// Instanced mesh shader for the 3D viewport.
//
// Same lighting model as mesh.wgsl but reads per-instance data from a
// storage buffer indexed by @builtin(instance_index) instead of a uniform.
//
// Group 0: Camera + shadow atlas + lights + clip planes + shadow info (unchanged from mesh.wgsl).
// Group 1: Storage buffer containing array<InstanceData> (binding 0)
// + Albedo texture (binding 1) + sampler (binding 2)
// + normal map (binding 3) + AO map (binding 4).
struct Camera {
view_proj: mat4x4<f32>,
eye_pos: vec3<f32>,
_pad: f32,
forward: vec3<f32>,
_pad1: f32,
};
struct SingleLight {
light_view_proj: mat4x4<f32>,
pos_or_dir: vec3<f32>,
light_type: u32,
color: vec3<f32>,
intensity: f32,
range: f32,
inner_angle: f32,
outer_angle: f32,
spot_direction: vec3<f32>,
_pad: vec2<f32>,
};
struct Lights {
count: u32,
shadow_bias: f32,
shadows_enabled: u32,
_pad: u32,
sky_color: vec3<f32>,
hemisphere_intensity: f32,
ground_color: vec3<f32>,
_pad2: f32,
lights: array<SingleLight, 8>,
};
struct ClipPlanes {
planes: array<vec4<f32>, 6>,
count: u32,
_pad0: u32,
viewport_width: f32,
viewport_height: f32,
};
struct ShadowAtlas {
cascade_vp: array<mat4x4<f32>, 4>,
cascade_splits: vec4<f32>,
cascade_count: u32,
atlas_size: f32,
shadow_filter: u32,
pcss_light_radius: f32,
atlas_rects: array<vec4<f32>, 8>,
};
struct InstanceData {
model: mat4x4<f32>,
color: vec4<f32>,
selected: u32,
wireframe: u32,
ambient: f32,
diffuse: f32,
specular: f32,
shininess: f32,
has_texture: u32,
use_pbr: u32,
metallic: f32,
roughness: f32,
has_normal_map: u32,
has_ao_map: u32,
};
struct ClipVolumeUB {
volume_type: u32,
_pad0: u32, _pad1: u32, _pad2: u32,
plane_normal: vec3<f32>,
plane_dist: f32,
box_center: vec3<f32>,
_padB0: f32,
box_half_extents: vec3<f32>,
_padB1: f32,
box_col0: vec3<f32>,
_padB2: f32,
box_col1: vec3<f32>,
_padB3: f32,
box_col2: vec3<f32>,
_padB4: f32,
sphere_center: vec3<f32>,
sphere_radius: f32,
};
@group(0) @binding(0) var<uniform> camera: Camera;
@group(0) @binding(1) var shadow_map: texture_depth_2d;
@group(0) @binding(2) var shadow_sampler: sampler_comparison;
@group(0) @binding(3) var<uniform> lights_uniform: Lights;
@group(0) @binding(4) var<uniform> clip_planes: ClipPlanes;
@group(0) @binding(5) var<uniform> shadow_atlas: ShadowAtlas;
@group(0) @binding(6) var<uniform> clip_volume: ClipVolumeUB;
fn clip_volume_test(p: vec3<f32>) -> bool {
if clip_volume.volume_type == 0u { return true; }
if clip_volume.volume_type == 1u {
return dot(p, clip_volume.plane_normal) + clip_volume.plane_dist >= 0.0;
}
if clip_volume.volume_type == 2u {
let d = p - clip_volume.box_center;
let local = vec3<f32>(
dot(d, clip_volume.box_col0),
dot(d, clip_volume.box_col1),
dot(d, clip_volume.box_col2),
);
return abs(local.x) <= clip_volume.box_half_extents.x
&& abs(local.y) <= clip_volume.box_half_extents.y
&& abs(local.z) <= clip_volume.box_half_extents.z;
}
let ds = p - clip_volume.sphere_center;
return dot(ds, ds) <= clip_volume.sphere_radius * clip_volume.sphere_radius;
}
@group(1) @binding(0) var<storage, read> instances: array<InstanceData>;
@group(1) @binding(1) var obj_texture: texture_2d<f32>;
