diff --git a/Source/Glide64/Debugger.cpp b/Source/Glide64/Debugger.cpp
index 8775524d4..c0ac22f38 100644
--- a/Source/Glide64/Debugger.cpp
+++ b/Source/Glide64/Debugger.cpp
@@ -41,15 +41,6 @@
 #include "Util.h"
 #include "Debugger.h"
 
-/*
- * required to include OpenGL library without errors
- * Dependency on OpenGL in this module is limited to just `glGetError`.
- */
-#ifdef _WIN32
-#include <windows.h>
-#endif
-#include <GL/gl.h>
-
 GLIDE64_DEBUGGER _debugger;
 
 #define SX(x) ((x)*rdp.scale_1024)
@@ -1027,52 +1018,3 @@ void output (float x, float y, int scale, const char *fmt, ...)
     x+=8;
   }
 }
-
-static const char * GL_errors[7 + 1] = {
-    "GL_NO_ERROR", /* "There is no current error." */
-    "GL_INVALID_ENUM", /* "Invalid parameter." */
-    "GL_INVALID_VALUE", /* "Invalid enum parameter value." */
-    "GL_INVALID_OPERATION", /* "Illegal call." */
-    "GL_STACK_OVERFLOW",
-    "GL_STACK_UNDERFLOW",
-    "GL_OUT_OF_MEMORY", /* "Unable to allocate memory." */
-
-    "GL_UNKNOWN_ERROR" /* ??? */
-};
-
-int grDisplayGLError(const char* message)
-{
-    GLenum status;
-    unsigned int error_index;
-    int failure;
-
-    status = glGetError();
-    failure = 1;
-
-    if (status == GL_NO_ERROR)
-        error_index = failure = 0;
-    else
-        error_index =
-            (status < GL_INVALID_ENUM) /* to avoid underflow when subtracting */
-          ? ( 7 ) /* our own, made-up "GL_UNKNOWN_ERROR" error */
-          : (status - GL_INVALID_ENUM) + 1;
-
-    if (error_index > 7)
-        error_index = 7;
-
-#if !0
-/*
- * In most cases, we don't want to spam the screen to repeatedly say that
- * there were no OpenGL errors yet, though sometimes one may need verbosity.
- */
-    if (failure == 0)
-        return (failure);
-#endif
-
-#ifdef _WIN32
-    MessageBoxA(NULL, message, GL_errors[error_index], MB_ICONERROR);
-#else
-    fprintf(stderr, "%s\n%s\n\n", GL_errors[error_index], message);
-#endif
-    return (failure);
-}
diff --git a/Source/Glide64/Debugger.h b/Source/Glide64/Debugger.h
index f304d4eea..cc6b7444c 100644
--- a/Source/Glide64/Debugger.h
+++ b/Source/Glide64/Debugger.h
@@ -135,5 +135,3 @@ void debug_cacheviewer ();
 void debug_mouse ();
 void debug_keys ();
 void output (float x, float y, int scale, const char *fmt, ...);
-
-extern int grDisplayGLError( const char * message );
diff --git a/Source/Glide64/Glide64.vcxproj b/Source/Glide64/Glide64.vcxproj
index 667393cc2..4c87f0ee4 100644
--- a/Source/Glide64/Glide64.vcxproj
+++ b/Source/Glide64/Glide64.vcxproj
@@ -44,6 +44,8 @@
     </ClCompile>
     <Link>
       <AdditionalLibraryDirectories>$(Root)Source\3rd Party\wx\lib\vc_lib;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
+      <SubSystem Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">Windows</SubSystem>
+      <SubSystem Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">Windows</SubSystem>
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
diff --git a/Source/Glide64/Main.cpp b/Source/Glide64/Main.cpp
index ea4f83e02..2b3dfc2ed 100644
--- a/Source/Glide64/Main.cpp
+++ b/Source/Glide64/Main.cpp
@@ -1890,10 +1890,6 @@ void CALL UpdateScreen (void)
   if (fullscreen && (*gfx.VI_ORIGIN_REG  > width))
     update_screen_count++;
 
