fix(UI): Background Blur with Upscaling

package/SKSE/Plugins/CommunityShaders/Themes/Default.json

@@ -44,7 +44,7 @@
         "ShowFooter": true,
         "CenterHeader": true,
         "TooltipHoverDelay": 0.5,
-        "BackgroundBlurEnabled": false,
+        "BackgroundBlurEnabled": true,
         "Palette": {
             "Background": [0.03, 0.03, 0.03, 0.39216],
             "Text": [1.0, 1.0, 1.0, 1.0],

package/SKSE/Plugins/CommunityShaders/Themes/DragonBlood.json

@@ -44,7 +44,7 @@
         "UseMonochromeIcons": true,
         "CenterHeader": true,
         "TooltipHoverDelay": 0.5,
-        "BackgroundBlurEnabled": false,
+        "BackgroundBlurEnabled": true,
         "Palette": {
             "Background": [0.25, 0.05, 0.05, 0.9],
             "Text": [1.0, 0.85, 0.85, 1.0],

package/SKSE/Plugins/CommunityShaders/Themes/DwemerBronze.json

@@ -46,7 +46,7 @@
         "ShowFooter": false,
         "CenterHeader": true,
         "TooltipHoverDelay": 0.5,
-        "BackgroundBlurEnabled": false,
+        "BackgroundBlurEnabled": true,
         "Palette": {
             "Background": [0.15, 0.12, 0.08, 0.9],
             "Text": [0.9, 0.75, 0.5, 1.0],

package/SKSE/Plugins/CommunityShaders/Themes/HighContrast.json

@@ -44,7 +44,7 @@
         "UseMonochromeIcons": false,
         "CenterHeader": true,
         "TooltipHoverDelay": 0.5,
-        "BackgroundBlurEnabled": false,
+        "BackgroundBlurEnabled": true,
         "Palette": {
             "Background": [0.0, 0.0, 0.0, 0.95],
             "Text": [1.0, 1.0, 1.0, 1.0],

package/SKSE/Plugins/CommunityShaders/Themes/Light.json

@@ -44,7 +44,7 @@
         "ShowFooter": false,
         "CenterHeader": true,
         "TooltipHoverDelay": 0.5,
-        "BackgroundBlurEnabled": false,
+        "BackgroundBlurEnabled": true,
         "Palette": {
             "Background": [0.98, 0.98, 0.98, 0.9],
             "Text": [0.08, 0.08, 0.08, 1.0],

package/SKSE/Plugins/CommunityShaders/Themes/NordicFrost.json

@@ -44,7 +44,7 @@
         "UseMonochromeIcons": true,
         "CenterHeader": true,
         "TooltipHoverDelay": 0.5,
-        "BackgroundBlurEnabled": false,
+        "BackgroundBlurEnabled": true,
         "Palette": {
             "Background": [0.05, 0.15, 0.25, 0.9],
             "Text": [0.9, 0.95, 1.0, 1.0],

