grid cables - make the thorn pulse move in continuous wave

This wave is rooted in the strongest power source - for example your most powerful solar.
So it can go against the "actual flow".
Revert at will

Author: Licho1

LuaRules/Gadgets/Shaders/gfx_overdrive_cables.frag.glsl

@@ -591,9 +591,12 @@ void main() {
 		//      at twig-local 0 and propagates through the twig at
 		//      TWIG_SWEEP_SPEED. Inter-twig stagger feels snappy while motion
 		//      *within* a twig stays comfortable.
-		// `spawnAlongMain` is what lets us decouple these — without it both
-		// speeds would be tied to the same propagation rate.
-		float wavePassedElmos = mod(gameTime * CABLE_PROP_SPEED * (1.0 + 1.2 * maxxed) - spawnAlongMain, CABLE_PROP_PERIOD / (1.0 + 0.5 * maxxed));
+		// Stagger by the twig root's distance-from-root (packed into gridData.y by
+		// the GS), not the per-edge along — so the wave is one wavefront radiating
+		// from the grid root, chaining across joints instead of restarting per
+		// edge. The within-twig sweep below still uses edge-local spawnAlongMain.
+		float globalRoot = gridData.y;
+		float wavePassedElmos = mod(gameTime * CABLE_PROP_SPEED * (1.0 + 1.2 * maxxed) - globalRoot, CABLE_PROP_PERIOD / (1.0 + 0.5 * maxxed));
 		float subwavePos = TWIG_SWEEP_SPEED * (wavePassedElmos / CABLE_PROP_SPEED);
 		float localAlong = along - spawnAlongMain;
 		float d = localAlong - subwavePos;

LuaRules/Gadgets/Shaders/gfx_overdrive_cables.geom.glsl

@@ -64,6 +64,8 @@ out DataGS {
 	float width;
 	vec2 cableUV;
 	vec2 timeData;
+	// (gridEfficiency, flow, isOwnAlly). For twigs (isBranch>0.5) .y is overloaded
+	// to the twig root's distance-from-root (flow is unused there) → pulse stagger.
 	vec3 gridData;
 	// Smooth per-vertex cable along-direction (3D). Linearly interpolated by
 	// the rasteriser so the FS frame (perp3D/trueUp → cylinder normal) rotates
@@ -181,7 +183,7 @@ void emitVtx(vec3 wp, vec3 tangent3D, vec2 cuv,
 	width = w;
 	cableUV = cuv;
 	timeData = td;
-	gridData = grid.xyw;          // .z dropped (unused by FS); see DataGS BUDGET NOTE
+	gridData = grid.xyw;          // .z (per-end rootDist) used in main() for twig globalRoot, not forwarded; see DataGS BUDGET NOTE
 	cableTangent = tangent3D;     // smooth along-dir → FS interpolates the lit frame
 	spawnAlongMain = gOutSpawnAlong;
 	gsSlot = gOutSlot;
@@ -525,7 +527,12 @@ void emitTentHalf(float side, vec2 a, vec2 d, vec2 perpAB,
 void emitTwig(vec2 a, vec2 d, vec2 perpAB,
               float halfMainW, float widthVal, float effAmp, float seed,
               vec4 gridD, vec2 timeD, float cap, float tCenter,
-              float spawnAlongMain, int twigIdx, float arcDh, int numSeg) {
+              float spawnAlongMain, int twigIdx, float arcDh, int numSeg,
+              float globalRoot) {
+	// Pack this twig's distance-from-root into gridData.y (flow, unused by twigs)
+	// for the FS pulse stagger — see the DataGS gridData note.
+	vec4 gridTwig = gridD;
+	gridTwig.y = globalRoot;
 	// Resolve spawn point on the wiggly main path at tCenter so twigs root on
 	// the visible cable.
 	float lenAB = length(d);
@@ -612,9 +619,9 @@ void emitTwig(vec2 a, vec2 d, vec2 perpAB,
 	// follows the twig's pointing direction.
 	gOutBranch = 1.0;
 	gOutSpawnAlong = spawnAlongMain;   // shared by all 4 twig vertices; lets FS compute twig-local along
-	emitVtx(rootL, twigDir3D, vec2(spawnAlongMain,        -1.0), twigW,        gridD, timeD, cap);
-	emitVtx(rootR, twigDir3D, vec2(spawnAlongMain,         1.0), twigW,        gridD, timeD, cap);
-	emitVtx(tipL,  twigDir3D, vec2(spawnAlongMain + bLen, -1.0), twigW, gridD, timeD, cap);
+	emitVtx(rootL, twigDir3D, vec2(spawnAlongMain,        -1.0), twigW,        gridTwig, timeD, cap);
+	emitVtx(rootR, twigDir3D, vec2(spawnAlongMain,         1.0), twigW,        gridTwig, timeD, cap);
+	emitVtx(tipL,  twigDir3D, vec2(spawnAlongMain + bLen, -1.0), twigW, gridTwig, timeD, cap);
 	EndPrimitive();
 	gOutSpawnAlong = 0.0;
 }
@@ -795,7 +802,16 @@ void main() {
 		}
 		float tCenter        = float(idxArr[bestK]) / float(G);
 		float spawnAlongMain = alongArr[bestK];
+		// This twig root's distance-from-root: lerp the two ends' values (gridData.z,
+		// rootA on v0 / rootB on v1) by its fractional arc position, so it stays
+		// continuous with both pylons regardless of which end is nearer the root.
+		// totalArc > 0 always here (a twig only emits when len3D >= ~42).
+		float rootFrac   = spawnAlongMain / alongArr[numSeg];
+		float baseRootA  = gridD.z;
+		float baseRootB  = dataIn[1].vsGridData.z;
+		float globalRoot = baseRootA + (baseRootB - baseRootA) * rootFrac;
 		emitTwig(a, d, perpAB, halfW, widthVal, effAmp, seed,
-		         gridD, timeD, cap, tCenter, spawnAlongMain, twigIdx, arcDh, numSeg);
+		         gridD, timeD, cap, tCenter, spawnAlongMain, twigIdx, arcDh, numSeg,
+		         globalRoot);
 	}
 }

