diff --git a/src/lib/graphics/TwkGLF/BasicGLProgram.cpp b/src/lib/graphics/TwkGLF/BasicGLProgram.cpp
index a8bf63de5..6473c309c 100644
--- a/src/lib/graphics/TwkGLF/BasicGLProgram.cpp
+++ b/src/lib/graphics/TwkGLF/BasicGLProgram.cpp
@@ -85,17 +85,32 @@ namespace TwkGLF
         }
     }
 
+    namespace
+    {
+        // Returns "#version 150\n" for GL3+, empty string for GL2.
+        // Must be called after a GL context is current.
+        const char* basicGLVersionHeader()
+        {
+            const char* glVersion = (const char*)glGetString(GL_VERSION);
+            if (glVersion && glVersion[0] >= '3')
+                return "#version 150\n";
+            return "";
+        }
+    } // namespace
+
     bool BasicGLProgram::compile()
     {
         GLuint v, f;
         m_programId = glCreateProgram();
         v = glCreateShader(GL_VERTEX_SHADER);
         f = glCreateShader(GL_FRAGMENT_SHADER);
-        const char* vcode = m_vertexCode.c_str();
-        glShaderSource(v, 1, &vcode, NULL);
+
+        const char* versionHeader = basicGLVersionHeader();
+        const char* vsrc[2] = {versionHeader, m_vertexCode.c_str()};
+        glShaderSource(v, 2, vsrc, NULL);
         glCompileShader(v);
-        const char* fcode = m_fragmentCode.c_str();
-        glShaderSource(f, 1, &fcode, NULL);
+        const char* fsrc[2] = {versionHeader, m_fragmentCode.c_str()};
+        glShaderSource(f, 2, fsrc, NULL);
         glCompileShader(f);
 
         GLint status = GL_TRUE;
diff --git a/src/lib/graphics/TwkGLF/glsl/CheckerboardBGFrag.glsl b/src/lib/graphics/TwkGLF/glsl/CheckerboardBGFrag.glsl
index b41eb7409..d6c48b3d0 100755
--- a/src/lib/graphics/TwkGLF/glsl/CheckerboardBGFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/CheckerboardBGFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/CloneFrag.glsl b/src/lib/graphics/TwkGLF/glsl/CloneFrag.glsl
index 20975f123..866944875 100644
--- a/src/lib/graphics/TwkGLF/glsl/CloneFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/CloneFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/CloneVertex.glsl b/src/lib/graphics/TwkGLF/glsl/CloneVertex.glsl
index 66b1e8ba9..87d6a0c6d 100644
--- a/src/lib/graphics/TwkGLF/glsl/CloneVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/CloneVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #define out varying
diff --git a/src/lib/graphics/TwkGLF/glsl/CrosshatchBGFrag.glsl b/src/lib/graphics/TwkGLF/glsl/CrosshatchBGFrag.glsl
index 296c3fa07..43205eeb5 100755
--- a/src/lib/graphics/TwkGLF/glsl/CrosshatchBGFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/CrosshatchBGFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/DefaultFrag.glsl b/src/lib/graphics/TwkGLF/glsl/DefaultFrag.glsl
index 8e01a6396..cc6e5728d 100644
--- a/src/lib/graphics/TwkGLF/glsl/DefaultFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/DefaultFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/DefaultVertex.glsl b/src/lib/graphics/TwkGLF/glsl/DefaultVertex.glsl
index 14b8c6b87..4d7a67986 100644
--- a/src/lib/graphics/TwkGLF/glsl/DefaultVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/DefaultVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #endif
diff --git a/src/lib/graphics/TwkGLF/glsl/DirectionPaintFrag.glsl b/src/lib/graphics/TwkGLF/glsl/DirectionPaintFrag.glsl
index 09f1f2372..64f3e9461 100644
--- a/src/lib/graphics/TwkGLF/glsl/DirectionPaintFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/DirectionPaintFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/DirectionPaintVertex.glsl b/src/lib/graphics/TwkGLF/glsl/DirectionPaintVertex.glsl
index 7bce0c101..0dfe0ee86 100644
--- a/src/lib/graphics/TwkGLF/glsl/DirectionPaintVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/DirectionPaintVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #define out varying
diff --git a/src/lib/graphics/TwkGLF/glsl/EraseFrag.glsl b/src/lib/graphics/TwkGLF/glsl/EraseFrag.glsl
index 52efe6ae5..9808973b0 100644
--- a/src/lib/graphics/TwkGLF/glsl/EraseFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/EraseFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/EraseVertex.glsl b/src/lib/graphics/TwkGLF/glsl/EraseVertex.glsl
index 546327e3a..0d1aaadc0 100644
--- a/src/lib/graphics/TwkGLF/glsl/EraseVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/EraseVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #define out varying
diff --git a/src/lib/graphics/TwkGLF/glsl/OldReplaceFrag.glsl b/src/lib/graphics/TwkGLF/glsl/OldReplaceFrag.glsl
index c46ca6bb9..f2f35555e 100644
--- a/src/lib/graphics/TwkGLF/glsl/OldReplaceFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/OldReplaceFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/PaintColoredFrag.glsl b/src/lib/graphics/TwkGLF/glsl/PaintColoredFrag.glsl
index c0c2f475e..2c395a101 100644
--- a/src/lib/graphics/TwkGLF/glsl/PaintColoredFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/PaintColoredFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor;