package/Shaders/Menu/BackgroundBlurComposite.hlsl

@@ -0,0 +1,142 @@
+// Composite Blur Pass Shader with Rounded Rectangle Mask
+// Part of the BackgroundBlur system - applies blurred texture with rounded corners
+
+cbuffer WindowBuffer : register(b1)
+{
+    float4 WindowRect;    // x = minX, y = minY, z = maxX, w = maxY (in pixels)
+    float4 WindowParams;  // x = cornerRadius, y = screenWidth, z = screenHeight, w = unused
+};
+
+SamplerState LinearSampler : register(s0);
+Texture2D InputTexture : register(t0);
+
+static const float TWO_PI = 6.28318530718f;
+static const int NUM_JITTER_SAMPLES = 4;
+static const float DOWNSAMPLE_FACTOR = 8.0f;
+static const float CLIP_EPSILON = 0.001f;
+
+struct VS_OUTPUT
+{
+    float4 Position : SV_POSITION;
+    float2 TexCoord : TEXCOORD0;
+};
+
+VS_OUTPUT VS_Main(uint vertexID : SV_VertexID)
+{
+    VS_OUTPUT output;
+    output.TexCoord = float2((vertexID << 1) & 2, vertexID & 2);
+    output.Position = float4(output.TexCoord * 2.0f - 1.0f, 0.0f, 1.0f);
+    output.Position.y = -output.Position.y;
+    return output;
+}
+
+// High quality 2D hash - returns two independent random values in [0,1]
+// Uses different prime multipliers to avoid correlation between x and y
+float2 Hash22(float2 p)
+{
+    // Two independent hashes using different constants
+    float3 p3 = frac(float3(p.xyx) * float3(0.1031f, 0.1030f, 0.0973f));
+    p3 += dot(p3, p3.yzx + 33.33f);
+    return frac((p3.xx + p3.yz) * p3.zy);
+}
+
+// Soft sampling with blurred dithering - takes 4 samples with jittered offsets
+// and averages them to smooth out the noise while still breaking up blocky pixels
+float4 SampleWithSoftening(float2 uv, float2 pixelPos, float2 texelSize)
+{
+    // Get base random offset for this pixel
+    float2 noise = Hash22(pixelPos);
+
+    // Rotated grid offsets (45 degree rotation for better coverage)
+    // This creates a smooth disc-like sampling pattern
+    static const float2 offsets[NUM_JITTER_SAMPLES] = {
+        float2(-0.25f, -0.25f),
+        float2( 0.25f, -0.25f),
+        float2(-0.25f,  0.25f),
+        float2( 0.25f,  0.25f)
+    };
+
+    // Random rotation angle based on pixel position
+    float angle = noise.x * TWO_PI;
+    float s, c;
+    sincos(angle, s, c);
+    float2x2 rotation = float2x2(c, -s, s, c);
+
+    // Sample 4 points with rotated jittered offsets and average
+    float4 result = 0;
+    [unroll]
+    for (int i = 0; i < NUM_JITTER_SAMPLES; i++)
+    {
+        float2 jitter = mul(rotation, offsets[i]) * texelSize;
+        result += InputTexture.Sample(LinearSampler, uv + jitter);
+    }
+
+    return result / (float)NUM_JITTER_SAMPLES;
+}
+
+// Compute signed distance to a rounded rectangle
+// Returns negative inside, positive outside
+float RoundedRectSDF(float2 pixelPos, float2 rectMin, float2 rectMax, float radius)
+{
+    // Center of the rectangle
+    float2 rectCenter = (rectMin + rectMax) * 0.5f;
+    float2 rectHalfSize = (rectMax - rectMin) * 0.5f;
+
+    // Clamp radius to not exceed half the smallest dimension
+    radius = min(radius, min(rectHalfSize.x, rectHalfSize.y));
+
+    // Distance from center
+    float2 p = abs(pixelPos - rectCenter) - rectHalfSize + radius;
+
+    // SDF for rounded rectangle
+    return length(max(p, 0.0f)) + min(max(p.x, p.y), 0.0f) - radius;
+}
+
+float4 PS_Main(VS_OUTPUT input) : SV_TARGET
+{
+    // Convert UV to pixel coordinates
+    float2 pixelPos = input.TexCoord * float2(WindowParams.y, WindowParams.z);
+
+    // Get window bounds and corner radius
+    float2 rectMin = WindowRect.xy;
+    float2 rectMax = WindowRect.zw;
+    float cornerRadius = WindowParams.x;
+
+    // Calculate signed distance to rounded rectangle
+    float sdf = RoundedRectSDF(pixelPos, rectMin, rectMax, cornerRadius);
+
+    // Create smooth edge (anti-aliased)
+    // Negative = inside, positive outside
+    // Use 1.0 pixel transition for smooth edge
+    float alpha = saturate(-sdf);
+
+    // Early out if completely outside
+    if (alpha <= 0.0f)
+    {
+        discard;
+    }
+
+    float2 blurTexelSize = DOWNSAMPLE_FACTOR / float2(WindowParams.y, WindowParams.z);
+
+    // Sample with soft dithering to hide blocky pixels from the downsampled blur
+    float4 blurColor = SampleWithSoftening(input.TexCoord, pixelPos, blurTexelSize);
+
+    // Apply rounded corner mask to alpha
+    // The blur strength is applied via blend state, so just use the rounded mask here
+    blurColor.a = alpha;
+
+    return blurColor;
+}
+
+// Clear shader entry point - outputs transparent black inside rounded rect only
+// Used to clear UI buffer (HUD) in the exact same shape as the blur
+float4 PS_Clear(VS_OUTPUT input) : SV_TARGET
+{
+    float2 pixelPos = input.TexCoord * float2(WindowParams.y, WindowParams.z);
+    float sdf = RoundedRectSDF(pixelPos, WindowRect.xy, WindowRect.zw, WindowParams.x);
+
+    // Discard pixels outside rounded rect to preserve HUD in corners
+    clip(-sdf - CLIP_EPSILON);
+
+    return float4(0.0f, 0.0f, 0.0f, 0.0f);
+}

src/Features/Upscaling.cpp

@@ -1541,6 +1541,14 @@ IDXGISwapChain* Upscaling::GetProxySwapChain()
 	return dx12SwapChain.GetSwapChainProxy();
 }
 
