Camera/Projection restoration in Android

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

@@ -144,6 +144,8 @@ public class PGraphicsAndroid3D extends PGraphics {
   protected float[] pcamera;
   protected float[] pcameraInv;
   
+  protected float[] pprojection;
+  
   protected float[] gltemp;
   
   // PMatrix3D version for use in Processing.
@@ -154,6 +156,12 @@ public class PGraphicsAndroid3D extends PGraphics {
   public PMatrix3D camera;
   public PMatrix3D cameraInv;
   
+  /** 
+   * Marks when changes to the size have occurred, so that the camera 
+   * will be reset in beginDraw().
+   */
+  protected boolean sizeChanged;    
+  
   protected boolean modelviewUpdated;
   protected boolean projectionUpdated;
 
@@ -546,6 +554,9 @@ public class PGraphicsAndroid3D extends PGraphics {
     cameraNear = cameraZ / 10.0f;
     cameraFar = cameraZ * 10.0f;
     cameraAspect = (float) width / (float) height;
+    
+    // set this flag so that beginDraw() will do an update to the camera.
+    sizeChanged = true;    
   }
 
   
@@ -558,6 +569,7 @@ public class PGraphicsAndroid3D extends PGraphics {
       glmodelviewInv = new float[16];
       pcamera = new float[16];
       pcameraInv = new float[16];
+      pprojection = new float[16];
       gltemp = new float[16];
       
       projection = new PMatrix3D();
@@ -1034,13 +1046,24 @@ public class PGraphicsAndroid3D extends PGraphics {
     gl.glGetIntegerv(GL11.GL_VIEWPORT, viewport, 0);
     gl.glViewport(0, 0, width, height);
     
-    // set up the default camera and initializes modelview matrix.
-    camera();
+    if (sizeChanged) {    
+      // set up the default camera and initializes modelview matrix.
+      camera();
 
-    // defaults to perspective, if the user has setup up their
-    // own projection, they'll need to fix it after resize anyway.
-    // this helps the people who haven't set up their own projection.
-    perspective();
+      // defaults to perspective, if the user has setup up their
+      // own projection, they'll need to fix it after resize anyway.
+      // this helps the people who haven't set up their own projection.
+      perspective();
+      // clear the flag
+      sizeChanged = false;
+    } else {
+      // The pcamera and pprojection arrays, saved when calling camera() and frustrum()
+      // are set as the current modelview and projection matrices. This is done to
+      // remove any additional modelview transformation (and less likely, projection
+      // transformations) applied by the user after setting the camera and/or projection      
+      restoreCamera();
+      restoreProjection();
+    }
         
     noLights();
     lightFalloff(1, 0, 0);
@@ -4105,11 +4128,27 @@ public class PGraphicsAndroid3D extends PGraphics {
       gl.glMatrixMode(GL10.GL_MODELVIEW);
     }    
     if (usingGLMatrixStack) {
-      projection.set(glmodelview);
+      projectionStack.set(glprojection);
     }
     projectionUpdated = true;
   }
   
+  public void restoreProjection() {
+    PApplet.arrayCopy(pprojection, glprojection);
+    copyGLArrayToPMatrix(pprojection, projection);
+    
+    gl.glMatrixMode(GL10.GL_PROJECTION);
+    gl.glLoadMatrixf(glprojection, 0);
+    if (matrixMode == MODELVIEW) { 
+      gl.glMatrixMode(GL10.GL_MODELVIEW);
+    }    
+    if (usingGLMatrixStack) {
+      projectionStack.set(glprojection);
+    }
+    projectionUpdated = true;    
+  }
+  
+  
   //////////////////////////////////////////////////////////////
 
   // CAMERA
@@ -4514,12 +4553,28 @@ public class PGraphicsAndroid3D extends PGraphics {
     modelviewUpdated = true;
 
     calculateModelviewInvNoScaling();
+    
     PApplet.arrayCopy(glmodelview, pcamera);
     PApplet.arrayCopy(glmodelviewInv, pcameraInv);
     copyGLArrayToPMatrix(pcamera, camera);
     copyGLArrayToPMatrix(pcameraInv, cameraInv);
   }
 
+  public void restoreCamera() {
+    PApplet.arrayCopy(pcamera, glmodelview);
+    PApplet.arrayCopy(pcameraInv, glmodelviewInv);
+    copyGLArrayToPMatrix(pcamera, camera);
+    copyGLArrayToPMatrix(pcameraInv, cameraInv);
+    
+    gl.glMatrixMode(GL10.GL_MODELVIEW);
+    gl.glLoadMatrixf(glmodelview, 0);
+    if (usingGLMatrixStack) {
+      modelviewStack.set(glmodelview);
+    }
+    copyGLArrayToPMatrix(glmodelview, modelview);
+    modelviewUpdated = true;    
+  }  
+  
   /**
    * Print the current camera matrix.
    */
@@ -4678,6 +4733,8 @@ public class PGraphicsAndroid3D extends PGraphics {
     copyGLArrayToPMatrix(glprojection, projection);
     projectionUpdated = true;
 
+    PApplet.arrayCopy(glprojection, pprojection);    
+    
     // The matrix mode is always MODELVIEW, because the user will be doing
     // geometrical transformations all the time, projection transformations 
     // only a few times.