Bind shared lighting ABI and shade authored local lights

docs/manual/editor/lighting.md

@@ -0,0 +1,92 @@
+# Add lights to a 3D scene
+
+Add a **Light** component to a scene entity. The entity's transform places a point
+or spot light; its rotation aims a spot light along local negative Z. A directional
+light uses the entity's orientation. Light colors and intensity contribute to the
+mesh's linear PBR illumination before tone mapping. Sprites and UI retain their
+unlit tint.
+
+The version-1 `faset.light` component has three `kind` values:
+
+| Kind | Position and direction | Useful fields |
+| --- | --- | --- |
+| `directional` | Direction from the entity transform | `color`, `intensity`, `casts_shadow` |
+| `point` | Position from the entity transform; illuminates every direction | `color`, `intensity`, `range` |
+| `spot` | Position and local negative-Z direction | `color`, `intensity`, `range`, `inner_angle`, `outer_angle` |
+
+Angles are radians. A spot's inner angle must not exceed its outer angle. Intensity
+must be nonnegative and range positive. `enabled: false` keeps the component in the
+scene without contributing light. The `shadow_priority` integer is reserved for the
+bounded local-shadow scheduler; it does not change brightness.
+
+In the current rendering checkpoint, one enabled directional light can cast the
+existing single-map shadow. Point and spot lights illuminate meshes but do not yet
+cast shadows. The [P3 lighting plan](https://github.com/emil28092005/Faset_Engine/blob/main/docs/superpowers/plans/2026-09-24-p3-lighting.md)
+tracks cascades and the bounded local-shadow atlas. A scene with no Light component
+keeps the legacy white sun so older projects retain their appearance. Adding any
+Light component, even a disabled one, turns off that compatibility fallback. If
+several directionals are enabled, Faset chooses the one with the smallest stable
+entity ID and reports a diagnostic for the others.
+
+## Author a point light through MCP
+
+Use `faset_schema` to inspect the current field IDs, then send a `faset_scene_edit`
+batch with the document ID, current revision, and target entity ID. For example:
+
+```json
+{
+  "document": "REPLACE_WITH_DOCUMENT_ID",
+  "revision": 4,
+  "idempotency_key": "add-red-point-light",
+  "operations": [{
+    "op": "component.add",
+    "entity": "REPLACE_WITH_ENTITY_ID",
+    "type": "faset.light",
+    "fields": {
+      "kind": "point",
+      "color": [1, 0.15, 0.1, 1],
+      "intensity": 8,
+      "range": 6
+    }
+  }]
+}
+```
+
+Move the entity with its Transform component. `component.add` fills any omitted
+light fields from the version-1 schema; use `component.set` for later edits. See
+[MCP and command line](mcp.md) for revision and retry handling.
+
+## Supply lights directly from C++
+
+When building a `faset::render::Snapshot` yourself, set
+`authored_lights_present` to suppress the compatibility sun in a local-only scene.
+Provide a stable ID for each light so future shadow scheduling remains independent
+of submission order.
+
+```cpp
+faset::render::Snapshot snapshot;
+snapshot.authored_lights_present = true;
+
+faset::render::LocalLight point;
+point.kind = faset::render::LocalLight::Kind::Point;
+point.stable_id = "level/torch";
+point.position = {-2, 1.5f, 0};
+point.color = {1, 0.3f, 0.1f, 1};
+point.intensity = 8;
+point.range = 6;
+snapshot.local_lights.push_back(point);
+
+faset::render::LocalLight spot;
+spot.kind = faset::render::LocalLight::Kind::Spot;
+spot.stable_id = "level/lamp";
+spot.position = {2, 3, 0};
+spot.direction = {0, -1, 0};
+spot.inner_angle = 0.25f;
+spot.outer_angle = 0.55f;
+spot.intensity = 5;
+spot.range = 9;
+snapshot.local_lights.push_back(spot);
+```
+
+The renderer submits at most 128 local lights per frame in stable-ID order. Later
+P3 work adds explicit overflow diagnostics and measured light-list optimization.

mkdocs.yml

@@ -44,6 +44,7 @@ nav:
       - Editor workspace: editor/workspace.md
       - Scene templates: editor/templates.md
       - Assets and Blender: editor/assets.md
+      - Lighting: editor/lighting.md
       - GPU visibility and mesh LOD: editor/visibility-lod.md
       - Build, Play, and export: editor/export.md
       - Profiling and measurements: editor/profiling.md