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/ReplaceColoredVertex.glsl b/src/lib/graphics/TwkGLF/glsl/ReplaceColoredVertex.glsl
index 239103a27..ee4c01ae0 100644
--- a/src/lib/graphics/TwkGLF/glsl/ReplaceColoredVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/ReplaceColoredVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #define out varying
diff --git a/src/lib/graphics/TwkGLF/glsl/ReplaceFrag.glsl b/src/lib/graphics/TwkGLF/glsl/ReplaceFrag.glsl
index 8025f51fa..5f8b9fbc0 100644
--- a/src/lib/graphics/TwkGLF/glsl/ReplaceFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/ReplaceFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/ReplaceVertex.glsl b/src/lib/graphics/TwkGLF/glsl/ReplaceVertex.glsl
index 448d8cefc..82abd26a1 100644
--- a/src/lib/graphics/TwkGLF/glsl/ReplaceVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/ReplaceVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #define out varying
diff --git a/src/lib/graphics/TwkGLF/glsl/ScaleFrag.glsl b/src/lib/graphics/TwkGLF/glsl/ScaleFrag.glsl
index f07cba553..872769732 100644
--- a/src/lib/graphics/TwkGLF/glsl/ScaleFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/ScaleFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/ScaleVertex.glsl b/src/lib/graphics/TwkGLF/glsl/ScaleVertex.glsl
index 356b6875e..829da36f6 100644
--- a/src/lib/graphics/TwkGLF/glsl/ScaleVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/ScaleVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #define out varying
diff --git a/src/lib/graphics/TwkGLF/glsl/SoftCloneFrag.glsl b/src/lib/graphics/TwkGLF/glsl/SoftCloneFrag.glsl
index 2b085b868..6656f2b75 100644
--- a/src/lib/graphics/TwkGLF/glsl/SoftCloneFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/SoftCloneFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/SoftDirectionPaintFrag.glsl b/src/lib/graphics/TwkGLF/glsl/SoftDirectionPaintFrag.glsl
index c06b02f36..5113da06d 100644
--- a/src/lib/graphics/TwkGLF/glsl/SoftDirectionPaintFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/SoftDirectionPaintFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/SoftEraseFrag.glsl b/src/lib/graphics/TwkGLF/glsl/SoftEraseFrag.glsl
index f58b5d6a6..5b3af1877 100644
--- a/src/lib/graphics/TwkGLF/glsl/SoftEraseFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/SoftEraseFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/SoftOldReplaceFrag.glsl b/src/lib/graphics/TwkGLF/glsl/SoftOldReplaceFrag.glsl
index 563b64d0e..16889b4fe 100644
--- a/src/lib/graphics/TwkGLF/glsl/SoftOldReplaceFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/SoftOldReplaceFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/SoftPaintFrag.glsl b/src/lib/graphics/TwkGLF/glsl/SoftPaintFrag.glsl
index 4acfb403d..b0322727e 100644
--- a/src/lib/graphics/TwkGLF/glsl/SoftPaintFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/SoftPaintFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/SoftReplaceFrag.glsl b/src/lib/graphics/TwkGLF/glsl/SoftReplaceFrag.glsl
index 338ed395f..d42b7f3fb 100755
--- a/src/lib/graphics/TwkGLF/glsl/SoftReplaceFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/SoftReplaceFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/SoftScaleFrag.glsl b/src/lib/graphics/TwkGLF/glsl/SoftScaleFrag.glsl
index 52dae81f3..6b3973659 100644
--- a/src/lib/graphics/TwkGLF/glsl/SoftScaleFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/SoftScaleFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/StereoCheckerFrag.glsl b/src/lib/graphics/TwkGLF/glsl/StereoCheckerFrag.glsl
index 7508ec2b8..a0b29d6c5 100755
--- a/src/lib/graphics/TwkGLF/glsl/StereoCheckerFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/StereoCheckerFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/StereoScanlineFrag.glsl b/src/lib/graphics/TwkGLF/glsl/StereoScanlineFrag.glsl
index a81ba973a..b2a31a9f9 100755
--- a/src/lib/graphics/TwkGLF/glsl/StereoScanlineFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/StereoScanlineFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/TexRectFrag.glsl b/src/lib/graphics/TwkGLF/glsl/TexRectFrag.glsl
index 102719013..f70130fdc 100644
--- a/src/lib/graphics/TwkGLF/glsl/TexRectFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/TexRectFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor; 
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/TextureFrag.glsl b/src/lib/graphics/TwkGLF/glsl/TextureFrag.glsl
index 0f9cd98f2..fe6c06ac2 100644
--- a/src/lib/graphics/TwkGLF/glsl/TextureFrag.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/TextureFrag.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 out vec4 FragColor;
 #define FRAGCOLOR FragColor
 #else
diff --git a/src/lib/graphics/TwkGLF/glsl/TextureVertex.glsl b/src/lib/graphics/TwkGLF/glsl/TextureVertex.glsl
index 975732268..173647b28 100644
--- a/src/lib/graphics/TwkGLF/glsl/TextureVertex.glsl
+++ b/src/lib/graphics/TwkGLF/glsl/TextureVertex.glsl
@@ -4,7 +4,6 @@
 // SPDX-License-Identifier: Apache-2.0 
 //
 #if __VERSION__ >= 150
-#version 150
 #else
 #define in attribute
 #define out varying