Correct normal bias for entities

Remove use of magic constants.
Apply cameraOffset
Calculate distance projected on SM plane

1 files changed, 7 insertions, 3 deletions

diff --git a/client/shaders/object_shader/opengl_vertex.glsl b/client/shaders/object_shader/opengl_vertex.glsl
index 12078f532..185551c58 100644
--- a/client/shaders/object_shader/opengl_vertex.glsl
+++ b/client/shaders/object_shader/opengl_vertex.glsl
@@ -3,6 +3,7 @@ uniform vec3 dayLight;
 uniform vec3 eyePosition;
 uniform float animationTimer;
 uniform vec4 emissiveColor;
+uniform vec3 cameraOffset;
 
 
 varying vec3 vNormal;
@@ -110,10 +111,13 @@ void main(void)
 	// Calculate normal offset scale based on the texel size adjusted for 
 	// curvature of the SM texture. This code must be change together with
 	// getPerspectiveFactor or any light-space transformation.
-	float distanceToPlayer = length((eyePosition - worldPosition).xyz) / f_shadowfar;
+	vec3 eyeToVertex = worldPosition - eyePosition + cameraOffset;
+	// Distance from the vertex to the player
+	float distanceToPlayer = length(eyeToVertex - v_LightDirection * dot(eyeToVertex, v_LightDirection)) / f_shadowfar;
+	// perspective factor estimation according to the 
 	float perspectiveFactor = distanceToPlayer * bias0 + bias1;
-	float texelSize = 1.0 / f_textureresolution;
-	texelSize *= f_shadowfar * perspectiveFactor / (bias1 / perspectiveFactor - texelSize * bias0) * 0.15;
+	float texelSize = f_shadowfar * perspectiveFactor * perspectiveFactor /
+			(f_textureresolution * bias1  - perspectiveFactor * bias0);
 	float slopeScale = clamp(pow(1.0 - cosLight*cosLight, 0.5), 0.0, 1.0);
 	normalOffsetScale = texelSize * slopeScale;