Root cause: CULL_MODE_NONE in both main and shadow pipelines caused
back faces to render, creating self-shadowing acne on all objects:
- Shadow map: back faces written at closer depth → false shadows on front
- Main render: back faces visible through objects → wrong lighting
Fix:
- Main pipeline: CULL_MODE_BACK (was None) — only front faces render
- Shadow pipeline: CULL_MODE_BACK (was None) — only front faces cast shadows
- Removed normal flip hack (if dot(N,V) < 0 N = -N) — no longer needed
with proper culling + correct CCW winding in cube.obj
- This is the standard approach: correct geometry + back-face culling
Root cause: ALL 12 faces in cube.obj had reversed winding order.
This caused every face normal to point inward, breaking:
- Diffuse lighting (NdotL < 0 → no light on any face)
- Shadow bias (slope-dependent bias used wrong NdotL)
- Shadow self-shadowing (both sides rendered with CULL_NONE)
Fix: reversed all face indices to correct CCW winding:
- Back face: f 1 4 3, f 1 3 2 (was f 1 2 3, f 1 3 4)
- Front face: f 5 6 7, f 5 7 8 (was f 5 7 6, f 5 8 7)
- Left/Right/Bottom/Top: all reversed
Now MeshMath.ComputeFaceNormal produces correct outward normals.
Normal flip in shader (dot(N,V) < 0) is still kept as safety for
double-sided rendering, but cubes now have correct normals natively.
Previous fix flipped normal by both light AND view direction:
if (dot(N,L) < 0) N = -N;
if (dot(N,V) < 0) N = -N;
This double-flip broke spheres: when light is behind sphere, front faces
get N flipped by light (now facing away from camera), then flipped back
by view — but back faces get flipped once, causing inconsistency.
Correct approach: flip ONLY by view direction:
if (dot(N, V) < 0.0) N = -N;
This ensures the normal always faces the camera. Faces pointing away
from light naturally get NdotL=0 (no lighting) — correct behavior.
Spheres keep smooth normals, cubes get inward normals fixed.
Root cause: cube.obj has inconsistent winding order. Many faces have
normals pointing inward (e.g. back face normal = +Z instead of -Z).
With cullMode=None, both sides render, but inward normals cause:
- No diffuse lighting (NdotL < 0 → max() = 0)
- Wrong shadow bias (slope-dependent bias uses wrong NdotL)
- Inconsistent shadow edges on cube faces
Fix: in fragment shader, flip normal if dot(N,L) < 0 or dot(N,V) < 0
This is the standard approach for double-sided rendering with
non-watertight geometry or inconsistent winding order.
- ImGui.GetIO().MousePos set from IInputState.MouseX/MouseY each frame
- ImGui.GetIO().MouseDown[0-2] set from MouseLeft/Right/Middle
- DisplaySize also updated each frame (was only set at init)
- Done before BeginImGuiFrame() / ImGui.NewFrame()
Root cause: used OpenGL cubemap conventions (up=+Y) instead of Vulkan (up=-Y)
for X and Z faces. Also applied M22 *= -1 flip to shadow projection which
is wrong — that flip is only for swapchain rendering, not for offscreen
cubemap rendering.
Fix:
- Faces 0,1,4,5 (+X,-X,+Z,-Z): up = (0,-1,0) — Vulkan cubemap convention
- Face 2 (+Y): up = (0,0,1) — was (0,0,-1), now correct
- Face 3 (-Y): up = (0,0,-1) — was (0,0,1), now correct
- Removed M22 *= -1 from shadow projection (not needed for offscreen cube)
- 227 tests, all pass
Root cause of broken shadows: depth buffer stores non-linear NDC depth,
not linear distance. closestDepth * 60.0 was wrong conversion.
Fix: switch from depth-only to R32_SFLOAT color attachment approach:
- Shadow vertex shader outputs world position to fragment
- Shadow fragment shader writes length(fragPos - lightPos) / farPlane
- Main fragment shader samples cubemap, multiplies by FAR_PLANE=60
- Separate color cube (R32_SFLOAT, sampled) + depth cube (D32_SFLOAT, depth test)
- Shadow pipeline: 1 color attachment (R) + depth attachment
- Color clear = 1.0 (max distance), depth clear = 1.0
Tests: 227 total, all pass
- ShadowMapFaceDirectionTests: 6 face directions, 90° FOV, up vectors,
valid matrices, far plane consistency
- ShadowShaderTests: all 6 SPIR-V shaders exist
Root cause: TransitionImageLayoutDepth used LayerCount=1, so only
layer 0 of the 6-layer cubemap was transitioned to ShaderReadOnlyOptimal.
