diff --git a/core/src/processing/opengl/PJOGL.java b/core/src/processing/opengl/PJOGL.java
index d7e0df101..4418d67f0 100644
--- a/core/src/processing/opengl/PJOGL.java
+++ b/core/src/processing/opengl/PJOGL.java
@@ -614,49 +614,51 @@ public class PJOGL extends PGL {
 
   @Override
   protected void beginGL() {
-    if (projMatrix == null) {
-      projMatrix = new float[16];
-    }
-    gl2x.glMatrixMode(GLMatrixFunc.GL_PROJECTION);
-    projMatrix[ 0] = pg.projection.m00;
-    projMatrix[ 1] = pg.projection.m10;
-    projMatrix[ 2] = pg.projection.m20;
-    projMatrix[ 3] = pg.projection.m30;
-    projMatrix[ 4] = pg.projection.m01;
-    projMatrix[ 5] = pg.projection.m11;
-    projMatrix[ 6] = pg.projection.m21;
-    projMatrix[ 7] = pg.projection.m31;
-    projMatrix[ 8] = pg.projection.m02;
-    projMatrix[ 9] = pg.projection.m12;
-    projMatrix[10] = pg.projection.m22;
-    projMatrix[11] = pg.projection.m32;
-    projMatrix[12] = pg.projection.m03;
-    projMatrix[13] = pg.projection.m13;
-    projMatrix[14] = pg.projection.m23;
-    projMatrix[15] = pg.projection.m33;
-    gl2x.glLoadMatrixf(projMatrix, 0);
+    if (gl2x != null) {
+      if (projMatrix == null) {
+        projMatrix = new float[16];
+      }
+      gl2x.glMatrixMode(GLMatrixFunc.GL_PROJECTION);
+      projMatrix[ 0] = pg.projection.m00;
+      projMatrix[ 1] = pg.projection.m10;
+      projMatrix[ 2] = pg.projection.m20;
+      projMatrix[ 3] = pg.projection.m30;
+      projMatrix[ 4] = pg.projection.m01;
+      projMatrix[ 5] = pg.projection.m11;
+      projMatrix[ 6] = pg.projection.m21;
+      projMatrix[ 7] = pg.projection.m31;
+      projMatrix[ 8] = pg.projection.m02;
+      projMatrix[ 9] = pg.projection.m12;
+      projMatrix[10] = pg.projection.m22;
+      projMatrix[11] = pg.projection.m32;
+      projMatrix[12] = pg.projection.m03;
+      projMatrix[13] = pg.projection.m13;
+      projMatrix[14] = pg.projection.m23;
+      projMatrix[15] = pg.projection.m33;
+      gl2x.glLoadMatrixf(projMatrix, 0);
 
-    if (mvMatrix == null) {
-      mvMatrix = new float[16];
+      if (mvMatrix == null) {
+        mvMatrix = new float[16];
+      }
+      gl2x.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);
+      mvMatrix[ 0] = pg.modelview.m00;
+      mvMatrix[ 1] = pg.modelview.m10;
+      mvMatrix[ 2] = pg.modelview.m20;
+      mvMatrix[ 3] = pg.modelview.m30;
+      mvMatrix[ 4] = pg.modelview.m01;
+      mvMatrix[ 5] = pg.modelview.m11;
+      mvMatrix[ 6] = pg.modelview.m21;
+      mvMatrix[ 7] = pg.modelview.m31;
+      mvMatrix[ 8] = pg.modelview.m02;
+      mvMatrix[ 9] = pg.modelview.m12;
+      mvMatrix[10] = pg.modelview.m22;
+      mvMatrix[11] = pg.modelview.m32;
+      mvMatrix[12] = pg.modelview.m03;
+      mvMatrix[13] = pg.modelview.m13;
+      mvMatrix[14] = pg.modelview.m23;
+      mvMatrix[15] = pg.modelview.m33;
+      gl2x.glLoadMatrixf(mvMatrix, 0);
     }
-    gl2x.glMatrixMode(GLMatrixFunc.GL_MODELVIEW);
-    mvMatrix[ 0] = pg.modelview.m00;
-    mvMatrix[ 1] = pg.modelview.m10;
-    mvMatrix[ 2] = pg.modelview.m20;
-    mvMatrix[ 3] = pg.modelview.m30;
-    mvMatrix[ 4] = pg.modelview.m01;
-    mvMatrix[ 5] = pg.modelview.m11;
-    mvMatrix[ 6] = pg.modelview.m21;
-    mvMatrix[ 7] = pg.modelview.m31;
-    mvMatrix[ 8] = pg.modelview.m02;
-    mvMatrix[ 9] = pg.modelview.m12;
-    mvMatrix[10] = pg.modelview.m22;
-    mvMatrix[11] = pg.modelview.m32;
-    mvMatrix[12] = pg.modelview.m03;
-    mvMatrix[13] = pg.modelview.m13;
-    mvMatrix[14] = pg.modelview.m23;
-    mvMatrix[15] = pg.modelview.m33;
-    gl2x.glLoadMatrixf(mvMatrix, 0);
   }
 
