Moved bilinear filtering of shadow maps into the shader. Previously, the filtering on the shadowmap was set to linear outside of the shader and this doesn't work for filtering a depth comparison. For PCF, the filtering needs to be done post-depth-comparison. i.e. in the shader.

src/extras/renderers/plugins/ShadowMapPlugin.js

@@ -139,7 +139,7 @@ THREE.ShadowMapPlugin = function ( ) {
 
 			if ( ! light.shadowMap ) {
 
-				var pars = { minFilter: THREE.LinearFilter, magFilter: THREE.LinearFilter, format: THREE.RGBAFormat };
+				var pars = { minFilter: THREE.NearestFilter, magFilter: THREE.NearestFilter, format: THREE.RGBAFormat };
 
 				light.shadowMap = new THREE.WebGLRenderTarget( light.shadowMapWidth, light.shadowMapHeight, pars );
 				light.shadowMapSize = new THREE.Vector2( light.shadowMapWidth, light.shadowMapHeight );

src/renderers/WebGLShaders.js

@@ -1586,37 +1586,63 @@ THREE.ShaderChunk = {
 						"float xPixelOffset = 1.0 / shadowMapSize[ i ].x;",
 						"float yPixelOffset = 1.0 / shadowMapSize[ i ].y;",
 
-						"float dx0 = -1.25 * xPixelOffset;",
-						"float dy0 = -1.25 * yPixelOffset;",
-						"float dx1 = 1.25 * xPixelOffset;",
-						"float dy1 = 1.25 * yPixelOffset;",
+						"float dx0 = -1.0 * xPixelOffset;",
+						"float dy0 = -1.0 * yPixelOffset;",
+						"float dx1 = 1.0 * xPixelOffset;",
+						"float dy1 = 1.0 * yPixelOffset;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx0, dy0 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"mat3 shadowKernel;",
+						"mat3 depthKernel;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( 0.0, dy0 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[0][0] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx0, dy0 ) ) );",
+						"if ( depthKernel[0][0] < shadowCoord.z ) shadowKernel[0][0] = 0.25;",
+						"else shadowKernel[0][0] = 0.0;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx1, dy0 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[0][1] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx0, 0.0 ) ) );",
+						"if ( depthKernel[0][1] < shadowCoord.z ) shadowKernel[0][1] = 0.25;",
+						"else shadowKernel[0][1] = 0.0;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx0, 0.0 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[0][2] = unpackDepth( texture2D( shadowMap[ i], shadowCoord.xy + vec2( dx0, dy1 ) ) );",
+						"if ( depthKernel[0][2] < shadowCoord.z ) shadowKernel[0][2] = 0.25;",
+						"else shadowKernel[0][2] = 0.0;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[1][0] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( 0.0, dy0 ) ) );",
+						"if ( depthKernel[1][0] < shadowCoord.z ) shadowKernel[1][0] = 0.25;",
+						"else shadowKernel[1][0] = 0.0;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx1, 0.0 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[1][1] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy ) );",
+						"if ( depthKernel[1][1] < shadowCoord.z ) shadowKernel[1][1] = 0.25;",
+						"else shadowKernel[1][1] = 0.0;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx0, dy1 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[1][2] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( 0.0, dy1 ) ) );",
+						"if ( depthKernel[1][2] < shadowCoord.z ) shadowKernel[1][2] = 0.25;",
+						"else shadowKernel[1][2] = 0.0;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( 0.0, dy1 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[2][0] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx1, dy0 ) ) );",
+						"if ( depthKernel[2][0] < shadowCoord.z ) shadowKernel[2][0] = 0.25;",
+						"else shadowKernel[2][0] = 0.0;",
 
-						"fDepth = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx1, dy1 ) ) );",
-						"if ( fDepth < shadowCoord.z ) shadow += shadowDelta;",
+						"depthKernel[2][1] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx1, 0.0 ) ) );",
+						"if ( depthKernel[2][1] < shadowCoord.z ) shadowKernel[2][1] = 0.25;",
+						"else shadowKernel[2][1] = 0.0;",
+
+						"depthKernel[2][2] = unpackDepth( texture2D( shadowMap[ i ], shadowCoord.xy + vec2( dx1, dy1 ) ) );",
+						"if ( depthKernel[2][2] < shadowCoord.z ) shadowKernel[2][2] = 0.25;",
+						"else shadowKernel[2][2] = 0.0;",
+
+						"vec2 fractionalCoord = 1.0 - fract(shadowCoord.xy * shadowMapSize[i].xy );",
+
+						
+						"shadowKernel[0] = mix( shadowKernel[1], shadowKernel[0], fractionalCoord.x );",
+						"shadowKernel[1] = mix( shadowKernel[2], shadowKernel[1], fractionalCoord.x );",
+
+						"vec4 shadowValues;",
+						"shadowValues.x = mix(shadowKernel[0][1], shadowKernel[0][0], fractionalCoord.y );",
+						"shadowValues.y = mix(shadowKernel[0][2], shadowKernel[0][1], fractionalCoord.y );",
+						"shadowValues.z = mix(shadowKernel[1][1], shadowKernel[1][0], fractionalCoord.y );",
+						"shadowValues.w = mix(shadowKernel[1][2], shadowKernel[1][1], fractionalCoord.y );",
+
+						"shadow = dot(shadowValues, vec4(1.0));",
 
 						"shadowColor = shadowColor * vec3( ( 1.0 - shadowDarkness[ i ] * shadow ) );",