shaders/baseline.slang

@@ -24,6 +24,32 @@ struct FrameParameters {
 [[vk::binding(1,0)]] SamplerState shadowSampler;
 [[vk::binding(2,0)]] Texture2D<float4> colorMap;
 [[vk::binding(3,0)]] SamplerState colorSampler;
+// Shared Direct/P2 graphics ABI. The legacy material set remains set 0;
+// GPU-only instance/visibility records occupy set 2.
+struct LightingHeader {
+    uint4 counts;                    // local count, sun enabled, sun shadow enabled, view count
+    float4 sunDirectionIntensity;    // xyz world-space ray direction, w intensity
+    float4 sunColor;
+    float4 cameraForwardShadowDistance;
+    float4 cascadeSplits;
+};
+struct LocalLightGpu {
+    float4 positionRange;
+    float4 directionCosOuter;
+    float4 colorIntensity;
+    float4 coneTypeShadowView;       // cos(inner), 0=point/1=spot, shadow view, flags
+    float4 reserved;
+};
+struct ShadowViewGpu {
+    column_major float4x4 viewProjection;
+    float4 tileScaleOffset;
+    float4 guardedClamp;
+    float4 biasFlags;
+};
+[[vk::binding(0,1)]] StructuredBuffer<LightingHeader> lightingFrame;
+[[vk::binding(1,1)]] StructuredBuffer<LocalLightGpu> localLights;
+[[vk::binding(2,1)]] StructuredBuffer<ShadowViewGpu> shadowViews;
+[[vk::binding(3,1)]] Texture2D<float> localShadowAtlas;
 [shader("vertex")]
 VertexOutput vertexMain(VertexInput v) {
     VertexOutput o;
@@ -32,6 +58,22 @@ VertexOutput vertexMain(VertexInput v) {
 }
 [shader("vertex")]
 float4 shadowMain(VertexInput v) : SV_Position { return mul(frame.lightViewProjection, float4(v.world,1)); }
+float3 directBRDF(float3 base, float rough, float metal, float3 n, float3 view, float3 l) {
+    const float pi = 3.14159265;
+    float nl = max(dot(n,l),0.0);
+    if (nl <= 0.0) return float3(0);
+    float3 halfVector = l + view;
+    float halfLengthSquared = dot(halfVector, halfVector);
+    float3 h = halfLengthSquared > 1e-8 ? halfVector * rsqrt(halfLengthSquared) : n;
+    float nv=max(dot(n,view),0.001), nh=max(dot(n,h),0.0), vh=max(dot(view,h),0.0);
+    float a=rough*rough, a2=a*a, denom=nh*nh*(a2-1.0)+1.0;
+    float d=a2/(pi*denom*denom+0.0001);
+    float k=(rough+1.0)*(rough+1.0)/8.0;
+    float g=(nl/(nl*(1.0-k)+k))*(nv/(nv*(1.0-k)+k));
+    float3 f0=lerp(float3(0.04),base,metal), fresnel=f0+(1.0-f0)*pow(1.0-vh,5.0);
+    float3 spec=d*g*fresnel/max(4.0*nv*nl,0.001);
+    return ((1.0-fresnel)*(1.0-metal)*base/pi+spec)*nl;
+}
 [shader("fragment")]
 float4 fragmentMain(VertexOutput v) : SV_Target {
     float4 sampled = colorMap.Sample(colorSampler, v.uv);
@@ -41,28 +83,52 @@ float4 fragmentMain(VertexOutput v) : SV_Target {
         return v.color * sampled;
     }
     float4 base = v.color * sampled;
-    const float pi = 3.14159265;
+    LightingHeader lighting = lightingFrame[0];
-    float3 n=normalize(v.normal), l=normalize(-frame.lightDirection.xyz), view=normalize(frame.eye.xyz-v.world), h=normalize(l+view);
+    float3 n=normalize(v.normal);
-    float nl=max(dot(n,l),0.0), nv=max(dot(n,view),0.001), nh=max(dot(n,h),0.0), vh=max(dot(view,h),0.0);
+    float3 viewDelta=frame.eye.xyz-v.world;
+    float viewLengthSquared=dot(viewDelta,viewDelta);
+    float3 view=viewLengthSquared > 1e-8 ? viewDelta*rsqrt(viewLengthSquared) : n;
     float rough=clamp(v.material.x,0.08,1.0), metal=saturate(v.material.y);
-    float a=rough*rough, a2=a*a, denom=nh*nh*(a2-1.0)+1.0;
+    float3 linear=base.rgb*.12;
-    float d=a2/(pi*denom*denom+0.0001);
+    if (lighting.counts.y != 0 && lighting.sunDirectionIntensity.w > 0) {
-    float k=(rough+1.0)*(rough+1.0)/8.0;
+        float3 l=normalize(-lighting.sunDirectionIntensity.xyz);
-    float g=(nl/(nl*(1.0-k)+k))*(nv/(nv*(1.0-k)+k));
+        float nl=max(dot(n,l),0.0);
-    float3 f0=lerp(float3(0.04),base.rgb,metal), fresnel=f0+(1.0-f0)*pow(1.0-vh,5.0);
+        float visibility=1.0;
-    float3 spec=d*g*fresnel/max(4.0*nv*nl,0.001);
+        if (lighting.counts.z != 0 && nl > 0) {
-    float4 lightClip=mul(frame.lightViewProjection,float4(v.world,1));
+            float4 lightClip=mul(frame.lightViewProjection,float4(v.world,1));
-    float3 projected=lightClip.xyz/lightClip.w;
+            float3 projected=lightClip.xyz/lightClip.w;
-    float2 uv=projected.xy*.5+.5;
+            float2 uv=projected.xy*.5+.5;
-    float visibility=1.0;
+            if(all(uv>=0.0)&&all(uv<=1.0)&&projected.z>=0.0&&projected.z<=1.0) {
-    if(all(uv>=0.0)&&all(uv<=1.0)&&projected.z>=0.0&&projected.z<=1.0) {
+                visibility=0.0;
-        visibility=0.0;
+                for(int y=-1;y<=1;++y) for(int x=-1;x<=1;++x) {
-        for(int y=-1;y<=1;++y) for(int x=-1;x<=1;++x) {
+                    float depth=shadowMap.SampleLevel(shadowSampler,uv+float2(x,y)/1024.0,0);
-            float depth=shadowMap.SampleLevel(shadowSampler,uv+float2(x,y)/1024.0,0);
+                    visibility += projected.z-max(0.0008,0.003*(1.0-nl)) <= depth ? 1.0/9.0 : 0.0;
-            visibility += projected.z-max(0.0008,0.003*(1.0-nl)) <= depth ? 1.0/9.0 : 0.0;
+                }
+            }
         }
+        linear += directBRDF(base.rgb, rough, metal, n, view, l) *
+                  lighting.sunColor.rgb * (lighting.sunDirectionIntensity.w * 3.0 * visibility);
+    }
+    for (uint i=0; i<lighting.counts.x; ++i) {
+        LocalLightGpu light=localLights[i];
+        float3 delta=light.positionRange.xyz-v.world;
+        float distanceSquared=max(dot(delta,delta),1e-6);
+        float distance=sqrt(distanceSquared);
+        float range=max(light.positionRange.w,1e-4);
+        if (distance >= range || light.colorIntensity.w <= 0) continue;
+        float3 l=delta/distance;
+        float relative=distance/range;
+        float cutoff=1.0-relative*relative*relative*relative;
+        float attenuation=cutoff*cutoff/(1.0+distanceSquared);
+        if (light.coneTypeShadowView.y > 0.5) {
+            float cosAngle=dot(-l,normalize(light.directionCosOuter.xyz));
+            float denominator=max(light.coneTypeShadowView.x-light.directionCosOuter.w,1e-4);
+            float cone=saturate((cosAngle-light.directionCosOuter.w)/denominator);
+            attenuation *= cone*cone*(3.0-2.0*cone);
+        }
+        linear += directBRDF(base.rgb, rough, metal, n, view, l) *
+                  light.colorIntensity.rgb * (light.colorIntensity.w * attenuation);
     }
-    float3 linear=base.rgb*.12 + ((1.0-fresnel)*(1.0-metal)*base.rgb/pi+spec)*nl*3.0*visibility;
     linear=linear/(1.0+linear);
     return float4(pow(max(linear,0),float3(1.0/2.2)),base.a);
 }

shaders/gpu_scene.slang

@@ -57,9 +57,9 @@ struct GpuFrameParameters {
     uint4 drawInfo; // x=visible ID range base; firstInstance is always zero
 };
 [[vk::push_constant]] ConstantBuffer<GpuFrameParameters> gpuFrame;
-[[vk::binding(0,1)]] StructuredBuffer<InstanceRecord> gfxInstances;
+[[vk::binding(0,2)]] StructuredBuffer<InstanceRecord> gfxInstances;
-[[vk::binding(1,1)]] StructuredBuffer<uint> gfxVisibleIds;
+[[vk::binding(1,2)]] StructuredBuffer<uint> gfxVisibleIds;
-[[vk::binding(2,1)]] StructuredBuffer<ViewRecord> gfxViews;
+[[vk::binding(2,2)]] StructuredBuffer<ViewRecord> gfxViews;
 
