Render temporal scene with motion, resolve and sharp UI

shaders/baseline.slang

@@ -122,8 +122,7 @@ float3 directBRDF(float3 base, float rough, float metal, float3 n, float3 view,
     float3 spec=d*g*fresnel/max(4.0*nv*nl,0.001);
     return ((1.0-fresnel)*(1.0-metal)*base/pi+spec)*nl;
 }
-[shader("fragment")]
-float4 fragmentMain(VertexOutput v) : SV_Target {
+float4 shadeScene(VertexOutput v) {
     float4 sampled = colorMap.Sample(colorSampler, v.uv);
     if (dot(v.normal,v.normal) < 1e-12) {
         // UI/sprite tint is in display space; sRGB textures were decoded by Vulkan.
@@ -202,3 +201,57 @@ float4 fragmentMain(VertexOutput v) : SV_Target {
     linear=linear/(1.0+linear);
     return float4(pow(max(linear,0),float3(1.0/2.2)),base.a);
 }
+[shader("fragment")]
+float4 fragmentMain(VertexOutput v) : SV_Target { return shadeScene(v); }
+
+struct TemporalVertexInput {
+    float4 clip : POSITION;
+    float3 world : TEXCOORD0;
+    float3 normal : NORMAL;
+    float4 color : COLOR0;
+    float2 material : TEXCOORD1;
+    float2 uv : TEXCOORD2;
+    float4 previousClip : TEXCOORD3;
+    float motionValid : TEXCOORD4;
+};
+struct TemporalVertexOutput {
+    float4 position : SV_Position;
+    float3 world : TEXCOORD0;
+    float3 normal : NORMAL;
+    float4 color : COLOR0;
+    float2 material : TEXCOORD1;
+    float2 uv : TEXCOORD2;
+    float4 previousClip : TEXCOORD3;
+    float4 currentClip : TEXCOORD4;
+    float motionValid : TEXCOORD5;
+};
+[shader("vertex")]
+TemporalVertexOutput temporalVertexMain(TemporalVertexInput v) {
+    TemporalVertexOutput o;
+    o.position=v.clip; o.world=v.world; o.normal=v.normal; o.color=v.color;
+    o.material=v.material; o.uv=v.uv; o.previousClip=v.previousClip;
+    o.currentClip=v.clip; o.motionValid=v.motionValid;
+    return o;
+}
+struct TemporalFragmentOutput {
+    float4 color : SV_Target0;
+    float4 velocity : SV_Target1;
+};
+[shader("fragment")]
+TemporalFragmentOutput temporalFragmentMain(TemporalVertexOutput v) {
+    VertexOutput shading;
+    shading.position=v.position; shading.world=v.world; shading.normal=v.normal;
+    shading.color=v.color; shading.material=v.material; shading.uv=v.uv;
+    TemporalFragmentOutput result;
+    result.color=shadeScene(shading);
+    result.velocity=float4(0);
+    if (v.motionValid > .5 && result.color.a >= .999 &&
+        all(isfinite(v.currentClip)) && all(isfinite(v.previousClip)) &&
+        v.currentClip.w > 0 && v.previousClip.w > 0) {
+        result.velocity.xy=(v.currentClip.xy / v.currentClip.w -
+                            v.previousClip.xy / v.previousClip.w) * .5;
+        result.velocity.z=v.previousClip.z / v.previousClip.w;
+        result.velocity.w=1;
+    }
+    return result;
+}