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shaders/xyla-exposure-chart/shader.slang

@@ -1,5 +1,7 @@
 float boxMask(float2 point, float2 halfSize, float feather)
 {
+	// Signed-distance box mask gives the chart and border pixel-sized feathered
+	// edges without branching per side.
 	float2 distanceToEdge = abs(point) - halfSize;
 	float outsideDistance = length(max(distanceToEdge, float2(0.0, 0.0)));
 	float insideDistance = min(max(distanceToEdge.x, distanceToEdge.y), 0.0);
@@ -31,6 +33,8 @@ float applyToneCurve(float linearLevel)
 float patchBrightness(int patchIndex, int count)
 {
 	int clampedIndex = clamp(patchIndex, 0, max(count - 1, 0));
+	// Each patch is one stop brighter than the previous patch until it clips at
+	// the requested peak level, matching the Xyla-style exposure ramp.
 	float linearLevel = baseLevel * exp2(float(clampedIndex));
 	linearLevel = min(linearLevel, peakLevel);
 	return applyToneCurve(linearLevel);
@@ -60,6 +64,8 @@ float4 shadeVideo(ShaderContext context)
 	if (reverseOrder)
 		patchIndex = count - 1 - patchIndex;
 
+	// Build each patch as a slot along the main axis, then mask the cross-axis
+	// extents so vertical and horizontal charts share the same logic.
 	float patchSlotCenter = (floor(patchPosition) + 0.5) / float(count);
 	float localAxis = abs(normalizedAxis - patchSlotCenter) * float(count) * 2.0;
 	float safeGapSize = saturate(gapSize);