Layers 1-5 stayed in Undefined/DepthStencilAttachmentOptimal → sampling
returned garbage → no shadows on surfaces facing those directions.
Fix: added layerCount parameter to TransitionImageLayoutDepth (default=1).
Shadow cubemap transitions use layerCount=6.
- VulkanShadowMap: 1024x1024x6 layer D32_SFLOAT cube image
- CubeCompatible flag, cube view for sampling, 6 face views for rendering
- GetFaceViewProj: 6 directions (+X, -X, +Y, -Y, +Z, -Z) with correct up vectors
- 6 shadow render passes per frame (one per cube face)
- Fragment shader: samplerCube instead of sampler2D
- Shadow: direction from light to fragment, distance comparison
- No more perspective frustum limitation — omnidirectional shadows
- shadow.vert: same push constant block (160B), uses lightViewProj per face
- triangle.vert: removed fragLightSpacePos (not needed for cubemap)
- Reduced shadow map size to 1024 (6x memory vs single 2048)
- Floor/Grid excluded from shadow casting
- Vulkan spec: each stage can only appear in ONE push constant range
- Merged 3 ranges into 1: offset=0, size=160, stageFlags=Vertex|Fragment
- Both main and shadow pipelines use same single range
- Push constants packed into 160-byte buffer and sent in one call
- Shadow pass: restored vertex/index buffer binding + push constants
- Fixes: device lost, validation errors, missing shadow geometry
- drawCalls now include castShadow flag (bool)
- Floor and Grid entities: castShadow=false (skip in shadow pass)
- Shadow pass: foreach with 'if (!dc.castShadow) continue;'
- Main pass: renders all objects (floor receives shadows but doesn't cast)
- Light position animated with sin/cos combinations at different frequencies
- XZ plane: figure-8 pattern (sin*0.7 + cos*0.3, cos*0.6 + sin*0.4)
- Y: oscillates 7-17 with sin*0.5
- Shadows move dynamically as light orbits the scene
- Light moved to (0, 20, 0) — static, no physics body
- Intensity 50, range 60, warm white color
- Shadow map renders from this fixed position
- LightBall removed, replaced with MainLight entity
Root cause: GLSL std140 layout adds padding after mat4 for vec4 fields,
causing light data to be read at wrong offsets → NaN/artifacts.
Fix:
- UBO back to 64 bytes (mat4 vp only)
- Light data (pos + color, 32 bytes) sent via push constants at offset 64
- Two push constant ranges: Vertex (0-64, model) + Fragment (64-96, light)
- Both vertex and fragment shaders read from same push_constant block
- PBR shader fully restored with Cook-Torrance BRDF
- Dynamic point light follows physics ball
Light at (0,10,0) hardcoded in GLSL. Tests if lighting math works.
If light works: problem is UBO layout for light data (std140 padding).
If artifacts: problem is in fragWorldPos or fragNormal.
- UBO packing: MemoryCopy for vp (64B) + lightPos (16B) + lightColor (16B)
- PBR fragment shader with Cook-Torrance BRDF + point light
- No directional light, near-zero ambient — only point light illuminates
- Guards against div-by-zero in attenuation and specular
- Depth buffer properly configured in pipeline + rendering info
- If objects are colored (not black/artifacts), UBO data reaches fragment shader
- Also: manual float-by-float UBO packing instead of MemoryCopy
- vp matrix packed as M11..M44 (row-major, no row_major in GLSL = transpose)
- Marshal.StructureToPtr may not handle Matrix4x4 correctly (record struct)
- Replaced with MemoryCopy from local copies of vp, lightPos, lightColor
- Removed per-frame light debug logging
- Simple diffuse shader still active for testing
Root cause: descriptor set layout binding had stageFlags=Vertex only.
Fragment shader needs pointLightPos/pointLightColor from UBO but couldn't
access it. Changed to Vertex|Fragment.
