Add test for original history feature.

test/history.slang

@@ -0,0 +1,38 @@
+#version 450
+
+layout(std140, set = 0, binding = 0) uniform UBO
+{
+   mat4 MVP;
+   vec4 SourceSize;
+   vec4 OriginalHistorySize1;
+   vec4 OriginalHistorySize3;
+} global;
+
+#pragma stage vertex
+layout(location = 0) in vec4 Position;
+layout(location = 1) in vec2 TexCoord;
+layout(location = 0) out vec2 vTexCoord;
+
+void main()
+{
+   gl_Position = global.MVP * Position;
+   vTexCoord = TexCoord;
+}
+
+#pragma stage fragment
+layout(location = 0) in vec2 vTexCoord;
+layout(location = 0) out vec4 FragColor;
+layout(set = 0, binding = 1) uniform sampler2D Source;
+layout(set = 0, binding = 2) uniform sampler2D OriginalHistory1;
+layout(set = 0, binding = 3) uniform sampler2D OriginalHistory3;
+
+void main()
+{
+   vec2 tex = floor(global.OriginalHistorySize1.xy * vTexCoord);
+   tex = (tex + 0.5) * global.OriginalHistorySize1.zw;
+
+   vec3 current = texture(Source, tex).rgb;
+   vec3 prev = texture(OriginalHistory1, tex).rgb;
+   vec3 prev2 = texture(OriginalHistory3, tex).rgb;
+   FragColor = vec4(abs(current - prev + prev2), 1.0);
+}

test/history.slangp

@@ -0,0 +1,2 @@
+shaders = 1
+shader0 = history.slang