Make shader lighting attenuation agree with fixed function version

git-svn-id: svn://cook.msm.cam.ac.uk:745/thrust3d/thrust3d@63 84d2e878-0bd5-11dd-ad15-13eda11d74c5

1 files changed, 3 insertions, 1 deletions

diff --git a/data/shaders/lighting.frag b/data/shaders/lighting.frag
index 4947e98..e7a5b3b 100644
--- a/data/shaders/lighting.frag
+++ b/data/shaders/lighting.frag
@@ -41,7 +41,9 @@ void main() {
 	emit = col_emit;
 	
 	/* Spotlight (light 0) - positional, spotlight */
-	float falloff = 1 - length(light0vc) * gl_LightSource[0].linearAttenuation;
+	float falloff = 1/ (  gl_LightSource[0].constantAttenuation
+	                    + gl_LightSource[0].linearAttenuation * length(light0vc)
+	                    + gl_LightSource[0].quadraticAttenuation * pow(length(light0vc), 2.0) );
 	float spot = max(dot(normalize(-light0vc), gl_LightSource[0].spotDirection), 0.0);
 	spot = pow(spot, gl_LightSource[0].spotExponent);
 	diff += col_ambi_diff * gl_LightSource[0].diffuse.rgb * spot * falloff * max(dot(normalize(light0vc).xyz, norm), 0.0);