[sparticle] 2d hud particles (#849)

* wip, taking a break to work on asm stuff first

* the goal code for sparticle

* mips2c the first sparticle asm function

* temp

* particle processing no longer crashing

* temp

* working texture cache for vi1 and hud textures

* sprites

* cleanup 1

* temp

* temp

* add zstd library

* temp

* working

* tests

* include fix

* uncomment

* better decomp of sparticle stuff, part 1

* update references

decompiler/Function/CfgVtx.cpp

@@ -59,6 +59,18 @@ void CfgVtx::replace_succ_and_check(CfgVtx* old_succ, CfgVtx* new_succ) {
   assert(replaced);
 }
 
+void CfgVtx::remove_pred(CfgVtx* to_remove) {
+  bool found = false;
+  for (auto it = pred.begin(); it != pred.end(); it++) {
+    if (*it == to_remove) {
+      pred.erase(it);
+      found = true;
+      break;
+    }
+  }
+  assert(found);
+}
+
 /*!
  * Replace references to old_preds with a single new_pred.
  * Doesn't insert duplicates.
@@ -477,7 +489,15 @@ bool ControlFlowGraph::is_while_loop(CfgVtx* b0, CfgVtx* b1, CfgVtx* b2) {
   if (!b0 || !b1 || !b2)
     return false;
 
+  bool debug = b0->to_string() == "Seq CONDNE104 ... Block 18100";
+
+  if (debug) {
+    fmt::print("try while: {} | {} | {}\n", b0->to_string(), b1->to_string(), b2->to_string());
+  }
+
   if (b0->end_branch.asm_branch || b1->end_branch.asm_branch) {
+    if (debug)
+      fmt::print("reject 1 {} {}\n", b0->end_branch.asm_branch, b1->end_branch.asm_branch);
     return false;
   }
 
@@ -1101,10 +1121,19 @@ bool ControlFlowGraph::clean_up_asm_branches() {
       return true;
     }
 
-    if (!b0->end_branch.asm_branch) {
+    if (!b0->end_branch.asm_branch || !b0->end_branch.has_branch) {
       return true;
     }
 
+    if (b1->succ_branch == b1) {
+      // asm branch to yourself. just remove it.
+      b1->succ_branch = nullptr;
+      b1->end_branch.has_branch = false;
+      b1->remove_pred(b1);
+      replaced = true;
+      return false;
+    }
+
     // don't want to combine two with an incoming edge in between.
     if (b1->pred.size() > 1) {
       return true;
@@ -2094,6 +2123,10 @@ bool ControlFlowGraph::find_cond_n_else() {
           return true;
         }
 
+        if (prev_condition->end_branch.asm_branch) {
+          return true;
+        }
+
         // prev_body should fall through to end todo - this was wrong?
         if (prev_body->succ_ft != end_block) {
           printf("reject 7\n");