medfall

commit 32106351c8a51e2dc2500356b947e863a01ddcdc
parent ccb3229cbc04605c52635b8156ae60d83effb94f
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Mon Aug 28 11:36:19 +0100

Use Cook-Torrance BRDF in shadow map test

Diffstat:
shaders/common.glsl
 | 
18
++++++++++++++++++
shaders/pbr.glsl
 | 
55
+++++++++++++++++++++++++++++++++++++++++++++++++++++++
shaders/shadowed_vertex_colours.glsl
 | 
12
+++++++-----
shaders/skybox.glsl
 | 
8
--------
shadow_map.cc
 | 
2
+-
5 files changed, 81 insertions(+), 14 deletions(-)
diff --git a/shaders/common.glsl b/shaders/common.glsl
@@ -1,5 +1,23 @@
+const float PI = 3.14159265359;
+
 vec3 alu_noise( vec2 uv ) {
 	vec3 dither = vec3( dot( vec2( 171.0, 231.0 ), uv ) );
 	dither = fract( dither / vec3( 103.0, 71.0, 97.0 ) ) - vec3( 0.5, 0.5, 0.5 );
 	return ( dither / 256.0 ) * 0.5;
 }
+
+float saturate( float x ) {
+	return clamp( x, 0.0, 1.0 );
+}
+
+float unlerp( float x, float lo, float hi ) {
+	return ( x - lo ) / ( hi - lo );
+}
+
+float unlerp_sat( float x, float lo, float hi ) {
+	return saturate( unlerp( x, lo, hi ) );
+}
+
+float dot_sat( vec3 a, vec3 b ) {
+	return saturate( dot( a, b ) );
+}
diff --git a/shaders/pbr.glsl b/shaders/pbr.glsl
@@ -0,0 +1,55 @@
+float normal_distribution_ggx( vec3 N, vec3 H, float roughness ) {
+	float a = roughness * roughness;
+	float a2 = a * a;
+	float NdotH = dot_sat( N, H );
+	float NdotH2 = NdotH * NdotH;
+
+	float denom = ( NdotH2 * ( a2 - 1.0 ) + 1.0 );
+	denom = PI * denom * denom;
+
+	return a2 / denom;
+}
+
+float geometry_distribution_schlick_ggx( float NdotV, float roughness ) {
+	float r = ( roughness + 1.0 );
+	float k = ( r * r ) / 8.0;
+
+	return NdotV / ( NdotV * ( 1.0 - k ) + k );
+}
+
+float geometry_distribution_smith( vec3 N, vec3 V, vec3 L, float roughness ) {
+	float NdotV = dot_sat( N, V );
+	float NdotL = dot_sat( N, L );
+	float ggx2 = geometry_distribution_schlick_ggx( NdotV, roughness );
+	float ggx1 = geometry_distribution_schlick_ggx( NdotL, roughness );
+
+	return ggx1 * ggx2;
+}
+
+vec3 fresnel_schlick( float cos_theta, vec3 F0 ) {
+	return F0 + ( 1.0 - F0 ) * pow( 1.0 - cos_theta, 5.0 );
+}
+
+vec3 cook_torrance_brdf( vec3 to_camera, vec3 surface_position, vec3 surface_normal, vec3 light_position, vec3 light_colour, vec3 albedo, float roughness, float metalness ) {
+	vec3 L = normalize( light_position - surface_position );
+	float distance = length( light_position - surface_position );
+	float attenuation = 1.0 / ( distance * distance );
+	vec3 radiance = light_colour * attenuation;
+
+	vec3 H = normalize( to_camera + L );
+
+	vec3 F0 = vec3( 0.04 );
+	F0 = mix( F0, albedo, metalness );
+
+	float NdotL = dot_sat( surface_normal, L );
+
+	float NDF = normal_distribution_ggx( surface_normal, H, roughness );
+	float G = geometry_distribution_smith( surface_normal, to_camera, L, roughness );
+	vec3 F = fresnel_schlick( dot_sat( H, to_camera ), F0 );
+	vec3 diffuse_amount = ( vec3( 1.0 ) - F ) * ( 1.0 - metalness );
+
+	float denom = 4.0 * dot_sat( to_camera, surface_normal ) * NdotL + 0.001;
+	vec3 specular = ( NDF * G * F ) / denom;
+
+	return ( diffuse_amount * albedo / PI + specular ) * radiance * NdotL;
+}
diff --git a/shaders/shadowed_vertex_colours.glsl b/shaders/shadowed_vertex_colours.glsl
@@ -5,6 +5,7 @@ layout( std140 ) uniform model {
 layout( std140 ) uniform view {
 	mat4 V;
 	mat4 P;
+	vec3 camera_pos;
 };
 
 layout( std140 ) uniform light_view {
@@ -49,11 +50,9 @@ in VSOut v2f;
 out vec4 screen_colour;
 
 void main() {
-	vec3 light_colour = vec3( 1.0, 1.0, 1.0 );
+	vec3 light_colour = vec3( 400.0, 400.0, 400.0 );
 	vec3 lightdir = normalize( v2f.position - light_pos );
-
-	float ambient = 0.1;
-	float lambert = max( 0, dot( -lightdir, normalize( v2f.normal ) ) );
+	vec3 to_camera = normalize( camera_pos - v2f.position );
 
 	vec3 light_ndc = v2f.light_space_position.xyz / v2f.light_space_position.w;
 	vec3 light_norm = light_ndc * 0.5 + 0.5;
@@ -76,7 +75,10 @@ void main() {
 		}
 	}
 
-	screen_colour = vec4( v2f.colour * light_colour * ( ambient + ( 1 - ambient ) * ( lambert * shadow ) ), 1.0 );
+	vec3 ambient = vec3( 0.03 ) * v2f.colour;
+	vec3 Lo = cook_torrance_brdf( to_camera, v2f.position, v2f.normal, light_pos, light_colour, v2f.colour, 0.75, 0.0 );
+
+	screen_colour = vec4( ambient + Lo * shadow, 1.0 );
 }
 
 #endif
diff --git a/shaders/skybox.glsl b/shaders/skybox.glsl
@@ -23,14 +23,6 @@ layout( std140 ) uniform sun {
 	float sun_angle;
 };
 
-float saturate( float x ) {
-	return clamp( x, 0.0, 1.0 );
-}
-
-float unlerp_sat( float x, float lo, float hi ) {
-	return saturate( ( x - lo ) / ( hi - lo ) );
-}
-
 float hdot( vec3 u, vec3 v ) {
 	float d = dot( u, v ) * 0.5 + 0.5;
 	return d * d;
diff --git a/shadow_map.cc b/shadow_map.cc
@@ -132,7 +132,7 @@ GAME_FRAME( game_frame ) {
 
 	renderer_begin_frame();
 
-	renderer_ub_easy( ub_view, V, P );
+	renderer_ub_easy( ub_view, V, P, game->pos );
 
 	{
 		m4 lightVP;