 // All indirect commands use firstInstance=0. The raw Vulkan index avoids the
 // BaseInstance read that Slang adds for SV_InstanceID (DrawParameters feature).

src/authoring/schema.cpp

@@ -156,6 +156,15 @@ void SchemaRegistry::validate_component(const Json& component) const {
     for (const auto& [id, value] : component["fields"].items())
         if (metadata["fields"].contains(id))
             validate_field(value, metadata["fields"][id]);
+    if (type == "faset.light") {
+        auto effective = default_fields(type);
+        effective.update(component.at("fields"));
+        if (effective.at("kind") == "spot")
+            require(effective.at("inner_angle").get<double>() <=
+                        effective.at("outer_angle").get<double>(),
+                    "validation.light_cone",
+                    "Spotlight inner_angle must not exceed outer_angle");
+    }
 }
 void SchemaRegistry::add_migration(const std::string& type, int from_version, Json rules) {
     require(contains(type) && from_version > 0 && from_version < schema(type).value("version", 1) &&
@@ -267,7 +276,10 @@ SchemaRegistry builtin_schemas() {
                               {"default", 0.7}, {"min", 0.001}, {"max", 1.55},
                               {"unit", "radians"}}},
          {"casts_shadow", field("boolean", true)},
-         {"shadow_priority", field("integer", 0)}});
+         {"shadow_priority", Json{{"type", "integer"},
+                                   {"default", 0},
+                                   {"min", std::numeric_limits<int>::min()},
+                                   {"max", std::numeric_limits<int>::max()}}}});
     for (int dimension : {2, 3}) {
         Json vector = dimension == 2 ? Json{0, 0} : Json{0, 0, 0};
         Json extents = dimension == 2 ? Json{0.5, 0.5} : Json{0.5, 0.5, 0.5};

src/player/SceneView.cpp

@@ -397,7 +397,9 @@ render::Snapshot SceneView::build(const Json& scene, float aspect, CameraSetting
                     for (const auto coordinate : local.position)
                         if (!std::isfinite(coordinate))
                             invalid("position");
-                    local.direction = normalized(direction(model, {0, 0, -1}), id, "direction");
+                    if (local.kind == render::LocalLight::Kind::Spot)
+                        local.direction = normalized(direction(model, {0, 0, -1}), id,
+                                                     "direction");
                     local.color = color;
                     local.intensity = intensity;
                     local.range = number("range", 10);
@@ -405,13 +407,19 @@ render::Snapshot SceneView::build(const Json& scene, float aspect, CameraSetting
                         invalid("range");
                     local.inner_angle = number("inner_angle", 0.35f);
                     local.outer_angle = number("outer_angle", 0.7f);
-                    if (local.inner_angle < 0 || local.inner_angle > local.outer_angle ||
+                    if (local.kind == render::LocalLight::Kind::Spot &&
-                        local.outer_angle <= 0 || local.outer_angle >= std::numbers::pi_v<float> / 2)
+                        (local.inner_angle < 0 || local.inner_angle > local.outer_angle ||
+                         local.outer_angle <= 0 ||
+                         local.outer_angle >= std::numbers::pi_v<float> / 2))
                         invalid("inner_angle/outer_angle");
                     local.casts_shadow = castsShadow;
                     if (fields.contains("shadow_priority")) {
                         if (!fields.at("shadow_priority").is_number_integer())
                             invalid("shadow_priority");
+                        const auto priority = fields.at("shadow_priority").get<double>();
+                        if (priority < std::numeric_limits<int>::min() ||
+                            priority > std::numeric_limits<int>::max())
+                            invalid("shadow_priority");
                         local.shadow_priority = fields.at("shadow_priority").get<int>();
                     }
                     out.local_lights.push_back(std::move(local));

