Add getIndices to ConvexShape

bjornbytes · Dec 27, 2024 · 4d27e2d · 4d27e2d
1 parent c74c1c3
commit 4d27e2d
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Showing 4 changed files with 62 additions and 0 deletions.
diff --git a/src/api/l_physics_shapes.c b/src/api/l_physics_shapes.c
@@ -1,6 +1,7 @@
 #include "api.h"
 #include "physics/physics.h"
 #include "data/image.h"
+#include "data/blob.h"
 #include "core/maf.h"
 #include "util.h"
 #include <stdlib.h>
@@ -562,6 +563,29 @@ static int l_lovrConvexShapeGetFace(lua_State* L) {
   return 1;
 }
 
+static int l_lovrConvexShapeGetIndices(lua_State* L) {
+  ConvexShape* convex = luax_checktype(L, 1, ConvexShape);
+  uint32_t icount, maxFaceVcount;
+  lovrConvexShapeGetIndicesCount(convex, &icount, &maxFaceVcount);
+  uint32_t size = icount * sizeof(uint16_t);
+  uint16_t* indices = lovrMalloc(size);
+  luax_assert(L, lovrConvexShapeGetIndices(convex, indices, maxFaceVcount));
+
+  if (lua_gettop(L) > 1 && lua_toboolean(L, 2)) {
+    Blob* blob = lovrBlobCreate(indices, size, "ConvexIndices");
+    luax_pushtype(L, Blob, blob);
+    lovrRelease(blob, lovrBlobDestroy);
+  } else {
+    lua_createtable(L, (int)icount, 0);
+    for (uint32_t i = 0; i < icount; i++) {
+      lua_pushinteger(L, indices[i] + 1);
+      lua_rawseti(L, -2, i + 1);
+    }
+    lovrFree(indices);
+  }
+  return 1;
+}
+
 static int l_lovrConvexShapeGetScale(lua_State* L) {
   ConvexShape* convex = luax_checktype(L, 1, ConvexShape);
   float scale = lovrConvexShapeGetScale(convex);
@@ -575,6 +599,7 @@ const luaL_Reg lovrConvexShape[] = {
   { "getPoint", l_lovrConvexShapeGetPoint },
   { "getFaceCount", l_lovrConvexShapeGetFaceCount },
   { "getFace", l_lovrConvexShapeGetFace },
+  { "getIndices", l_lovrConvexShapeGetIndices },
   { "getScale", l_lovrConvexShapeGetScale },
   { NULL, NULL }
 };

diff --git a/src/modules/physics/physics.c b/src/modules/physics/physics.c
@@ -2320,6 +2320,35 @@ uint32_t lovrConvexShapeGetFace(ConvexShape* shape, uint32_t index, uint32_t* po
   return JPH_ConvexHullShape_GetFaceVertices(hull, index, capacity, pointIndices);
 }
 
+bool lovrConvexShapeGetIndicesCount(ConvexShape* shape, uint32_t* icount, uint32_t* maxFaceVcount) {
+  const JPH_ConvexHullShape* hull = (const JPH_ConvexHullShape*) JPH_DecoratedShape_GetInnerShape((const JPH_DecoratedShape*) shape->handle);
+  *icount = 0;
+  *maxFaceVcount = 0;
+  for (int i = 0; i < JPH_ConvexHullShape_GetNumFaces(hull); i++) {
+    int n = JPH_ConvexHullShape_GetNumVerticesInFace(hull, i);
+    *maxFaceVcount = MAX(*maxFaceVcount, n);
+    *icount = *icount + (n - 2) * 3;
+  }
+  return true;
+}
+
+bool lovrConvexShapeGetIndices(ConvexShape* shape, uint16_t* indices, uint32_t maxFaceVcount) {
+  const JPH_ConvexHullShape* hull = (const JPH_ConvexHullShape*) JPH_DecoratedShape_GetInnerShape((const JPH_DecoratedShape*) shape->handle);
+  uint32_t* fvs = lovrMalloc(maxFaceVcount * sizeof(uint32_t));
+  uint32_t idx = 0;
+  for (int i = 0; i < JPH_ConvexHullShape_GetNumFaces(hull); i++) {
+    int n = JPH_ConvexHullShape_GetFaceVertices(hull, i, maxFaceVcount, fvs);
+    for (int i = 2; i < n; i++) {
+      indices[idx] = fvs[0];
+      indices[idx + 1] = fvs[i - 1];
+      indices[idx + 2] = fvs[i];
+      idx += 3;
+    }
+  }
+  lovrFree(fvs);
+  return true;
+}
+
 float lovrConvexShapeGetScale(ConvexShape* shape) {
   JPH_Vec3 v;
   JPH_ScaledShape_GetScale((JPH_ScaledShape*) shape->handle, &v);

diff --git a/src/modules/physics/physics.h b/src/modules/physics/physics.h
@@ -260,6 +260,8 @@ uint32_t lovrConvexShapeGetPointCount(ConvexShape* shape);
 bool lovrConvexShapeGetPoint(ConvexShape* shape, uint32_t index, float point[3]);
 uint32_t lovrConvexShapeGetFaceCount(ConvexShape* shape);
 uint32_t lovrConvexShapeGetFace(ConvexShape* shape, uint32_t index, uint32_t* pointIndices, uint32_t capacity);
+bool lovrConvexShapeGetIndicesCount(ConvexShape* shape, uint32_t* icount, uint32_t* maxFaceVcount);
+bool lovrConvexShapeGetIndices(ConvexShape* shape, uint16_t* indices, uint32_t maxFaceVcount);
 float lovrConvexShapeGetScale(ConvexShape* shape);
 
 MeshShape* lovrMeshShapeCreate(uint32_t vertexCount, float vertices[], uint32_t indexCount, uint32_t indices[], float scale);

diff --git a/test/lovr/physics.lua b/test/lovr/physics.lua
@@ -98,6 +98,12 @@ group('physics', function()
         mesh:setIndices({ 1, 2, 3, 1, 3, 4, 1, 2, 4, 2, 3, 4 })
         shape = lovr.physics.newConvexShape(mesh)
         expect(shape:getPointCount()).to.equal(4)
+        expect(shape:getIndices()).to.equal({
+          1, 2, 3,
+          2, 4, 3,
+          4, 1, 3,
+          1, 4, 2
+        })
       end
     end)