//	glsl fragment shader
				static const char *cubic_fragmentshaderGL2D = "\
					uniform sampler2D texUnit0;	\
					uniform sampler2D texUnit1;	\
					uniform sampler2D texUnit2;	\
					uniform sampler2D texUnit3;	\
					uniform vec4	weights;\
					uniform float	newalpha;\
					void main(void)\
					{\
						vec4 c0 = texture2D( texUnit0, gl_TexCoord[0].st );\
						vec4 c1 = texture2D( texUnit1, gl_TexCoord[0].st );\
						vec4 c2 = texture2D( texUnit2, gl_TexCoord[0].st );\
						vec4 c3 = texture2D( texUnit3, gl_TexCoord[0].st );\
						gl_FragColor = ( c0 * weights.x ) + ( c1 * weights.y ) + ( c2 * weights.z ) + ( c3 * weights.w ); \
						gl_FragColor.a = newalpha;\
					}";