medfall

commit d5bdd4f1f1f17df87f8d694e1b5d8f16b25035b2
parent ee467f003cf4bb64c6e2eb619ec875b507f08cfb
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Wed,  1 Nov 2017 23:04:51 +0200

Sample normal/horizonmaps in the vertex shader. Fixes blockiness at the sides of the screen with high FOV

Diffstat:
shaders/clipmap.glsl
 | 
26
++++++++++++--------------

1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/shaders/clipmap.glsl b/shaders/clipmap.glsl
@@ -16,8 +16,7 @@ layout( std140 ) uniform clipmap {
 
 struct VSOut {
 	vec3 pos;
-	vec3 normal;
-	float horizon;
+	vec2 uv;
 };
 
 uniform sampler2D heightmap;
@@ -35,15 +34,8 @@ void main() {
 	vec2 uv = floor( xy / scale ) * scale / textureSize( heightmap, 0 ) + 0.5;
 	float z = 255.0 * texture( heightmap, uv ).r + texture( heightmap, uv ).g;
 
-	vec2 normal_xy = texture( normalmap, uv ).xy * 2.0 - 1.0;
-	float normal_z = sqrt( 1.0 - normal_xy.x * normal_xy.x - normal_xy.y * normal_xy.y );
-	vec3 normal = vec3( normal_xy.x, normal_xy.y, normal_z );
-
-	float horizon_angle = texture( horizonmap, uv ).r;
-
 	v2f.pos = vec3( xy, z );
-	v2f.normal = normal;
-	v2f.horizon = horizon_angle;
+	v2f.uv = uv;
 	gl_Position = P * V * vec4( floor( xy ), z, 1.0 );
 }
 
@@ -53,11 +45,17 @@ in VSOut v2f;
 out vec4 screen_colour;
 
 void main() {
+	vec2 normal_xy = texture( normalmap, v2f.uv ).xy * 2.0 - 1.0;
+	float normal_z = sqrt( 1.0 - normal_xy.x * normal_xy.x - normal_xy.y * normal_xy.y );
+	vec3 normal = vec3( normal_xy.x, normal_xy.y, normal_z );
+
+	float horizon = texture( horizonmap, v2f.uv ).r;
+
 	// ground colour
 	vec3 ground;
 	if( v2f.pos.z > 175 ) {
 		// snow/rocks
-		if( v2f.normal.z > 0.5 ) {
+		if( normal.z > 0.5 ) {
 			ground = vec3( 0.8, 0.8, 0.8 );
 		}
 		else {
@@ -68,7 +66,7 @@ void main() {
 		ground = vec3( 0.0, 0.25, 1.0 );
 	}
 	else {
-		if( v2f.normal.z > 0.8 ) {
+		if( normal.z > 0.8 ) {
 			ground = vec3( 0.4, 1.0, 0.4 );
 		}
 		else {
@@ -78,8 +76,8 @@ void main() {
 
 	// sunlight + sky ambient lighting
 	// area of a chord is somewhat similar to smoothstep
-	float sun_visible_fraction = smoothstep( -0.2, 0.2, sun_angle - v2f.horizon );
-	float sunlight_lambert = max( 0, dot( v2f.normal, sun_dir ) );
+	float sun_visible_fraction = smoothstep( -0.2, 0.2, sun_angle - horizon );
+	float sunlight_lambert = max( 0, dot( normal, sun_dir ) );
 	vec3 sunlight = sun_visible_fraction * sunlight_lambert * vec3( 0.9, 0.9, 0.5 );
 	vec3 ambient = vec3( 0.05, 0.05, 0.15 );