Adjust shadowmap distortion to use entire SM texture (#12166)

4 files changed, 83 insertions, 51 deletions

diff --git a/client/shaders/nodes_shader/opengl_fragment.glsl b/client/shaders/nodes_shader/opengl_fragment.glsl
index 3dc66bdb3..4d0d107d1 100644
--- a/client/shaders/nodes_shader/opengl_fragment.glsl
+++ b/client/shaders/nodes_shader/opengl_fragment.glsl
@@ -17,6 +17,7 @@ uniform float animationTimer;
 	uniform mat4 m_ShadowViewProj;
 	uniform float f_shadowfar;
 	uniform float f_shadow_strength;
+	uniform vec4 CameraPos;
 	varying float normalOffsetScale;
 	varying float adj_shadow_strength;
 	varying float cosLight;
@@ -53,12 +54,13 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
-
-	float pDistance = length(shadowPosition.xy);
+	vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+	vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+	float pDistance = length(l);
 	float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
-
-	shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+	l /= pFactor;
+	shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+	shadowPosition.z *= zPerspectiveBias;
 	return shadowPosition;
 }
 
@@ -171,13 +173,13 @@ float getHardShadowDepth(sampler2D shadowsampler, vec2 smTexCoord, float realDis
 
 float getBaseLength(vec2 smTexCoord)
 {
-	float l = length(2.0 * smTexCoord.xy - 1.0);     // length in texture coords
+	float l = length(2.0 * smTexCoord.xy - 1.0 - CameraPos.xy);     // length in texture coords
 	return xyPerspectiveBias1 / (1.0 / l - xyPerspectiveBias0); 				 // return to undistorted coords
 }
 
 float getDeltaPerspectiveFactor(float l)
 {
-	return 0.1 / (xyPerspectiveBias0 * l + xyPerspectiveBias1);                      // original distortion factor, divided by 10
+	return 0.04 * pow(512.0 / f_textureresolution, 0.4) / (xyPerspectiveBias0 * l + xyPerspectiveBias1);                      // original distortion factor, divided by 10
 }
 
 float getPenumbraRadius(sampler2D shadowsampler, vec2 smTexCoord, float realDistance, float multiplier)
@@ -185,7 +187,6 @@ float getPenumbraRadius(sampler2D shadowsampler, vec2 smTexCoord, float realDist
 	float baseLength = getBaseLength(smTexCoord);
 	float perspectiveFactor;
 
-	if (PCFBOUND == 0.0) return 0.0;
 	// Return fast if sharp shadows are requested
 	if (PCFBOUND == 0.0)
 		return 0.0;
@@ -489,11 +490,13 @@ void main(void)
 		vec3 shadow_color = vec3(0.0, 0.0, 0.0);
 		vec3 posLightSpace = getLightSpacePosition();
 
-		float distance_rate = (1 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 50.0));
+		float distance_rate = (1.0 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 10.0));
+		if (max(abs(posLightSpace.x - 0.5), abs(posLightSpace.y - 0.5)) > 0.5)
+			distance_rate = 0.0;
 		float f_adj_shadow_strength = max(adj_shadow_strength-mtsmoothstep(0.9,1.1,  posLightSpace.z),0.0);
 
 		if (distance_rate > 1e-7) {
-		
+
 #ifdef COLORED_SHADOWS
 			vec4 visibility;
 			if (cosLight > 0.0)
@@ -527,7 +530,7 @@ void main(void)
 		}
 
 		shadow_int *= f_adj_shadow_strength;
-		
+
 		// calculate fragment color from components:
 		col.rgb =
 				adjusted_night_ratio * col.rgb + // artificial light
diff --git a/client/shaders/object_shader/opengl_fragment.glsl b/client/shaders/object_shader/opengl_fragment.glsl
index 2b9a59cd7..2611bf8ef 100644
--- a/client/shaders/object_shader/opengl_fragment.glsl
+++ b/client/shaders/object_shader/opengl_fragment.glsl
@@ -6,8 +6,33 @@ uniform vec4 skyBgColor;
 uniform float fogDistance;
 uniform vec3 eyePosition;
 
