Ensure that the alpha channel of our pixels is clamped within 0.0 to 1.0 in the default shader. It seems that some drivers fail at that, so we do it for them.

Resources/Shaders/oolite-default-shader.fragment

@@ -414,6 +414,9 @@ void main(void)
 	totalColor += specularLight * gl_LightSource[1].specular;
 #endif
 
+	// apparently some drivers fail to clamp alpha properly, so let's do it for them
+	totalColor.a = clamp(totalColor.a, 0.0, 1.0);
+
 	// gamma correction
 	// using Jim Hejl's filmic tonemapping and gamma correction approximation. 
 	// Normally this would require HDR, but I think it works extremely well in Oolite.