src/render/renderer.cpp

@@ -6,6 +6,7 @@
 #include <bit>
 #include <chrono>
 #include <cmath>
+#include <cstddef>
 #include <cstring>
 #include <faset/core/io.hpp>
 #include <faset/render/render_graph.hpp>
@@ -14,6 +15,7 @@
 #include <fstream>
 #include <iostream>
 #include <limits>
+#include <numbers>
 #include <optional>
 #include <stdexcept>
 #include <unordered_map>
@@ -72,6 +74,40 @@ struct ScenePush {
     std::array<std::uint32_t, 4> draw_info;
 };
 static_assert(sizeof(ScenePush) == 112);
+struct LightingHeaderGpu {
+    std::array<std::uint32_t, 4> counts{};
+    std::array<float, 4> sun_direction_intensity{};
+    std::array<float, 4> sun_color{};
+    std::array<float, 4> camera_forward_shadow_distance{};
+    std::array<float, 4> cascade_splits{};
+};
+struct LocalLightGpu {
+    std::array<float, 4> position_range{};
+    std::array<float, 4> direction_cos_outer{};
+    std::array<float, 4> color_intensity{};
+    std::array<float, 4> cone_type_shadow_view{};
+    std::array<float, 4> reserved{};
+};
+struct ShadowViewGpu {
+    Mat4 view_projection{identity};
+    std::array<float, 4> tile_scale_offset{};
+    std::array<float, 4> guarded_clamp{};
+    std::array<float, 4> bias_flags{};
+};
+static_assert(sizeof(LightingHeaderGpu) == 80 &&
+              offsetof(LightingHeaderGpu, sun_direction_intensity) == 16 &&
+              offsetof(LightingHeaderGpu, sun_color) == 32 &&
+              offsetof(LightingHeaderGpu, camera_forward_shadow_distance) == 48 &&
+              offsetof(LightingHeaderGpu, cascade_splits) == 64);
+static_assert(sizeof(LocalLightGpu) == 80 &&
+              offsetof(LocalLightGpu, direction_cos_outer) == 16 &&
+              offsetof(LocalLightGpu, color_intensity) == 32 &&
+              offsetof(LocalLightGpu, cone_type_shadow_view) == 48 &&
+              offsetof(LocalLightGpu, reserved) == 64);
+static_assert(sizeof(ShadowViewGpu) == 112 &&
+              offsetof(ShadowViewGpu, tile_scale_offset) == 64 &&
+              offsetof(ShadowViewGpu, guarded_clamp) == 80 &&
+              offsetof(ShadowViewGpu, bias_flags) == 96);
 std::array<float, 4> point(const Mat4& m, std::array<float, 4> p) {
     std::array<float, 4> o{};
     for (int r = 0; r < 4; ++r)
@@ -196,6 +232,7 @@ struct Renderer::Impl {
     std::vector<VkImageLayout> swap_layouts;
     Image color, depth, shadow;
     Buffer vertices, readback;
+    Buffer lighting_header, lighting_locals, lighting_views;
     SceneResources scene;
     InstanceTracker instance_tracker;
     std::unordered_map<std::string, std::size_t> previous_lods;
@@ -212,6 +249,9 @@ struct Renderer::Impl {
     std::unordered_map<const Texture*, CachedOpacity> opacity_cache;
     VkDescriptorSetLayout descriptor_layout{};
     VkDescriptorPool descriptor_pool{};
+    VkDescriptorSetLayout lighting_layout{};
+    VkDescriptorPool lighting_pool{};
+    VkDescriptorSet lighting_set{};
     VkSampler shadow_sampler{}, color_sampler{};
     VkPipelineLayout pipeline_layout{};
     VkPipeline pipeline{}, ui_pipeline{}, shadow_pipeline{}, sprite_pipeline{};
@@ -316,6 +356,9 @@ struct Renderer::Impl {
         destroy(scene.hzb[1]);
         destroy(vertices);
         destroy(readback);
+        destroy(lighting_header);
+        destroy(lighting_locals);
+        destroy(lighting_views);
         destroy(color);
         destroy(depth);
         destroy(shadow);
@@ -333,8 +376,12 @@ struct Renderer::Impl {
                 vkDestroyPipelineLayout(device, pipeline_layout, nullptr);
             if (descriptor_pool)
                 vkDestroyDescriptorPool(device, descriptor_pool, nullptr);
+            if (lighting_pool)
+                vkDestroyDescriptorPool(device, lighting_pool, nullptr);
             if (descriptor_layout)
                 vkDestroyDescriptorSetLayout(device, descriptor_layout, nullptr);
+            if (lighting_layout)
+                vkDestroyDescriptorSetLayout(device, lighting_layout, nullptr);
             if (shadow_sampler)
                 vkDestroySampler(device, shadow_sampler, nullptr);
             if (color_sampler)
@@ -889,6 +936,31 @@ struct Renderer::Impl {
         pi.pPoolSizes = sizes;
         check(vkCreateDescriptorPool(device, &pi, nullptr, &descriptor_pool),
               "Create descriptor pool");
+        std::array<VkDescriptorSetLayoutBinding, 4> lighting_bindings{};
+        for (std::uint32_t i = 0; i < lighting_bindings.size(); ++i)
+            lighting_bindings[i] = {i,
+                                    i == 3 ? VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE
+                                           : VK_DESCRIPTOR_TYPE_STORAGE_BUFFER,
+                                    1, VK_SHADER_STAGE_FRAGMENT_BIT, nullptr};
+        li.bindingCount = static_cast<std::uint32_t>(lighting_bindings.size());
+        li.pBindings = lighting_bindings.data();
+        check(vkCreateDescriptorSetLayout(device, &li, nullptr, &lighting_layout),
+              "Create lighting descriptor layout");
+        VkDescriptorPoolSize lighting_sizes[] = {
+            {VK_DESCRIPTOR_TYPE_STORAGE_BUFFER, 3}, {VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE, 1}};
+        pi.flags = 0;
+        pi.maxSets = 1;
+        pi.poolSizeCount = 2;
+        pi.pPoolSizes = lighting_sizes;
+        check(vkCreateDescriptorPool(device, &pi, nullptr, &lighting_pool),
+              "Create lighting descriptor pool");
+        VkDescriptorSetAllocateInfo lighting_allocation{};
+        lighting_allocation.sType = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
+        lighting_allocation.descriptorPool = lighting_pool;
+        lighting_allocation.descriptorSetCount = 1;
+        lighting_allocation.pSetLayouts = &lighting_layout;
+        check(vkAllocateDescriptorSets(device, &lighting_allocation, &lighting_set),
+              "Allocate lighting descriptors");
         VkSamplerCreateInfo si{};
         si.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
         si.magFilter = si.minFilter = VK_FILTER_NEAREST;
@@ -1009,8 +1081,9 @@ struct Renderer::Impl {
                                  sizeof(Push)};
         VkPipelineLayoutCreateInfo li{};
         li.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
-        li.setLayoutCount = 1;
+        const std::array<VkDescriptorSetLayout, 2> set_layouts{descriptor_layout, lighting_layout};
-        li.pSetLayouts = &descriptor_layout;
+        li.setLayoutCount = static_cast<std::uint32_t>(set_layouts.size());
+        li.pSetLayouts = set_layouts.data();
         li.pushConstantRangeCount = 1;
         li.pPushConstantRanges = &push;
         check(vkCreatePipelineLayout(device, &li, nullptr, &pipeline_layout),
@@ -1220,14 +1293,14 @@ struct Renderer::Impl {
         layout.pBindings = hzb.data();
         check(vkCreateDescriptorSetLayout(device, &layout, nullptr, &scene.hzb_layout),
               "Create HZB descriptor layout");
-        const std::array<VkDescriptorSetLayout, 2> scene_layouts{descriptor_layout,
+        const std::array<VkDescriptorSetLayout, 3> scene_layouts{
-                                                                  scene.graphics_layout};
+            descriptor_layout, lighting_layout, scene.graphics_layout};
         VkPushConstantRange graphics_push{VK_SHADER_STAGE_VERTEX_BIT |
                                               VK_SHADER_STAGE_FRAGMENT_BIT,
                                           0, sizeof(ScenePush)};
         VkPipelineLayoutCreateInfo pipeline_info{};
         pipeline_info.sType = VK_STRUCTURE_TYPE_PIPELINE_LAYOUT_CREATE_INFO;
-        pipeline_info.setLayoutCount = 2;
+        pipeline_info.setLayoutCount = static_cast<std::uint32_t>(scene_layouts.size());
         pipeline_info.pSetLayouts = scene_layouts.data();
         pipeline_info.pushConstantRangeCount = 1;
         pipeline_info.pPushConstantRanges = &graphics_push;
@@ -1533,6 +1606,29 @@ struct Renderer::Impl {
                              VkBufferUsageFlags usage = 0) {
         upload_scene_buffer(buffer, values.data(), values.size() * sizeof(T), usage);
     }
+    void update_lighting_descriptors() {
+        const std::array<VkDescriptorBufferInfo, 3> buffers{{
+            {lighting_header.handle, 0, lighting_header.size},
+            {lighting_locals.handle, 0, lighting_locals.size},
+            {lighting_views.handle, 0, lighting_views.size}}};
+        const VkDescriptorImageInfo atlas{VK_NULL_HANDLE, shadow.view,
+                                          VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL};
+        std::array<VkWriteDescriptorSet, 4> writes{};
+        for (std::uint32_t i = 0; i < writes.size(); ++i) {
+            writes[i].sType = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
+            writes[i].dstSet = lighting_set;
+            writes[i].dstBinding = i;
+            writes[i].descriptorCount = 1;
+            writes[i].descriptorType = i == 3 ? VK_DESCRIPTOR_TYPE_SAMPLED_IMAGE
+                                               : VK_DESCRIPTOR_TYPE_STORAGE_BUFFER;
+            if (i == 3)
+                writes[i].pImageInfo = &atlas;
+            else
+                writes[i].pBufferInfo = &buffers[i];
+        }
+        vkUpdateDescriptorSets(device, static_cast<std::uint32_t>(writes.size()),
+                               writes.data(), 0, nullptr);
+    }
     void update_scene_descriptors(bool occlusion) {
         auto write_buffers = [&](VkDescriptorSet set, std::span<const Buffer* const> buffers,
                                  std::uint32_t first_binding) {
@@ -2017,15 +2113,87 @@ struct Renderer::Impl {
                                     VK_BUFFER_USAGE_TRANSFER_DST_BIT);
             update_scene_descriptors(occlusion);
         }
-        Vec3 direction = snapshot.light_direction;
+        std::optional<SunLight> sun = snapshot.sun;
+        if (!sun && !snapshot.authored_lights_present && snapshot.local_lights.empty())
+            sun = SunLight{"legacy-sun", snapshot.light_direction, {1, 1, 1, 1}, 1, true};
+        Vec3 direction = sun ? sun->direction : snapshot.light_direction;
         float length = std::sqrt(direction[0] * direction[0] + direction[1] * direction[1] +
                                  direction[2] * direction[2]);
-        if (length < 1e-5f) {
+        if (!std::isfinite(length) || length < 1e-5f) {
+            if (sun && sun->stable_id != "legacy-sun")
+                throw std::invalid_argument("Authored sun direction must be finite and nonzero");
             direction = {-.5f, -1, -.3f};
