░░░ ░░░░░ ░░░░░ ░░░░░░░░░░
//##############################################################################
/// Handles data reads from GPU every loop.
/// Based on https://docs.rs/bevy/latest/src/gpu_readback/gpu_readback.rs.html
pub(crate) fn handle_gpu_readback(
render_device: Res<RenderDevice>,
tree_gpu_view: Option<ResMut<OctreeGPUView>>,
svx_pipeline: Option<ResMut<SvxRenderPipeline>>,
) {
// Data updates triggered by debug interface
if let (Some(ref mut tree_gpu_view), Some(ref mut pipeline)) = (tree_gpu_view, svx_pipeline) {
let resources = pipeline.resources.as_ref().unwrap();
let mut data_handler = tree_gpu_view.data_handler.lock().unwrap();

// Read node requests from GPU
let buffer_slice = resources.readable_node_requests_buffer.slice(..);
let (s, r) = crossbeam::channel::unbounded::<()>();
buffer_slice.map_async(
bevy::render::render_resource::MapMode::Read,
move |d| match d {
Ok(_) => s.send(()).expect("Failed to send map update"),
Err(err) => panic!("Couldn't map debug interface buffer!: {err}"),
},
);

render_device
.poll(bevy::render::render_resource::Maintain::wait())
.panic_on_timeout();

r.recv().expect("Failed to receive the map_async message");
{
let buffer_view = buffer_slice.get_mapped_range();

let data = buffer_view
.chunks(std::mem::size_of::<u32>())
.map(|chunk| u32::from_ne_bytes(chunk.try_into().expect("should be a u32")))
.collect::<Vec<u32>>();
// println!("node_requests: {:?}", data);
}
resources.readable_node_requests_buffer.unmap();

// +++ DEBUG +++
// Data updates triggered by debug interface
if tree_gpu_view.do_the_thing {
let mut data_handler = tree_gpu_view.data_handler.lock().unwrap();
// GPU buffer read
// https://docs.rs/bevy/latest/src/gpu_readback/gpu_readback.rs.html
let buffer_slice = pipeline
.resources
.as_ref()
.unwrap()
.readable_debug_gpu_interface
.slice(..);
let buffer_slice = resources.readable_debug_gpu_interface.slice(..);
let (s, r) = crossbeam::channel::unbounded::<()>();
buffer_slice.map_async(
bevy::render::render_resource::MapMode::Read,
Expand All @@ -216,15 +243,11 @@ pub(crate) fn handle_gpu_readback(
data_handler.read_back = data[0];
// println!("received_data: {:?}", data);
}
pipeline
.resources
.as_ref()
.unwrap()
.readable_debug_gpu_interface
.unmap();
resources.readable_debug_gpu_interface.unmap();
std::mem::drop(data_handler);
tree_gpu_view.do_the_thing = false;
}
// --- DEBUG ---
}
}

Expand Down
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