Added clamping to specular term.

This is necessary for OpenGL where pow(0,0) is undefined and apparently can be negative, leading to negative specular light (in DirectX you just get zero).

examples/js/ShaderTerrain.js

@@ -173,7 +173,7 @@ THREE.ShaderTerrain = {
 						"float pointDotNormalHalf = max( dot( normal, pointHalfVector ), 0.0 );",
 						"float pointDiffuseWeight = max( dot( normal, lVector ), 0.0 );",
 
-						"float pointSpecularWeight = specularTex.r * pow( pointDotNormalHalf, uShininess );",
+						"float pointSpecularWeight = specularTex.r * max( pow( pointDotNormalHalf, uShininess ), 0.0 );",
 
 						"pointDiffuse += pointDistance * pointLightColor[ i ] * uDiffuseColor * pointDiffuseWeight;",
 						"pointSpecular += pointDistance * pointLightColor[ i ] * uSpecularColor * pointSpecularWeight * pointDiffuseWeight;",
@@ -199,7 +199,7 @@ THREE.ShaderTerrain = {
 						"float dirDotNormalHalf = max( dot( normal, dirHalfVector ), 0.0 );",
 						"float dirDiffuseWeight = max( dot( normal, dirVector ), 0.0 );",
 
-						"float dirSpecularWeight = specularTex.r * pow( dirDotNormalHalf, uShininess );",
+						"float dirSpecularWeight = specularTex.r * max( pow( dirDotNormalHalf, uShininess ), 0.0 );",
 
 						"dirDiffuse += directionalLightColor[ i ] * uDiffuseColor * dirDiffuseWeight;",
 						"dirSpecular += directionalLightColor[ i ] * uSpecularColor * dirSpecularWeight * dirDiffuseWeight;",

src/extras/ShaderUtils.js

@@ -277,7 +277,7 @@ THREE.ShaderUtils = {
 
 							"vec3 pointHalfVector = normalize( vPointLight[ i ].xyz + viewPosition );",
 							"float pointDotNormalHalf = max( dot( normal, pointHalfVector ), 0.0 );",
-							"float pointSpecularWeight = specularTex.r * pow( pointDotNormalHalf, uShininess );",
+							"float pointSpecularWeight = specularTex.r * max( pow( pointDotNormalHalf, uShininess ), 0.0 );",
 
 							"pointSpecular += pointDistance * pointLightColor[ i ] * uSpecularColor * pointSpecularWeight * pointDiffuseWeight;",
 
@@ -318,7 +318,7 @@ THREE.ShaderUtils = {
 
 							"vec3 dirHalfVector = normalize( lDirection.xyz + viewPosition );",
 							"float dirDotNormalHalf = max( dot( normal, dirHalfVector ), 0.0 );",
-							"float dirSpecularWeight = specularTex.r * pow( dirDotNormalHalf, uShininess );",
+							"float dirSpecularWeight = specularTex.r * max( pow( dirDotNormalHalf, uShininess ), 0.0 );",
 
 							"dirSpecular += directionalLightColor[ i ] * uSpecularColor * dirSpecularWeight * dirDiffuseWeight;",
 

src/renderers/WebGLShaders.js

@@ -486,7 +486,7 @@ THREE.ShaderChunk = {
 
 				"vec3 pointHalfVector = normalize( lVector + viewPosition );",
 				"float pointDotNormalHalf = max( dot( normal, pointHalfVector ), 0.0 );",
-				"float pointSpecularWeight = pow( pointDotNormalHalf, shininess );",
+				"float pointSpecularWeight = max( pow( pointDotNormalHalf, shininess ), 0.0 );",
 
 				"#ifdef PHYSICALLY_BASED_SHADING",
 
@@ -534,7 +534,7 @@ THREE.ShaderChunk = {
 
 				"vec3 dirHalfVector = normalize( lDirection.xyz + viewPosition );",
 				"float dirDotNormalHalf = max( dot( normal, dirHalfVector ), 0.0 );",
-				"float dirSpecularWeight = pow( dirDotNormalHalf, shininess );",
+				"float dirSpecularWeight = max( pow( dirDotNormalHalf, shininess ), 0.0 );",
 
 				"#ifdef PHYSICALLY_BASED_SHADING",