Fog

TODO

@@ -1,5 +1,4 @@
 Rendering:
-* "Fog"
 * Improved light sources
 * Secondary rays
 * Shadows

raymarcher.cc

@@ -50,6 +50,7 @@ void T_Raymarcher::render( )
 		U_NEAR_PLANE		= 5 ,
 		U_LIGHT_DIR		= 6 ,
 		U_RAYMARCHER		= 7 ,
+		U_FOG			= 8 ,
 	};
 
 	const auto id( program_.program( E_ShaderType::FRAGMENT ) );
@@ -66,6 +67,8 @@ void T_Raymarcher::render( )
 	glProgramUniform4f( id , U_RAYMARCHER , rmIterations , rmStep ,
 			rmEpsilon , rmMaxDist );
 
+	glProgramUniform1f( id , U_FOG , fog );
+
 	glDrawArrays( GL_TRIANGLE_STRIP , 0 , 4 );
 
 	PEND( );
@@ -75,16 +78,15 @@ void T_Raymarcher::makeUI( )
 {
 	camera_.makeUI( );
 
-	if ( !ImGui::CollapsingHeader( "Raymarcher" ) ) {
-		return;
-	}
-
-	ImGui::DragInt( "Iterations" , &rmIterations , .1 , 1 , 512 );
-	ImGui::DragFloat( "Step" , &rmStep , .005 , .1 , 2 );
-	ImGui::DragFloat( "Max. dist." , &rmMaxDist , .1f ,
-			0.01 , 1000.0 , "%.2f" );
-	if ( ImGui::DragFloat( "Epsilon" , &epsLog , .01f ,
-			-10 , -0.5 , "10 ^ %.2f" ) ) {
-		rmEpsilon = pow( 10 , epsLog );
+	if ( ImGui::CollapsingHeader( "Raymarcher" ) ) {
+		ImGui::DragInt( "Iterations" , &rmIterations , .01 , 1 , 512 );
+		ImGui::DragFloat( "Step" , &rmStep , .00005 , .1 , 2 );
+		ImGui::DragFloat( "Max. dist." , &rmMaxDist , .1f ,
+				0.01 , 1000.0 , "%.2f" );
+		if ( ImGui::DragFloat( "Epsilon" , &epsLog , .01f ,
+				-10 , -0.5 , "10 ^ %.2f" ) ) {
+			rmEpsilon = pow( 10 , epsLog );
+		}
+		ImGui::DragFloat( "Fog" , &fog , .000001 , 0 , 1 , "%.5f" );
 	}
 }

raymarcher.hh

@@ -37,5 +37,6 @@ struct T_Raymarcher
 	float rmStep = 1.2;
 	float rmEpsilon = .001;
 	float rmMaxDist = 250;
+	float fog = .00015;
 	float epsLog = log( rmEpsilon ) / log( 10 );
 };

shaders/chunks/raymarcher.glsl

@@ -8,6 +8,7 @@ layout( location = 4 ) uniform vec3 u_CamUp;
 layout( location = 5 ) uniform float u_NearPlane;
 layout( location = 6 ) uniform vec3 u_LightDir;
 layout( location = 7 ) uniform vec4 u_Render;
+layout( location = 8 ) uniform float u_FogAttenuation;
 
 layout( location = 0 ) out vec3 o_Color;
 layout( location = 1 ) out float o_Z;

shaders/lib/fog.glsl

@@ -0,0 +1,10 @@
+//! type library
+
+vec3 FOG_Apply(
+	in vec3 color ,
+	in float dist ,
+	in float attenuation ,
+	in vec3 background )
+{
+	return mix( background , color , exp( - dist * dist * attenuation ) );
+}

shaders/scene.f.glsl

@@ -4,6 +4,7 @@
 //! include chunks/raymarcher.glsl
 //! include lib/shading-pbr.glsl
 //! include lib/shading-blinnphong.glsl
+//! include lib/fog.glsl
 
 
 T_BPMaterial BPMaterials[1] = {
@@ -64,8 +65,9 @@ void main( )
 			int( u_Render.x ) , u_Render.y ,
 			u_Render.z , .001 , u_Render.w );
 	vec3 hitPos = u_CamPos + rayDir * r.x;
+	const vec3 background = vec3( .01 );
 
-	vec3 bc = vec3( 0 );
+	vec3 bc = background;
 	if ( r.y >= 0. ) {
 		const int midx = int( r.y );
 		const vec3 normal = RM_GetNormal( hitPos );
@@ -85,6 +87,7 @@ void main( )
 		if ( glowidx >= 0 ) {
 			bc += Glow[ glowidx ];
 		}
+		bc = FOG_Apply( bc , r.x , u_FogAttenuation , background );
 	}
 
 	o_Color = bc;