GI, traced reflections and some fixes

editor/Workspace/MainWindowViewModel.cs

@@ -1035,7 +1035,6 @@ private async Task ReloadGame() {
 		tasks.Add(LoaderTask.Run(
 			"cmake build",
 			"cmake",
-			// the game shares std types with the engine so both must use the same CRT
 			// RelWithDebInfo keeps game PDB and ttracy
 #if DEBUG
 			"--build .toast/cmake_cache --config Debug --parallel"
@@ -1064,8 +1063,6 @@ private async Task ReloadGame() {
 		await new SimpleLoaderWindow(vm).ShowDialog(owner);
 	}
 
-	// The release build packs the files on disk, so unsaved edits (e.g. init_scene in the project settings) would silently be
-	// left out of player.exe; returns false when the user cancels
 	private async Task<bool> SaveBeforeBuild(Avalonia.Controls.Window owner) {
 		var dirtyWorkspaces = m_workspaces.Values.Where(ws => ws.IsModified).ToList();
 		if (dirtyWorkspaces.Count == 0 && CollectDirtyTools().Count == 0) return true;
@@ -1245,13 +1242,25 @@ await Task.Run(() => {
 			LoaderTask.Run(
 				"cmake configure (Release)",
 				"cmake",
-				$"lib/ -B .toast/cmake_release_cache {cmakeGenerator} -DTOAST_PATH={toastPath} -DCMAKE_BUILD_TYPE=Release"
+				#if DEBUG
+                			$"lib/ -B .toast/cmake_release_cache {cmakeGenerator} -DTOAST_PATH={toastPath} -DCMAKE_BUILD_TYPE=Debug"
+                #elif RELWITHDEBINFO
+                			$"lib/ -B .toast/cmake_release_cache {cmakeGenerator} -DTOAST_PATH={toastPath} -DCMAKE_BUILD_TYPE=RelWithDebInfo"
+                #else
+                			$"lib/ -B .toast/cmake_release_cache {cmakeGenerator} -DTOAST_PATH={toastPath} -DCMAKE_BUILD_TYPE=Release"
+                #endif
 			),
 			// Build Game DLL on Release
 			LoaderTask.Run(
 				"cmake build (Release)",
 				"cmake",
-				"--build .toast/cmake_release_cache --config Release --parallel"
+				#if DEBUG
+                			"--build .toast/cmake_release_cache --config Debug --parallel"
+                #elif RELWITHDEBINFO
+                			"--build .toast/cmake_release_cache --config RelWithDebInfo --parallel"
+                #else
+                			"--build .toast/cmake_release_cache --config Release --parallel"
+                #endif
 			),
 			// Copy Engine libs
 			LoaderTask.Do("copy libraries", CopyDlls),

engine/assets/shaders/bloom.slang

@@ -53,25 +53,28 @@ float4 fragmentDownsample(VSOutput input, uniform bool applyKaris) : SV_Target0
     float2 texel = gParams.inverseSourceSize;
     float2 uv = input.uv;
 
-    float3 a = gSource.Sample(uv + float2(-2.0, 2.0) * texel).rgb;
-    float3 b = gSource.Sample(uv + float2( 0.0, 2.0) * texel).rgb;
-    float3 c = gSource.Sample(uv + float2( 2.0, 2.0) * texel).rgb;
-    float3 d = gSource.Sample(uv + float2(-2.0, 0.0) * texel).rgb;
-    float3 e = gSource.Sample(uv).rgb;
-    float3 f = gSource.Sample(uv + float2( 2.0, 0.0) * texel).rgb;
-    float3 g = gSource.Sample(uv + float2(-2.0,-2.0) * texel).rgb;
-    float3 h = gSource.Sample(uv + float2( 0.0,-2.0) * texel).rgb;
-    float3 i = gSource.Sample(uv + float2( 2.0,-2.0) * texel).rgb;
-
+    // Interleaved so the texture queue never throttles and live registers stay low
     float3 j = gSource.Sample(uv + float2(-1.0, 1.0) * texel).rgb;
     float3 k = gSource.Sample(uv + float2( 1.0, 1.0) * texel).rgb;
     float3 l = gSource.Sample(uv + float2(-1.0,-1.0) * texel).rgb;
     float3 m = gSource.Sample(uv + float2( 1.0,-1.0) * texel).rgb;
-
     float3 group0 = (j + k + l + m) * 0.25;
+
+    float3 e = gSource.Sample(uv).rgb;
+    float3 b = gSource.Sample(uv + float2( 0.0, 2.0) * texel).rgb;
+    float3 d = gSource.Sample(uv + float2(-2.0, 0.0) * texel).rgb;
+    float3 a = gSource.Sample(uv + float2(-2.0, 2.0) * texel).rgb;
     float3 group1 = (a + b + d + e) * 0.25;
+
+    float3 c = gSource.Sample(uv + float2( 2.0, 2.0) * texel).rgb;
+    float3 f = gSource.Sample(uv + float2( 2.0, 0.0) * texel).rgb;
     float3 group2 = (b + c + e + f) * 0.25;
+
+    float3 g = gSource.Sample(uv + float2(-2.0,-2.0) * texel).rgb;
+    float3 h = gSource.Sample(uv + float2( 0.0,-2.0) * texel).rgb;
     float3 group3 = (d + e + g + h) * 0.25;
+
+    float3 i = gSource.Sample(uv + float2( 2.0,-2.0) * texel).rgb;
     float3 group4 = (e + f + h + i) * 0.25;
 