LuaRules/Gadgets/Shaders/gfx_overdrive_cables.vert.glsl

@@ -10,7 +10,7 @@
 
 layout (location = 0) in vec2 vertPos;     // (x, z) world coords
 layout (location = 1) in vec3 vertData;    // (capacity, appearTime, witherTime)
-layout (location = 2) in vec4 vertGrid;    // (gridEfficiency, flow, bubblePhase, isOwnAlly)
+layout (location = 2) in vec4 vertGrid;    // (gridEfficiency, flow, rootDist, isOwnAlly); .z = per-end distance-from-root (ex-bubblePhase)
 layout (location = 3) in float vertSlot;   // coverage SSBO slot (-1 = disabled)
 
 out gl_PerVertex {

LuaRules/Gadgets/gfx_overdrive_cables.lua

@@ -1390,6 +1390,23 @@ local function BuildMpCache()
 		end
 	end
 
+	-- Per-node tree-path distance from the component root. Forward pass: parent
+	-- precedes child in `order`, so the parent's distance is already final.
+	-- Topology-stable, so free to accumulate here. Drives the twig-pulse stagger
+	-- so thorn pulses chain across edges instead of restarting per cable.
+	local distFromRoot = {}
+	for i = 1, #order do
+		local u = order[i]
+		local pi = parentInTree[u]
+		if not pi then
+			distFromRoot[u] = 0
+		else
+			local e = edges[pi.key]
+			local dx, dz = e.px - e.cx, e.pz - e.cz
+			distFromRoot[u] = distFromRoot[pi.parent] + sqrt(dx * dx + dz * dz)
+		end
+	end
+
 	-- Static per-subtree aggregates (post-order over `order`).
 	local subPmax = {}
 	local subDmax = {}
@@ -1442,6 +1459,7 @@ local function BuildMpCache()
 	mpCache.subPmaxNonWind = subPmaxNonWind
 	mpCache.subWindCount   = subWindCount
 	mpCache.subWindBase    = subWindBase
+	mpCache.distFromRoot   = distFromRoot
 	mpCache.valid          = true
 end
 