             length = std::sqrt(1.34f);
         }
         for (auto& v : direction)
             v /= length;
+        LightingHeaderGpu lighting{};
+        lighting.counts[1] = sun ? 1u : 0u;
+        lighting.counts[2] = sun && sun->casts_shadow ? 1u : 0u;
+        lighting.sun_direction_intensity = {direction[0], direction[1], direction[2],
+                                            sun ? sun->intensity : 0};
+        lighting.sun_color = sun ? sun->color : Color{0, 0, 0, 1};
+        if (sun && (!std::isfinite(sun->intensity) || sun->intensity < 0 ||
+                    std::any_of(sun->color.begin(), sun->color.end(),
+                                [](float v) { return !std::isfinite(v) || v < 0; })))
+            throw std::invalid_argument("Authored sun radiance must be finite and nonnegative");
+        lighting.camera_forward_shadow_distance = {0, 0, -1, 80};
+        if (snapshot.camera_frustum) {
+            const auto& view = snapshot.camera_frustum->view;
+            lighting.camera_forward_shadow_distance = {-view[2], -view[6], -view[10], 80};
+        }
+        auto sorted_lights = snapshot.local_lights;
+        std::stable_sort(sorted_lights.begin(), sorted_lights.end(),
+                         [](const auto& a, const auto& b) { return a.stable_id < b.stable_id; });
+        constexpr std::size_t max_local_lights = 128;
+        std::vector<LocalLightGpu> gpu_lights;
+        gpu_lights.reserve(std::min(sorted_lights.size(), max_local_lights));
+        for (const auto& local : sorted_lights) {
+            if (gpu_lights.size() == max_local_lights)
+                break;
+            const auto finite_color = std::all_of(local.color.begin(), local.color.end(),
+                                                  [](float v) { return std::isfinite(v) && v >= 0; });
+            const auto finite_position = std::all_of(local.position.begin(), local.position.end(),
+                                                      [](float v) { return std::isfinite(v); });
+            if (!finite_color || !finite_position || !std::isfinite(local.intensity) ||
+                local.intensity < 0 || !std::isfinite(local.range) || local.range <= 0)
+                throw std::invalid_argument("Local light radiance, position and range must be finite");
+            if (local.kind == LocalLight::Kind::Spot &&
+                (!std::isfinite(local.inner_angle) || !std::isfinite(local.outer_angle) ||
+                 local.inner_angle < 0 || local.inner_angle > local.outer_angle ||
+                 local.outer_angle >= std::numbers::pi_v<float> / 2))
+                throw std::invalid_argument("Spotlight cone angles are invalid");
+            auto spot_direction = local.direction;
+            float spot_length = std::hypot(spot_direction[0], spot_direction[1],
+                                           spot_direction[2]);
+            if (!std::isfinite(spot_length) || spot_length < 1e-6f) {
+                if (local.kind == LocalLight::Kind::Spot)
+                    throw std::invalid_argument("Spotlight direction must be finite and nonzero");
+                spot_direction = {0, 0, -1};
+                spot_length = 1;
+            }
+            for (auto& axis : spot_direction)
+                axis /= spot_length;
+            LocalLightGpu gpu{};
+            gpu.position_range = {local.position[0], local.position[1], local.position[2],
+                                  local.range};
+            const bool spot = local.kind == LocalLight::Kind::Spot;
+            gpu.direction_cos_outer = {spot_direction[0], spot_direction[1], spot_direction[2],
+                                       spot ? std::cos(local.outer_angle) : 0.f};
+            gpu.color_intensity = {local.color[0], local.color[1], local.color[2],
+                                   local.intensity};
+            gpu.cone_type_shadow_view = {spot ? std::cos(local.inner_angle) : 1.f,
+                                         spot ? 1.f : 0.f, -1, 0};
+            gpu_lights.push_back(gpu);
+        }
+        lighting.counts[0] = static_cast<std::uint32_t>(gpu_lights.size());
+        if (gpu_lights.empty())
+            gpu_lights.push_back({}); // Descriptors always point at a full initialized record.
+        const ShadowViewGpu empty_shadow_view{};
+        upload_scene_buffer(lighting_header, &lighting, sizeof(lighting), 0);
+        upload_scene_vector(lighting_locals, gpu_lights);
+        upload_scene_buffer(lighting_views, &empty_shadow_view, sizeof(empty_shadow_view), 0);
+        update_lighting_descriptors();
         Vec3 light_eye{-direction[0] * 30, -direction[1] * 30, -direction[2] * 30};
         Vec3 light_up = std::abs(direction[1]) > .98f ? Vec3{0, 0, 1} : Vec3{0, 1, 0};
         Push push{multiply(orthographic(-20, 20, -20, 20, .1f, 80),
@@ -2078,6 +2246,12 @@ struct Renderer::Impl {
             vkCmdSetViewport(command, 0, 1, &viewport);
             vkCmdSetScissor(command, 0, 1, &scissor);
         };
+        auto bind_material = [&](VkDescriptorSet material) {
+            const std::array<VkDescriptorSet, 2> sets{material, lighting_set};
+            vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline_layout,
+                                    0, static_cast<std::uint32_t>(sets.size()), sets.data(),
+                                    0, nullptr);
+        };
         auto draw_transparent = [&] {
             if (transparent_batches.empty())
                 return;
@@ -2088,8 +2262,7 @@ struct Renderer::Impl {
                                0, sizeof(push), &push);
             for (auto batch : transparent_batches) {
                 auto descriptor = textures.at(batch.texture).descriptor;
-                vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS,
+                bind_material(descriptor);
-                                        pipeline_layout, 0, 1, &descriptor, 0, nullptr);
                 vkCmdDraw(command, batch.count, 1, batch.first, 0);
                 ++statistics.draw_calls;
             }
@@ -2102,8 +2275,7 @@ struct Renderer::Impl {
                                sizeof(push), &push);
             for (auto batch : sprite_batches) {
                 auto descriptor = textures.at(batch.texture).descriptor;
-                vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline_layout,
+                bind_material(descriptor);
-                                        0, 1, &descriptor, 0, nullptr);
                 vkCmdDraw(command, batch.count, 1, batch.first, 0);
                 ++statistics.draw_calls;
             }
@@ -2125,8 +2297,7 @@ struct Renderer::Impl {
                     continue;
                 vkCmdSetScissor(command, 0, 1, &scissor);
                 auto descriptor = textures.at(batch.texture).descriptor;
-                vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline_layout,
+                bind_material(descriptor);
-                                        0, 1, &descriptor, 0, nullptr);
                 vkCmdDraw(command, batch.count, 1, batch.first, 0);
                 ++statistics.draw_calls;
             }
@@ -2313,8 +2484,7 @@ struct Renderer::Impl {
             vkCmdPushConstants(command, pipeline_layout,
                                VK_SHADER_STAGE_VERTEX_BIT | VK_SHADER_STAGE_FRAGMENT_BIT, 0,
                                sizeof(push), &push);
-            vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline_layout, 0, 1,
+            bind_material(white_descriptor);
-                                    &white_descriptor, 0, nullptr);
             if (gpu_active && !gpu_frame.bins.empty()) {
                 VkDeviceSize scene_offset{};
                 vkCmdBindVertexBuffers(command, 0, 1, &scene.vertices.handle, &scene_offset);
@@ -2322,7 +2492,7 @@ struct Renderer::Impl {
                                   scene.graphics_pipeline);
                 for (std::uint32_t bin = 0; bin < gpu_frame.bins.size(); ++bin) {
                     auto descriptor = textures.at(gpu_frame.textures[bin]).descriptor;
-                    const std::array<VkDescriptorSet, 2> sets{descriptor,
+                    const std::array<VkDescriptorSet, 3> sets{descriptor, lighting_set,
                                                                scene.graphics_main};
                     vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS,
                                             scene.graphics_pipeline_layout, 0, sets.size(),
@@ -2346,8 +2516,7 @@ struct Renderer::Impl {
             }
             for (auto batch : scene_batches) {
                 auto descriptor = textures.at(batch.texture).descriptor;
-                vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS, pipeline_layout,
+                bind_material(descriptor);
-                                        0, 1, &descriptor, 0, nullptr);
                 vkCmdDraw(command, batch.count, 1, batch.first, 0);
                 ++statistics.draw_calls;
             }
@@ -2446,7 +2615,7 @@ struct Renderer::Impl {
                                       scene.graphics_pipeline);
                     for (std::uint32_t bin = 0; bin < gpu_frame.bins.size(); ++bin) {
                         auto descriptor = textures.at(gpu_frame.textures[bin]).descriptor;
-                        const std::array<VkDescriptorSet, 2> sets{descriptor,
+                        const std::array<VkDescriptorSet, 3> sets{descriptor, lighting_set,
                                                                    scene.graphics_post};
                         vkCmdBindDescriptorSets(command, VK_PIPELINE_BIND_POINT_GRAPHICS,
                                                 scene.graphics_pipeline_layout, 0,
@@ -2618,7 +2787,10 @@ struct Renderer::Impl {
         ++statistics.frame;
         statistics.gpu_allocated_bytes = vertices.allocation_size + readback.allocation_size +
                                          color.allocation_size + depth.allocation_size +
-                                         shadow.allocation_size;
+                                         shadow.allocation_size +
+                                         lighting_header.allocation_size +
+                                         lighting_locals.allocation_size +
+                                         lighting_views.allocation_size;
         statistics.texture_count = static_cast<std::uint32_t>(textures.size());
         for (const auto& [_, texture] : textures)
             statistics.gpu_allocated_bytes += texture.image.allocation_size;

