Fixed a couple of bugs in the calculation of the normal matrix

android/core/src/processing/core/FillShaderVertFull.glsl

@@ -73,6 +73,7 @@ float blinnPhongFactor(vec3 lightDir, vec3 lightPos, vec3 vecNormal, float shine
 }
 
 void main() {
+  // Vertex in clip coordinates
   gl_Position = projmodelviewMatrix * inVertex;
     
   // Vertex in eye coordinates
@@ -99,8 +100,8 @@ void main() {
       falloff = one_float;
       lightDir = -lightNormal[i];
     } else {
-      falloff = falloffFactor(lightPos, ecVertex, lightFalloffCoefficients[i]);      
-      lightDir = lightPos - ecVertex;
+      falloff = falloffFactor(lightPos, ecVertex, lightFalloffCoefficients[i]);  
+      lightDir = normalize(lightPos - ecVertex);
     }
   
     spotf = spotExp > zero_float ? spotFactor(lightPos, ecVertex, lightNormal[i], 
@@ -110,21 +111,24 @@ void main() {
     if (any(greaterThan(lightAmbient[i], zero_vec3))) {
       totalAmbient  += lightAmbient[i] * falloff;
     }
+    
     if (any(greaterThan(lightDiffuse[i], zero_vec3))) {
       totalDiffuse  += lightDiffuse[i] * falloff * spotf * 
                        lambertFactor(-lightDir, ecNormal);
     }
+    
     if (any(greaterThan(lightSpecular[i], zero_vec3))) {
       totalSpecular += lightSpecular[i] * falloff * spotf * 
                        blinnPhongFactor(-lightDir, lightPos, ecNormal, inShine);
-    }
+    }    
   }    
   
+  // Calculating final color as result of all lights (plus emissive term)
   vertColor = vec4(totalAmbient, 1) * inAmbient + 
               vec4(totalDiffuse, 1) * inColor + 
               vec4(totalSpecular, 1) * inSpecular + 
               inEmissive;
               
   // Passing texture coordinates to the fragment shader
-  vertTexcoord = inTexcoord;              
+  vertTexcoord = inTexcoord;                
 }

android/core/src/processing/core/FillShaderVertLit.glsl

@@ -71,6 +71,7 @@ float blinnPhongFactor(vec3 lightDir, vec3 lightPos, vec3 vecNormal, float shine
 }
 
 void main() {
+  // Vertex in clip coordinates
   gl_Position = projmodelviewMatrix * inVertex;
     
   // Vertex in eye coordinates
@@ -97,7 +98,7 @@ void main() {
       falloff = one_float;
       lightDir = -lightNormal[i];
     } else {
-      falloff = falloffFactor(lightPos, ecVertex, lightFalloffCoefficients[i]);      
+      falloff = falloffFactor(lightPos, ecVertex, lightFalloffCoefficients[i]);  
       lightDir = normalize(lightPos - ecVertex);
     }
   
@@ -120,6 +121,7 @@ void main() {
     }    
   }    
   
+  // Calculating final color as result of all lights (plus emissive term)
   vertColor = vec4(totalAmbient, 1) * inAmbient + 
               vec4(totalDiffuse, 1) * inColor + 
               vec4(totalSpecular, 1) * inSpecular + 

android/core/src/processing/core/PGraphicsAndroid3D.java

@@ -1437,6 +1437,7 @@ public class PGraphicsAndroid3D extends PGraphics {
       // remove any additional modelview transformation (and less likely, projection
       // transformations) applied by the user after setting the camera and/or projection      
       modelview.set(camera);
+      modelviewInv.set(cameraInv);
       calcProjmodelview();
     }
       
@@ -1672,7 +1673,9 @@ public class PGraphicsAndroid3D extends PGraphics {
     }
     
     // The normal matrix is the transpose of the inverse of the
-    // modelview:
+    // modelview (remember that gl matrices are column-major, 
+    // meaning that elements 0, 1, 2 are the first column,
+    // 3, 4, 5 the second, etc.:
     glNormal[0] = modelviewInv.m00; 
     glNormal[1] = modelviewInv.m01; 
     glNormal[2] = modelviewInv.m02;
@@ -2202,7 +2205,7 @@ public class PGraphicsAndroid3D extends PGraphics {
       }          
       
       if (flushMode == FLUSH_WHEN_FULL && !hints[DISABLE_TRANSFORM_CACHE]) {
-        popMatrix();
+        //popMatrix();
       }
     }
     
@@ -7662,9 +7665,9 @@ public class PGraphicsAndroid3D extends PGraphics {
         fillVertices[index  ] = x * mm.m20 + y * mm.m21 + z * mm.m22 + mm.m23;
         
         index = 3 * fillVertexCount;
-        fillNormals[index++] = nx * nm.m00 + ny * nm.m10 + nz * nm.m02;
-        fillNormals[index++] = nx * nm.m01 + ny * nm.m11 + nz * nm.m12;
-        fillNormals[index  ] = nx * nm.m02 + ny * nm.m21 + nz * nm.m22;
+        fillNormals[index++] = nx * nm.m00 + ny * nm.m10 + nz * nm.m20;
+        fillNormals[index++] = nx * nm.m01 + ny * nm.m11 + nz * nm.m21;
+        fillNormals[index  ] = nx * nm.m02 + ny * nm.m12 + nz * nm.m22;
       } else {
         index = 3 * fillVertexCount;
         fillVertices[index++] = x;