diff --git a/core/src/processing/opengl/PGraphics2D.java b/core/src/processing/opengl/PGraphics2D.java
index c781c379e..509a6f909 100644
--- a/core/src/processing/opengl/PGraphics2D.java
+++ b/core/src/processing/opengl/PGraphics2D.java
@@ -120,7 +120,7 @@ public class PGraphics2D extends PGraphicsOpenGL {
 
   @Override
   protected void defaultPerspective() {
-    super.ortho(0, width, height, 0, -1, +1);
+    super.ortho(0, width, 0, height, -1, +1);
   }
 
 
diff --git a/core/src/processing/opengl/PGraphics3D.java b/core/src/processing/opengl/PGraphics3D.java
index c214d0c2c..1924206bd 100644
--- a/core/src/processing/opengl/PGraphics3D.java
+++ b/core/src/processing/opengl/PGraphics3D.java
@@ -85,7 +85,7 @@ public class PGraphics3D extends PGraphicsOpenGL {
   @Override
   protected void begin2D() {
     pushProjection();
-    ortho(0, width, height, 0, -1, +1);
+    ortho(0, width, 0, height, -1, +1);
     pushMatrix();
     camera(width/2, height/2);
   }
diff --git a/core/src/processing/opengl/PGraphicsOpenGL.java b/core/src/processing/opengl/PGraphicsOpenGL.java
index d47b86136..dab31340c 100644
--- a/core/src/processing/opengl/PGraphicsOpenGL.java
+++ b/core/src/processing/opengl/PGraphicsOpenGL.java
@@ -4054,7 +4054,7 @@ public class PGraphicsOpenGL extends PGraphics {
    */
   @Override
   public void ortho() {
-    ortho(0, width, height, 0, cameraNear, cameraFar);
+    ortho(0, width, 0, height, cameraNear, cameraFar);
   }
 
 
@@ -4094,10 +4094,10 @@ public class PGraphicsOpenGL extends PGraphics {
     float tz = -(far + near)   / (far - near);
 
     // The minus sign is needed to invert the Y axis.
-    projection.set(x, 0, 0, tx,
-                   0, y, 0, ty,
-                   0, 0, z, tz,
-                   0, 0, 0,  1);
+    projection.set(x,  0, 0, tx,
+                   0, -y, 0, ty,
+                   0,  0, z, tz,
+                   0,  0, 0,  1);
 
     calcProjmodelview();
 
@@ -4140,7 +4140,7 @@ public class PGraphicsOpenGL extends PGraphics {
     float ymin = -ymax;
     float xmin = ymin * aspect;
     float xmax = ymax * aspect;
-    frustum(xmin, xmax, ymax, ymin, zNear, zFar);
+    frustum(xmin, xmax, ymin, ymax, zNear, zFar);
   }
 
 
@@ -4161,10 +4161,10 @@ public class PGraphicsOpenGL extends PGraphics {
     float h = top - bottom;
     float d = zfar - znear;
 
-    projection.set(n2 / w,      0,  (right + left) / w,                0,
-                        0, n2 / h,  (top + bottom) / h,                0,
-                        0,      0, -(zfar + znear) / d, -(n2 * zfar) / d,
-                        0,      0,                  -1,                0);
+    projection.set(n2 / w,       0,  (right + left) / w,                0,
+                        0, -n2 / h,  (top + bottom) / h,                0,
+                        0,       0, -(zfar + znear) / d, -(n2 * zfar) / d,
+                        0,       0,                  -1,                0);
 
     calcProjmodelview();