-#if defined(_DEBUG) || 0
-  grDisplayGLError("UpdateScreen");
-#endif
-
 #ifdef FPS
   // vertical interrupt has occurred, increment counter
   vi_count ++;
diff --git a/Source/Glitch64/combiner.cpp b/Source/Glitch64/combiner.cpp
index d195d6369..d3620cb81 100644
--- a/Source/Glitch64/combiner.cpp
+++ b/Source/Glitch64/combiner.cpp
@@ -167,6 +167,8 @@ void updateCombiner(int i)
   glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_RGB_ARB, operand1[i]);
   glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE2_RGB_ARB, source2[i]);
   glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_RGB_ARB, operand2[i]);
+
+  grDisplayGLError("updateCombiner");
 }
 
 void updateCombinera(int i)
@@ -179,6 +181,8 @@ void updateCombinera(int i)
   glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_ALPHA_ARB, operanda1[i]);
   glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE2_ALPHA_ARB, sourcea2[i]);
   glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_ALPHA_ARB, operanda2[i]);
+
+  grDisplayGLError("updateCombinera");
 }
 
 void init_combiner()
@@ -301,6 +305,8 @@ void init_combiner()
   dither_enabled = 0;
   blackandwhite0 = 0;
   blackandwhite1 = 0;
+
+  grDisplayGLError("init_combiner");
 }
 
 void compile_chroma_shader()
@@ -339,6 +345,8 @@ void compile_chroma_shader()
 
   strcat(fragment_shader_chroma, "if (color.rgb == chroma_color.rgb) discard; \n");
   strcat(fragment_shader_chroma, "}");
+
+  grDisplayGLError("compile_chroma_shader");
 }
 
 typedef struct _shader_program_key
@@ -525,6 +533,8 @@ void compile_shader()
 
   set_lambda();
   number_of_programs++;
+
+  grDisplayGLError("compile_shader");
 }
 
 void free_combiners()
@@ -541,6 +551,8 @@ void set_copy_shader()
   glUseProgramObjectARB(program_object_default);
   texture0_location = glGetUniformLocationARB(program_object, "texture0");
   glUniform1iARB(texture0_location, 0);
+
+  grDisplayGLError("set_copy_shader");
 }
 
 void set_depth_shader()
@@ -550,12 +562,16 @@ void set_depth_shader()
   glUseProgramObjectARB(program_object_depth);
   texture0_location = glGetUniformLocationARB(program_object, "texture0");
   glUniform1iARB(texture0_location, 0);
+
+  grDisplayGLError("set_depth_shader");
 }
 
 void set_lambda()
 {
   int lambda_location = glGetUniformLocationARB(program_object, "lambda");
   glUniform1fARB(lambda_location, lambda);
+
+  grDisplayGLError("set_lambda");
 }
 
 FX_ENTRY void FX_CALL 
@@ -583,6 +599,8 @@ grConstantColorValue( GrColor_t value )
   constant_color_location = glGetUniformLocationARB(program_object, "constant_color");
   glUniform4fARB(constant_color_location, texture_env_color[0], texture_env_color[1], 
     texture_env_color[2], texture_env_color[3]);
+
+  grDisplayGLError("grConstantColorValue");
 }
 
 int setOtherColorSource(int other)
@@ -1470,6 +1488,8 @@ grAlphaBlendFunction(
     glBlendFuncSeparateEXT(sfactorRGB, dfactorRGB, sfactorAlpha, dfactorAlpha);
   else
     glBlendFunc(sfactorRGB, dfactorRGB);
+
+  grDisplayGLError("grAlphaBlendFunction");
 }
 
 FX_ENTRY void FX_CALL
@@ -1496,12 +1516,15 @@ grAlphaTestFunction( GrCmpFnc_t function )
   case GR_CMP_ALWAYS:
     glAlphaFunc(GL_ALWAYS, alpha_ref/255.0f);
     glDisable(GL_ALPHA_TEST);
+    grDisplayGLError("grAlphaTestFunction :: GR_CMP_ALWAYS");
     return;
     break;
   default:
     display_warning("grAlphaTestFunction : unknown function : %x", function);
   }
+
   glEnable(GL_ALPHA_TEST);
+  grDisplayGLError("grAlphaTestFunction");
 }
 
 // fog
@@ -1530,6 +1553,8 @@ grFogMode( GrFogMode_t mode )
     display_warning("grFogMode : unknown mode : %x", mode);
   }
   need_to_compile = 1;
+
+  grDisplayGLError("grFogMode");
 }
 