@group(1) @binding(2) var obj_sampler: sampler;
@group(1) @binding(3) var normal_map: texture_2d<f32>;
@group(1) @binding(4) var ao_map: texture_2d<f32>;
struct VertexIn {
@location(0) position: vec3<f32>,
@location(1) normal: vec3<f32>,
@location(2) color: vec4<f32>,
@location(3) uv: vec2<f32>,
@location(4) tangent: vec4<f32>,
};
struct VertexOut {
@builtin(position) clip_pos: vec4<f32>,
@location(0) color: vec4<f32>,
@location(1) world_normal: vec3<f32>,
@location(2) world_pos: vec3<f32>,
@location(3) uv: vec2<f32>,
@location(4) world_tangent: vec4<f32>,
@location(5) @interpolate(flat) instance_idx: u32,
};
@vertex
fn vs_main(in: VertexIn, @builtin(instance_index) idx: u32) -> VertexOut {
let inst = instances[idx];
var out: VertexOut;
let world_pos = inst.model * vec4<f32>(in.position, 1.0);
out.clip_pos = camera.view_proj * world_pos;
out.color = in.color;
out.world_pos = world_pos.xyz;
let model3 = mat3x3<f32>(
inst.model[0].xyz,
inst.model[1].xyz,
inst.model[2].xyz,
);
out.world_normal = normalize(model3 * in.normal);
out.world_tangent = vec4<f32>(normalize(model3 * in.tangent.xyz), in.tangent.w);
out.uv = in.uv;
out.instance_idx = idx;
return out;
}
// ---------------------------------------------------------------------------
// Poisson disk + CSM shadow sampling (mirrors mesh.wgsl)
// ---------------------------------------------------------------------------
const POISSON_DISK: array<vec2<f32>, 32> = array<vec2<f32>, 32>(
vec2<f32>(-0.94201624, -0.39906216), vec2<f32>( 0.94558609, -0.76890725),
vec2<f32>(-0.09418410, -0.92938870), vec2<f32>( 0.34495938, 0.29387760),
vec2<f32>(-0.91588581, 0.45771432), vec2<f32>(-0.81544232, -0.87912464),
vec2<f32>(-0.38277543, 0.27676845), vec2<f32>( 0.97484398, 0.75648379),
vec2<f32>( 0.44323325, -0.97511554), vec2<f32>( 0.53742981, -0.47373420),
vec2<f32>(-0.26496911, -0.41893023), vec2<f32>( 0.79197514, 0.19090188),
vec2<f32>(-0.24188840, 0.99706507), vec2<f32>(-0.81409955, 0.91437590),
vec2<f32>( 0.19984126, 0.78641367), vec2<f32>( 0.14383161, -0.14100790),
vec2<f32>(-0.44451570, 0.67055830), vec2<f32>( 0.70509040, -0.15854630),
vec2<f32>( 0.07130650, -0.64599580), vec2<f32>( 0.39881030, 0.55789810),
vec2<f32>(-0.60554040, -0.34964830), vec2<f32>( 0.85095100, 0.47178830),
vec2<f32>(-0.47994860, 0.08443340), vec2<f32>(-0.12494190, -0.76098760),
vec2<f32>( 0.64839320, 0.74738240), vec2<f32>(-0.96815740, -0.12345680),
vec2<f32>( 0.27682050, -0.80927180), vec2<f32>(-0.73016460, 0.18344200),
vec2<f32>( 0.54754660, 0.06234570), vec2<f32>(-0.30967360, -0.61021430),
vec2<f32>(-0.57774330, 0.80459740), vec2<f32>( 0.18238670, -0.37596540),
);
fn sample_shadow_csm(
world_pos: vec3<f32>,
eye_pos: vec3<f32>,
surface_normal: vec3<f32>,
light_dir: vec3<f32>,
) -> f32 {
let dist = dot(world_pos - eye_pos, camera.forward);
var cascade_idx = 0u;
for (var i = 0u; i < shadow_atlas.cascade_count; i++) {
if dist > shadow_atlas.cascade_splits[i] {
cascade_idx = i + 1u;
}
}
cascade_idx = min(cascade_idx, shadow_atlas.cascade_count - 1u);
// Project the actual surface position for the correct shadow-map UV.
