[graphics] merc2 renderer (#1374)

* tfrag3 data for merc2

* dma hooks for merc2

* start designing merc2 opengl, seems like the simple approach will be the best here

* before bone packing experiment

* fix up bones.gc

* use uniform buffer

* speedup, fix faces and eyes

* final fixes

decompiler/level_extractor/extract_common.cpp

@@ -0,0 +1,44 @@
+#include "extract_common.h"
+
+u32 clean_up_vertex_indices(std::vector<u32>& idx) {
+  std::vector<u32> fixed;
+  u32 num_tris = 0;
+
+  bool looking_for_start = true;
+  size_t i_of_start;
+  for (size_t i = 0; i < idx.size(); i++) {
+    if (looking_for_start) {
+      if (idx[i] != UINT32_MAX) {
+        looking_for_start = false;
+        i_of_start = i;
+      }
+    } else {
+      if (idx[i] == UINT32_MAX) {
+        looking_for_start = true;
+        size_t num_verts = i - i_of_start;
+        if (num_verts >= 3) {
+          if (!fixed.empty()) {
+            fixed.push_back(UINT32_MAX);
+          }
+          fixed.insert(fixed.end(), idx.begin() + i_of_start, idx.begin() + i);
+          num_tris += (num_verts - 2);
+        }
+      }
+    }
+  }
+
+  if (!looking_for_start) {
+    size_t num_verts = idx.size() - i_of_start;
+    if (num_verts >= 3) {
+      if (!fixed.empty()) {
+        fixed.push_back(UINT32_MAX);
+      }
+      fixed.insert(fixed.end(), idx.begin() + i_of_start, idx.begin() + idx.size());
+      num_tris += (num_verts - 2);
+    }
+  }
+
+  idx = std::move(fixed);
+
+  return num_tris;
+}