diff --git a/core/src/processing/core/PConstants.java b/core/src/processing/core/PConstants.java
index 7437520aa..776c1f4e0 100644
--- a/core/src/processing/core/PConstants.java
+++ b/core/src/processing/core/PConstants.java
@@ -550,35 +550,37 @@ public interface PConstants {
   // hints - hint values are positive for the alternate version,
   // negative of the same value returns to the normal/default state
 
-  static final int ENABLE_NATIVE_FONTS         =  1;
-  static final int DISABLE_NATIVE_FONTS        = -1;
+  static final int ENABLE_NATIVE_FONTS                 =  1;
+  static final int DISABLE_NATIVE_FONTS                = -1;
   
-  static final int DISABLE_DEPTH_TEST          =  2;
-  static final int ENABLE_DEPTH_TEST           = -2;
+  static final int DISABLE_DEPTH_TEST                  =  2;
+  static final int ENABLE_DEPTH_TEST                   = -2;
       
-  static final int ENABLE_DEPTH_SORT           =  3;
-  static final int DISABLE_DEPTH_SORT          = -3;
+  static final int ENABLE_DEPTH_SORT                   =  3;
+  static final int DISABLE_DEPTH_SORT                  = -3;
   
-  static final int DISABLE_OPENGL_ERROR_REPORT =  4;
-  static final int ENABLE_OPENGL_ERROR_REPORT  = -4;
+  static final int DISABLE_OPENGL_ERROR_REPORT         =  4;
+  static final int ENABLE_OPENGL_ERROR_REPORT          = -4;
   
-  static final int ENABLE_ACCURATE_TEXTURES    =  5;
-  static final int DISABLE_ACCURATE_TEXTURES   = -5;
+  static final int ENABLE_ACCURATE_TEXTURES            =  5;
+  static final int DISABLE_ACCURATE_TEXTURES           = -5;
 
-  static final int DISABLE_DEPTH_MASK          =  6;
-  static final int ENABLE_DEPTH_MASK           = -6;
+  static final int DISABLE_DEPTH_MASK                  =  6;
+  static final int ENABLE_DEPTH_MASK                   = -6;
 
-  static final int ENABLE_ACCURATE_2D          =  7;
-  static final int DISABLE_ACCURATE_2D         = -7;
+  static final int ENABLE_ACCURATE_2D                  =  7;
+  static final int DISABLE_ACCURATE_2D                 = -7;
 
-  static final int DISABLE_TEXTURE_CACHE       =  8;
-  static final int ENABLE_TEXTURE_CACHE        = -8;
+  static final int DISABLE_TEXTURE_CACHE               =  8;
+  static final int ENABLE_TEXTURE_CACHE                = -8;
 
-  static final int DISABLE_TRANSFORM_CACHE     =  9;
-  static final int ENABLE_TRANSFORM_CACHE      = -9;  
+  static final int DISABLE_TRANSFORM_CACHE             =  9;
+  static final int ENABLE_TRANSFORM_CACHE              = -9;  
+
+  static final int ENABLE_PERSPECTIVE_CORRECTED_LINES  =  10;
+  static final int DISABLE_PERSPECTIVE_CORRECTED_LINES = -10;  
   
-  static final int HINT_COUNT                  =  10;
-
+  static final int HINT_COUNT                  =  11;
 
   // error messages
 
diff --git a/java/libraries/opengl/src/processing/opengl/LineShaderVert.glsl b/java/libraries/opengl/src/processing/opengl/LineShaderVert.glsl
index 3546e48ad..140f14b5b 100644
--- a/java/libraries/opengl/src/processing/opengl/LineShaderVert.glsl
+++ b/java/libraries/opengl/src/processing/opengl/LineShaderVert.glsl
@@ -104,19 +104,17 @@ void main() {
   float thickness = attribs.w;
   vec2 window_offset = perp * thickness;
 