// Keeping UV at world_pos prevents tangential normal shift from moving
// samples into shallower shadow-map regions on curved surfaces.
let light_clip = shadow_atlas.cascade_vp[cascade_idx] * vec4<f32>(world_pos, 1.0);
let ndc = light_clip.xyz / light_clip.w;
let tile_uv = vec2<f32>(ndc.x * 0.5 + 0.5, -ndc.y * 0.5 + 0.5);
if tile_uv.x < 0.0 || tile_uv.x > 1.0 || tile_uv.y < 0.0 || tile_uv.y > 1.0 ||
ndc.z < 0.0 || ndc.z > 1.0 {
return 1.0;
}
let rect = shadow_atlas.atlas_rects[cascade_idx];
let atlas_uv = vec2<f32>(
mix(rect.x, rect.z, tile_uv.x),
mix(rect.y, rect.w, tile_uv.y),
);
let texel_size = 1.0 / shadow_atlas.atlas_size;
// Normal-offset depth bias: move the comparison point toward the light and
// increase the offset at grazing angles to suppress sphere terminator acne.
let n_dot_l = dot(surface_normal, light_dir);
let offset_sign = select(-1.0, 1.0, n_dot_l >= 0.0);
let normal_bias = mix(0.006, 0.0015, clamp(abs(n_dot_l), 0.0, 1.0));
let offset_world = world_pos + surface_normal * (offset_sign * normal_bias);
let offset_clip = shadow_atlas.cascade_vp[cascade_idx] * vec4<f32>(offset_world, 1.0);
let biased_depth = (offset_clip.xyz / offset_clip.w).z - lights_uniform.shadow_bias;
let noise = fract(52.9829189 * fract(dot(world_pos.xz, vec2<f32>(0.06711056, 0.00583715))));
let rot = noise * 6.28318530;
let sin_r = sin(rot);
let cos_r = cos(rot);
if shadow_atlas.shadow_filter == 1u {
let search_radius = shadow_atlas.pcss_light_radius * 16.0 * texel_size;
var blocker_sum = 0.0;
var blocker_count = 0.0;
for (var i = 0u; i < 16u; i++) {
let d = POISSON_DISK[i];
let rd = vec2<f32>(d.x * cos_r - d.y * sin_r, d.x * sin_r + d.y * cos_r);
let sample_uv = atlas_uv + rd * search_radius;
let clamped_uv = clamp(sample_uv, rect.xy, rect.zw);
let sample_depth = textureSampleCompare(shadow_map, shadow_sampler, clamped_uv, biased_depth);
if sample_depth < 1.0 {
let coords = vec2<i32>(clamped_uv * shadow_atlas.atlas_size);
let raw_depth = textureLoad(shadow_map, coords, 0);
blocker_sum += raw_depth;
blocker_count += 1.0;
}
}
if blocker_count < 1.0 { return 1.0; }
let avg_blocker = blocker_sum / blocker_count;
let penumbra_width = shadow_atlas.pcss_light_radius * (biased_depth - avg_blocker) / max(avg_blocker, 0.001);
let filter_radius = max(penumbra_width * 16.0 * texel_size, texel_size);
var shadow = 0.0;
for (var i = 0u; i < 32u; i++) {
let d = POISSON_DISK[i];
let rd = vec2<f32>(d.x * cos_r - d.y * sin_r, d.x * sin_r + d.y * cos_r);
let sample_uv = atlas_uv + rd * filter_radius;
let clamped_uv = clamp(sample_uv, rect.xy, rect.zw);
shadow += textureSampleCompare(shadow_map, shadow_sampler, clamped_uv, biased_depth);
}
return shadow / 32.0;
} else {
let pcf_radius = 4.0 * texel_size;
var shadow = 0.0;
for (var i = 0u; i < 32u; i++) {
let d = POISSON_DISK[i];
let rd = vec2<f32>(d.x * cos_r - d.y * sin_r, d.x * sin_r + d.y * cos_r);
let sample_uv = atlas_uv + rd * pcf_radius;
let clamped_uv = clamp(sample_uv, rect.xy, rect.zw);
