medfall

commit 3fab8fc96fd345f76ceecd678ee85f9393fe29a4
parent c83bfce1a14a562c54f7f9a9cb7eb64176861288
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Wed Nov 30 20:37:35 +0200

Copy the terrain shader to btt.so

Diffstat:
mod_btt.cc
 | 
41
+++++++++++++++++++++++++++--------------
1 file changed, 27 insertions(+), 14 deletions(-)
diff --git a/mod_btt.cc b/mod_btt.cc
@@ -46,27 +46,40 @@ static const char * frag_src = GLSL(
 
 	void main() {
 		vec3 normal = normalize( texture( normals, smooth_position.xy / dimensions ).xyz );
+		float horizon = texture( horizons, smooth_position.xy / dimensions ).r;
 
+		// ground colour
 		vec3 ground;
-		if( normal.z > 0.9 ) {
-			ground = vec3( 0.4, 1.0, 0.4 );
+		if( smooth_position.z > 175 ) {
+			// snow/rocks
+			if( normal.z > 0.5 ) {
+				ground = vec3( 0.8, 0.8, 0.8 );
+			}
+			else {
+				ground = vec3( 0.6, 0.6, 0.6 );
+			}
+		}
+		else if( smooth_position.z < 5 ) {
+			ground = vec3( 0.0, 0.25, 1.0 );
 		}
 		else {
-			ground = vec3( 0.7, 0.7, 0.5 );
+			if( normal.z > 0.8 ) {
+				ground = vec3( 0.4, 1.0, 0.4 );
+			}
+			else {
+				ground = vec3( 0.7, 0.7, 0.5 );
+			}
 		}
 
-		vec3 sunv = normalize( vec3( 1, 1, -sun ) );
-		float horizon = texture( horizons, smooth_position.xy / dimensions ).r;
-		float l = sun > horizon ? 1.0 : 0.0;
-
-		float d = max( 0, -dot( normal, sunv ) );
-		float light = max( 0.2, l * d );
-
-		vec3 fog = vec3( 0.6, 0.6, 0.6 );
-
-		float t = smoothstep( 400, 600, depth );
+		// sunlight + sky ambient lighting
+		// TODO: use formula for area of a chord?
+		float sun_visible_fraction = smoothstep( 0, 0.2, sun - horizon );
+		vec3 sun_direction = normalize( vec3( -1, 0, sun ) );
+		float sunlight_lambert = max( 0, dot( normal, sun_direction ) );
+		vec3 sunlight = sun_visible_fraction * sunlight_lambert * vec3( 0.9, 0.9, 0.5 );
+		vec3 ambient = vec3( 0.02, 0.02, 0.15 );
 
-		colour = vec4( ( 1.0 - t ) * ground * light + t * fog, 1.0 );
+		colour = vec4( ( sunlight + ambient ) * ground, 1.0 );
 	}
 );