     float3 result;
@@ -113,20 +116,18 @@ float4 fragmentUpsample(VSOutput input) : SV_Target0
     float2 offset = gParams.inverseSourceSize * gParams.filterRadius;
     float2 uv = input.uv;
 
-    float3 a = gSource.Sample(uv + float2(-1.0,  1.0) * offset).rgb;
+    float3 e = gSource.Sample(uv).rgb;
     float3 b = gSource.Sample(uv + float2( 0.0,  1.0) * offset).rgb;
-    float3 c = gSource.Sample(uv + float2( 1.0,  1.0) * offset).rgb;
     float3 d = gSource.Sample(uv + float2(-1.0,  0.0) * offset).rgb;
-    float3 e = gSource.Sample(uv).rgb;
     float3 f = gSource.Sample(uv + float2( 1.0,  0.0) * offset).rgb;
-    float3 g = gSource.Sample(uv + float2(-1.0, -1.0) * offset).rgb;
     float3 h = gSource.Sample(uv + float2( 0.0, -1.0) * offset).rgb;
-    float3 i = gSource.Sample(uv + float2( 1.0, -1.0) * offset).rgb;
+    float3 result = e * 4.0 + (b + d + f + h) * 2.0;
 
-    float3 result = e * 4.0;
-    result += (b + d + f + h) * 2.0;
-    result += (a + c + g + i);
-    result *= 1.0 / 16.0;
+    float3 a = gSource.Sample(uv + float2(-1.0,  1.0) * offset).rgb;
+    float3 c = gSource.Sample(uv + float2( 1.0,  1.0) * offset).rgb;
+    float3 g = gSource.Sample(uv + float2(-1.0, -1.0) * offset).rgb;
+    float3 i = gSource.Sample(uv + float2( 1.0, -1.0) * offset).rgb;
+    result = (result + a + c + g + i) * 0.0625;
 
