Clean up a little bit of API code. Fix an issue with missing operator. Port random semi complex shader.

test/codegen/night_time.golden

@@ -0,0 +1,93 @@
+float4 apply_night(float4 color);
+float4 apply_twilight(float4 color);
+float4 apply_morning(float4 color);
+float4 apply_dawn(float4 color);
+
+cbuffer __PROPERTIES : register(b0) 
+{
+    float __PROPERTIES__hour_of_day;
+}
+
+Texture2D __PROPERTIES__input_tex : register(t0);
+SamplerState __PROPERTIES__tex_sampler : register(s0);
+
+struct VS_Input
+{
+    float3 pos : POSITION;
+    float2 uv : TEXCOORD0;
+};
+
+struct VS_Output
+{
+    float4 pos : SV_POSITION;
+    float2 uv : TEXCOORD0;
+};
+
+VS_Output vs_main(VS_Input input)
+{
+    VS_Output output;
+    output.pos = float4(input.pos, 1.0f);
+    output.uv = input.uv;
+    return output;
+}
+
+float4 apply_night(float4 color)
+{
+    float4 result = color;
+    (result -= float4(0.3f, 0.2f, 0.0f, 0.0f));
+    (result *= 0.8f);
+    return result;
+}
+
+float4 apply_twilight(float4 color)
+{
+    float4 result = color;
+    (result += float4(0.2f, -0.1f, 0.1f, 0.0f));
+    (result *= 0.9f);
+    return result;
+}
+
+float4 apply_morning(float4 color)
+{
+    return (color * 1.3f);
+}
+
+float4 apply_dawn(float4 color)
+{
+    return color;
+}
+
+float4 ps_main(VS_Output input)
+{
+    float4 sampled_color = __PROPERTIES__input_tex.Sample(__PROPERTIES__tex_sampler, input.uv);
+    float t = 0.0f;
+    float4 a = float4(0, 0, 0, 0);
+    float4 b = float4(0, 0, 0, 0);
+    if (__PROPERTIES__hour_of_day > 16)
+    {
+        t = ((__PROPERTIES__hour_of_day - 16) / 6);
+        a = apply_twilight(sampled_color);
+        b = apply_night(sampled_color);
+    }
+    else if (__PROPERTIES__hour_of_day > 12)
+    {
+        t = ((__PROPERTIES__hour_of_day - 12) / 6);
+        a = sampled_color;
+        b = apply_twilight(sampled_color);
+    }
+    else if (__PROPERTIES__hour_of_day > 6)
+    {
+        t = ((__PROPERTIES__hour_of_day - 6) / 6);
+        a = apply_morning(sampled_color);
+        b = sampled_color;
+    }
+    else if (__PROPERTIES__hour_of_day >= 0)
+    {
+        t = (__PROPERTIES__hour_of_day / 6);
+        a = apply_night(sampled_color);
+        b = apply_morning(sampled_color);
+    }
+
+    return lerp(a, b, t);
+}
+