ADD: Clipmap shadow better quality

src/core/config.h

@@ -13,10 +13,29 @@ inline constexpr int kShadowCascadeCount = 4;
 inline constexpr float kShadowCSMFar = 800.0f;
 // Shadow map resolution used for stabilization (texel snapping). Must match actual image size.
 inline constexpr float kShadowMapResolution = 2048.0f;
+// Extra XY expansion for cascade footprint (safety against FOV/aspect changes)
+inline constexpr float kShadowCascadeRadiusScale = 1.1f;
+// Additive XY margin in world units beyond the scaled half-size
+inline constexpr float kShadowCascadeRadiusMargin = 10.0f;
 // Clipmap shadow configuration (used when cascades operate in clipmap mode)
 // Base coverage radius of level 0 around the camera (world units). Each level doubles the radius.
-inline constexpr float kShadowClipBaseRadius = 20.0f;
-// Pullback distance of the light eye from the clipmap center along the light direction (world units)
-inline constexpr float kShadowClipLightPullback = 160.0f;
+inline constexpr float kShadowClipBaseRadius = 30.0f;
+// When using dynamic pullback, compute it from the covered XY range of each level.
+// pullback = max(kShadowClipPullbackMin, cover * kShadowClipPullbackFactor)
+inline constexpr float kShadowClipPullbackFactor = 1.5f;   // fraction of XY half-size behind center
+inline constexpr float kShadowClipForwardFactor  = 1.5f;   // fraction of XY half-size in front of center for zFar
+inline constexpr float kShadowClipPullbackMin    = 10.0f;   // lower bound on pullback so near levels don’t collapse
 // Additional Z padding for the orthographic frustum along light direction
-inline constexpr float kShadowClipZPadding = 80.0f;
+inline constexpr float kShadowClipZPadding = 40.0f;
+
+// Shadow quality & filtering
+// Soft cross-fade band between cascades in light-space NDC (0..1)
+inline constexpr float kShadowBorderSmoothNDC = 0.08f;
+// Base PCF radius in texels for cascade 0; higher cascades scale up slightly
+inline constexpr float kShadowPCFBaseRadius   = 1.35f;
+// Additional radius added by the farthest cascade (0..+)
+inline constexpr float kShadowPCFCascadeGain  = 2.0f;
+
+// Raster depth-bias parameters for shadow map rendering (tuned conservatively)
+inline constexpr float kShadowDepthBiasConstant = 1.25f;
+inline constexpr float kShadowDepthBiasSlope    = 1.5f;