 
@@ -1631,7 +1633,9 @@ public class PJOGL extends PGL {
 
   @Override
   public void vertexAttribPointer(int index, int size, int type, boolean normalized, int stride, Buffer data) {
-    gl2x.glVertexAttribPointer(index, size, type, normalized, stride, data);
+    if (gl2x != null) {
+      gl2x.glVertexAttribPointer(index, size, type, normalized, stride, data);
+    }
   }
 
   @Override
@@ -1656,7 +1660,9 @@ public class PJOGL extends PGL {
 
   @Override
   public void drawElements(int mode, int count, int type, Buffer indices) {
-    gl2x.glDrawElements(mode, count, type, indices);
+    if (gl2x != null) {
+      gl2x.glDrawElements(mode, count, type, indices);
+    }
   }
 
   //////////////////////////////////////////////////////////////////////////////
diff --git a/core/src/processing/opengl/PShader.java b/core/src/processing/opengl/PShader.java
index 652d93c97..4dcdc12cd 100644
--- a/core/src/processing/opengl/PShader.java
+++ b/core/src/processing/opengl/PShader.java
@@ -59,6 +59,9 @@ public class PShader implements PConstants {
   protected PGL pgl;
   protected int context;      // The context that created this shader.
 
+  // The shader type: POINT, LINE, POLY, etc.
+  protected int type;
+
   public int glProgram;
   public int glVertex;
   public int glFragment;
@@ -83,9 +86,7 @@ public class PShader implements PConstants {
   protected IntBuffer intBuffer;
   protected FloatBuffer floatBuffer;
 
-
-
-  protected int type;
+  // Uniforms common to all shader types
   protected int transformMatLoc;
   protected int modelviewMatLoc;
   protected int projectionMatLoc;
@@ -93,20 +94,11 @@ public class PShader implements PConstants {
   protected int bufferUnit;
   protected int viewportLoc;
 
-  protected int vertexLoc;
-  protected int colorLoc;
-  protected int normalLoc;
-  protected int texCoordLoc;
-  protected int normalMatLoc;
-
-  // For lines
+  // Uniforms only for lines and points
   protected int perspectiveLoc;
   protected int scaleLoc;
-  protected int directionLoc;
-
-  // For points
-  protected int offsetLoc;
 
+  // Lighting uniforms
   protected int lightCountLoc;
   protected int lightPositionLoc;
   protected int lightNormalLoc;
@@ -116,21 +108,27 @@ public class PShader implements PConstants {
   protected int lightFalloffLoc;
   protected int lightSpotLoc;
 
+  // Texturing uniforms
+  protected Texture texture;
+  protected int texUnit;
+  protected int textureLoc;
+  protected int texMatrixLoc;
+  protected int texOffsetLoc;
+  protected float[] tcmat;
+
+  // Vertex attributes
+  protected int vertexLoc;
+  protected int colorLoc;
+  protected int normalLoc;
+  protected int texCoordLoc;
+  protected int normalMatLoc;
+  protected int directionLoc;
+  protected int offsetLoc;
   protected int ambientLoc;
   protected int specularLoc;
   protected int emissiveLoc;
   protected int shininessLoc;
 
-  protected Texture texture;
-  protected int texUnit;
-
-  protected int textureLoc;
-  protected int texMatrixLoc;
-  protected int texOffsetLoc;
-
-  protected float[] tcmat;
-
-
   public PShader() {
     parent = null;
     pgl = null;
@@ -470,14 +468,16 @@ public class PShader implements PConstants {
   }
 
 
-
-  protected boolean setup() {
-
-    return true;
+  /**
+   * Extra initialization method that can be used by subclasses, called after
+   * compiling and attaching the vertex and fragment shaders, and before
+   * linking the shader program.
+   *
+   */
+  protected void setup() {
   }
 
 
-
   /**
    * Returns the ID location of the attribute parameter given its name.
    *