src/render/shader_contract.cpp

@@ -34,13 +34,21 @@ void validate_layout(const Json& layout, std::string_view entry) {
     const bool fragment = entry == "fragmentMain";
     require(layout.at("stage") == (fragment ? "fragment" : "vertex"), "shader stage changed");
     const auto& descriptors = layout.at("descriptors");
-    require(descriptors.is_array() && descriptors.size() == 4, "descriptor count changed");
+    require(descriptors.is_array() && descriptors.size() == 8, "descriptor count changed");
     for (std::size_t i = 0; i < descriptors.size(); ++i) {
         const auto& binding = descriptors[i];
-        require(binding.at("set") == 0 && binding.at("binding") == i && binding.at("count") == 1,
+        const auto set = i < 4 ? 0 : 1;
+        const auto slot = i % 4;
+        require(binding.at("set") == set && binding.at("binding") == slot &&
+                    binding.at("count") == 1,
                 "descriptor set, binding or array count changed");
-        require(binding.at("type") == (i % 2 ? "sampler" : "sampled_image_2d"),
+        const auto* expected_type = set == 0 ? (slot % 2 ? "sampler" : "sampled_image_2d")
+                                    : slot == 3 ? "sampled_image_2d" : "storage_buffer";
+        require(binding.at("type") == expected_type,
                 "descriptor type changed");
+        if (set == 1 && slot < 3)
+            require(binding.at("element_stride") == (slot == 2 ? 112 : 80),
+                    "lighting storage record stride changed");
         require(fragment || !binding.at("used").get<bool>(),
                 "vertex texture bindings are unsupported");
     }
@@ -98,7 +106,7 @@ void validate_gpu_layout(const Json& layout, std::string_view entry) {
     const std::array<int, 3> graphics_strides{224, 4, 208};
     for (std::size_t i = 0; i < expected_count; ++i) {
         const auto& binding = descriptors[i];
-        require(binding.at("set") == (graphics ? 1 : 0) && binding.at("binding") == i &&
+        require(binding.at("set") == (graphics ? 2 : 0) && binding.at("binding") == i &&
                     binding.at("count") == 1,
                 "GPU descriptor set, binding or count changed");
         const int stride = graphics ? graphics_strides[i] : hzb ? 0 : compute_strides[i];

tests/authoring_tests.cpp

@@ -2,6 +2,7 @@
 #include <faset/authoring/templates.hpp>
 #include <faset/authoring/transforms.hpp>
 #include <faset/core/io.hpp>
+#include <cstdint>
 #include <iostream>
 