shadow += textureSampleCompare(shadow_map, shadow_sampler, clamped_uv, biased_depth);
}
return shadow / 32.0;
}
}
// ---------------------------------------------------------------------------
// PBR BRDF helpers (Cook-Torrance) — mirrors mesh.wgsl
// ---------------------------------------------------------------------------
fn D_GGX(NdotH: f32, roughness: f32) -> f32 {
let a = roughness * roughness;
let a2 = a * a;
let denom = NdotH * NdotH * (a2 - 1.0) + 1.0;
return a2 / (3.14159265 * denom * denom);
}
fn G1_Smith(NdotV: f32, roughness: f32) -> f32 {
let r = roughness + 1.0;
let k = (r * r) / 8.0;
return NdotV / (NdotV * (1.0 - k) + k);
}
fn G_Smith(NdotV: f32, NdotL: f32, roughness: f32) -> f32 {
return G1_Smith(NdotV, roughness) * G1_Smith(NdotL, roughness);
}
fn F_Schlick(cos_theta: f32, F0: vec3<f32>) -> vec3<f32> {
return F0 + (vec3<f32>(1.0) - F0) * pow(clamp(1.0 - cos_theta, 0.0, 1.0), 5.0);
}
fn pbr_light_contrib(
N: vec3<f32>, V: vec3<f32>, L: vec3<f32>, radiance: vec3<f32>,
base_color: vec3<f32>, metallic: f32, roughness: f32, F0: vec3<f32>,
) -> vec3<f32> {
let H = normalize(L + V);
let NdotL = max(dot(N, L), 0.0);
if NdotL <= 0.0 { return vec3<f32>(0.0); }
let NdotV = max(dot(N, V), 0.001);
let NdotH = max(dot(N, H), 0.0);
let HdotV = max(dot(H, V), 0.0);
let D = D_GGX(NdotH, roughness);
let G = G_Smith(NdotV, NdotL, roughness);
let F = F_Schlick(HdotV, F0);
let kS = F;
let kD = (vec3<f32>(1.0) - kS) * (1.0 - metallic);
let specular = (D * G * F) / (4.0 * NdotV * NdotL + 0.001);
return (kD * base_color / 3.14159265 + specular) * radiance * NdotL;
}
@fragment
fn fs_main(in: VertexOut) -> @location(0) vec4<f32> {
let inst = instances[in.instance_idx];
for (var i = 0u; i < clip_planes.count; i++) {
let plane = clip_planes.planes[i];
if dot(in.world_pos, plane.xyz) + plane.w < 0.0 { discard; }
}
if !clip_volume_test(in.world_pos) { discard; }
if inst.wireframe != 0u { return vec4<f32>(0.08, 0.08, 0.08, 1.0); }
var tex_color = vec4<f32>(1.0);
if inst.has_texture == 1u { tex_color = textureSample(obj_texture, obj_sampler, in.uv); }
let obj_color = vec4<f32>(inst.color.rgb * in.color.rgb * tex_color.rgb,
inst.color.a * in.color.a * tex_color.a);
let base_color = obj_color.rgb;
var N: vec3<f32>;
if inst.has_normal_map != 0u {
let nm_sample = textureSample(normal_map, obj_sampler, in.uv).rgb;
let ts_normal = normalize(nm_sample * 2.0 - vec3<f32>(1.0));
let T = normalize(in.world_tangent.xyz);
let Ng = normalize(in.world_normal);
let T_orth = normalize(T - dot(T, Ng) * Ng);
let B = cross(Ng, T_orth) * in.world_tangent.w;
let TBN = mat3x3<f32>(T_orth, B, Ng);
N = normalize(TBN * ts_normal);
} else {
N = normalize(in.world_normal);
}
var ao_factor = 1.0;
if inst.has_ao_map != 0u { ao_factor = textureSample(ao_map, obj_sampler, in.uv).r; }
// Use the geometric fragment normal for shadowing so the receiver test
// matches the faceted mesh that was rasterized into the shadow atlas.