     return float4(result, 1.0);
 }

engine/assets/shaders/fog_media.slang

@@ -0,0 +1,71 @@
+// Fog media shared by the volumetrics pass and GI rays
+import lighting;
+
+// Mirrors VulkanRenderer::FogVolumeGpu
+struct FogVolume
+{
+    float4x4 worldToLocal;
+    /// xyz half extents w edge fade in meters
+    float4 extentsFade;
+    /// rgb albedo a extinction per meter
+    float4 albedoDensity;
+    /// rgb radiance per meter at density 1 a noise strength
+    float4 emissionNoise;
+    /// xyz wind in meters per second w noise scale in meters
+    float4 windScale;
+    /// x anisotropy y ambient scale
+    float4 phase;
+    /// xyz box centre in world space
+    float4 centre;
+};
+
+[[vk::binding(22, 0)]]
+StructuredBuffer<FogVolume> gFogVolumes;
+
+uint fogVolumeCount()
+{
+    return uint(gCamera.fogMedium.w);
+}
+
+/// Height fog extinction along origin + direction * t integrated over [near, far]
+float heightFogDepth(float3 origin, float3 direction, float near, float far)
+{
+    const float density = gCamera.fogMedium.x;
+    if (density <= 0.0 || far <= near)
+    {
+        return 0.0;
+    }
+    const float falloff = gCamera.fogMedium.z;
+    const float startHeight = origin.y + direction.y * near - gCamera.fogMedium.y;
+    const float atStart = density * exp(-clamp(falloff * startHeight, -20.0, 20.0));
+    const float slope = falloff * direction.y;
+    const float span = far - near;
+    return abs(slope) < 1e-4 ? atStart * span : atStart * (1.0 - exp(-clamp(slope * span, -20.0, 20.0))) / slope;
+}
+
+/// Volumes count as uniform boxes since noise averages out and the edge fade is thin
+float fogOpticalDepth(float3 origin, float3 direction, float near, float far)
+{
+    float depth = heightFogDepth(origin, direction, near, far);
+    const uint count = fogVolumeCount();
+    for (uint v = 0u; v < count; ++v)
+    {
+        const FogVolume volume = gFogVolumes[v];
+        const float3 localOrigin = mul(volume.worldToLocal, float4(origin, 1.0)).xyz;
+        const float3 localDirection = mul(volume.worldToLocal, float4(direction, 0.0)).xyz;
+        const float3 inverse = 1.0 / select(abs(localDirection) > 1e-8, localDirection, float3(1e-8, 1e-8, 1e-8));
+        const float3 t0 = (-volume.extentsFade.xyz - localOrigin) * inverse;
+        const float3 t1 = (volume.extentsFade.xyz - localOrigin) * inverse;
+        const float3 low = min(t0, t1);
+        const float3 high = max(t0, t1);
+        const float enter = max(max(low.x, low.y), max(low.z, near));
+        const float exit = min(min(high.x, high.y), min(high.z, far));
+        depth += max(exit - enter, 0.0) * volume.albedoDensity.a;
+    }
+    return depth;
+}
+
+float fogTransmittance(float3 origin, float3 direction, float near, float far)
+{
+    return exp(-fogOpticalDepth(origin, direction, near, far));
+}

engine/assets/shaders/fog_media.slang.meta

@@ -0,0 +1,4 @@
+uid = "F0gM3d1aSh4"
+type = "shader"
+created_at = "2026-10-26T00:00:00.0000000Z"
+modified_at = "2026-10-26T00:00:00.0000000Z"

engine/assets/shaders/ggx_sampling.slang

@@ -0,0 +1,38 @@
+// GGX visible normal sampling shared by SSR and traced specular
+
+static const float kGgxPi = 3.14159265;
+
+float ggxD(float NdotH, float alpha)
+{
+    const float a2 = alpha * alpha;
+    const float d = NdotH * NdotH * (a2 - 1.0) + 1.0;
+    return a2 / max(kGgxPi * d * d, 1e-8);
+}
+
+float smithG1(float NdotX, float alpha)
+{
+    const float a2 = alpha * alpha;
+    return 2.0 * NdotX / max(NdotX + sqrt(a2 + (1.0 - a2) * NdotX * NdotX), 1e-8);
+}
+
+/// Heitz 2018 visible normal sampling in a frame with z up
+float3 sampleVisibleNormal(float3 view, float alpha, float2 u)
+{
+    const float3 stretched = normalize(float3(alpha * view.x, alpha * view.y, view.z));
+    const float lengthSquared = stretched.x * stretched.x + stretched.y * stretched.y;
+    const float3 t1 = lengthSquared > 0.0 ? float3(-stretched.y, stretched.x, 0.0) * rsqrt(lengthSquared) : float3(1.0, 0.0, 0.0);
+    const float3 t2 = cross(stretched, t1);
+    const float r = sqrt(u.x);
+    const float phi = 2.0 * kGgxPi * u.y;
+    const float p1 = r * cos(phi);
+    const float s = 0.5 * (1.0 + stretched.z);
+    const float p2 = (1.0 - s) * sqrt(max(1.0 - p1 * p1, 0.0)) + s * r * sin(phi);
+    const float3 h = p1 * t1 + p2 * t2 + sqrt(max(1.0 - p1 * p1 - p2 * p2, 0.0)) * stretched;
+    return normalize(float3(alpha * h.x, alpha * h.y, max(h.z, 0.0)));
+}
+
+/// Of a direction sampled through sampleVisibleNormal
+float visibleNormalPdf(float NdotV, float NdotH, float alpha)
+{
+    return smithG1(NdotV, alpha) * ggxD(NdotH, alpha) / max(4.0 * NdotV, 1e-8);
+}

engine/assets/shaders/ggx_sampling.slang.meta

@@ -0,0 +1,4 @@
+uid = "G9xSampl1ng"
+type = "shader"
+created_at = "2026-10-25T00:00:00.0000000Z"
+modified_at = "2026-10-25T00:00:00.0000000Z"