Pass depth range to depth map visualization shader

Fixes #895

data/shaders/hlsl/shadowmapping/quad.frag

@@ -3,10 +3,23 @@
 Texture2D textureColor : register(t1);
 SamplerState samplerColor : register(s1);
 
+struct UBO
+{
+	float4x4 projection;
+	float4x4 view;
+	float4x4 model;
+	float4x4 lightSpace;
+	float4 lightPos;
+	float zNear;
+	float zFar;
+};
+
+cbuffer ubo : register(b0) { UBO ubo; }
+
 float LinearizeDepth(float depth)
 {
-  float n = 1.0; // camera z near
-  float f = 128.0; // camera z far
+  float n = ubo.zNear;
+  float f = ubo.zFar;
   float z = depth;
   return (2.0 * n) / (f + n - z * (f - n));
 }

data/shaders/hlsl/shadowmapping/scene.vert

@@ -14,7 +14,9 @@ struct UBO
 	float4x4 view;
 	float4x4 model;
 	float4x4 lightSpace;
-	float3 lightPos;
+	float4 lightPos;
+	float zNear;
+	float zFar;
 };
 
 cbuffer ubo : register(b0) { UBO ubo; }
@@ -45,7 +47,7 @@ VSOutput main(VSInput input)
 
     float4 pos = mul(ubo.model, float4(input.Pos, 1.0));
     output.Normal = mul((float3x3)ubo.model, input.Normal);
-    output.LightVec = normalize(ubo.lightPos - input.Pos);
+    output.LightVec = normalize(ubo.lightPos.xyz - input.Pos);
     output.ViewVec = -pos.xyz;
 
 	output.ShadowCoord = mul(biasMat, mul(ubo.lightSpace, mul(ubo.model, float4(input.Pos, 1.0))));