From 20c32dcb055058b770062b7e9dd07f79d33a8caa Mon Sep 17 00:00:00 2001
From: yum <yum.food.vr@gmail.com>
Date: Tue, 11 Feb 2025 16:54:10 -0800
Subject: Add code

Implement basic diffuse and specular BRDF based heavily on silent's
filamented shader.
---
 yum_lighting.cginc | 127 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 yum_lighting.cginc

(limited to 'yum_lighting.cginc')

diff --git a/yum_lighting.cginc b/yum_lighting.cginc
new file mode 100644
index 0000000..d62b95e
--- /dev/null
+++ b/yum_lighting.cginc
@@ -0,0 +1,127 @@
+#ifndef __YUM_LIGHTING_INC
+#define __YUM_LIGHTING_INC
+
+#include "UnityCG.cginc"
+#include "AutoLight.cginc"
+#include "UnityPBSLighting.cginc"
+
+#include "yum_pbr.cginc"
+
+struct YumLighting {
+	float3 view_dir;
+	float3 dir;
+	float3 direct;
+	float3 diffuse;
+  float3 specular;
+	float NoL;
+};
+
+float getShadowAttenuation(v2f i)
+{
+	float attenuation;
+	// This whole block is yoinked from AutoLight.cginc. I needed a way to
+	// control shadow strength so I had to duplicate the code.
+#if defined(DIRECTIONAL_COOKIE)
+	DECLARE_LIGHT_COORD(i, i.worldPos);
+	float shadow = UNITY_SHADOW_ATTENUATION(i, i.worldPos);
+	attenuation = tex2D(_LightTexture0, lightCoord).w;
+#elif defined(POINT_COOKIE)
+	DECLARE_LIGHT_COORD(i, i.worldPos);
+	float shadow = UNITY_SHADOW_ATTENUATION(i, i.worldPos);
+	attenuation = tex2D(_LightTextureB0, dot(lightCoord, lightCoord).rr).r *
+		texCUBE(_LightTexture0, lightCoord).w;
+#elif defined(DIRECTIONAL)
+	float shadow = UNITY_SHADOW_ATTENUATION(i, i.worldPos);
+	attenuation = 1;
+#elif defined(SPOT)
+	DECLARE_LIGHT_COORD(i, i.worldPos);
+	float shadow = UNITY_SHADOW_ATTENUATION(i, i.worldPos);
+	attenuation = (lightCoord.z > 0) * UnitySpotCookie(lightCoord) * UnitySpotAttenuate(lightCoord.xyz);
+#elif defined(POINT)
+	unityShadowCoord3 lightCoord = mul(unity_WorldToLight, unityShadowCoord4(i.worldPos, 1)).xyz;
+	float shadow = UNITY_SHADOW_ATTENUATION(i, i.worldPos);
+	attenuation = tex2D(_LightTexture0, dot(lightCoord, lightCoord).rr).r;
+#else
+	float shadow = 1;
+	attenuation = 1;
+#endif
+	//attenuation *= lerp(1, shadow, _Shadow_Strength);
+	return attenuation;
+}
+
+float3 getDirectLightDirection(v2f i) {
+#if defined(POINT) || defined(POINT_COOKIE) || defined(SPOT)
+	return normalize((_WorldSpaceLightPos0 - i.worldPos).xyz);
+#else
+	return _WorldSpaceLightPos0;
+#endif
+}
+
+float GetLodRoughness(float roughness) {
+	return (1.0 / UNITY_SPECCUBE_LOD_STEPS) * roughness * (1.7 - 0.7 * roughness);
+}
+
+float3 getIndirectSpecular(v2f i, YumPbr pbr, float3 view_dir) {
+  float roughness = GetLodRoughness(pbr.roughness_perceptual);
+	float3 reflect_dir = reflect(-view_dir, pbr.normal);
+
+  UnityGIInput data;
+  data.worldPos = i.worldPos;
+  data.worldViewDir = view_dir;
+  data.probeHDR[0] = unity_SpecCube0_HDR;
+  data.probeHDR[1] = unity_SpecCube1_HDR;
+#if defined(UNITY_SPECCUBE_BLENDING) || defined(UNITY_SPECCUBE_BOX_PROJECTION)
+  data.boxMin[0] = unity_SpecCube0_BoxMin; // .w holds lerp value for blending
+#endif
+#ifdef UNITY_SPECCUBE_BOX_PROJECTION
+  data.boxMax[0] = unity_SpecCube0_BoxMax;
+  data.probePosition[0] = unity_SpecCube0_ProbePosition;
+  data.boxMax[1] = unity_SpecCube1_BoxMax;
+  data.boxMin[1] = unity_SpecCube1_BoxMin;
+  data.probePosition[1] = unity_SpecCube1_ProbePosition;
+#endif
+  return UnityGI_prefilteredRadiance(data, pbr.roughness_perceptual, reflect_dir);
+}
+
+float4 getIndirectDiffuse(v2f i, float4 vertexLightColor) {
+	float4 diffuse = vertexLightColor;
+#if defined(FORWARD_BASE_PASS)
+#if defined(LIGHTMAP_ON)
+	diffuse.xyz = DecodeLightmap(UNITY_SAMPLE_TEX2D(unity_Lightmap, i.uv2));
+#else
+	diffuse.xyz += max(0, BetterSH9(float4(0, 0, 0, 1)));
+#endif
+#endif
+	return diffuse;
+}
+
+YumLighting GetYumLighting(v2f i, YumPbr pbr) {
+	YumLighting light;
+
+	light.view_dir = normalize(_WorldSpaceCameraPos - i.worldPos);
+
+#if defined(POINT) || defined(POINT_COOKIE) || defined(SPOT)
+	light.dir = normalize((_WorldSpaceLightPos0 - i.worldPos).xyz);
+#else
+	light.dir = _WorldSpaceLightPos0;
+#endif
+
+	light.direct = _LightColor0.rgb;
+	// TODO filament's spherical harmonics look nicer than this.
+	// See FilamentLightIndirect.cginc::UnityGI_Irradiance in filamented.
+  //ifex _Spherical_Harmonics==0
+	light.diffuse = max(0, BetterSH9(float4(i.normal, 1)));
+  //endex
+  //ifex _Spherical_Harmonics==1
+	light.diffuse = max(0, BetterSH9(float4(0, 0, 0, 1)));
+  //endex
+
+  light.specular = getIndirectSpecular(i, pbr, light.view_dir);
+
+	light.NoL = saturate(dot(i.normal, light.dir));
+
+	return light;
+}
+
+#endif  // __YUM_LIGHTING_INC
+
-- 
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