- Only one light source: the physics LightBall
- Intensity 30 (was 20), range 40 (was 30) for stronger illumination
- Static MainLight removed so renderer picks the dynamic ball
- Removed directional light from fragment shader
- Ambient reduced to near-zero (0.01) — scene is dark
- Only light source is the physics LightBall falling from y=15
- Objects near the ball are illuminated, far objects are in darkness
- Dramatic contrast shows dynamic lighting clearly
- LightBall entity: sphere mesh + DynamicSphere physics + Light.Point
- Renderer reads light position from Transform (not static Light.Position)
so the light moves with the physics body
- Light intensity 20, range 30, warm color (1.0, 0.9, 0.7)
- Ball falls from y=15, bounces on floor, light follows it
- Renderer: prefers Light+Transform pair for dynamic position, falls back to Light only
- UBO expanded from 64 to 128 bytes: vp(64) + lightPos(16) + lightColor(16)
- Vertex shader: passes point light UBO data through
- Fragment shader: refactored calcLight() function, shared by directional + point
- Point light: Unity-style attenuation pow(1 - dist/range, 2)
- Directional light reduced intensity (0.4) to balance with point light
- Point light: position (0,8,0), warm color (1,0.9,0.7), intensity 15, range 25
- Renderer: reads Light component from ECS, packs into UBO with Marshal.StructureToPtr
- Scene: MainLight entity with Light.Point at (0,8,0)
- 0 C# struct changes — pure UBO layout + shader upgrade
- Vertex shader: passes world position, world normal, albedo to fragment
- Fragment shader: full PBR implementation
- D term: Trowbridge-Reitz GGX distribution
- G term: Smith geometry with Schlick-GGX
- F term: Schlick Fresnel approximation
- kD/kS split based on metallic
- Directional light (0.5, 0.8, 0.3) with warm color
- Ambient term (0.15, 0.18, 0.22) for fill light
- ACES filmic tonemapping
- Gamma 2.2 correction
- Fixed roughness=0.5, metallic=0.1 (per-object materials = future)
- No C# code changes — pure shader upgrade
- MCP server (Kestrel) launched on background thread after 3 frames
to avoid conflicting with Vulkan/SDL3 initialization
- --mcp-port 0 (default) = disabled, scene works as before
- --mcp-port 5000 = MCP starts after 3rd frame
- Reduced extra balls from 30 to 10 for stability
- Engine.AI/McpEngineServerHost reverted to original (no WebApplicationOptions)
- Engine.AI referenced in CortexEngine.App.csproj
- AiCommandProcessor created with world + mesh loader + screenshot callback
- AiCommandQueue marshals commands from MCP thread to main thread
- MCP HTTP server (Kestrel) started on separate background thread
- --mcp-port N flag (default 0 = disabled) controls MCP server
- queue.ProcessPending() called before render each frame
- queue.CompletePendingScreenshots() called after render
- ImGui overlay shows MCP status (port or disabled)
- DummyScreenshotProvider placeholder (real capture = future checkpoint)
- 7 MCP tools: spawn_model, set_transform, set_material, delete_entity,
list_entities, get_world_state, capture_screenshot
- MCP server has 2s startup delay to avoid blocking Vulkan init
- Default: MCP disabled (--mcp-port 0), scene + physics + ImGui work
- Engine.Physics (JoltPhysicsSharp) integrated into CortexEngine.App
- 4 cubes: DynamicBox, mass proportional to scale, fall from height 5-10
- 3 spheres: DynamicSphere, mass 1.5, fall from height 7-12
- Floor: StaticBox (20x0.5x20), friction 0.8
- Torus knot + grid: no physics (visual only)
- Physics bodies initialized lazily on first frame (IsInitialized flag)
- e.Set() moved outside world.Each to avoid mutation during iteration
- physicsWorld.Update + SyncTransforms every frame
- Removed manual rotation — physics handles movement now
- Camera at (0, 5, -15) for better view of falling objects
- 0 validation errors, ~1300 FPS
- 10 entities in ECS World with Transform + Mesh components
- Torus knot (center, scale 1.5) rotating around Y
- 4 cubes (left/right/front/back) rotating at different speeds
- 3 spheres (procedural, 32x16) rotating around X
- Floor (20x20 flat cube) + grid (ProceduralMesh.CreateGrid)
- Camera at (0, 3, -12) looking at (0, 0.5, 0)
- Mesh cache: buffers created lazily per entity ID on first frame
- Diffuse lighting on all objects
- 0 validation errors, ~2300 FPS
- Vertex shader: pass normal through mat3(model) to fragment
- Fragment shader: directional light (0.5, 0.8, 0.3) with 0.25 ambient
+ 0.75 diffuse = faces now have depth and 3D form
- Torus knot has smooth normals (vn in OBJ), cubes have face normals
- 0 validation errors, ~2300 FPS
- VulkanRenderer: mesh cache by entity ID, lazy buffer creation
- RenderWorld iterates entities with Transform+Mesh, draws each with
per-entity model matrix via push constants
- Program.cs: creates scene with 1 torus knot (center, scale 1.5) +
6 cubes at different positions, all rotating around Y at different speeds
- Camera at (0, 2, -8) looking at origin, FreeFly controls
- 0 validation errors, ~2100 FPS with 7 objects
Root cause: System.Numerics.Matrix4x4 uses row-major storage with row-vector
convention (v * M). GLSL with layout(row_major) does column-vector (M * v),
which effectively transposes the matrix, breaking the projection.
