From 473c6be2e3b19205fb8dd6dc6764a2aee2cb7c64 Mon Sep 17 00:00:00 2001
From: Jay Robson <jsrobson10@gmail.com>
Date: Sat, 24 Feb 2024 20:36:27 +1100
Subject: [PATCH] shader optimisations

---
 assets/scene.blend     |  4 ++--
 assets/shader/main.fsh | 36 ++++++++++--------------------------
 2 files changed, 12 insertions(+), 28 deletions(-)

diff --git a/assets/scene.blend b/assets/scene.blend
index 6c0b67d..adb4d3d 100644
--- a/assets/scene.blend
+++ b/assets/scene.blend
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:aac24055bb22a36ac073e572d7d668d97b6ea9bfe4e08e912f4f021f57efcc20
-size 12241421
+oid sha256:1e02c14af3ac4cef4a7e844810cee21e78e71e487c89d80de6eeca41cf50f6c7
+size 12241645
diff --git a/assets/shader/main.fsh b/assets/shader/main.fsh
index 4992239..8d5b4c0 100644
--- a/assets/shader/main.fsh
+++ b/assets/shader/main.fsh
@@ -75,38 +75,22 @@ float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
     return ggx1 * ggx2;
 }
 
-float LinRGB_To_sRGB(float c)
-{
-	if (c < 0.0031308f) {
-		return (c < 0.0f) ? 0.0f : c * 12.92f;
-	}
-
-	return 1.055f * pow(c, 1.0f / 2.4f) - 0.055f;
-}
-
 vec3 LinRGB_To_sRGB(vec3 c)
 {
-	c.r = LinRGB_To_sRGB(c.r);
-	c.g = LinRGB_To_sRGB(c.g);
-	c.b = LinRGB_To_sRGB(c.b);
-	return c;
-}
+	bvec3 th = lessThan(c, vec3(0.0031308f));
+	vec3 high = pow(c, vec3(1.0f / 2.4f)) * vec3(1.055f) - vec3(0.055f);
+	vec3 low = c * vec3(12.92f);
 
-float sRGB_To_LinRGB(float c)
-{
-	if (c < 0.04045f) {
-		return (c < 0.0f) ? 0.0f : c * (1.0f / 12.92f);
-	}
-
-	return pow((c + 0.055f) * (1.0f / 1.055f), 2.4f);
+	return mix(high, low, th);
 }
 
 vec3 sRGB_To_LinRGB(vec3 c)
 {
-	c.r = sRGB_To_LinRGB(c.r);
-	c.g = sRGB_To_LinRGB(c.g);
-	c.b = sRGB_To_LinRGB(c.b);
-	return c;
+	bvec3 th = lessThan(c, vec3(0.04045f));
+	vec3 high = pow((c + vec3(0.055f)) * vec3(1.0f / 1.055f), vec3(2.4f));
+	vec3 low = c * vec3(1.0f / 12.92f);
+
+	return mix(high, low, th);
 }
 
 void main()
@@ -157,7 +141,7 @@ void main()
 	vec3 ambient = vec3(0.03f) * albedo_lin * brightness;
 	vec3 light = LinRGB_To_sRGB(ambient + Lo);
 
-	light = light * (1 - luminance) + albedo.rgb * luminance;
+	light = mix(light, albedo.rgb, luminance);
 	frag_colour = vec4(light, albedo.a);
 
 	if(frag_colour.a == 0.f) discard;