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voxel-rs
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Add comments to raycast shader

This commit is contained in:
Jarrod Doyle 2023-05-04 11:44:55 +01:00
parent c09014e34e
commit 2cfea8e440
Signed by: Jayrude
GPG Key ID: 38B57B16E7C0ADF7
1 changed files with 25 additions and 9 deletions
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34
assets/shaders/voxel_volume.wgsl
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@ -100,7 +100,10 @@ fn point_inside_aabb(p: vec3<i32>, min: vec3<i32>, max: vec3<i32>) -> bool {
}
fn voxel_hit(brickmap_idx: u32, p: vec3<i32>) -> bool {
// Convert the global position into an index within the brickmap
let local_index = to_1d_index(p % 8, vec3<i32>(8));
// Is the bit at local_index within the bitmask a 1?
let bitmask_segment = brickmap_cache[brickmap_idx].bitmask[local_index / 32u];
return (bitmask_segment >> (local_index % 32u) & 1u) != 0u;
}
@ -121,11 +124,11 @@ fn brick_ray_cast(
var tmin = aabbHit.distance;
if (aabbHit.hit) {
// Accelerate ray
// tmin is greater than 0 if the ray is outside of the AABB, so we need to
// accelerate the ray to be on the edge of the AABB.
if (tmin > 0.0) {
ray_pos += ray_dir * (tmin + 0.0001);
}
tmin = max(0.0, tmin);
// DDA setup
let delta_dist = abs(length(ray_dir) / ray_dir);
@ -137,6 +140,8 @@ fn brick_ray_cast(
let max_brick_depth = 8 + 8 + 8;
for (var i: i32 = 0; i < max_brick_depth; i++) {
if (!point_inside_aabb(map_pos, vec3<i32>(0), vec3<i32>(8))) {
// If the ray has left the brickmap AABB there's no point in continuing
// to trace against it
break;
}
@ -147,6 +152,7 @@ fn brick_ray_cast(
break;
}
// What side of the voxel are we on?
let smallest = min(side_dist.x, min(side_dist.y, side_dist.z));
if (smallest == side_dist.x) {
hit_info.mask = vec3<bool>(true, false, false);
@ -158,6 +164,7 @@ fn brick_ray_cast(
hit_info.mask = vec3<bool>(false, false, true);
}
// Step the ray based on which voxel side we're on
side_dist += vec3<f32>(hit_info.mask) * delta_dist;
map_pos += vec3<i32>(hit_info.mask) * ray_step;
}
@ -175,14 +182,11 @@ fn grid_cast_ray(orig_ray_pos: vec3<f32>, ray_dir: vec3<f32>) -> HitInfo {
var ray_pos = orig_ray_pos;
var tmin = aabbHit.distance;
if (aabbHit.hit) {
// Accelerate ray
// tmin is greater than 0 if the ray is outside of the AABB, so we need to
// accelerate the ray to be on the edge of the AABB.
if (tmin > 0.0) {
ray_pos += ray_dir * (tmin + 0.0001);
}
tmin = max(0.0, tmin);
// Convert ray_pos into chunk scale
// ray_pos /= 8.0;
// DDA setup
let delta_dist = abs(length(ray_dir) / ray_dir);
@ -194,6 +198,8 @@ fn grid_cast_ray(orig_ray_pos: vec3<f32>, ray_dir: vec3<f32>) -> HitInfo {
let max_grid_depth = i32(dims.x + dims.y + dims.z);
for (var i: i32 = 0; i < max_grid_depth; i++) {
if (!point_inside_aabb(map_pos, vec3<i32>(0), vec3<i32>(world_state.brickmap_cache_dims))) {
// If the ray has left the brickmap AABB there's no point in continuing
// to trace against it
break;
}
@ -208,9 +214,15 @@ fn grid_cast_ray(orig_ray_pos: vec3<f32>, ray_dir: vec3<f32>) -> HitInfo {
// 4 = loaded
let flags = brick_ptr & 0xFu;
if flags == 1u {
// Add to the load queue
// The brickmap we're in is currently unloaded so we'll try and add it
// to the load queue. Heavy atomic use here because multiple shader
// dispatches might be trying to add the same brickmap
if (atomicLoad(&cpu_feedback.count) < cpu_feedback.max_count) {
// This is checking that in the time since the flags were calculated
// another dispatch hasn't already started loading the brickmap
if ((atomicOr(&brickgrid[grid_idx], 2u) & 0x2u) == 0u) {
// If there's still space in the queue at this point, add the
// brickmap. Otherwise, revert any changes made
let index = atomicAdd(&cpu_feedback.count, 1u);
if (index < cpu_feedback.max_count) {
cpu_feedback.positions[index] = vec4<i32>(map_pos, 0);
@ -222,13 +234,15 @@ fn grid_cast_ray(orig_ray_pos: vec3<f32>, ray_dir: vec3<f32>) -> HitInfo {
}
}
// Set hit info stuff?
// TODO: Set hit info stuff?
break;
}
else if flags == 4u {
// The brickmap is loaded so we try and cast against it
let brickmap_idx = brick_ptr >> 8u;
let tmp_voxel_hit = brick_ray_cast(map_pos, brickmap_idx, orig_ray_pos, ray_dir);
// If we hit a voxel in the brickmap, update hitinfo and stop casting
if (tmp_voxel_hit.hit == true){
hit_info.hit = tmp_voxel_hit.hit;
hit_info.hit_pos = tmp_voxel_hit.hit_pos + (map_pos * 8);
@ -237,6 +251,7 @@ fn grid_cast_ray(orig_ray_pos: vec3<f32>, ray_dir: vec3<f32>) -> HitInfo {
}
}
// What side of the voxel are we on?
let smallest = min(side_dist.x, min(side_dist.y, side_dist.z));
if (smallest == side_dist.x) {
hit_info.mask = vec3<bool>(true, false, false);
@ -248,6 +263,7 @@ fn grid_cast_ray(orig_ray_pos: vec3<f32>, ray_dir: vec3<f32>) -> HitInfo {
hit_info.mask = vec3<bool>(false, false, true);
}
// Step the ray based on which voxel side we're on
side_dist += vec3<f32>(hit_info.mask) * delta_dist;
map_pos += vec3<i32>(hit_info.mask) * ray_step;
}