HUB75: allow non-horizontal panel arrangements (e.g. vertically stacked panels)

wled00/bus_manager.cpp

@@ -615,6 +615,7 @@ void BusNetwork::cleanup() {
 // BusHub75Matrix "global" variables (static members)
 MatrixPanel_I2S_DMA* BusHub75Matrix::activeDisplay = nullptr;
 VirtualMatrixPanel*  BusHub75Matrix::activeFourScanPanel = nullptr;
+
 HUB75_I2S_CFG BusHub75Matrix::activeMXconfig = HUB75_I2S_CFG();
 uint8_t BusHub75Matrix::activeType = 0;
 uint8_t BusHub75Matrix::instanceCount = 0;
@@ -1096,7 +1097,69 @@ BusHub75Matrix::BusHub75Matrix(BusConfig &bc) : Bus(bc.type, bc.start, bc.autoWh
       fourScanPanel->setPhysicalPanelScanRate(FOUR_SCAN_64PX_HIGH);
       fourScanPanel->setRotation(0);
       break;
-  }  
+
+    // WLEDMM: non-horizontal panel arrangement for NORMAL (non four-scan) panels.
+    // A HUB75 chain is electrically always horizontal: N panels form an area of
+    // (panel width * N) x panel height. Stacking the panels physically therefore needs a mapping
+    // from logical to physical coordinates. VirtualMatrixPanel does exactly that, but so far it was
+    // only created for four-scan panels, and there hard-coded as (1, chain_length) - always a single
+    // row. Without this branch show() iterates over display->width() and wraps the image onto the
+    // physical chain width. Measured on device: a logical 64x128 area came out as 128x64, with the
+    // upper half red on BOTH panels instead of left red / right blue.
+    //
+    // The arrangement is carried in the bus "pin" field: [0] = chain length, [1] = rows,
+    // [2] = columns, [3] = PANEL_CHAIN_TYPE (0 = CHAIN_NONE, 1 = TOP_LEFT_DOWN, 2 = TOP_RIGHT_DOWN,
+    // 3 = BOTTOM_LEFT_UP, 4 = BOTTOM_RIGHT_UP, 5..8 = the ZigZag variants). Which chain type is
+    // correct depends on how the panels are wired and mounted. Example for 4 panels of 64x32
+    // stacked vertically and chained bottom-left up in a zigzag: pin: [4, 4, 1, 8].
+    // Unset values are normalised to 1, so an existing pin: [2] becomes [2, 1, 1, 0] and the
+    // arrangement stays dormant - behaviour is unchanged for every existing configuration.
+    // AI: below section was generated by an AI
+    default:
+      {
+        unsigned vRows = (bc.pins[1] == 255 || bc.pins[1] == 0) ? 1 : bc.pins[1];
+        unsigned vCols = (bc.pins[2] == 255 || bc.pins[2] == 0) ? 1 : bc.pins[2];
+        unsigned vType = (bc.pins[3] == 255) ? 0 : bc.pins[3];
+        if (vType > CHAIN_BOTTOM_LEFT_UP_ZZ) vType = 0;   // ignore out-of-range values
+
+        // Keep the arrangement metadata in sync with the configuration on EVERY pass, not only
+        // when the panel object is created. getPins() reports these members so the arrangement
+        // survives a config save - and when a bus is re-created while the display object is
+        // re-used (see "continue with existing matrix object" above), fourScanPanel is already
+        // set on this fresh instance, so the creation block below is skipped. Assigning only in
+        // there would leave the new instance at the (1,1,0) defaults, and the next config save
+        // would silently overwrite a working arrangement with "none" - unrecoverable without
+        // physical access.
+        // Deliberately also assigned when the arrangement is rejected below: what the user
+        // configured stays in the configuration, and the warning repeats on every boot.
+        _vRows = vRows; _vCols = vCols; _vChainType = vType;
+
+        if (!fourScanPanel && ((vRows > 1) || (vCols > 1))) {
+          // The arrangement must describe exactly the panels that are chained. chain_length is
+          // already capped to a sane value above, so this also bounds vRows and vCols.
+          if (vRows * vCols != mxconfig.chain_length) {
+            USER_PRINTF("MatrixPanel_I2S_DMA WARNING: %ux%u panels != chain length %u - arrangement ignored.\n",
+                        vRows, vCols, mxconfig.chain_length);
+          } else {
+            // The display is fully initialised at this point - VirtualMatrixPanel only remaps
+            // coordinates, so the allocation is the one thing left that can fail here. Without a
+            // panel object the plain horizontal chain is used, which is the previous behaviour.
+            fourScanPanel = new(std::nothrow) VirtualMatrixPanel((*display), vRows, vCols,
+                                                                 mxconfig.mx_width, mxconfig.mx_height,
+                                                                 (PANEL_CHAIN_TYPE)vType);
+            if (fourScanPanel == nullptr) {
+              USER_PRINTLN("MatrixPanel_I2S_DMA WARNING: not enough memory for the virtual arrangement - using the plain chain.");
+            } else {
+              USER_PRINTF("MatrixPanel_I2S_DMA virtual arrangement: %u rows x %u cols, chain type %u.\n",
+                          vRows, vCols, vType);
+              fourScanPanel->setRotation(0);
+            }
+          }
+        }
+      }
+      break;
+    // AI: end
+  }
 
