diff --git a/doc/Makefile b/doc/Makefile
index c64ad654..41c41ab1 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -1,2 +1,7 @@
 all: 
 	./gendoc.py
+	
+clean:
+	$(RM) main.pdf
+	$(RM) plugins_generated.tex
+	$(RM) *.aux main.bbl main.blg main.log main.out main.toc
diff --git a/doc/gendoc.py b/doc/gendoc.py
index b7f23123..d83aed88 100755
--- a/doc/gendoc.py
+++ b/doc/gendoc.py
@@ -1,6 +1,6 @@
-#! /usr/bin/python
-# 
-# This script walks through all plugin files and 
+#!/usr/bin/env python
+#
+# This script walks through all plugin files and
 # extracts documentation that should go into the
 # reference manual
 
@@ -61,34 +61,40 @@ def process(path, target):
 	for entry in ordering:
 		extract(target, entry[1])
 
-os.chdir(os.path.dirname(__file__))
-f = open('plugins_generated.tex', 'w')
-f.write('\input{section_shapes}\n')
-process('../src/shapes', f)
-f.write('\input{section_bsdf}\n')
-process('../src/bsdfs', f)
-f.write('\input{section_textures}\n')
-process('../src/textures', f)
-f.write('\input{section_subsurface}\n')
-process('../src/subsurface', f)
-f.write('\input{section_media}\n')
-process('../src/medium', f)
-f.write('\input{section_phase}\n')
-process('../src/phase', f)
-f.write('\input{section_volumes}\n')
-process('../src/volume', f)
-f.write('\input{section_emitters}\n')
-process('../src/emitters', f)
-f.write('\input{section_sensors}\n')
-process('../src/sensors', f)
-f.write('\input{section_integrators}\n')
-process('../src/integrators', f)
-f.write('\input{section_samplers}\n')
-process('../src/samplers', f)
-f.write('\input{section_films}\n')
-process('../src/films', f)
-f.write('\input{section_rfilters}\n')
-f.close()
-os.system('bibtex main.aux')
-os.system('pdflatex main.tex')
-#os.system('pdflatex main.tex | grep -i warning | grep -v "Package \(typearea\|hyperref\)"')
+def process_src(target, src_subdir, section=None):
+	if section is None:
+		section = "section_" + src_subdir
+	target.write('\input{{{0}}}\n'.format(section))
+	process('../src/{0}'.format(src_subdir), target)
+
+def texify(texfile):
+	from subprocess import Popen, PIPE, check_call
+	version = Popen(["pdflatex", "-version"], stdout=PIPE).communicate()[0]
+	# Call decode() to convert from bytes to string, required in Python 3
+	if re.match('.*MiKTeX.*', version.decode()):
+		# MiKTeX's "texify" calls latex/bibtex in tandem automatically
+		print("Running texify on {0}...".format(texfile))
+		check_call(['texify', '-pq', texfile])
+	else:
+		check_call(['pdflatex', texfile])
+		check_call(['bibtex',   texfile.replace('.tex', '.aux')])
+		check_call(['pdflatex', texfile])
+		check_call(['pdflatex', texfile])
+
+os.chdir(os.path.dirname(os.path.abspath(__file__)))
+with open('plugins_generated.tex', 'w') as f:
+	process_src(f, 'shapes')
+	process_src(f, 'bsdfs', 'section_bsdf')
+	process_src(f, 'textures')
+	process_src(f, 'subsurface')
+	process_src(f, 'medium', 'section_media')
+	process_src(f, 'phase')
+	process_src(f, 'volume', 'section_volumes')
+	process_src(f, 'emitters')
+	process_src(f, 'sensors')
+	process_src(f, 'integrators')
+	process_src(f, 'samplers')
+	process_src(f, 'films')
+	process_src(f, 'rfilters')
+
+texify('main.tex')
diff --git a/src/libhw/glrenderer.cpp b/src/libhw/glrenderer.cpp
index 1c8c6083..cbe01eec 100644
--- a/src/libhw/glrenderer.cpp
+++ b/src/libhw/glrenderer.cpp
@@ -157,7 +157,7 @@ void GLRenderer::init(Device *device, Renderer *other) {
 		Log(m_warnLogLevel, "Capabilities: Vertex buffer objects are NOT supported!");
 	}
 
-	if (glewIsSupported("GL_EXT_geometry_shader4")) {
+	if (glewIsSupported("GL_EXT_geometry_shader4") && glewIsSupported("GL_EXT_gpu_shader4")) {
 		m_capabilities->setSupported(
 			RendererCapabilities::EGeometryShaders, true);
 		Log(m_logLevel, "Capabilities: Geometry shaders are supported.");