Fixes normal lighting in world space for PBR

Author: Nehon

jme3-core/src/main/java/com/jme3/shader/UniformBinding.java

@@ -195,7 +195,14 @@ public enum UniformBinding {
      * The light color when rendering in multi pass mode
      * Type: vec4
      */
-    LightColor("vec4");
+    LightColor("vec4"),
+
+    /**
+     * The normal matrix in world space for World space lighting. The inverse transpose of the world matrix.
+     * Converts normals from model space to world space.
+     * Type: mat3
+     */
+    WorldNormalMatrix("mat3");
 
     String glslType;
 

jme3-core/src/main/java/com/jme3/shader/UniformBindingManager.java

@@ -36,6 +36,7 @@
 import com.jme3.renderer.Camera;
 import com.jme3.renderer.RenderManager;
 import com.jme3.system.Timer;
+
 import java.util.ArrayList;
 
 /**
@@ -66,6 +67,7 @@ public class UniformBindingManager {
     private Matrix4f worldViewMatrix = new Matrix4f();
     private Matrix4f worldViewProjMatrix = new Matrix4f();
     private Matrix3f normalMatrix = new Matrix3f();
+    private Matrix3f worldNormalMatrix = new Matrix3f();
     private Matrix4f worldMatrixInv = new Matrix4f();
     private Matrix3f worldMatrixInvTrsp = new Matrix3f();
     private Matrix4f viewMatrixInv = new Matrix4f();
@@ -114,6 +116,13 @@ public void updateUniformBindings(Shader shader) {
                     normalMatrix.transposeLocal();
                     u.setValue(VarType.Matrix3, normalMatrix);
                     break;
+                case WorldNormalMatrix:
+                    tempMatrix.set(worldMatrix);
+                    tempMatrix.toRotationMatrix(worldNormalMatrix);
+                    worldNormalMatrix.invertLocal();
+                    worldNormalMatrix.transposeLocal();
+                    u.setValue(VarType.Matrix3, worldNormalMatrix);
+                    break;
                 case WorldViewProjectionMatrix:
                     worldViewProjMatrix.set(viewProjMatrix);
                     worldViewProjMatrix.multLocal(worldMatrix);

jme3-core/src/main/resources/Common/MatDefs/Light/PBRLighting.j3md

@@ -130,6 +130,7 @@ MaterialDef PBR Lighting {
             WorldViewProjectionMatrix
             CameraPosition
             WorldMatrix
+            WorldNormalMatrix
             ViewProjectionMatrix
             ViewMatrix
         }

jme3-core/src/main/resources/Common/ShaderLib/Instancing.glsllib

@@ -25,6 +25,7 @@ uniform mat4 g_WorldViewMatrix;
 uniform mat4 g_WorldViewProjectionMatrix;
 uniform mat4 g_ViewProjectionMatrix;
 uniform mat3 g_NormalMatrix;
+uniform mat3 g_WorldNormalMatrix;
 
 #if defined INSTANCING
 
@@ -101,7 +102,7 @@ vec3 TransformNormal(vec3 normal) {
 }
 
 vec3 TransformWorldNormal(vec3 normal) {
-    return normalize((g_WorldMatrix * vec4(normal,0.0)).xyz);
+    return normalize(g_WorldNormalMatrix * normal);
 }