UnbindTexture, PBR changes, Test scene

GlitchyEditor/content/Shaders/PBR.hlsl

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+/*
+ * This File contains Function for PBR.
+ */
+
+#ifndef __PBR_HLSL__
+#define __PBR_HLSL__
+
+#include "ShaderHelpers.hlsl"
+
+// #define PBR_IBL
+
+ /**
+  * Normal Distribution Function. (Trowbridge-Reits GGX)
+  * Calculates the relative surface area of microfacets exactly aligned to the halfway vector.
+  * @param normal The surface normal.
+  * @param halfway The halfway vector between the surface normal and the view direction.
+  * @param roughness Roughness value.
+  * @returns The relative surface area of microfacets exactly aligned to the halfway vector.
+  */
+float NormalDistributionGGX(float3 normal, float3 halfway, float roughness)
+{
+	// Square roughness because it looks better
+	float a = roughness * roughness;
+	float aa = a * a;
+
+	float n_dot_h = max(dot(normal, halfway), 0.0f);
+
+	float denom = (n_dot_h * n_dot_h) * (aa - 1.0f) + 1.0f;
+	denom = PI * denom * denom;
+
+	return aa / denom;
+}
+
+/**
+ * Geometry Function calculating the overshadowing of microfacets based on roughness. (Schlick-Beckmann GGX).
+ * @param dot-product of normal vector and vector from surface to camera.
+ * @param k Roughness value.
+ */
+float GeometrySchlickGGX(float n_dot_v, float k)
+{
+	return n_dot_v / (n_dot_v * (1 - k) + k);
+}
+
+/**
+ * Geometry Function calculating the overshadowing of microfacets based on roughness. (Smith)
+ * @param normal The surface normal.
+ * @param viewDir Vector from surface to viewer.
+ * @param lightDir Vector from surface to light source.
+ * @param roughness Roughness value.
+ */
+float GeometrySmith(float3 normal, float3 viewDir, float3 lightDir, float roughness)
+{
+#ifdef PBR_IBL
+	// IBL
+	float k = roughness * roughness / 2;
+#else
+	// Direct lighting
+	float k = (roughness + 1.0f);
+	k = (k * k) / 8;
+#endif
+
+	const float n_dot_v = max(dot(normal, viewDir), 0.0f);
+	float n_dot_l = max(dot(normal, lightDir), 0.0f);
+
+	return GeometrySchlickGGX(n_dot_v, k) * GeometrySchlickGGX(n_dot_l, k);
+}
+
+/**
+ * Calculates the fresnel value.
+ * @param n_dot_v Dot product of the normal and view direction
+ * @param F0 base reflectivity.
+ */
+float3 FresnelSchlick(float n_dot_v, float3 F0)
+{
+	return F0 + (1.0 - F0) * pow(clamp(1.0 - n_dot_v, 0.0, 1.0), 5.0);
+}
+
+#endif // __PBR_HLSL__