var shadow_normal = normalize(cross(dpdx(in.world_pos), dpdy(in.world_pos)));
if dot(shadow_normal, N) < 0.0 {
shadow_normal = -shadow_normal;
}
let V = normalize(camera.eye_pos - in.world_pos);
let tint = vec4<f32>(1.0, 1.0, 1.0, 1.0);
var final_rgb: vec3<f32>;
if inst.use_pbr != 0u {
let metallic = clamp(inst.metallic, 0.0, 1.0);
let roughness = max(inst.roughness, 0.04);
let F0 = mix(vec3<f32>(0.04), base_color, metallic);
var Lo = vec3<f32>(0.0);
for (var i = 0u; i < lights_uniform.count; i++) {
let l = lights_uniform.lights[i];
var L: vec3<f32>; var radiance: vec3<f32>;
if l.light_type == 0u {
L = normalize(l.pos_or_dir); radiance = l.color * l.intensity;
} else if l.light_type == 1u {
let to_light = l.pos_or_dir - in.world_pos; let dist = length(to_light);
L = to_light / max(dist, 0.0001);
let falloff = clamp(1.0 - dist / l.range, 0.0, 1.0);
radiance = l.color * l.intensity * falloff * falloff;
} else {
let to_light = l.pos_or_dir - in.world_pos; let dist = length(to_light);
L = to_light / max(dist, 0.0001);
let dist_falloff = clamp(1.0 - dist / l.range, 0.0, 1.0);
let spot_dir = normalize(l.spot_direction);
let cos_angle = dot(-L, spot_dir);
let cos_outer = cos(l.outer_angle); let cos_inner = cos(l.inner_angle);
let cone_att = clamp((cos_angle - cos_outer) / max(cos_inner - cos_outer, 0.0001), 0.0, 1.0);
radiance = l.color * l.intensity * dist_falloff * dist_falloff * cone_att;
}
var shadow_factor = 1.0;
if i == 0u && lights_uniform.shadows_enabled != 0u {
shadow_factor = sample_shadow_csm(in.world_pos, camera.eye_pos, shadow_normal, L);
let terminator = smoothstep(0.0, 0.75, dot(shadow_normal, L));
shadow_factor = mix(1.0, shadow_factor, terminator);
}
radiance *= shadow_factor;
Lo += pbr_light_contrib(N, V, L, radiance, base_color, metallic, roughness, F0);
}
let hemi_t = clamp(in.world_normal.y * 0.5 + 0.5, 0.0, 1.0);
let hemi_color = mix(lights_uniform.ground_color, lights_uniform.sky_color, hemi_t);
let ambient_scale = vec3<f32>(inst.ambient) + hemi_color * lights_uniform.hemisphere_intensity;
let ambient = ambient_scale * (base_color * (1.0 - metallic) + F0 * metallic) * ao_factor;
final_rgb = clamp((Lo + ambient) * tint.rgb, vec3<f32>(0.0), vec3<f32>(1.0));
} else {
var total_color_contrib = vec3<f32>(0.0);
for (var i = 0u; i < lights_uniform.count; i++) {
let l = lights_uniform.lights[i];
var light_dir: vec3<f32>; var attenuation = 1.0;
if l.light_type == 0u {
light_dir = normalize(l.pos_or_dir);
} else if l.light_type == 1u {
let to_light = l.pos_or_dir - in.world_pos; let dist = length(to_light);
light_dir = to_light / max(dist, 0.0001);
let falloff = clamp(1.0 - dist / l.range, 0.0, 1.0);
attenuation = falloff * falloff;
} else {
let to_light = l.pos_or_dir - in.world_pos; let dist = length(to_light);
light_dir = to_light / max(dist, 0.0001);
let dist_falloff = clamp(1.0 - dist / l.range, 0.0, 1.0);
let spot_dir = normalize(l.spot_direction);
let cos_angle = dot(-light_dir, spot_dir);
let cos_outer = cos(l.outer_angle); let cos_inner = cos(l.inner_angle);
let cone_att = clamp((cos_angle - cos_outer) / max(cos_inner - cos_outer, 0.0001), 0.0, 1.0);
attenuation = dist_falloff * dist_falloff * cone_att;
}
var shadow = 1.0;
if i == 0u && lights_uniform.shadows_enabled != 0u {
shadow = sample_shadow_csm(in.world_pos, camera.eye_pos, shadow_normal, light_dir);
let terminator = smoothstep(0.0, 0.75, dot(shadow_normal, light_dir));
shadow = mix(1.0, shadow, terminator);
}
let H = normalize(light_dir + V);
let n_dot_l = max(dot(N, light_dir), 0.0);
let n_dot_h = max(dot(N, H), 0.0);
let diffuse_contrib = inst.diffuse * n_dot_l * l.intensity * attenuation * shadow;
let specular_contrib = inst.specular * pow(n_dot_h, inst.shininess)
* l.intensity * attenuation * shadow;
total_color_contrib += (diffuse_contrib + specular_contrib) * l.color;
}
let ambient_contrib = inst.ambient;
let hemi_t = clamp(in.world_normal.y * 0.5 + 0.5, 0.0, 1.0);
let hemi_color = mix(lights_uniform.ground_color, lights_uniform.sky_color, hemi_t);
let hemi_ambient = hemi_color * lights_uniform.hemisphere_intensity;
let lit_rgb = base_color * (ambient_contrib + hemi_ambient) * ao_factor
+ base_color * total_color_contrib;
final_rgb = clamp(lit_rgb * tint.rgb, vec3<f32>(0.0), vec3<f32>(1.0));
}
return vec4<f32>(final_rgb, obj_color.a);
}