1 files changed, 74 insertions, 18 deletions

diff --git a/client/shaders/nodes_shader/opengl_vertex.glsl b/client/shaders/nodes_shader/opengl_vertex.glsl
index d316930b2..d1fba2830 100644
--- a/client/shaders/nodes_shader/opengl_vertex.glsl
+++ b/client/shaders/nodes_shader/opengl_vertex.glsl
@@ -32,10 +32,14 @@ centroid varying vec2 varTexCoord;
 	uniform float f_shadowfar;
 	uniform float f_shadow_strength;
 	uniform float f_timeofday;
+	uniform vec4 CameraPos;
+
 	varying float cosLight;
 	varying float normalOffsetScale;
 	varying float adj_shadow_strength;
 	varying float f_normal_length;
+	varying vec3 shadow_position;
+	varying float perspective_factor;
 #endif
 
 
@@ -45,8 +49,38 @@ varying float nightRatio;
 const vec3 artificialLight = vec3(1.04, 1.04, 1.04);
 const float e = 2.718281828459;
 const float BS = 10.0;
+uniform float xyPerspectiveBias0;
+uniform float xyPerspectiveBias1;
+uniform float zPerspectiveBias;
 
 #ifdef ENABLE_DYNAMIC_SHADOWS
+
+vec4 getRelativePosition(in vec4 position)
+{
+	vec2 l = position.xy - CameraPos.xy;
+	vec2 s = l / abs(l);
+	s = (1.0 - s * CameraPos.xy);
+	l /= s;
+	return vec4(l, s);
+}
+
+float getPerspectiveFactor(in vec4 relativePosition)
+{
+	float pDistance = length(relativePosition.xy);
+	float pFactor = pDistance * xyPerspectiveBias0 + xyPerspectiveBias1;
+	return pFactor;
+}
+
+vec4 applyPerspectiveDistortion(in vec4 position)
+{
+	vec4 l = getRelativePosition(position);
+	float pFactor = getPerspectiveFactor(l);
+	l.xy /= pFactor;
+	position.xy = l.xy * l.zw + CameraPos.xy;
+	position.z *= zPerspectiveBias;
+	return position;
+}
+
 // custom smoothstep implementation because it's not defined in glsl1.2
 // https://docs.gl/sl4/smoothstep
 float mtsmoothstep(in float edge0, in float edge1, in float x)
@@ -193,24 +227,46 @@ void main(void)
 	varColor = clamp(color, 0.0, 1.0);
 
 #ifdef ENABLE_DYNAMIC_SHADOWS
-	vec3 nNormal = normalize(vNormal);
-	cosLight = dot(nNormal, -v_LightDirection);
-	float texelSize = 767.0 / f_textureresolution;
-	float slopeScale = clamp(1.0 - abs(cosLight), 0.0, 1.0);
-	normalOffsetScale = texelSize * slopeScale;
-	
-	if (f_timeofday < 0.2) {
-		adj_shadow_strength = f_shadow_strength * 0.5 *
-			(1.0 - mtsmoothstep(0.18, 0.2, f_timeofday));
-	} else if (f_timeofday >= 0.8) {
-		adj_shadow_strength = f_shadow_strength * 0.5 *
-			mtsmoothstep(0.8, 0.83, f_timeofday);
-	} else {
-		adj_shadow_strength = f_shadow_strength *
-			mtsmoothstep(0.20, 0.25, f_timeofday) *
-			(1.0 - mtsmoothstep(0.7, 0.8, f_timeofday));
+	if (f_shadow_strength > 0.0) {
+		vec3 nNormal;
+		f_normal_length = length(vNormal);
+
+		/* normalOffsetScale is in world coordinates (1/10th of a meter)
+		   z_bias is in light space coordinates */
+		float normalOffsetScale, z_bias;
+		float pFactor = getPerspectiveFactor(getRelativePosition(m_ShadowViewProj * mWorld * inVertexPosition));
+		if (f_normal_length > 0.0) {
+			nNormal = normalize(vNormal);
+			cosLight = dot(nNormal, -v_LightDirection);
+			float sinLight = pow(1 - pow(cosLight, 2.0), 0.5);
+			normalOffsetScale = 2.0 * pFactor * pFactor * sinLight * min(f_shadowfar, 500.0) / 
+					xyPerspectiveBias1 / f_textureresolution;
+			z_bias = 1.0 * sinLight / cosLight;
+		}
+		else {
+			nNormal = vec3(0.0);
+			cosLight = clamp(dot(v_LightDirection, normalize(vec3(v_LightDirection.x, 0.0, v_LightDirection.z))), 1e-2, 1.0);
+			float sinLight = pow(1 - pow(cosLight, 2.0), 0.5);
+			normalOffsetScale = 0.0;
+			z_bias = 3.6e3 * sinLight / cosLight;
+		}
+		z_bias *= pFactor * pFactor / f_textureresolution / f_shadowfar;
+
+		shadow_position = applyPerspectiveDistortion(m_ShadowViewProj * mWorld * (inVertexPosition + vec4(normalOffsetScale * nNormal, 0.0))).xyz;
+		shadow_position.z -= z_bias;
+		perspective_factor = pFactor;
+
+		if (f_timeofday < 0.2) {
+			adj_shadow_strength = f_shadow_strength * 0.5 *
+				(1.0 - mtsmoothstep(0.18, 0.2, f_timeofday));
+		} else if (f_timeofday >= 0.8) {
+			adj_shadow_strength = f_shadow_strength * 0.5 *
+				mtsmoothstep(0.8, 0.83, f_timeofday);
+		} else {
+			adj_shadow_strength = f_shadow_strength *
+				mtsmoothstep(0.20, 0.25, f_timeofday) *
+				(1.0 - mtsmoothstep(0.7, 0.8, f_timeofday));
+		}
 	}
-	f_normal_length = length(vNormal);
 #endif
-
 }