 FX_ENTRY float FX_CALL
@@ -1548,6 +1573,8 @@ guFogGenerateLinear(GrFog_t * /*fogtable*/,
   glFogi(GL_FOG_COORDINATE_SOURCE_EXT, GL_FOG_COORDINATE_EXT);
   glFogf(GL_FOG_START, nearZ / 255.0f);
   glFogf(GL_FOG_END, farZ / 255.0f);
+
+  grDisplayGLError("guFogGenerateLinear");
 }
 
 FX_ENTRY void FX_CALL 
@@ -1581,6 +1608,7 @@ grFogColorValue( GrColor_t fogcolor )
   }
 
   glFogfv(GL_FOG_COLOR, color); 
+  grDisplayGLError("glFogfv");
 }
 
 // chroma
@@ -1630,6 +1658,7 @@ grChromakeyValue( GrColor_t value )
   chroma_color_location = glGetUniformLocationARB(program_object, "chroma_color");
   glUniform4fARB(chroma_color_location, chroma_color[0], chroma_color[1],
     chroma_color[2], chroma_color[3]);
+  grDisplayGLError("grChromakeyValue");
 }
 
 static void setPattern()
@@ -1667,6 +1696,8 @@ static void setPattern()
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
   glDisable(GL_TEXTURE_2D);
+
+  grDisplayGLError("setPattern");
 }
 
 FX_ENTRY void FX_CALL
@@ -1704,7 +1735,9 @@ grStippleMode( GrStippleMode_t mode )
   default:
     display_warning("grStippleMode:%x", mode);
   }
+
   need_to_compile = 1;
+  grDisplayGLError("grStippleMode");
 }
 
 FX_ENTRY void FX_CALL 
@@ -2748,4 +2781,5 @@ grConstantColorValueExt(GrChipID_t    tmu,
     ccolor1_location = glGetUniformLocationARB(program_object, "ccolor1");
     glUniform4fARB(ccolor1_location, ccolor1[0], ccolor1[1], ccolor1[2], ccolor1[3]);
   }
+  grDisplayGLError("grConstantColorValueExt");
 }
diff --git a/Source/Glitch64/geometry.cpp b/Source/Glitch64/geometry.cpp
index adfcc52b7..3bfbb28ca 100644
--- a/Source/Glitch64/geometry.cpp
+++ b/Source/Glitch64/geometry.cpp
@@ -55,6 +55,7 @@ void init_geometry()
 
   glDisable(GL_CULL_FACE);
   glDisable(GL_DEPTH_TEST);
+  grDisplayGLError("init_geometry");
 }
 
 FX_ENTRY void FX_CALL
@@ -141,6 +142,7 @@ grCullMode( GrCullMode_t mode )
   default:
     display_warning("unknown cull mode : %x", mode);
   }
+  grDisplayGLError("grCullMode");
 }
 
 // Depth buffer
@@ -168,6 +170,7 @@ grDepthBufferMode( GrDepthBufferMode_t mode )
   default:
     display_warning("unknown depth buffer mode : %x", mode);
   }
+  grDisplayGLError("grDepthBufferMode");
 }
 
 FX_ENTRY void FX_CALL
@@ -216,6 +219,7 @@ grDepthBufferFunction( GrCmpFnc_t function )
   default:
     display_warning("unknown depth buffer function : %x", function);
   }
+  grDisplayGLError("grDepthBufferFunction");
 }
 
 FX_ENTRY void FX_CALL
@@ -223,6 +227,7 @@ grDepthMask( FxBool mask )
 {
   LOG("grDepthMask(%d)\r\n", mask);
   glDepthMask((GLboolean)mask);
+  grDisplayGLError("grDepthMask");
 }
 
 float biasFactor = 0;
@@ -282,6 +287,7 @@ void FindBestDepthBias()
   }
   //printf(" --> bias factor %g\n", biasFactor);
   glPopAttrib();
+  grDisplayGLError("FindBestDepthBias");
 }
 
 FX_ENTRY void FX_CALL
@@ -301,6 +307,7 @@ grDepthBiasLevel( FxI32 level )
     glPolygonOffset(0,0);
     glDisable(GL_POLYGON_OFFSET_FILL);
   }
+  grDisplayGLError("grDepthBiasLevel");
 }
 