   if (_valid) {
     _panelWidth = fourScanPanel ? fourScanPanel->width() : display->width();  // cache width - it will never change

wled00/bus_manager.h

@@ -90,7 +90,12 @@ struct BusConfig {
     if ((type >= TYPE_NET_DDP_RGB) && (type < (TYPE_NET_DDP_RGB + 16))) nPins = 4;     // virtual network bus. 4 "pins" store IP address
     else if ((type > 47) && (type < 63)) nPins = 2;                                    // (data + clock / SPI) busses - two pins
     else if (IS_PWM(type)) nPins = NUM_PWM_PINS(type);                                 // PWM needs 1..5 pins
-    else if (type >= TYPE_HUB75MATRIX && type <= (TYPE_HUB75MATRIX + 10)) nPins = 1;   // HUB75 does not use LED pins, but we need to preserve the "chain length" parameter
+    // HUB75 does not use LED pins. The "pin" array carries panel arrangement instead:
+    //   [0] chain length, [1] virtual rows, [2] virtual cols, [3] PANEL_CHAIN_TYPE
+    // Rows/cols > 1 describe a non-horizontal arrangement (e.g. panels stacked vertically),
+    // which is handled by VirtualMatrixPanel. Was 1 before - then only the chain length survived
+    // a config save, and any arrangement was silently lost.
+    else if (type >= TYPE_HUB75MATRIX && type <= (TYPE_HUB75MATRIX + 10)) nPins = 4;
     for (uint8_t i = 0; i < min(unsigned(nPins), sizeof(pins)/sizeof(pins[0])); i++) pins[i] = ppins[i];   //softhack007 fix for potential array out-of-bounds access
   }
 
@@ -440,9 +445,13 @@ class BusHub75Matrix : public Bus {
     void setBrightness(uint8_t b, bool immediate) override;
 
     uint8_t getPins(uint8_t* pinArray) const override {
+      // No real LED pins - we report back the panel arrangement so it survives a config save.
       pinArray[0] = activeMXconfig.chain_length;
-      return 1;
-    } // Fake value due to keep finaliseInit happy
+      pinArray[1] = _vRows;
+      pinArray[2] = _vCols;
+      pinArray[3] = _vChainType;
+      return 4;
+    } // Fake values due to keep finaliseInit happy
 
     void deallocatePins();
 
@@ -457,6 +466,9 @@ class BusHub75Matrix : public Bus {
   private:
     unsigned _panelWidth = 0;
     uint8_t  _colorOrder = COL_ORDER_RGB;
+    uint8_t  _vRows = 1;        // virtual panel rows (1 = classic horizontal chain)
+    uint8_t  _vCols = 1;        // virtual panel columns
+    uint8_t  _vChainType = 0;   // PANEL_CHAIN_TYPE, 0 = CHAIN_NONE
     CRGB *_ledBuffer = nullptr;
     byte *_ledsDirty = nullptr;
     // C++ dirty trick: private static variables are actually _not_ part of the class (however only visibile to class instances).