1 files changed, 43 insertions, 0 deletions
diff --git a/client/shaders/shadow_shaders/pass1_vertex.glsl b/client/shaders/shadow_shaders/pass1_vertex.glsl
new file mode 100644
index 000000000..1dceb93c6
--- /dev/null
+++ b/client/shaders/shadow_shaders/pass1_vertex.glsl
@@ -0,0 +1,43 @@
+uniform mat4 LightMVP; // world matrix
+uniform vec4 CameraPos; // camera position
+varying vec4 tPos;
+
+uniform float xyPerspectiveBias0;
+uniform float xyPerspectiveBias1;
+uniform float zPerspectiveBias;
+
+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;
+}
+
+void main()
+{
+	vec4 pos = LightMVP * gl_Vertex;
+
+	tPos = applyPerspectiveDistortion(pos);
+
+	gl_Position = vec4(tPos.xyz, 1.0);
+	gl_TexCoord[0] = gl_TextureMatrix[0] * gl_MultiTexCoord0;
+}