@@ -1679,6 +1697,7 @@ local function SendAll()
 	end
 
 	-- Bin edges by ally, in one pass.
+	local distFromRoot = mpCache.distFromRoot
 	local perAlly = {}
 	for key, edge in pairs(edges) do
 		local ally = allyOfUnit[edge.parentID] or allyOfUnit[edge.childID]
@@ -1687,7 +1706,8 @@ local function SendAll()
 			if not pa then
 				pa = {
 					keys = {}, pxs = {}, pzs = {}, cxs = {}, czs = {},
-					caps = {}, maxxed = {}, flows = {}, effs = {}, n = 0,
+					caps = {}, maxxed = {}, flows = {}, effs = {},
+					rootAs = {}, rootBs = {}, n = 0,
 				}
 				perAlly[ally] = pa
 			end
@@ -1699,6 +1719,10 @@ local function SendAll()
 			pa.caps[i]  = capacities[key] or 0
 			pa.maxxed[i]  = (spGetUnitRulesParam(edge.parentID, "OD_gridMaxxed") or spGetUnitRulesParam(edge.childID, "OD_gridMaxxed")) == 1
 			pa.flows[i] = flows[key] or 0
+			-- Per-end distance-from-root for the twig pulse. v0 = parent end,
+			-- v1 = child end; keyed by node so flow reorientation just swaps them.
+			pa.rootAs[i] = distFromRoot[edge.parentID] or 0
+			pa.rootBs[i] = distFromRoot[edge.childID] or 0
 			-- Cached per-grid lookup; fall back to child end if parent's grid
 			-- is unknown. 0 → magenta in the shader (unit_mex_overdrive's
 			-- "no grid" sentinel).
@@ -1718,6 +1742,7 @@ local function SendAll()
 			keys = pa.keys, pxs = pa.pxs, pzs = pa.pzs,
 			cxs = pa.cxs, czs = pa.czs,
 			caps = pa.caps, maxxed = pa.maxxed, flows = pa.flows, effs = pa.effs,
+			rootAs = pa.rootAs, rootBs = pa.rootBs,
 		})
 		alliesWithEdges[ally] = true
 	end
@@ -2322,7 +2347,11 @@ local function GenerateOrganicTree()
 		local witherTime = e.witherFrame and (e.witherFrame / GAME_SPEED) or 0
 		local eff = (e.eff or 0) * (e.maxxed and -1 or 1)
 		local flow = e.flow or 0
-		local phase = e.bubblePhase or 0
+		-- vertGrid.z (ex-bubblePhase, now dead — GS drops gridData.z) carries each
+		-- end's distance-from-root: v0 = rootA, v1 = rootB. GS lerps it to twig
+		-- roots to chain pulses across edges.
+		local rootA = e.rootA or 0
+		local rootB = e.rootB or 0
 		local isOwn = (fullview and 2) or (e.isOwnAlly and 1) or 0
 		-- Coverage SSBO slot index, or -1 to disable bit updates / lookups
 		-- on the GS side. Stored as float here for VBO layout simplicity;
@@ -2333,12 +2362,12 @@ local function GenerateOrganicTree()
 		-- Vertex 0: parent end (10 floats: pos2 + data3 + grid4 + slot)
 		verts[k+1] = e.px;          verts[k+2] = e.pz
 		verts[k+3] = cap;           verts[k+4] = appearTime;  verts[k+5] = witherTime
-		verts[k+6] = eff;           verts[k+7] = flow;        verts[k+8] = phase;       verts[k+9] = isOwn
+		verts[k+6] = eff;           verts[k+7] = flow;        verts[k+8] = rootA;       verts[k+9] = isOwn
 		verts[k+10] = slot
-		-- Vertex 1: child end (same per-edge payload)
+		-- Vertex 1: child end (same per-edge payload, except rootB for its end)
 		verts[k+11] = e.cx;         verts[k+12] = e.cz
 		verts[k+13] = cap;          verts[k+14] = appearTime; verts[k+15] = witherTime
-		verts[k+16] = eff;          verts[k+17] = flow;       verts[k+18] = phase;      verts[k+19] = isOwn
+		verts[k+16] = eff;          verts[k+17] = flow;       verts[k+18] = rootB;      verts[k+19] = isOwn
 		verts[k+20] = slot
 		k = k + 20
 	end
@@ -2583,6 +2612,10 @@ function OnCableTreeFull(data)
 				e.eff      = data.effs and data.effs[i] or 0
 				e.px, e.pz = data.pxs[i], data.pzs[i]
 				e.cx, e.cz = data.cxs[i], data.czs[i]
+				-- Refresh with px/cx so the per-end root distances track the
+				-- current parent/child orientation.
+				e.rootA = data.rootAs and data.rootAs[i] or 0
+				e.rootB = data.rootBs and data.rootBs[i] or 0
 			end
 			e.isOwnAlly = ownAlly
 			-- Late-bind a coverage slot if missing (e.g., gadget was reloaded
@@ -2616,6 +2649,8 @@ function OnCableTreeFull(data)
 				maxxed   = data.maxxed[i],
 				flow     = newFlow,
 				eff      = data.effs and data.effs[i] or 0,
+				rootA    = data.rootAs and data.rootAs[i] or 0,
+				rootB    = data.rootBs and data.rootBs[i] or 0,
 				isOwnAlly = ownAlly,
 				appearFrame = af,
 				witherFrame = nil,