Pass:donut;

src/api/l_graphics_pass.c

@@ -517,6 +517,16 @@ static int l_lovrPassCircle(lua_State* L) {
   return 0;
 }
 
+static int l_lovrPassTorus(lua_State* L) {
+  Pass* pass = luax_checktype(L, 1, Pass);
+  float transform[16];
+  int index = luax_readmat4(L, 2, transform, -2);
+  uint32_t segmentsT = luax_optu32(L, index++, 64);
+  uint32_t segmentsP = luax_optu32(L, index++, 32);
+  lovrPassTorus(pass, transform, segmentsT, segmentsP);
+  return 0;
+}
+
 static int l_lovrPassText(lua_State* L) {
   Pass* pass = luax_checktype(L, 1, Pass);
   Font* font = luax_totype(L, 2, Font);
@@ -779,6 +789,7 @@ const luaL_Reg lovrPass[] = {
   { "cube", l_lovrPassCube },
   { "box", l_lovrPassBox },
   { "circle", l_lovrPassCircle },
+  { "torus", l_lovrPassTorus },
   { "text", l_lovrPassText },
   { "mesh", l_lovrPassMesh },
   { "multimesh", l_lovrPassMultimesh },

src/api/l_math_vectors.c

@@ -70,6 +70,9 @@ int luax_readscale(lua_State* L, int index, vec3 v, int components, const char*
     case LUA_TNUMBER:
       if (components == 1) {
         v[0] = v[1] = v[2] = luax_optfloat(L, index++, 0.f);
+      } else if (components == -2) { // -2 is special and means "2 components: xy and z"
+        v[0] = v[1] = luax_tofloat(L, index++);
+        v[2] = luax_optfloat(L, index++, 1.f);
       } else {
         v[0] = 1.f;
         for (int i = 0; i < components; i++) {

src/modules/graphics/graphics.c

@@ -2882,14 +2882,14 @@ void lovrPassBox(Pass* pass, float* transform, DrawStyle style) {
 }
 
 void lovrPassCircle(Pass* pass, float* transform, DrawStyle style, float angle1, float angle2, uint32_t segments) {
-  ShapeVertex* vertices;
-  uint16_t* indices;
-
   if (fabsf(angle1 - angle2) >= 2.f * (float) M_PI) {
     angle1 = 0.f;
     angle2 = 2.f * (float) M_PI;
   }
 
+  ShapeVertex* vertices;
+  uint16_t* indices;
+
   if (style == STYLE_LINE) {
     uint32_t vertexCount = segments + 1;
     uint32_t indexCount = segments * 2;
@@ -2942,6 +2942,59 @@ void lovrPassCircle(Pass* pass, float* transform, DrawStyle style, float angle1,
   }
 }
 
+void lovrPassTorus(Pass* pass, float* transform, uint32_t segmentsT, uint32_t segmentsP) {
+  float sx = vec3_length(transform + 0);
+  float sy = vec3_length(transform + 4);
+  float sz = vec3_length(transform + 8);
+  vec3_scale(transform + 0, 1.f / sx);
+  vec3_scale(transform + 4, 1.f / sy);
+  vec3_scale(transform + 8, 1.f / sz);
+  float radius = sx * .5f;
+  float thickness = sz * .5f;
+
+  uint32_t vertexCount = segmentsT * segmentsP;
+  uint32_t indexCount = segmentsT * segmentsP * 6;
+  ShapeVertex* vertices;
+  uint16_t* indices;
+
+  lovrPassDraw(pass, &(Draw) {
+    .mode = VERTEX_TRIANGLES,
+    .transform = transform,
+    .vertex.pointer = (void**) &vertices,
+    .vertex.count = vertexCount,
+    .index.pointer = (void**) &indices,
+    .index.count = indexCount
+  });
+
+  // T and P stand for toroidal and poloidal, or theta and phi
+  float dt = (2.f * (float) M_PI) / segmentsT;
+  float dp = (2.f * (float) M_PI) / segmentsP;
+  for (uint32_t t = 0; t < segmentsT; t++) {
+    float theta = t * dt;
+    float tx = cosf(theta);
+    float ty = sinf(theta);
+    for (uint32_t p = 0; p < segmentsP; p++) {
+      float phi = p * dp;
+      float nx = cosf(phi) * tx;
+      float ny = cosf(phi) * ty;
+      float nz = sinf(phi);
+
+      *vertices++ = (ShapeVertex) {
+        .position = { tx * radius + nx * thickness, ty * radius + ny * thickness, nz * thickness },
+        .normal = { nx, ny, nz }
+      };
+
+      uint16_t a = (t + 0) * segmentsP + p;
+      uint16_t b = (t + 1) % segmentsT * segmentsP + p;
+      uint16_t c = (t + 0) * segmentsP + (p + 1) % segmentsP;
+      uint16_t d = (t + 1) % segmentsT * segmentsP + (p + 1) % segmentsP;
+      uint16_t quad[] = { a, b, c, b, c, d };
+      memcpy(indices, quad, sizeof(quad));
+      indices += COUNTOF(quad);
+    }
+  }
+}
+
 void lovrPassText(Pass* pass, Font* font, const char* text, uint32_t length, float* transform, float wrap, HorizontalAlign halign, VerticalAlign valign) {
   if (!font) {
     font = lovrGraphicsGetDefaultFont();

src/modules/graphics/graphics.h

@@ -478,6 +478,7 @@ void lovrPassLine(Pass* pass, uint32_t count, float** vertices);
 void lovrPassPlane(Pass* pass, float* transform, DrawStyle style, uint32_t cols, uint32_t rows);
 void lovrPassBox(Pass* pass, float* transform, DrawStyle style);
 void lovrPassCircle(Pass* pass, float* transform, DrawStyle style, float angle1, float angle2, uint32_t segments);
+void lovrPassTorus(Pass* pass, float* transform, uint32_t segmentsT, uint32_t segmentsP);
 void lovrPassText(Pass* pass, Font* font, const char* text, uint32_t length, float* transform, float wrap, HorizontalAlign halign, VerticalAlign valign);
 void lovrPassMesh(Pass* pass, Buffer* vertices, Buffer* indices, float* transform, uint32_t start, uint32_t count, uint32_t instances);
 void lovrPassMultimesh(Pass* pass, Buffer* vertices, Buffer* indices, Buffer* indirect, uint32_t count, uint32_t offset, uint32_t stride);