Add slang shader for debug printf sample

shaders/slang/debugprintf/toon.slang

@@ -0,0 +1,73 @@
+/* Copyright (c) 2025, Sascha Willems
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ */
+
+struct VSInput
+{
+	float3 Pos;
+	float3 Normal;
+	float3 Color;
+};
+
+struct VSOutput
+{
+    float4 Pos : SV_POSITION;
+    float3 Normal;
+    float3 Color;
+    float3 ViewVec;
+    float3 LightVec;
+};
+
+struct UBO
+{
+	float4x4 projection;
+	float4x4 model;
+	float4 lightPos;
+};
+ConstantBuffer<UBO> ubo;
+
+[shader("vertex")]
+VSOutput vertexMain(VSInput input)
+{
+	VSOutput output;
+	output.Normal = input.Normal;
+	output.Color = input.Color;
+	output.Pos = mul(ubo.projection, mul(ubo.model, float4(input.Pos.xyz, 1.0)));
+
+	float4 pos = mul(ubo.model, float4(input.Pos, 1.0));
+	// Output the vertex position using debug printf
+	printf("Position = %v4f", pos);
+
+	output.Normal = mul((float4x3)ubo.model, input.Normal).xyz;
+	float3 lPos = mul((float4x3)ubo.model, ubo.lightPos.xyz).xyz;
+	output.LightVec = lPos - pos.xyz;
+	output.ViewVec = -pos.xyz;
+	return output;
+}
+
+[shader("fragment")]
+float4 fragmentMain(VSOutput input)
+{
+    // Desaturate color
+    float3 color = float3(lerp(input.Color, dot(float3(0.2126, 0.7152, 0.0722), input.Color).xxx, 0.65));
+
+    // High ambient colors because mesh materials are pretty dark
+    float3 ambient = color * float3(1.0, 1.0, 1.0);
+    float3 N = normalize(input.Normal);
+    float3 L = normalize(input.LightVec);
+    float3 V = normalize(input.ViewVec);
+    float3 R = reflect(-L, N);
+    float3 diffuse = max(dot(N, L), 0.0) * color;
+    float3 specular = pow(max(dot(R, V), 0.0), 16.0) * float3(0.75, 0.75, 0.75);
+
+    float intensity = dot(N, L);
+    float shade = 1.0;
+    shade = intensity < 0.5 ? 0.75 : shade;
+    shade = intensity < 0.35 ? 0.6 : shade;
+    shade = intensity < 0.25 ? 0.5 : shade;
+    shade = intensity < 0.1 ? 0.25 : shade;
+
+    return float4(input.Color * 3.0 * shade, 1);
+}