Revert "Fix normals when mesh has both two-sided material and negative scale (playcanvas#2375)" (playcanvas#2406)

raytranuk · web-flow · commit 9cedb852f535 · 2020-09-04T17:08:39.000+01:00
This reverts commit 4d5f59d. # Conflicts: # src/graphics/program-lib/programs/standard.js
diff --git a/src/graphics/program-lib/programs/standard.js b/src/graphics/program-lib/programs/standard.js
@@ -1332,21 +1332,16 @@ var standard = {
 
         code = this._fsAddStartCode(code, device, chunks, options);
 
-        if (needsNormal) {
-            code += "   getViewDir();\n";
-        }
-
         if (needsNormal) {
             if (options.twoSidedLighting) {
-                code += "   float normalDirSign = sign(dot(vNormalW, dViewDirW));\n";
-                code += "   dVertexNormalW = normalDirSign * vNormalW;\n";
+                code += "   dVertexNormalW = gl_FrontFacing ? vNormalW : -vNormalW;\n";
             } else {
                 code += "   dVertexNormalW = vNormalW;\n";
             }
             if ((options.heightMap || options.normalMap) && options.hasTangents) {
                 if (options.twoSidedLighting) {
-                    code += "   dTangentW = normalDirSign * vTangentW;\n";
-                    code += "   dBinormalW = normalDirSign * vBinormalW;\n";
+                    code += "   dTangentW = gl_FrontFacing ? vTangentW : -vTangentW;\n";
+                    code += "   dBinormalW = gl_FrontFacing ? vBinormalW : -vBinormalW;\n";
                 } else {
                     code += "   dTangentW = vTangentW;\n";
                     code += "   dBinormalW = vBinormalW;\n";
@@ -1371,6 +1366,7 @@ var standard = {
         var getGlossinessCalled = false;
 
         if (needsNormal) {
+            code += "   getViewDir();\n";
             if (options.heightMap || options.normalMap || options.clearCoatNormalMap || options.enableGGXSpecular) {
                 code += "   getTBN();\n";
             }