 #define CHECK(x)                                                                                   \
@@ -44,6 +45,13 @@ int main() {
         light_component["fields"]["range"] = 10;
         light_component["fields"]["intensity"] = -1;
         fails([&] { schemas.validate_component(light_component); }, "validation.minimum");
+        light_component["fields"] = {{"kind", "spot"}, {"inner_angle", 0.9}};
+        fails([&] { schemas.validate_component(light_component); }, "validation.light_cone");
+        light_component["fields"] = {{"kind", "spot"},
+                                      {"inner_angle", 0.2},
+                                      {"outer_angle", 0.5},
+                                      {"shadow_priority", std::int64_t{2147483648}}};
+        fails([&] { schemas.validate_component(light_component); }, "validation.maximum");
         AuthoringService service(root, schemas);
         auto created = service.create("Courtyard", 3);
         const std::string id = created["id"];

tests/render_gpu_shader_contract_tests.cpp

@@ -59,6 +59,15 @@ int main() {
         faset::atomic_write_json(reflection_file, metadata);
         must_reject([&] { (void)faset::render::detail::load_gpu_shader_bundle(temporary); },
                     "A consistently rehashed but incompatible GPU record stride must be rejected");
+        faset::atomic_write_json(reflection_file,
+                                 faset::read_json(original / "gpuPostCullMain.reflection.json"));
+        reflection_file = temporary / "gpuVertexMain.reflection.json";
+        metadata = faset::read_json(original / "gpuVertexMain.reflection.json");
+        metadata["layout"]["descriptors"][0]["set"] = 1;
+        metadata["layout_fingerprint"] = faset::sha256(metadata["layout"].dump());
+        faset::atomic_write_json(reflection_file, metadata);
+        must_reject([&] { (void)faset::render::detail::load_gpu_shader_bundle(temporary); },
+                    "GPU graphics scene buffers must stay in descriptor set two");
         fs::remove(temporary / "gpuHzbMain.spv");
         must_reject([&] { (void)faset::render::detail::load_gpu_shader_bundle(temporary); },
                     "Missing P2 entry must be rejected");

tests/render_reload_tests.cpp

@@ -59,6 +59,27 @@ int main() {
         const auto original_reflection = read_text(bundle / "fragmentMain.reflection.json");
         const auto original_fingerprint = Json::parse(original_reflection).at("layout_fingerprint");
         render::validate_shader_bundle(bundle);
+        auto bad_lighting_stride = Json::parse(original_reflection);
+        auto& lighting_descriptors = bad_lighting_stride["layout"]["descriptors"];
+        bool found_local_buffer = false;
+        for (auto& descriptor : lighting_descriptors)
+            if (descriptor["set"] == 1 && descriptor["binding"] == 1) {
+                descriptor["element_stride"] = 96;
+                found_local_buffer = true;
+            }
+        require(found_local_buffer, "Lighting stride fixture exists");
+        bad_lighting_stride["layout_fingerprint"] =
+            sha256(bad_lighting_stride["layout"].dump());
+        atomic_write_json(bundle / "fragmentMain.reflection.json", bad_lighting_stride);
+        bool rejected_lighting_stride = false;
+        try {
+            render::validate_shader_bundle(bundle);
+        } catch (const std::exception&) {
+            rejected_lighting_stride = true;
+        }
+        require(rejected_lighting_stride,
+                "Rehashed incompatible local-light element stride must be rejected");
+        atomic_write(bundle / "fragmentMain.reflection.json", original_reflection);
         render::RendererConfig configuration;
         configuration.width = configuration.height = 64;
         configuration.headless = true;
@@ -161,6 +182,18 @@ int main() {
         atomic_write(bundle / "fragmentMain.spv", "damaged bytecode");
         retained();
         restore();
+        auto incompatible = original_source;
+        auto at = incompatible.find("    float4 reserved;");
+        require(at != std::string::npos, "Local-light stride fixture exists");
+        incompatible.replace(at, std::string("    float4 reserved;").size(),
+                             "    float4 reserved;\n    float4 incompatibleExtraLane;");
+        atomic_write(source, incompatible);
+        require(compile(source, bundle) == 0, "Compile incompatible light-buffer stride");
+        require(read_json(bundle / "fragmentMain.reflection.json").at("layout_fingerprint") !=
+                    original_fingerprint,
+                "Lighting stride edit changes normalized layout fingerprint");
+        retained();
+        restore();
         auto malformed = original_spirv;
         for (int i = 0; i < 4; ++i)
             malformed[20 + i] = 0; // zero-word SPIR-V instruction
@@ -170,8 +203,8 @@ int main() {
         atomic_write_json(bundle / "fragmentMain.reflection.json", metadata);
         retained();
         restore();
-        auto incompatible = original_source;
+        incompatible = original_source;
-        auto at = incompatible.find("[[vk::binding(2,0)]]");
+        at = incompatible.find("[[vk::binding(2,0)]]");
         require(at != std::string::npos, "Shader descriptor fixture exists");
         incompatible.replace(at, std::string("[[vk::binding(2,0)]]").size(),
                              "[[vk::binding(7,0)]]");

