4 files changed, 69 insertions, 8 deletions
diff --git a/src/defines.h b/src/defines.h
index e9db543..0c0dcac 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -64,7 +64,7 @@ CORE_DEFINE_HANDLE(
 // NOTE: The below is now handled in xmake.lua
 // Platform will inform renderer backend (unless user overrides)
 #if defined(CEL_PLATFORM_LINUX)
-// #define CEL_REND_BACKEND_OPENGL 1
+#define CEL_REND_BACKEND_OPENGL 1
 // #define CEL_REND_BACKEND_VULKAN 1
 #endif
 
diff --git a/src/maths/primitives.c b/src/maths/primitives.c
index 3820426..551a5df 100644
--- a/src/maths/primitives.c
+++ b/src/maths/primitives.c
@@ -234,10 +234,6 @@ Geometry Geo_CreateUVsphere(f32 radius, u32 north_south_lines, u32 east_west_lin
   return geo;
 }
 
-Geometry Geo_CreateCylinder(f32 radius, f32 height, u32 resolution) {
-  TODO("implement cylinder meshing");
-}
-
 Geometry Geo_CreateCone(f32 radius, f32 height, u32 resolution) {
   Vertex_darray* vertices = Vertex_darray_new((resolution + 1) * 2);
   u32_darray* indices = u32_darray_new(resolution * 2 * 3);
@@ -289,4 +285,58 @@ Geometry Geo_CreateCone(f32 radius, f32 height, u32 resolution) {
     .indices = indices,
   };
   return geo;
-}
-\ No newline at end of file
+}
+
+Geometry Geo_CreateCylinder(f32 radius, f32 height, u32 resolution) {
+  Vertex_darray* vertices = Vertex_darray_new(1);
+  u32_darray* indices = u32_darray_new(1);
+
+  f32 step = TAU / resolution;
+
+  // bot cap
+  VERT_3D(vertices, VEC3_ZERO, VEC3_NEG_Y, vec2(0, 0));
+  for (u32 i = 0; i < resolution; i++) {
+      VERT_3D(vertices, vec3(cos(step * i) * radius, 0.0, sin(step * i) * radius), VEC3_NEG_Y, vec2(0, 0));
+  }
+  for (u32 i = 1; i < resolution; i++) {
+    push_triangle(indices, 0, i, i + 1);
+  }
+  push_triangle(indices, 0, resolution, 1);
+
+  // top cap
+  u32 center_idx = vertices->len;
+  VERT_3D(vertices, vec3(0.0, height, 0.0), VEC3_Y, vec2(0, 0));
+  for (u32 i = 0; i < resolution; i++) {
+    VERT_3D(vertices, vec3(cos(step * i) * radius, height, sin(step * i) * radius), VEC3_Y,
+            vec2(0, 0));
+  }
+  for (u32 i = 1; i < resolution; i++) {
+    push_triangle(indices, center_idx, center_idx + i + 1, center_idx + i);
+  }
+  push_triangle(indices, center_idx, center_idx + 1, center_idx + resolution);
+
+  // sides
+  u32 sides_start = vertices->len;
+  for (u32 i = 0; i < resolution; i++) {
+    f32 x = cos(step * i) * radius;
+    f32 z = sin(step * i) * radius;
+    // top then bottom
+    VERT_3D(vertices, vec3(x, height, z), vec3_normalise(vec3(x, 0.0, z)), vec2(0, 0));
+    VERT_3D(vertices, vec3(x, 0.0, z), vec3_normalise(vec3(x, 0.0, z)), vec2(0, 0));
+  }
+  for (u32 i = 0; i < resolution; i++) {
+      u32 current = sides_start + i * 2;
+      u32 next = sides_start + ((i + 1) % resolution) * 2;
+      push_triangle(indices, current, next, current + 1);
+      push_triangle(indices, current + 1, next, next + 1);
+  }
+
+  Geometry geo = {
+    .format = VERTEX_STATIC_3D,
+    .vertices = vertices,
+    .has_indices = true,
+    .index_count = indices->len,
+    .indices = indices,
+  };
+  return geo;
+}
diff --git a/src/render/immdraw.c b/src/render/immdraw.c
index d352ddf..8a10c65 100644
--- a/src/render/immdraw.c
+++ b/src/render/immdraw.c
@@ -28,6 +28,9 @@ void Immdraw_Init(Immdraw_Storage* storage) {
   Geometry cone_geo = Geo_CreateCone(1.0, 1.0, 8);
   storage->cone = Mesh_Create(&cone_geo, true);
 
+  Geometry cyl_geo = Geo_CreateCylinder(1.0, 2.0, 8);
+  storage->cylinder = Mesh_Create(&cyl_geo, true);
+
   storage->bbox = GenBboxMesh();
 
   // Pipeline / material
@@ -54,7 +57,7 @@ void Immdraw_Init(Immdraw_Storage* storage) {
     .vs = { .debug_name = "Immdraw Vertex Shader", .filepath = vert_path, .code = vert_shader },
     .fs = { .debug_name = "Immdraw Fragment Shader", .filepath = frag_path, .code = frag_shader },
     .depth_test = true,
-    .wireframe = false,
+    .wireframe = true,
   };
   GPU_Renderpass* rpass =
       GPU_Renderpass_Create((GPU_RenderpassDesc){ .default_framebuffer = true });
@@ -87,6 +90,12 @@ void Immdraw_Bbox(Transform tf, Vec4 colour, bool wireframe) {
   Immdraw_Primitive(tf, CEL_LINE, 1.0, colour, wireframe, imm->bbox);
 }
 
+void Immdraw_Cylinder(Transform tf, Vec4 colour, bool wireframe) {
+  TRACE("Draw cylinder");
+  Immdraw_Storage* imm = Render_GetImmdrawStorage();
+  Immdraw_Primitive(tf, CEL_TRI, 1.0, colour, wireframe, imm->cylinder);
+}
+
 void Immdraw_Cone(Transform tf, Vec4 colour, bool wireframe) {
   TRACE("Draw cone");
   Immdraw_Storage* imm = Render_GetImmdrawStorage();
@@ -164,4 +173,4 @@ Mesh GenBboxMesh() {
                    .indices = indices };
 
   return Mesh_Create(&geo, true);
-}
-\ No newline at end of file
+}
diff --git a/src/render/immdraw.h b/src/render/immdraw.h
index cf0bed5..2911350 100644
--- a/src/render/immdraw.h
+++ b/src/render/immdraw.h
@@ -13,6 +13,7 @@ typedef struct Immdraw_Storage {
   Mesh plane;
   Mesh cube;
   Mesh sphere;
+  Mesh cylinder;
   Mesh cone;
   Mesh bbox;
   GPU_Pipeline* colour_pipeline; /** @brief Pipeline for drawing geometry that has vertex colours */
@@ -31,6 +32,7 @@ PUB void Immdraw_Shutdown(Immdraw_Storage* storage);
 // These functions cause a pipeline switch and so aren't optimised for performance
 PUB void Immdraw_Plane(Transform tf, Vec4 colour, bool wireframe);
 PUB void Immdraw_Cuboid(Transform tf, Vec4 colour, bool wireframe);
+PUB void Immdraw_Cylinder(Transform tf, Vec4 colour, bool wireframe);
 PUB void Immdraw_Cone(Transform tf, Vec4 colour, bool wireframe);
 PUB void Immdraw_Sphere(Transform tf, Vec4 colour, bool wireframe);
 PUB void Immdraw_Bbox(Transform tf, Vec4 colour, bool wireframe);