 // draw
@@ -439,6 +446,7 @@ grDrawTriangle( const void *a, const void *b, const void *c )
     -(*c_y - (float)heighto) / (float)(height/2) / *c_q, ZCALC(*c_z ,*c_q), 1.0f / *c_q);
 
   glEnd();
+  grDisplayGLError("grDrawTriangle");
 }
 
 FX_ENTRY void FX_CALL
@@ -496,6 +504,7 @@ grDrawPoint( const void *pt )
     -(*y - (float)heighto) / (float)(height/2) / *q, ZCALC(*z ,*q), 1.0f / *q);
 
   glEnd();
+  grDisplayGLError("grDrawPoint");
 }
 
 FX_ENTRY void FX_CALL
@@ -588,6 +597,7 @@ grDrawLine( const void *a, const void *b )
     -(*b_y - (float)heighto) / (float)(height/2) / *b_q, ZCALC(*b_z, *b_q), 1.0f / *b_q);
 
   glEnd();
+  grDisplayGLError("grDrawLine");
 }
 
 FX_ENTRY void FX_CALL
@@ -659,6 +669,8 @@ grDrawVertexArray(FxU32 mode, FxU32 Count, void *pointers2)
       -(*y - (float)heighto) / (float)(height/2) / *q, ZCALC(*z, *q), 1.0f / *q);
   }
   glEnd();
+
+  grDisplayGLError("grDrawVertexArray");
 }
 
 FX_ENTRY void FX_CALL
@@ -735,4 +747,6 @@ grDrawVertexArrayContiguous(FxU32 mode, FxU32 Count, void *pointers, FxU32 strid
       -(*y - (float)heighto) / (float)(height/2) / *q, ZCALC(*z, *q), 1.0f / *q);
   }
   glEnd();
+
+  grDisplayGLError("grDrawVertexArrayContiguous");
 }
diff --git a/Source/Glitch64/main.cpp b/Source/Glitch64/main.cpp
index a53466923..7db272f07 100644
--- a/Source/Glitch64/main.cpp
+++ b/Source/Glitch64/main.cpp
@@ -249,6 +249,7 @@ static inline void opt_glCopyTexImage2D( GLenum target,
     //       printf("--> %dx%d newfmt %x\n", width, height, fmt);
     glCopyTexImage2D(target, level, internalFormat, x, y, width, height, border);
   }
+  grDisplayGLError("opt_glCopyTexImage2D");
 }
 #define glCopyTexImage2D opt_glCopyTexImage2D
 
@@ -649,6 +650,7 @@ grClipWindow( FxU32 minx, FxU32 miny, FxU32 maxx, FxU32 maxy )
     if (maxy < miny) maxy = miny;
     glScissor(minx, miny, maxx - minx, maxy - miny);
     glEnable(GL_SCISSOR_TEST);
+    grDisplayGLError("grClipWindow :: use_fbo");
     return;
   }
 
@@ -671,6 +673,7 @@ grClipWindow( FxU32 minx, FxU32 miny, FxU32 maxx, FxU32 maxy )
     glScissor(minx, (viewport_offset)+height-maxy, maxx - minx, maxy - miny);
   }
   glEnable(GL_SCISSOR_TEST);
+  grDisplayGLError("grClipWindow");
 }
 
 FX_ENTRY void FX_CALL
@@ -678,6 +681,7 @@ grColorMask( FxBool rgb, FxBool a )
 {
   LOG("grColorMask(%d, %d)\r\n", rgb, a);
   glColorMask((GLboolean)rgb, (GLboolean)rgb, (GLboolean)rgb, (GLboolean)a);
+  grDisplayGLError("grColorMask");
 }
 
 FX_ENTRY void FX_CALL
@@ -1384,6 +1388,7 @@ grSstWinOpen(
       ati_sucks = 0;
   }
 
+  grDisplayGLError("grSstWinOpen");
   return 1;
 }
 
@@ -1597,7 +1602,7 @@ FX_ENTRY void FX_CALL grTextureBufferExt( GrChipID_t  		tmu,
 
     glScissor(0, viewport_offset, width, height);
 
