WebGPURenderer: Introduce `biquadraticTexture` filtering (#28673)

examples/jsm/renderers/webgpu/nodes/WGSLNodeBuilder.js

@@ -126,6 +126,29 @@ fn threejs_repeatWrapping( uv : vec2<f32>, dimension : vec2<u32> ) -> vec2<u32>
 
 	return ( ( uvScaled % dimension ) + dimension ) % dimension;
 
+}
+` ),
+	biquadraticTexture: new CodeNode( `
+fn threejs_biquadraticTexture( map : texture_2d<f32>, coord : vec2f, level : i32 ) -> vec4f {
+
+	let res = vec2f( textureDimensions( map, level ) );
+
+	let uvScaled = coord * res;
+	let uvWrapping = ( ( uvScaled % res ) + res ) % res;
+
+	// https://www.shadertoy.com/view/WtyXRy
+
+	let uv = uvWrapping - 0.5;
+	let iuv = floor( uv );
+	let f = fract( uv );
+
+	let rg1 = textureLoad( map, vec2i( iuv + vec2( 0.5, 0.5 ) ), level );
+	let rg2 = textureLoad( map, vec2i( iuv + vec2( 1.5, 0.5 ) ), level );
+	let rg3 = textureLoad( map, vec2i( iuv + vec2( 0.5, 1.5 ) ), level );
+	let rg4 = textureLoad( map, vec2i( iuv + vec2( 1.5, 1.5 ) ), level );
+
+	return mix( mix( rg1, rg2, f.x ), mix( rg3, rg4, f.x ), f.y );
+
 }
 ` )
 };
@@ -164,7 +187,7 @@ class WGSLNodeBuilder extends NodeBuilder {
 
 		} else {
 
-			return this.generateTextureLod( texture, textureProperty, uvSnippet );
+			return this.generateFilteredTexture( texture, textureProperty, uvSnippet );
 
 		}
 
@@ -192,12 +215,20 @@ class WGSLNodeBuilder extends NodeBuilder {
 
 		} else {
 
-			return this.generateTextureLod( texture, textureProperty, uvSnippet, levelSnippet );
+			return this.generateFilteredTexture( texture, textureProperty, uvSnippet, levelSnippet );
 
 		}
 
 	}
 
+	generateFilteredTexture( texture, textureProperty, uvSnippet, levelSnippet = '0' ) {
+
+		this._include( 'biquadraticTexture' );
+
+		return `threejs_biquadraticTexture( ${ textureProperty }, ${ uvSnippet }, i32( ${ levelSnippet } ) )`;
+
+	}
+
 	generateTextureLod( texture, textureProperty, uvSnippet, levelSnippet = '0' ) {
 
 		this._include( 'repeatWrapping' );