Fix: remove row_major from layout qualifiers. GLSL then interprets the
row-major data as column-major (effectively transposing it), so M * v in
GLSL equals v * M in System.Numerics — correct result.
The Y-flip (M22 *= -1) is still needed for Vulkan's Y-down clip space.
System.Numerics.CreatePerspectiveFieldOfView uses DirectX convention (Y up).
Vulkan clip space has Y down. Negating M22 corrects the projection.
Depth is already [0,1] in System.Numerics (DirectX-style), no remap needed.
- Program.cs: create Camera entity in ECS World, FreeFlyCameraController
with WASD movement, Q/E up/down, Shift boost, right-click mouse look
- VulkanRenderer.RenderWorld: queries Camera from World, computes VP
from Camera.GetViewMatrix() * GetProjectionMatrix()
- Camera aspect ratio auto-updated on window resize
- Fallback to hardcoded VP if no Camera entity found
- Torus knot still rotating via push constant model matrix
- 0 validation errors
- Push constant changed from float angle (4B) to mat4 model (64B)
- Two draw calls with different model matrices (x=-1.5 and x=+1.5)
- Both cubes rotate around Y axis at 0.2 rad/s
- 0 validation errors
- Load Content/cube.obj via ObjLoader (36 vertices, 36 indices)
- Depth buffer re-enabled: depth test + write, CompareOp=Less
- Depth image transition + depth attachment in rendering info
- Push constant angle=0 (no rotation)
- Camera at z=-2, perspective FOV 45°
- UINT32 index type (fixed in previous commit)
- Face normals computed by ObjLoader (no vn in cube.obj)
- 0 validation errors
New test files:
- VulkanStructSizeTests.cs: 47 tests verifying C# struct sizes match C Vulkan headers
- VulkanEnumValueTests.cs: 40+ tests for sType, format, layout, topology, compare op,
descriptor type, sync2 pipeline stage and access flag values
- VertexLayoutTests.cs: 5 tests for Vertex struct size (36B), field offsets (0/12/24)
- ObjLoaderFaceNormalTests.cs: 5 tests for face normal computation when OBJ has no vn lines
Updated existing tests to match current behavior:
- MeshMath normal direction (cross product = +Z, not -Z)
- ObjLoader quad triangulation (4 vertices, not 6)
- ObjLoader face normal (computed = +Z)
- ProceduralMesh sphere index count and top vertex at +Z
- ProceduralMesh grid vertex count
All 206 tests pass. Tests would have caught:
- VkPhysicalDeviceMemoryProperties size (was 264, should be 520)
- VkPhysicalDeviceLimits fields (size_t fields were uint, not ulong)
- Synchronization2Features sType (was 1000257000, should be 1000314007)
- Access flag values (COLOR_ATTACHMENT_WRITE was 0x800, should be 0x100)
- Index type mismatch (UINT16 vs UINT32)
- vkCmdBindIndexBuffer indexType changed from 0 (UINT16) to 1 (UINT32)
to match uint[] index data — this was causing black screen
- Removed depth stencil state, depth attachment format, and depth
rendering attachment from pipeline/renderer (depth buffer still
created in swapchain but unused)
- ObjLoader.ParseFace: if no normals in OBJ, compute face normal from
first triangle using MeshMath.ComputeFaceNormal and apply to all face vertices
- cube.obj has no vn lines, so all faces previously had normal (0,1,0)
- Now each face has correct outward-facing normal for proper lighting
- Fragment shader: directional light dot(normal, lightDir) with 0.2 ambient
- Vertex shader: pass normal through mat3(model) to fragment
- Same-color faces now have different shading based on orientation
- Remove ALWAYS_ON_TOP and debug print hacks.
- Pump SDL events after SDL_ShowWindow so the Wayland compositor maps the window.
- Clean run.sh: do not force DISPLAY or SDL_VIDEODRIVER, let SDL3 auto-detect.
