From d76ccd41f73cfed9df9eb451fd9e8ac81aa0b40e Mon Sep 17 00:00:00 2001
From: Serge Bazanski <q3k@q3k.org>
Date: Thu, 8 Apr 2021 15:32:23 +0000
Subject: [PATCH] engine: fix normals, rework lighting and scene

Still not sure if this lighting is correct, for that we probably want a
more complex scene (and also some indirect lighting, or IBL, to see more
than just a handful of dynamic lights).
---
 engine/scene.lua            |  3 ++-
 engine/shaders/forward.frag |  4 +---
 engine/shaders/forward.vert |  3 +--
 engine/src/main.rs          | 43 ++++++++++++-------------------------
 engine/src/render/light.rs  |  2 +-
 5 files changed, 19 insertions(+), 36 deletions(-)

diff --git a/engine/scene.lua b/engine/scene.lua
index 4cfd604..9751b23 100644
--- a/engine/scene.lua
+++ b/engine/scene.lua
@@ -23,7 +23,8 @@ sent.register({
 for x=-2,2 do
     for y=-2,2 do
         for z=-2,2 do
-            if z > -2 and z < 2 and x > -2 and x < 2 then
+            --if z > -2 and z < 2 and x > -2 and x < 2 and y > 0 then
+            if x <= 0 and y <= 0 and z <= 0 then
             else
                 Cube.new(x, y, z)
             end
diff --git a/engine/shaders/forward.frag b/engine/shaders/forward.frag
index e2fc158..0ee1159 100644
--- a/engine/shaders/forward.frag
+++ b/engine/shaders/forward.frag
@@ -75,9 +75,7 @@ void main() {
     F0 = mix(F0, albedo, metallic);
 
     vec3 Lo = BRDFIlluminance(N, V, F0, albedo, dielectric, roughness);
-    // Add 500 nits ambient light.
-    vec3 ambient = vec3(500.00) * albedo;
-    vec3 color = XYZ_TO_SRGB * ((ambient + Lo) * CAMERA_EXPOSURE);
+    vec3 color = XYZ_TO_SRGB * (Lo * CAMERA_EXPOSURE);
 
     outColor = vec4(GammaCorrect(color.x), GammaCorrect(color.y), GammaCorrect(color.z), 1.0);
 }
diff --git a/engine/shaders/forward.vert b/engine/shaders/forward.vert
index bb38cc7..13bdb7e 100644
--- a/engine/shaders/forward.vert
+++ b/engine/shaders/forward.vert
@@ -39,10 +39,9 @@ out gl_PerVertex {
 
 void main() {
     vec4 world = model * vec4(pos, 1.0);
-    vec4 normal4 = model * vec4(normal, 1.0);
 
     fragTexCoord = tex;
-    fragNormal = normal4.xyz / normal4.w;
+    fragNormal = mat3(model) * normal;
     fragWorldPos = world.xyz / world.w;
 
     gl_Position = pco.view * world;
diff --git a/engine/src/main.rs b/engine/src/main.rs
index a9145f5..c6840e1 100644
--- a/engine/src/main.rs
+++ b/engine/src/main.rs
@@ -51,7 +51,7 @@ impl Time {
 
 struct Main {
     light1: ecs::EntityID,
-    light2: ecs::EntityID,
+    cube1: ecs::EntityID,
 
     cx: f32,
     cy: f32,
@@ -112,17 +112,6 @@ impl Main {
             roughness: Texture::from_image(String::from("//assets/test-128px-roughness.png")),
         }.build(), Some("test-128px"));
 
-        for x in -20..20 {
-            for y in -20..20 {
-                for z in -20..-10 {
-                    world.new_entity()
-                        .with(Transform::at((x as f32)*4.0, (y as f32)*4.0, (z as f32)*4.0))
-                        .with(Renderable::Mesh(mesh, material))
-                        .build();
-                }
-            }
-        }
-
         let light = rm.add(Light::omni_test(), Some("omni"));
 
         // The Sun (Sol) is 1AU from the Earth. We ignore the diameter of the Sun and the Earth, as
@@ -145,9 +134,9 @@ impl Main {
             .with(Transform::at(-10.0, -10.0, -5.0))
             .with(Renderable::Light(light))
             .build();
-        let light2 = world.new_entity()
+        let cube1 = world.new_entity()
             .with(Transform::at(-10.0, -10.0, -5.0))
-            .with(Renderable::Light(light))
+            .with(Renderable::Mesh(mesh, material))
             .build();
         world.new_entity()
             .with(Transform::at(0.0, sun_angle.sin() * sun_distance, sun_angle.cos() * sun_distance))
@@ -157,7 +146,7 @@ impl Main {
         world.set_global(rm);
 
         Self {
-            light1, light2,
+            light1, cube1,
             cx: 0.,
             cy: 0.,
         }
@@ -185,9 +174,9 @@ impl<'a> ecs::System <'a> for Main {
         self.cy += (dy);
 
         let camera = cgm::Point3::new(
-            self.cx.sin() * 10.0,
-            (self.cx.cos()*self.cy.cos()) * 10.0,
-            self.cy.sin() * 10.0,
+            self.cx.sin() * 20.0,
+            (self.cx.cos()*self.cy.cos()) * 20.0,
+            self.cy.sin() * 20.0,
         );
 
         let view = cgm::Matrix4::look_at(
@@ -200,18 +189,14 @@ impl<'a> ecs::System <'a> for Main {
         sd.scene_info.get().view = view;
         sd.scene_info.get().lock_cursor = true;
 
-        *sd.transforms.get_mut(self.light1).unwrap() = Transform::at(
-            -0.0 + (ts*3.0).sin() * 4.0,
-            -0.0 + (ts*4.0).cos() * 4.0,
-            -0.0 + (ts*2.0).sin() * 3.0,
-        );
-
-        *sd.transforms.get_mut(self.light2).unwrap() = Transform::at(
-            -0.0 + (ts*3.0).cos() * 4.0,
-            -0.0 + (ts*4.0).sin() * 4.0,
-            -0.0 + (ts*2.0).cos() * 3.0,
-        );
+        let lx = 0.0;
+        let ly = 4.0;
+        let lz = -0.0 + (ts*2.0).sin() * 4.0;
 
+        *sd.transforms.get_mut(self.light1).unwrap() = Transform::at(lx, ly, lz);
+        let mut ctransform = Transform::at(lx, ly, lz);
+        ctransform.0 = ctransform.0 * cgmath::Matrix4::from_scale(0.1);
+        *sd.transforms.get_mut(self.cube1).unwrap() = ctransform;
     }
 }
 
diff --git a/engine/src/render/light.rs b/engine/src/render/light.rs
index 85c91d7..1e66a14 100644
--- a/engine/src/render/light.rs
+++ b/engine/src/render/light.rs
@@ -40,7 +40,7 @@ impl Omni {
     // M. Krystek. 1985. "An algorithm to calculate correlated color temperature"
     // Color Research & Application, 10 (1), 38–40.
     pub fn test() -> Self {
-        Self::with_color(color::XYZ::new(234.7*100.0, 214.1*100.0, 207.9*100.0))
+        Self::with_color(color::XYZ::new(234.7*200.0, 214.1*200.0, 207.9*200.0))
     }
 
     pub fn with_color(color: color::XYZ) -> Self{