-
+    grDisplayGLError("grTextureBufferExt :: A");
   } else {
     if (!render_to_texture) //initialization
     {
@@ -1651,6 +1656,7 @@ FX_ENTRY void FX_CALL grTextureBufferExt( GrChipID_t  		tmu,
           }
           CHECK_FRAMEBUFFER_STATUS();
           curBufferAddr = pBufferAddress;
+          grDisplayGLError("grTextureBufferExt :: C");
           return;
         }
         else //create new FBO at the same address, delete old one
@@ -1695,6 +1701,7 @@ FX_ENTRY void FX_CALL grTextureBufferExt( GrChipID_t  		tmu,
     CHECK_FRAMEBUFFER_STATUS();
     curBufferAddr = pBufferAddress;
     nb_fb++;
+    grDisplayGLError("grTextureBufferExt :: B");
   }
 }
 
@@ -2052,6 +2059,7 @@ static void render_rectangle(int texture_number,
 
   glEnable(GL_DEPTH_TEST);
   glEnable(GL_BLEND);
+  grDisplayGLError("render_rectangle");
 }
 
 void reloadTexture()
@@ -2081,6 +2089,7 @@ void reloadTexture()
     width, height, -1);
   glBindTexture(GL_TEXTURE_2D, default_texture);
   glPopAttrib();
+  grDisplayGLError("reloadTexture");
 }
 
 void updateTexture()
@@ -2112,6 +2121,7 @@ void updateTexture()
     glBindTexture(GL_TEXTURE_2D, default_texture);
     glPopAttrib();
   }
+  grDisplayGLError("updateTexture");
 }
 
 FX_ENTRY void FX_CALL grFramebufferCopyExt(int /*x*/, int /*y*/, int /*w*/, int /*h*/,
@@ -2135,6 +2145,7 @@ FX_ENTRY void FX_CALL grFramebufferCopyExt(int /*x*/, int /*y*/, int /*w*/, int
       glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT,
         0, viewport_offset, tw, th, 0);
       glBindTexture(GL_TEXTURE_2D, default_texture);
+      grDisplayGLError("grFramebufferCopyExt :: A");
       return;
     }
     if (from == GR_FBCOPY_BUFFER_FRONT && to == GR_FBCOPY_BUFFER_BACK) {
@@ -2156,6 +2167,7 @@ FX_ENTRY void FX_CALL grFramebufferCopyExt(int /*x*/, int /*y*/, int /*w*/, int
       glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
       glBindTexture(GL_TEXTURE_2D, default_texture);
       glPopAttrib();
+      grDisplayGLError("grFramebufferCopyExt :: B");
       return;
     }
 
@@ -2276,6 +2288,7 @@ grRenderBuffer( GrBuffer_t buffer )
   default:
     display_warning("grRenderBuffer : unknown buffer : %x", buffer);
   }
+  grDisplayGLError("grRenderBuffer");
 }
 
 FX_ENTRY void FX_CALL
@@ -2300,6 +2313,7 @@ grAuxBufferExt( GrBuffer_t buffer )
     glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
     need_to_compile = 1;
   }
+  grDisplayGLError("grAuxBufferExt");
 }
 
 FX_ENTRY void FX_CALL
@@ -2333,6 +2347,7 @@ grBufferClear( GrColor_t color, GrAlpha_t alpha, FxU32 depth )
   // ZIGGY TODO check that color mask is on
   buffer_cleared = 1;
 
+  grDisplayGLError("grBufferClear");
 }
 
 // #include <unistd.h>
@@ -2454,6 +2469,7 @@ grLfbLock( GrLock_t type, GrBuffer_t buffer, GrLfbWriteMode_t writeMode,
     }
   }
 
+  grDisplayGLError("grLfbLock");
   return FXTRUE;
 }
 
@@ -2530,6 +2546,7 @@ grLfbReadRegion( GrBuffer_t src_buffer,
     free(buf);
   }
 
+  grDisplayGLError("grLfbReadRegion");
   return FXTRUE;
 }
 
@@ -2689,6 +2706,8 @@ grLfbWriteRegion( GrBuffer_t dst_buffer,
   }
   glDrawBuffer(current_buffer);
   glPopAttrib();
+
+  grDisplayGLError("grLfbWriteRegion");
   return FXTRUE;
 }
 
@@ -2817,12 +2836,14 @@ FX_ENTRY void FX_CALL
 grFinish(void)
 {
   glFinish();
+  grDisplayGLError("grFinish");
 }
 
 FX_ENTRY void FX_CALL
 grFlush(void)
 {
   glFlush();
+  grDisplayGLError("grFlush");
 }
 