-/*  
   if (0 < perspective) {
     // Perspective correction (lines will look thiner as they move away 
     // from the view position).  
     gl_Position.xy = clip_p.xy + window_offset.xy;
     gl_Position.zw = clip_p.zw;
   } else {
-  */
     // No perspective correction.	
     float clip_p_w = clip_p.w;
     vec4 offset_p = windowToClipVector(window_offset, viewport, clip_p_w);
     gl_Position = clip_p + offset_p;
-  //}  
+  }  
   
   vec4 color = vec4(0, 0, 0, 0);
   vec4 globalAmbient = gl_Color * gl_LightModel.ambient;  
diff --git a/java/libraries/opengl/src/processing/opengl/PGraphicsOpenGL.java b/java/libraries/opengl/src/processing/opengl/PGraphicsOpenGL.java
index 22bd32268..363388072 100644
--- a/java/libraries/opengl/src/processing/opengl/PGraphicsOpenGL.java
+++ b/java/libraries/opengl/src/processing/opengl/PGraphicsOpenGL.java
@@ -1413,7 +1413,7 @@ public class PGraphicsOpenGL extends PGraphics {
     }
 
     if (hints[ENABLE_ACCURATE_2D]) {
-      flushMode = FLUSH_CONTINUOUSLY;
+      flushMode = FLUSH_CONTINUOUSLY;      
     } else {
       flushMode = FLUSH_WHEN_FULL;
     }
@@ -1737,8 +1737,14 @@ public class PGraphicsOpenGL extends PGraphics {
   // HINTS
 
   public void hint(int which) {
-    super.hint(which);    
+    boolean oldValue = hints[which];
+    super.hint(which);
+    boolean newValue = hints[which];
 
+    if (oldValue == newValue) {
+      return;
+    }
+    
     if (which == DISABLE_DEPTH_TEST) {
       flush();
       pgl.disableDepthTest();
@@ -1768,6 +1774,17 @@ public class PGraphicsOpenGL extends PGraphics {
     } else if (which == DISABLE_TEXTURE_CACHE) {
       flush();
       
+    } else if (which == DISABLE_PERSPECTIVE_CORRECTED_LINES) {
+      if (0 < tessGeo.lineVertexCount && 0 < tessGeo.lineIndexCount) {
+        flush();
+      }
+      
+    } else if (which == ENABLE_PERSPECTIVE_CORRECTED_LINES &&
+               0 < tessGeo.lineVertexCount && 0 < tessGeo.lineIndexCount) {
+      if (0 < tessGeo.lineVertexCount && 0 < tessGeo.lineIndexCount) {
+        flush();
+      }      
+      
     }
 
   }
@@ -2442,6 +2459,12 @@ public class PGraphicsOpenGL extends PGraphics {
   protected void setupLineShader(int attrBufID, float[] attribs, int nvert) {
     lineShader.setVecUniform("viewport", viewport[0], viewport[1], viewport[2], viewport[3]);
     
+    if (hints[ENABLE_PERSPECTIVE_CORRECTED_LINES]) {
+      lineShader.setIntUniform("perspective", 1);
+    } else {
+      lineShader.setIntUniform("perspective", 0);
+    }
+    
     lineShader.setIntUniform("lights", lightCount);           
         
     lineShader.setVecUniform("eye", cameraEyeX, cameraEyeY, cameraEyeZ, 0);
@@ -2457,6 +2480,12 @@ public class PGraphicsOpenGL extends PGraphics {
   
   protected void setupLineShader(int attrBufID) {
     lineShader.setVecUniform("viewport", viewport[0], viewport[1], viewport[2], viewport[3]);
+
+    if (hints[ENABLE_PERSPECTIVE_CORRECTED_LINES]) {
+      lineShader.setIntUniform("perspective", 1);
+    } else {
+      lineShader.setIntUniform("perspective", 0);
+    }    
     
     lineShader.setIntUniform("lights", lightCount);