add chip description tooltip for systems in new song dialog (#1242)

* add chip description tooltip for systems in new song dialog

* give BeginTooltip() for chip descriptions its own line in code

src/gui/newSong.cpp

@@ -113,7 +113,35 @@ void FurnaceGUI::drawNewSong() {
             nextDescName=i.name;
             accepted=true;
           }
+          if (ImGui::IsItemHovered()) {
+            if (ImGui::BeginTooltip()) {
+              std::map<DivSystem, int> chipCounts;
+              std::vector<DivSystem> chips;
+              for (FurnaceGUISysDefChip chip: i.orig) {
+                if (chipCounts.find(chip.sys) == chipCounts.end()) {
+                  chipCounts[chip.sys] = 1;
+                  chips.push_back(chip.sys);
+                }
+                else {
+                  chipCounts[chip.sys] += 1;
+                }
+              }
+              int num_chips = chips.size();
+              for (int chipIndex = 0; chipIndex < num_chips; chipIndex++) {
+                DivSystem chip = chips[chipIndex];
+                const DivSysDef* sysDef = e->getSystemDef(chip);
+                ImGui::Text("%s (x%d): ", sysDef->name, chipCounts[chip]);
+                ImGui::TextWrapped("%s", sysDef->description);
+                if (chipIndex + 1 < num_chips) {
+                  ImGui::Separator();
+                }
+              }
+
+              ImGui::EndTooltip();
+            }
+          }
         }
+
         ImGui::EndTable();
       }