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#include "math/sdf_shapes"
#include "math/sdf_utils"
struct BVHNode {
min: vec3<f32>,
left_idx: i32,
max: vec3<f32>,
obj_idx_or_right: i32,
};
@group(0) @binding(2) var<storage, read> bvh_nodes: array<BVHNode>;
fn get_dist(p: vec3<f32>, obj_params: vec4<f32>) -> f32 {
let obj_type = obj_params.x;
if (obj_type == 1.0) { return length(p) - 1.0; } // Unit Sphere
if (obj_type == 2.0) { return sdBox(p, vec3<f32>(1.0)); } // Unit Box
if (obj_type == 3.0) { return sdTorus(p, vec2<f32>(1.0, 0.4)); } // Unit Torus
if (obj_type == 4.0) { return sdPlane(p, vec3<f32>(0.0, 1.0, 0.0), 0.0); }
if (obj_type == 5.0) { return sdBox(p, obj_params.yzw); } // MESH AABB
return 100.0;
}
fn map_scene(p: vec3<f32>, skip_idx: u32) -> f32 {
var d = 1000.0;
var stack: array<i32, 32>;
var stack_ptr = 0;
if (arrayLength(&bvh_nodes) > 0u) {
stack[stack_ptr] = 0;
stack_ptr++;
}
while (stack_ptr > 0) {
stack_ptr--;
let node_idx = stack[stack_ptr];
let node = bvh_nodes[node_idx];
if (aabb_sdf(p, node.min, node.max) < d) {
if (node.left_idx < 0) { // Leaf
let obj_idx = u32(node.obj_idx_or_right);
if (obj_idx == skip_idx) { continue; }
let obj = object_data.objects[obj_idx];
let q = (obj.inv_model * vec4<f32>(p, 1.0)).xyz;
let s = min(length(obj.model[0].xyz), min(length(obj.model[1].xyz), length(obj.model[2].xyz)));
// IMPORTANT: Plane (type 4.0) should not be scaled by 's' in this way.
// The sdPlane function expects its own scale/offset implicitly handled by the model matrix.
// The 's' factor is meant for primitives whose SDFs are defined relative to a unit size.
if (obj.params.x != 4.0) { // Only scale if not a plane
d = min(d, get_dist(q, obj.params) * s);
} else {
d = min(d, get_dist(q, obj.params));
}
} else { // Internal
if (stack_ptr < 31) {
stack[stack_ptr] = node.left_idx;
stack_ptr++;
stack[stack_ptr] = node.obj_idx_or_right;
stack_ptr++;
}
}
}
}
return d;
}
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