 FX_ENTRY void FX_CALL
@@ -3101,7 +3122,61 @@ void grTexChromaModeExt(GrChipID_t /*tmu*/, GrChromakeyMode_t /*mode*/)
   display_warning("grTexChromaRangeModeExt");
 }
 
+static const char * GL_errors[7 + 1] = {
+    "GL_NO_ERROR", /* "There is no current error." */
+    "GL_INVALID_ENUM", /* "Invalid parameter." */
+    "GL_INVALID_VALUE", /* "Invalid enum parameter value." */
+    "GL_INVALID_OPERATION", /* "Illegal call." */
+    "GL_STACK_OVERFLOW",
+    "GL_STACK_UNDERFLOW",
+    "GL_OUT_OF_MEMORY", /* "Unable to allocate memory." */
 
+    "GL_UNKNOWN_ERROR" /* ??? */
+};
+
+#ifndef _DEBUG
+int grDisplayGLError(const char* /*unused*/)
+{
+    return -1;
+}
+#else
+int grDisplayGLError(const char* message)
+{
+    GLenum status;
+    unsigned int error_index;
+    int failure;
+
+    status = glGetError();
+    failure = 1;
+
+    if (status == GL_NO_ERROR)
+        error_index = failure = 0;
+    else
+        error_index =
+            (status < GL_INVALID_ENUM) /* to avoid underflow when subtracting */
+          ? ( 7 ) /* our own, made-up "GL_UNKNOWN_ERROR" error */
+          : (status - GL_INVALID_ENUM) + 1;
+
+    if (error_index > 7)
+        error_index = 7;
+
+#if !0
+/*
+ * In most cases, we don't want to spam the screen to repeatedly say that
+ * there were no OpenGL errors yet, though sometimes one may need verbosity.
+ */
+    if (failure == 0)
+        return (failure);
+#endif
+
+#ifdef _WIN32
+    MessageBoxA(NULL, message, GL_errors[error_index], MB_ICONERROR);
+#else
+    fprintf(stderr, "%s\n%s\n\n", GL_errors[error_index], message);
+#endif
+    return (failure);
+}
+#endif
 
 // VP debug
 #ifdef VPDEBUG
@@ -3187,6 +3262,7 @@ void dump_stop()
     free(pixels);
   }
   glBindTexture(GL_TEXTURE_2D, default_texture);
+  grDisplayGLError("dump_stop");
 }
 
 void dump_tex(int id)
diff --git a/Source/Glitch64/main.h b/Source/Glitch64/main.h
index b12de4401..141ca5a2e 100644
--- a/Source/Glitch64/main.h
+++ b/Source/Glitch64/main.h
@@ -27,6 +27,9 @@ extern wrapper_config config;
 // returns the bytes per pixel of a given GR texture format
 int grTexFormatSize(int fmt);
 
+/* 2015.03.07 cxd4 -- regulated GL state machine debugging using glGetError */
+extern int grDisplayGLError(const char* message);
+
 extern int packed_pixels_support;
 extern int ati_sucks;
 extern float largest_supported_anisotropy;
diff --git a/Source/Glitch64/textures.cpp b/Source/Glitch64/textures.cpp
index 02f90b8fc..5b56384c0 100644
--- a/Source/Glitch64/textures.cpp
+++ b/Source/Glitch64/textures.cpp
@@ -639,6 +639,7 @@ grTexDownloadMipMap( GrChipID_t tmu,
   }
 
   glBindTexture(GL_TEXTURE_2D, default_texture);
+  grDisplayGLError("grTexDownloadMipMap");
 }
 
 int CheckTextureBufferFormat(GrChipID_t tmu, FxU32 startAddress, GrTexInfo *info );
@@ -722,6 +723,7 @@ grTexSource( GrChipID_t tmu,
     grAuxBufferExt(auxbuffer);
   oldbuffer = auxbuffer;
 #endif
+  grDisplayGLError("grTexSource");
 }
 
 FX_ENTRY void FX_CALL
@@ -788,6 +790,7 @@ grTexFilterMode(
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, min_filter1);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, mag_filter1);
   }
+  grDisplayGLError("grTexFilterMode");
 }
 
 FX_ENTRY void FX_CALL
@@ -867,4 +870,5 @@ grTexClampMode(
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrap_s1);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrap_t1);
   }
+  grDisplayGLError("grTexClampMode");
 }