+// The cameraOffset is the current center of the visible world.
+uniform vec3 cameraOffset;
+uniform float animationTimer;
+#ifdef ENABLE_DYNAMIC_SHADOWS
+	// shadow texture
+	uniform sampler2D ShadowMapSampler;
+	// shadow uniforms
+	uniform vec3 v_LightDirection;
+	uniform float f_textureresolution;
+	uniform mat4 m_ShadowViewProj;
+	uniform float f_shadowfar;
+	uniform float f_shadow_strength;
+	uniform vec4 CameraPos;
+	varying float normalOffsetScale;
+	varying float adj_shadow_strength;
+	varying float cosLight;
+	varying float f_normal_length;
+#endif
+
+
 varying vec3 vNormal;
 varying vec3 vPosition;
+// World position in the visible world (i.e. relative to the cameraOffset.)
+// This can be used for many shader effects without loss of precision.
+// If the absolute position is required it can be calculated with
+// cameraOffset + worldPosition (for large coordinates the limits of float
+// precision must be considered).
 varying vec3 worldPosition;
 varying lowp vec4 varColor;
 #ifdef GL_ES
@@ -15,32 +40,15 @@ varying mediump vec2 varTexCoord;
 #else
 centroid varying vec2 varTexCoord;
 #endif
-
 varying vec3 eyeVec;
 varying float nightRatio;
 
 varying float vIDiff;
 
-const float e = 2.718281828459;
-const float BS = 10.0;
 const float fogStart = FOG_START;
 const float fogShadingParameter = 1.0 / (1.0 - fogStart);
 
-#ifdef ENABLE_DYNAMIC_SHADOWS
-	// shadow texture
-	uniform sampler2D ShadowMapSampler;
-	// shadow uniforms
-	uniform vec3 v_LightDirection;
-	uniform float f_textureresolution;
-	uniform mat4 m_ShadowViewProj;
-	uniform float f_shadowfar;
-	uniform float f_timeofday;
-	uniform float f_shadow_strength;
-	varying float normalOffsetScale;
-	varying float adj_shadow_strength;
-	varying float cosLight;
-	varying float f_normal_length;
-#endif
+
 
 #ifdef ENABLE_DYNAMIC_SHADOWS
 uniform float xyPerspectiveBias0;
@@ -49,15 +57,22 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
-
-	float pDistance = length(shadowPosition.xy);
+	vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+	vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+	float pDistance = length(l);
 	float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
-
-	shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+	l /= pFactor;
+	shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+	shadowPosition.z *= zPerspectiveBias;
 	return shadowPosition;
 }
 
+// assuming near is always 1.0
+float getLinearDepth()
+{
+	return 2.0 * f_shadowfar / (f_shadowfar + 1.0 - (2.0 * gl_FragCoord.z - 1.0) * (f_shadowfar - 1.0));
+}
+
 vec3 getLightSpacePosition()
 {
 	vec4 pLightSpace;
@@ -161,13 +176,13 @@ float getHardShadowDepth(sampler2D shadowsampler, vec2 smTexCoord, float realDis
 
 float getBaseLength(vec2 smTexCoord)
 {
-	float l = length(2.0 * smTexCoord.xy - 1.0);     // length in texture coords
+	float l = length(2.0 * smTexCoord.xy - 1.0 - CameraPos.xy);     // length in texture coords
 	return xyPerspectiveBias1 / (1.0 / l - xyPerspectiveBias0); 				 // return to undistorted coords
 }
 
 float getDeltaPerspectiveFactor(float l)
 {
-	return 0.1 / (xyPerspectiveBias0 * l + xyPerspectiveBias1);                      // original distortion factor, divided by 10
+	return 0.04 * pow(512.0 / f_textureresolution, 0.4) / (xyPerspectiveBias0 * l + xyPerspectiveBias1);                      // original distortion factor, divided by 10
 }
 
 float getPenumbraRadius(sampler2D shadowsampler, vec2 smTexCoord, float realDistance, float multiplier)
@@ -178,7 +193,7 @@ float getPenumbraRadius(sampler2D shadowsampler, vec2 smTexCoord, float realDist
 	// Return fast if sharp shadows are requested
 	if (PCFBOUND == 0.0)
 		return 0.0;
-		
+
 	if (SOFTSHADOWRADIUS <= 1.0) {
 		perspectiveFactor = getDeltaPerspectiveFactor(baseLength);
 		return max(2 * length(smTexCoord.xy) * 2048 / f_textureresolution / pow(perspectiveFactor, 3), SOFTSHADOWRADIUS);
@@ -418,6 +433,7 @@ float getShadow(sampler2D shadowsampler, vec2 smTexCoord, float realDistance)
 #endif
 
 #if ENABLE_TONE_MAPPING
+
 /* Hable's UC2 Tone mapping parameters
 	A = 0.22;
 	B = 0.30;
@@ -448,12 +464,14 @@ vec4 applyToneMapping(vec4 color)
 }
 #endif
 
+
+
 void main(void)
 {
 	vec3 color;
 	vec2 uv = varTexCoord.st;
-	vec4 base = texture2D(baseTexture, uv).rgba;
 