+Upscaling::BlurResources Upscaling::GetBlurResources() const
+{
+	if (d3d12SwapChainActive) {
+		return dx12SwapChain.GetBlurResources();
+	}
+	return {};
+}
+
 void Upscaling::Upscale()
 {
 	auto upscaleMethod = GetUpscaleMethod();

src/Features/Upscaling.h

@@ -231,6 +231,11 @@ struct Upscaling : Feature
 	void CreateProxyInterop();
 	IDXGISwapChain* GetProxySwapChain();
 
+	using BlurResources = DX12SwapChain::BlurResources;
+
+	// Get all D3D11 resources needed for background blur when D3D12 swap chain is active
+	BlurResources GetBlurResources() const;
+
 private:
 	struct Main_UpdateJitter
 	{

src/Features/Upscaling/DX12SwapChain.cpp

@@ -399,6 +399,21 @@ void DX12SwapChain::SetUIBuffer()
 	}
 }
 
+DX12SwapChain::BlurResources DX12SwapChain::GetBlurResources() const
+{
+	BlurResources res;
+	if (swapChainBufferWrapped) {
+		res.backbufferTex = swapChainBufferWrapped->resource11;
+		res.backbufferRTV = swapChainBufferWrapped->rtv;
+		res.backbufferSRV = swapChainBufferWrapped->srv;
+	}
+	if (uiBufferWrapped) {
+		res.uiBufferSRV = uiBufferWrapped->srv;
+		res.uiBufferRTV = uiBufferWrapped->rtv;
+	}
+	return res;
+}
+
 void DX12SwapChain::CreateSharedResources()
 {
 	auto renderer = globals::game::renderer;

src/Features/Upscaling/DX12SwapChain.h

@@ -113,6 +113,19 @@ class DX12SwapChain
 
 	void SetUIBuffer();
 
+	// Resources needed by BackgroundBlur when D3D12 swap chain is active
+	struct BlurResources
+	{
+		ID3D11Texture2D* backbufferTex = nullptr;
+		ID3D11RenderTargetView* backbufferRTV = nullptr;
+		ID3D11ShaderResourceView* backbufferSRV = nullptr;
+		ID3D11ShaderResourceView* uiBufferSRV = nullptr;
+		ID3D11RenderTargetView* uiBufferRTV = nullptr;
+	};
+
+	// Get all resources needed for background blur in one call
+	BlurResources GetBlurResources() const;
+
 	// D3D12 interop resource management
 	void CreateSharedResources();
 };

src/Menu.h

@@ -248,14 +248,14 @@ class Menu
 			return roles;
 		}();
 
-		bool UseSimplePalette = false;       // DEPRECATED: No longer affects behavior. UI now shows both Simple and Advanced controls.
-		bool ShowActionIcons = true;         // whether to show action buttons as icons
-		bool UseMonochromeIcons = false;     // whether to use monochrome (white) action icons with text color tinting
-		bool UseMonochromeLogo = false;      // whether to use monochrome CS logo
-		bool ShowFooter = true;              // whether to show the footer with game version/GPU info
-		bool CenterHeader = false;           // whether to center the header title and logo
-		float TooltipHoverDelay = 0.5f;      // tooltip hover delay in seconds
-		bool BackgroundBlurEnabled = false;  // enable background blur effect
+		bool UseSimplePalette = false;      // DEPRECATED: No longer affects behavior. UI now shows both Simple and Advanced controls.
+		bool ShowActionIcons = true;        // whether to show action buttons as icons
+		bool UseMonochromeIcons = false;    // whether to use monochrome (white) action icons with text color tinting
+		bool UseMonochromeLogo = false;     // whether to use monochrome CS logo
+		bool ShowFooter = true;             // whether to show the footer with game version/GPU info
+		bool CenterHeader = false;          // whether to center the header title and logo
+		float TooltipHoverDelay = 0.5f;     // tooltip hover delay in seconds
+		bool BackgroundBlurEnabled = true;  // enable background blur effect
 		// Scrollbar opacity settings
 		struct ScrollbarOpacitySettings
 		{