added inverse matrix utility methods

Author: codeanticode

core/src/processing/opengl/PGraphicsOpenGL.java

@@ -3958,9 +3958,16 @@ protected void translateImpl(float tx, float ty, float tz) {
   static protected void invTranslate(PMatrix3D matrix,
                                      float tx, float ty, float tz) {
     matrix.preApply(1, 0, 0, -tx,
-                    0, 1, 0, -ty,
-                    0, 0, 1, -tz,
-                    0, 0, 0, 1);
+        0, 1, 0, -ty,
+        0, 0, 1, -tz,
+        0, 0, 0, 1);
+  }
+
+
+  static protected void invTranslate(PMatrix2D matrix,
+                                     float tx, float ty) {
+    matrix.preApply(1, 0, -tx,
+        0, 1, -ty);
   }
 
 
@@ -4049,16 +4056,21 @@ protected void rotateImpl(float angle, float v0, float v1, float v2) {
   }
 
 
-  static private void invRotate(PMatrix3D matrix, float angle,
-                                float v0, float v1, float v2) {
+  static protected void invRotate(PMatrix3D matrix, float angle,
+                                  float v0, float v1, float v2) {
     float c = PApplet.cos(-angle);
     float s = PApplet.sin(-angle);
     float t = 1.0f - c;
 
     matrix.preApply((t*v0*v0) + c, (t*v0*v1) - (s*v2), (t*v0*v2) + (s*v1), 0,
-                    (t*v0*v1) + (s*v2), (t*v1*v1) + c, (t*v1*v2) - (s*v0), 0,
-                    (t*v0*v2) - (s*v1), (t*v1*v2) + (s*v0), (t*v2*v2) + c, 0,
-                    0, 0, 0, 1);
+        (t*v0*v1) + (s*v2), (t*v1*v1) + c, (t*v1*v2) - (s*v0), 0,
+        (t*v0*v2) - (s*v1), (t*v1*v2) + (s*v0), (t*v2*v2) + c, 0,
+        0, 0, 0, 1);
+  }
+
+
+  static protected void invRotate(PMatrix2D matrix, float angle) {
+    matrix.rotate(-angle);
   }
 
 
@@ -4103,6 +4115,11 @@ static protected void invScale(PMatrix3D matrix, float x, float y, float z) {
   }
 
 
+  static protected void invScale(PMatrix2D matrix, float x, float y) {
+    matrix.preApply(1/x, 0, 0, 1/y, 0, 0);
+  }
+
+
   @Override
   public void shearX(float angle) {
     float t = (float) Math.tan(angle);
@@ -6690,7 +6707,7 @@ protected Object initCache(PImage img) {
     if (tex == null || tex.contextIsOutdated()) {
       tex = addTexture(img);
       if (tex != null) {
-        boolean dispose = !img.loaded;
+        boolean dispose = img.pixels == null;
         img.loadPixels();
         tex.set(img.pixels, img.format);
         img.setModified();