+	vec4 base = texture2D(baseTexture, uv).rgba;
 	// If alpha is zero, we can just discard the pixel. This fixes transparency
 	// on GPUs like GC7000L, where GL_ALPHA_TEST is not implemented in mesa,
 	// and also on GLES 2, where GL_ALPHA_TEST is missing entirely.
@@ -467,8 +485,7 @@ void main(void)
 #endif
 
 	color = base.rgb;
-	vec4 col = vec4(color.rgb, base.a);
-	col.rgb *= varColor.rgb;
+	vec4 col = vec4(color.rgb * varColor.rgb, 1.0);
 	col.rgb *= vIDiff;
 
 #ifdef ENABLE_DYNAMIC_SHADOWS
@@ -477,11 +494,13 @@ void main(void)
 		vec3 shadow_color = vec3(0.0, 0.0, 0.0);
 		vec3 posLightSpace = getLightSpacePosition();
 
-		float distance_rate = (1 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 50.0));
+		float distance_rate = (1.0 - pow(clamp(2.0 * length(posLightSpace.xy - 0.5),0.0,1.0), 10.0));
+		if (max(abs(posLightSpace.x - 0.5), abs(posLightSpace.y - 0.5)) > 0.5)
+			distance_rate = 0.0;
 		float f_adj_shadow_strength = max(adj_shadow_strength-mtsmoothstep(0.9,1.1,  posLightSpace.z),0.0);
 
 		if (distance_rate > 1e-7) {
-	
+
 #ifdef COLORED_SHADOWS
 			vec4 visibility;
 			if (cosLight > 0.0)
@@ -506,8 +525,8 @@ void main(void)
 		// Power ratio was measured on torches in MTG (brightness = 14).
 		float adjusted_night_ratio = pow(max(0.0, nightRatio), 0.6);
 
-		// cosine of the normal-to-light angle when
-		// we start to apply self-shadowing
+		// Apply self-shadowing when light falls at a narrow angle to the surface
+		// Cosine of the cut-off angle.
 		const float self_shadow_cutoff_cosine = 0.14;
 		if (f_normal_length != 0 && cosLight < self_shadow_cutoff_cosine) {
 			shadow_int = max(shadow_int, 1 - clamp(cosLight, 0.0, self_shadow_cutoff_cosine)/self_shadow_cutoff_cosine);
@@ -541,5 +560,7 @@ void main(void)
 	float clarity = clamp(fogShadingParameter
 		- fogShadingParameter * length(eyeVec) / fogDistance, 0.0, 1.0);
 	col = mix(skyBgColor, col, clarity);
-	gl_FragColor = vec4(col.rgb, base.a);
+	col = vec4(col.rgb, base.a);
+	
+	gl_FragColor = col;
 }
diff --git a/client/shaders/shadow_shaders/pass1_trans_vertex.glsl b/client/shaders/shadow_shaders/pass1_trans_vertex.glsl
index 6d2877d18..c2f575876 100644
--- a/client/shaders/shadow_shaders/pass1_trans_vertex.glsl
+++ b/client/shaders/shadow_shaders/pass1_trans_vertex.glsl
@@ -1,4 +1,5 @@
 uniform mat4 LightMVP; // world matrix
+uniform vec4 CameraPos;
 varying vec4 tPos;
 #ifdef COLORED_SHADOWS
 varying vec3 varColor;
@@ -10,10 +11,13 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
-	float pDistance = length(shadowPosition.xy);
+	vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+	vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+	float pDistance = length(l);
 	float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
-	shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+	l /= pFactor;
+	shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+	shadowPosition.z *= zPerspectiveBias;
 	return shadowPosition;
 }
 
diff --git a/client/shaders/shadow_shaders/pass1_vertex.glsl b/client/shaders/shadow_shaders/pass1_vertex.glsl
index 3873ac6e6..38aef3619 100644
--- a/client/shaders/shadow_shaders/pass1_vertex.glsl
+++ b/client/shaders/shadow_shaders/pass1_vertex.glsl
@@ -1,4 +1,5 @@
 uniform mat4 LightMVP; // world matrix
+uniform vec4 CameraPos; // camera position
 varying vec4 tPos;
 
 uniform float xyPerspectiveBias0;
@@ -7,10 +8,13 @@ uniform float zPerspectiveBias;
 
 vec4 getPerspectiveFactor(in vec4 shadowPosition)
 {
-	float pDistance = length(shadowPosition.xy);
+	vec2 s = vec2(shadowPosition.x > CameraPos.x ? 1.0 : -1.0, shadowPosition.y > CameraPos.y ? 1.0 : -1.0);
+	vec2 l = s * (shadowPosition.xy - CameraPos.xy) / (1.0 - s * CameraPos.xy);
+	float pDistance = length(l);
 	float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
-	shadowPosition.xyz *= vec3(vec2(1.0 / pFactor), zPerspectiveBias);
-
+	l /= pFactor;
+	shadowPosition.xy = CameraPos.xy * (1.0 - l) + s * l;
+	shadowPosition.z *= zPerspectiveBias;
 	return shadowPosition;
 }