From 42b516c87bc318f0d2f0b94c4f5e95692aa78b6c Mon Sep 17 00:00:00 2001
From: XProger <xproger@list.ru>
Date: Sun, 20 May 2018 16:31:09 +0300
Subject: [PATCH] fix rgba8 depth packing precision

---
 src/core.h              |  4 ++--
 src/shaders/common.hlsl | 12 ++++--------
 src/shaders/shader.glsl | 29 +++++++++++++----------------
 3 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/src/core.h b/src/core.h
index 90888d4..e14e550 100644
--- a/src/core.h
+++ b/src/core.h
@@ -12,8 +12,8 @@
 
 #ifdef WIN32
     #define _OS_WIN      1
-    //#define _GAPI_GL     1
-    #define _GAPI_D3D9   1
+    #define _GAPI_GL     1
+    //#define _GAPI_D3D9   1
     //#define _GAPI_VULKAN 1
 
     #include <windows.h>
diff --git a/src/shaders/common.hlsl b/src/shaders/common.hlsl
index 21a8eca..5793055 100644
--- a/src/shaders/common.hlsl
+++ b/src/shaders/common.hlsl
@@ -3,7 +3,7 @@
 #define WATER_FOG_DIST		(1.0 / (6.0 * 1024.0))
 #define UNDERWATER_COLOR	float3(0.6, 0.9, 0.9)
 #define SHADOW_NORMAL_BIAS	16.0
-#define SHADOW_CONST_BIAS	0.18
+#define SHADOW_CONST_BIAS	0.04
 #define PI	 				3.141592653589793
 
 static const float3 SHADOW_TEXEL = float3(1.0 / 1024.0, 1.0 / 1024.0, 0.0);
@@ -67,14 +67,10 @@ float4		uContacts[MAX_CONTACTS]	: register( c94 );
 #define OPT_CAUSTICS			uFlags[11]
 
 float4 pack(float value) {
-	float4 bitSh = float4(256.0*256.0*256.0, 256.0*256.0, 256.0, 1.0);
-	float4 bitMsk = float4(0.0, 1.0/256.0, 1.0/256.0, 1.0/256.0);
-	float4 res = frac(value * bitSh);
-	res -= res.xxyz * bitMsk;
-	return res;
+	float4 v = frac(value * float4(1.0, 255.0, 65025.0, 16581375.0));
+	return v - v.yzww * float4(1.0/255.0, 1.0/255.0, 1.0/255.0, 0.0);
 }
 
 float unpack(float4 value) {
-	float4 bitSh = float4(1.0/(256.0*256.0*256.0), 1.0/(256.0*256.0), 1.0/256.0, 1.0);
-	return dot(value, bitSh);
+	return dot(value, float4(1.0, 1/255.0, 1/65025.0, 1/16581375.0));
 }
\ No newline at end of file
diff --git a/src/shaders/shader.glsl b/src/shaders/shader.glsl
index 91ff2c2..a04946a 100644
--- a/src/shaders/shader.glsl
+++ b/src/shaders/shader.glsl
@@ -9,6 +9,9 @@ R"====(
 #define WATER_FOG_DIST		(1.0 / (6.0 * 1024.0))
 #define UNDERWATER_COLOR	vec3(0.6, 0.9, 0.9)
 
+#define SHADOW_NORMAL_BIAS	16.0
+#define SHADOW_CONST_BIAS	0.04
+
 #if (defined(PASS_AMBIENT) || defined(PASS_COMPOSE)) && !defined(TYPE_FLASH)
 	varying vec3 vCoord;
 #endif
@@ -250,15 +253,14 @@ uniform vec4 uFogParams;
 		uniform samplerCube sEnvironment;
 	#endif
 
-	#if defined(PASS_SHADOW) && defined(SHADOW_COLOR)
-		vec4 pack(in float value) {
-			vec4 bitSh = vec4(256.0*256.0*256.0, 256.0*256.0, 256.0, 1.0);
-			vec4 bitMsk = vec4(0.0, 1.0/256.0, 1.0/256.0, 1.0/256.0);
-			vec4 res = fract(value * bitSh);
-			res -= res.xxyz * bitMsk;
-			return res;
-		}
-	#endif
+	vec4 pack(in float value) {
+		float v = fract(value * vec4(1.0, 255.0, 65025.0, 16581375.0));
+		return v - v.yzww * vec4(1.0/255.0, 1.0/255.0, 1.0/255.0, 0.0);
+	}
+
+	float unpack(vec4 value) {
+		return dot(value, vec4(1.0, 1/255.0, 1/65025.0, 1/16581375.0));
+	}
 
 	#ifdef OPT_SHADOW
 		#ifdef SHADOW_SAMPLER
@@ -271,11 +273,6 @@ uniform vec4 uFogParams;
 		#else
 			uniform sampler2D sShadow;
 
-			float unpack(vec4 value) {
-				vec4 bitSh = vec4(1.0/(256.0*256.0*256.0), 1.0/(256.0*256.0), 1.0/256.0, 1.0);
-				return dot(value, bitSh);
-			}
-
 			float SHADOW(vec2 p) {
 				#ifdef SHADOW_DEPTH
 					return texture2D(sShadow, p).x;
@@ -288,7 +285,7 @@ uniform vec4 uFogParams;
 		float getShadow(vec3 lightVec, vec3 normal, vec4 lightProj) {
 			vec3 p = lightProj.xyz / lightProj.w;
 			p.xyz = p.xyz * 0.5 + 0.5;
-			p.z -= 0.04 * SHADOW_TEXEL.x;
+			p.z -= SHADOW_CONST_BIAS * SHADOW_TEXEL.x;
 
 			float vis = lightProj.w;
 			#ifdef TYPE_ROOM
@@ -317,7 +314,7 @@ uniform vec4 uFogParams;
 
 		float getShadow(vec3 lightVec, vec3 normal) {
 			float factor = clamp(1.0 - dot(normalize(lightVec), normal), 0.0, 1.0);
-			factor *= 16.0;
+			factor *= SHADOW_NORMAL_BIAS;
 			return getShadow(lightVec, normal, uLightProj * vec4(vCoord + normal * factor, 1.0));
 		}
 	#endif