Added ambient light support in PBR shader (#1077)

* Added ambient light support in PBR shader

* Updated to auto inject the define value if ambient light found

jme3-core/src/main/java/com/jme3/material/logic/SinglePassAndImageBasedLightingLogic.java

@@ -48,8 +48,10 @@ public final class SinglePassAndImageBasedLightingLogic extends DefaultTechnique
     private static final String DEFINE_SINGLE_PASS_LIGHTING = "SINGLE_PASS_LIGHTING";
     private static final String DEFINE_NB_LIGHTS = "NB_LIGHTS";
     private static final String DEFINE_NB_PROBES = "NB_PROBES";
+    private static final String DEFINE_USE_AMBIENT_LIGHT = "USE_AMBIENT_LIGHT";
     private static final RenderState ADDITIVE_LIGHT = new RenderState();
 
+    private boolean useAmbientLight;
     private final ColorRGBA ambientLightColor = new ColorRGBA(0, 0, 0, 1);
     private List<LightProbe> lightProbes = new ArrayList<>(3);
 
@@ -61,12 +63,14 @@ public final class SinglePassAndImageBasedLightingLogic extends DefaultTechnique
     private final int singlePassLightingDefineId;
     private final int nbLightsDefineId;
     private final int nbProbesDefineId;
+    private final int useAmbientLightDefineId;
 
     public SinglePassAndImageBasedLightingLogic(TechniqueDef techniqueDef) {
         super(techniqueDef);
         singlePassLightingDefineId = techniqueDef.addShaderUnmappedDefine(DEFINE_SINGLE_PASS_LIGHTING, VarType.Boolean);
         nbLightsDefineId = techniqueDef.addShaderUnmappedDefine(DEFINE_NB_LIGHTS, VarType.Int);
         nbProbesDefineId = techniqueDef.addShaderUnmappedDefine(DEFINE_NB_PROBES, VarType.Int);
+        useAmbientLightDefineId = techniqueDef.addShaderUnmappedDefine(DEFINE_USE_AMBIENT_LIGHT, VarType.Boolean);
     }
 
     @Override
@@ -83,6 +87,7 @@ public final class SinglePassAndImageBasedLightingLogic extends DefaultTechnique
             lightProbes.clear();
             extractIndirectLights(lights, false);
             defines.set(nbProbesDefineId, lightProbes.size());
+            defines.set(useAmbientLightDefineId, useAmbientLight);
         }
 
         return super.makeCurrent(assetManager, renderManager, rendererCaps, lights, defines);
@@ -260,9 +265,11 @@ public final class SinglePassAndImageBasedLightingLogic extends DefaultTechnique
 
     protected void extractIndirectLights(LightList lightList, boolean removeLights) {
         ambientLightColor.set(0, 0, 0, 1);
+        useAmbientLight = false;
         for (int j = 0; j < lightList.size(); j++) {
             Light l = lightList.get(j);
             if (l instanceof AmbientLight) {
+                useAmbientLight = true;
                 ambientLightColor.addLocal(l.getColor());
                 if(removeLights){
                     lightList.remove(l);

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

@@ -12,6 +12,7 @@ varying vec4 Color;
 
 uniform vec4 g_LightData[NB_LIGHTS];
 uniform vec3 g_CameraPosition;
+uniform vec4 g_AmbientLightColor;
 
 uniform float m_Roughness;
 uniform float m_Metallic;
@@ -294,6 +295,12 @@ void main(){
             weight2 /= weightSum;
             weight3 /= weightSum;
         #endif
+
+        #if USE_AMBIENT_LIGHT
+            color1.rgb *= g_AmbientLightColor.rgb;
+            color2.rgb *= g_AmbientLightColor.rgb;
+            color3.rgb *= g_AmbientLightColor.rgb;
+        #endif
         gl_FragColor.rgb += color1 * clamp(weight1,0.0,1.0) + color2 * clamp(weight2,0.0,1.0) + color3 * clamp(weight3,0.0,1.0);
 
     #endif

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

@@ -53,7 +53,7 @@ MaterialDef PBR Lighting {
         // Parallax/height map
         Texture2D ParallaxMap -LINEAR
 
-        //Set to true is parallax map is stored in the alpha channel of the normal map
+        //Set to true if parallax map is stored in the alpha channel of the normal map
         Boolean PackedNormalParallax   
 
         //Sets the relief height for parallax mapping