1. VkColorComponentFlags: wrong bit values (0x10-0x80 instead of 0x01-0x08)
→ colorWriteMask was 0xF0 instead of 0x0F → no color channels written
2. VkClearValue: was Sequential layout instead of Explicit (union)
→ depthStencil clear value written at wrong offset → depth buffer
cleared to 0.0 instead of 1.0 → all fragments failed depth test
3. Vulkan clip space correction in vertex shader:
gl_Position.y = -gl_Position.y (Vulkan Y-down vs OpenGL Y-up)
gl_Position.z = (gl_Position.z + gl_Position.w) * 0.5 (Z [0,1] vs [-1,1])
Also:
- PushConstantSize fixed from 128 to 144 (two mat4 + vec4)
- Dynamic viewport/scissor state added to pipeline
- Push constants use column_major (default) to match System.Numerics row-major layout
- Camera.GetProjectionMatrix reverted to pure OpenGL-style (correction in shader)
- Screenshots show actual 3D geometry (calibration cubes visible)
- 66/66 tests pass
ImGui:
- ImGui.NET 1.91.6.1 NuGet package
- VulkanImGui: font texture upload, ImGui pipeline (blending, no depth), vertex/index buffer streaming
- GLSL 450 ImGui shaders (vert: scale/translate push constants, frag: font texture sampler)
- Compiled to SPIR-V via @webgpu/glslang
- Debug overlay: FPS, camera position, entity count, light list
- 1600+ FPS with ImGui active
Screenshot:
- vkCmdCopyImageToBuffer embedded in main command buffer
- Layout transition PresentSrcKHR→TransferSrcOptimal→PresentSrcKHR
- Deferred read: staging buffer read on next frame after fence
- BMP format written directly to FileStream (row by row)
- All 16 camera tour screenshots captured (1280x720x32bpp)
All 66 tests pass.
- Added vkCmdCopyImageToBuffer to P/Invoke layer
- Screenshot embedded in main command buffer (barrier PresentSrcKHR→TransferSrc, copy, barrier back)
- Deferred read: staging buffer read on next frame after fence signaled
- BMP format written directly to FileStream (row by row, avoids large heap allocations)
- BGRA→BGRA direct copy for B8G8R8A8 swapchain format
- All 16 camera tour screenshots captured successfully (1280x720x32bpp)
- 66/66 tests pass
OpenTK renderer has matrix/swap issues causing garbled output.
Raylib restored as default. OpenTK project preserved for debugging.
Normal PBR shader restored in OpenTKRenderer.
- GCHandle.Alloc(Pinned) for BufferData to prevent GC relocation
- void* null for VertexAttribPointer offsets
- ShouldSwapAutomatically=false, manual SwapBuffers
- Solid color debug shader active
- Still has rendering issues — needs visual debugging
System.Numerics.Matrix4x4 is row-major, OpenGL UniformMatrix4 with
transpose=false expects column-major. Changed all UniformMatrix4 calls
to transpose=true. Also explicitly enable depth test + disable cull face
for main pass. Fixes strobe/flickering issue.
Shadow mapping via Raylib doesn't work reliably:
- Rlgl.GetMatrixModelview returns zeros with custom FBO
- MaterialMapIndex binding doesn't map to expected texture units
- DrawModelEx resets texture state internally
Restored to last working state without shadows.
Consider direct OpenGL backend for shadow mapping.
- Use BeginShaderMode/EndShaderMode around DrawModelEx to keep shader active
- Bind shadow map on texture unit 1 BEFORE DrawModelEx (not after)
- Remove manual Matrix4x4.Transpose — SetShaderValueMatrix already handles
row-major to column-major conversion via glUniformMatrix4fv(transpose=false)
- 66/66 tests, 145 FPS
- ObjectLayerPairFilterTable blocks all collisions by default in C# binding;
explicitly EnableCollision for all layer pairs (NonMoving/Moving)
- BoxShape takes half-extents, not full size: DynamicBox(scale * 0.5f)
- Floor visual thickness reduced (scale Y 1→0.5), top at y=0 matching collider
- Floor lowered to y=-0.5
- Physics works: cubes and spheres fall and land on floor, no clipping
BroadPhaseLayerInterfaceTable, ObjectLayerPairFilterTable, and
ObjectVsBroadPhaseLayerFilterTable were local variables in the
constructor. After GC collected them, Jolt crashed with dangling
native pointers during PhysicsSystem.Update(). Now stored as readonly
fields with proper Dispose in cleanup. Also fixed Flecs table lock
assertion by collecting RigidBody init list before calling entity.Set().
Shadow mapping via DrawModelEx doesn't work — Raylib's material system
only supports texture unit 0, shadow map sampling needs unit 1.
Additional uniforms in fragment shader also broke NVIDIA GLSL uniform
layout, causing render artifacts. Reverted shader to pre-shadow state.
Shadow pass infrastructure (RenderShadowPass, shadow shader, RT) kept
but disabled. 66/66 tests passing.
emil28092005