From 4fcfb2690a9757c02a3f7b618548e5bf9800db1d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dominik=20Madar=C3=A1sz?= <zaklaus@outlook.com>
Date: Wed, 20 Mar 2024 22:49:11 +0100
Subject: [PATCH] improve pbr analytical lights

---
 demos/06-material.c                   |  6 ++++--
 engine/art/shaders/fs_32_4_model.glsl | 20 ++++++--------------
 2 files changed, 10 insertions(+), 16 deletions(-)

diff --git a/demos/06-material.c b/demos/06-material.c
index aa1b22d..19af976 100644
--- a/demos/06-material.c
+++ b/demos/06-material.c
@@ -7,15 +7,15 @@
 
 
 const char *skyboxes[][2] = { // reflection, env, metadata
-    {"hdr/mesto.hdr","hdr/mesto_Env.hdr"},
+    {"hdr/Tokyo_BigSight_1k.hdr","hdr/Tokyo_BigSight_Env.hdr"},
     {"hdr/graffiti_shelter_4k.hdr","hdr/graffiti_shelter_Env.hdr"},
     {"hdr/music_hall_01_4k.hdr","hdr/music_hall_01_Env.hdr"},
     {"hdr/the_sky_is_on_fire_2k.hdr","hdr/the_sky_is_on_fire_Env.hdr"},
-    {"hdr/Tokyo_BigSight_1k.hdr","hdr/Tokyo_BigSight_Env.hdr"},
     {"hdr/GCanyon_C_YumaPoint_1k.hdr","hdr/GCanyon_C_YumaPoint_Env.hdr"},
     {"hdr/Factory_Catwalk_1k.hdr","hdr/Factory_Catwalk_Env.hdr"},
     {"hdr/MonValley_G_DirtRoad_1k.hdr","hdr/MonValley_G_DirtRoad_Env.hdr"},
     {"hdr/Shiodome_Stairs_1k.hdr","hdr/Shiodome_Stairs_Env.hdr"},
+    {"hdr/mesto.hdr","hdr/mesto_Env.hdr"},
 };
 
 int main() {
@@ -73,8 +73,10 @@ int main() {
     object_pivot(obj4, vec3(0,0,90));
 
     // create point light
+    scene_spawn_light(); // sun
     light_t* l = scene_spawn_light();
     light_type(l, LIGHT_POINT);
+    l->diffuse = vec3(1,0,0);
 
     // load skybox
     scene_get_active()->skybox = skybox_pbr(skyboxes[0][0], skyboxes[0][0], skyboxes[0][1]);
diff --git a/engine/art/shaders/fs_32_4_model.glsl b/engine/art/shaders/fs_32_4_model.glsl
index f0ddf70..f2f1604 100644
--- a/engine/art/shaders/fs_32_4_model.glsl
+++ b/engine/art/shaders/fs_32_4_model.glsl
@@ -535,6 +535,7 @@ void main(void)
     F0 = mix( F0, baseColor, metallic );
 
     bool use_ibl = has_tex_skysphere;
+    // use_ibl = false;
 
     // Add contributions from analytic lights.
 
@@ -569,21 +570,12 @@ void main(void)
                 continue;
             }
 
-            // vec3 n = normalize(v_normal_ws);
-
-            // float diffuse = max(dot(n, lightDir), 0.0);
-
-            // vec3 halfVec = normalize(lightDir + u_cam_dir);
-            // float specular = pow(max(dot(n, halfVec), 0.0), l.power);
-
-            // return (attenuation*l.ambient + diffuse*attenuation*l.diffuse + specular*attenuation*l.specular);
-
-            vec3 radiance = l.diffuse;
+            vec3 radiance = l.diffuse * BOOST_LIGHTING;
 
             vec3 L = normalize( lightDir );
-            vec3 H = normalize( u_cam_dir + L );
+            vec3 H = normalize( V + L );
 
-            vec3 F = fresnel_schlick( H, u_cam_dir, F0 );
+            vec3 F = fresnel_schlick( H, V, F0 );
             vec3 kS = F;
             vec3 kD = vec3(1.0) - kS;
             kD *= 1.0 - metallic;
@@ -592,10 +584,10 @@ void main(void)
             kD *= alpha;
 
             float D = distribution_ggx( N, H, roughness );
-            float G = geometry_smith( N, u_cam_dir, L, roughness );
+            float G = geometry_smith( N, V, L, roughness );
 
             vec3 num = D * F * G;
-            float denom = 4. * max( 0., dot( N, u_cam_dir ) ) * max( 0., dot( N, L ) );
+            float denom = 4. * max( 0., dot( N, V ) ) * max( 0., dot( N, L ) );
 
             vec3 specular = kS * (num / max( 0.001, denom ));