diff --git a/src/modules/graphics/opengl/PixelEffect.cpp b/src/modules/graphics/opengl/PixelEffect.cpp
index 8e570fb27..9accd90ed 100644
--- a/src/modules/graphics/opengl/PixelEffect.cpp
+++ b/src/modules/graphics/opengl/PixelEffect.cpp
@@ -51,9 +51,7 @@ namespace opengl
 
 PixelEffect *PixelEffect::current = NULL;
 
-std::map<std::string, GLint> PixelEffect::_texture_unit_pool;
-GLint PixelEffect::_current_texture_unit = 0;
-GLint PixelEffect::_max_texture_units = 0;
+std::vector<bool> PixelEffect::_unit_available;
 
 GLint PixelEffect::getTextureUnit(const std::string &name)
 {
@@ -62,18 +60,35 @@ GLint PixelEffect::getTextureUnit(const std::string &name)
 	if (it != _texture_unit_pool.end())
 		return it->second;
 
-	if (++_current_texture_unit >= _max_texture_units)
+	GLint unit = -1;
+	for (int i = 1; i < _unit_available.size(); ++i)
+	{
+		if (_unit_available[i])
+		{
+			unit = i;
+			break;
+		}
+	}
+
+	if (unit == -1)
 		throw love::Exception("No more texture units available");
 
-	_texture_unit_pool[name] = _current_texture_unit;
-	return _current_texture_unit;
+	_unit_available[unit] = false;
+	_texture_unit_pool[name] = unit;
+	return unit;
 }
 
 PixelEffect::PixelEffect(const std::string &code)
 	: _program(0)
 	, _code(code)
 {
-	glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &_max_texture_units);
+	if (_unit_available.empty())
+	{
+		GLint max_units;
+		glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &max_units);
+		_unit_available.resize(max_units, true);
+		_unit_available[0] = false;
+	}
 	loadVolatile();
 }
 
diff --git a/src/modules/graphics/opengl/PixelEffect.h b/src/modules/graphics/opengl/PixelEffect.h
index e1818e735..b0d7fc704 100644
--- a/src/modules/graphics/opengl/PixelEffect.h
+++ b/src/modules/graphics/opengl/PixelEffect.h
@@ -24,6 +24,7 @@
 #include "common/Object.h"
 #include <string>
 #include <map>
+#include <vector>
 #include "OpenGL.h"
 #include "Image.h"
 #include "Canvas.h"
@@ -67,10 +68,9 @@ private:
 	std::map<std::string, GLint> _uniforms;
 
 	// texture unit pool for setting images
-	static std::map<std::string, GLint> _texture_unit_pool;
-	static GLint _current_texture_unit;
-	static GLint _max_texture_units;
-	static GLint getTextureUnit(const std::string &name);
+	std::map<std::string, GLint> _texture_unit_pool;
+	GLint getTextureUnit(const std::string &name);
+	static std::vector<bool> _unit_available;
 };
 
 } // opengl