tests/render_tests.cpp

@@ -134,6 +134,65 @@ int main(int argc, char** argv) {
         renderer.render(scene);
         pixels = renderer.pixels();
         require(pixels[index + 2] > 220, "Texture revision upload");
+        Snapshot two_lights;
+        two_lights.eye = {0, 0, 6};
+        two_lights.projection = perspective(.85f, 320.f / 240.f, .1f, 30.f);
+        two_lights.view_projection =
+            multiply(two_lights.projection, look_at(two_lights.eye, {0, 0, 0}));
+        two_lights.authored_lights_present = true;
+        two_lights.draws.push_back(
+            {cube_mesh(), transform({-1.4f, 0, 0}), {.5f, .5f, .5f, 1}, .6f, 0, false});
+        two_lights.draws.back().instance_key = "left-light-receiver";
+        two_lights.draws.push_back(
+            {cube_mesh(), transform({1.4f, 0, 0}), {.5f, .5f, .5f, 1}, .6f, 0, false});
+        two_lights.draws.back().instance_key = "right-light-receiver";
+        two_lights.ui_quads.push_back({8, 8, 40, 20, {.8f, .1f, .15f, 1}});
+        for (auto mode : {VisibilityMode::Direct, VisibilityMode::GpuFrustum}) {
+            renderer.set_visibility_mode(mode);
+            renderer.render(two_lights);
+            const auto dark = renderer.pixels();
+            require(renderer.stats().validation_errors == 0,
+                    "Zero-local-light descriptors are initialized");
+            auto legacy_lights = two_lights;
+            legacy_lights.authored_lights_present = false;
+            renderer.render(legacy_lights);
+            const auto legacy = renderer.pixels();
+            const auto left = (120 * 320 + 99) * 4;
+            require(legacy[left] > dark[left] + 15,
+                    "Authored-light presence suppresses the legacy sun even without a local light");
+            two_lights.local_lights = {
+                {LocalLight::Kind::Point, "red", {-1.4f, 0, 1.4f}, {0, 0, -1},
+                 {1, 0, 0, 1}, 8, 2.2f, .35f, .7f, false, 0},
+                {LocalLight::Kind::Point, "blue", {1.4f, 0, 1.4f}, {0, 0, -1},
+                {0, 0, 1, 1}, 8, 2.5f, .35f, .7f, false, 0}};
+            renderer.render(two_lights);
+            const auto lit = renderer.pixels();
+            const auto right = (120 * 320 + 221) * 4;
+            const auto ui = (10 * 320 + 10) * 4;
+            require(lit[left] > dark[left] + 20 && lit[right + 2] > dark[right + 2] + 20,
+                    "Separated red and blue point lights illuminate their receivers");
+            require(std::abs(int(lit[left + 2]) - int(dark[left + 2])) < 6 &&
+                        std::abs(int(lit[right]) - int(dark[right])) < 6,
+                    "Local light range keeps the opposite colored light off each receiver");
+            for (int channel = 0; channel < 4; ++channel)
+                require(lit[ui + channel] == dark[ui + channel],
+                        "Lighting changes leave UI tint unchanged");
+            require(renderer.stats().validation_errors == 0,
+                    "Direct and GPU local lighting report no Vulkan errors");
+            if (mode == VisibilityMode::GpuFrustum)
+                require(renderer.stats().effective_visibility_mode == VisibilityMode::GpuFrustum,
+                        "Local light image test actually exercises the GPU visibility path");
+            two_lights.local_lights[1].kind = LocalLight::Kind::Spot;
+            renderer.render(two_lights);
+            const auto aimed = renderer.pixels();
+            two_lights.local_lights[1].direction = {1, 0, 0};
+            renderer.render(two_lights);
+            const auto turned = renderer.pixels();
+            require(aimed[right + 2] > turned[right + 2] + 20,
+                    "Spotlight cone direction changes receiver illumination");
+            two_lights.local_lights.clear();
+        }
+        renderer.set_visibility_mode(VisibilityMode::Direct);
         if (argc > 2)
             renderer.capture(argv[2]);
         renderer.resize(400, 300);

tests/runtime_player_tests.cpp

@@ -134,6 +134,18 @@ void lightingExtraction(faset::player::SceneView& view) {
     rejectsContaining([&] { view.build(scene, 1); }, "bad-light", "inner_angle");
     scene["entities"][0]["components"][0]["fields"] = {{"kind", "area"}};
     rejectsContaining([&] { view.build(scene, 1); }, "bad-light", "kind");
+    scene["entities"][0]["components"][0]["fields"] =
+        {{"kind", "point"}, {"shadow_priority", std::int64_t{2147483648}}};
+    rejectsContaining([&] { view.build(scene, 1); }, "bad-light", "shadow_priority");
+    scene["entities"][0]["components"][0]["fields"] = {{"kind", "point"}};
+    scene["entities"][0]["components"].insert(
+        scene["entities"][0]["components"].begin(),
+        component("faset.transform", {{"scale", {1, 1, 0}}}));
+    const auto flatPoint = view.build(scene, 1);
+    check(flatPoint.local_lights.size() == 1 &&
+              flatPoint.local_lights[0].kind == faset::render::LocalLight::Kind::Point,
+          "Point light accepts a zero Z scale because it needs only a position");
+    scene["entities"][0]["components"].erase(scene["entities"][0]["components"].begin());
     scene["entities"][0]["components"][0]["fields"] =
         {{"kind", "point"},
          {"color", Json::array({1, std::numeric_limits<double>::quiet_NaN(), 1, 1})}};

tests/test_shader_reflection.py

@@ -36,6 +36,35 @@ def parameter(name: str, index: int, shape: str, access: str, stride: int | None
 
 
 class ReflectionTests(unittest.TestCase):
+    def test_graphics_lighting_abi(self):
+        compiler = os.environ["FASET_TEST_SLANGC"]
+        with tempfile.TemporaryDirectory(prefix="faset-lighting-abi-") as directory:
+            for source, entry, defines in (
+                ("baseline.slang", "fragmentMain", []),
+                ("gpu_scene.slang", "gpuVertexMain", ["--define", "FASET_GPU_GRAPHICS=1"]),
+            ):
+                process = subprocess.run(
+                    [sys.executable, str(SCRIPT), "--compiler", compiler, "--source",
+                     str(SCRIPT.parents[1] / "shaders" / source), "--entry", entry,
+                     *defines, "--output", directory],
+                    capture_output=True, text=True,
+                )
+                self.assertEqual(process.returncode, 0, process.stderr)
+            fragment = json.loads((Path(directory) / "fragmentMain.reflection.json").read_text())
+            gpu_vertex = json.loads((Path(directory) / "gpuVertexMain.reflection.json").read_text())
+            lighting = {
+                (d["set"], d["binding"]): (d["type"], d.get("element_stride"))
+                for d in fragment["layout"]["descriptors"]
+            }
+            self.assertEqual([lighting[1, i] for i in range(4)],
+                             [("storage_buffer", 80), ("storage_buffer", 80),
+                              ("storage_buffer", 112), ("sampled_image_2d", None)])
+            graphics = {
+                (d["set"], d["binding"]): d["element_stride"]
+                for d in gpu_vertex["layout"]["descriptors"]
+            }
+            self.assertEqual([graphics[2, i] for i in range(3)], [224, 4, 208])
+
     def test_gpu_vertex_paths_do_not_require_shader_draw_parameters(self):
         # SV_InstanceID makes Slang subtract BaseInstance and emit DrawParameters.
         # Our indirect commands always use firstInstance=0, so the Vulkan instance