CCDrawNode is extremely slow.

CCDrawNode is extremely slow.
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My game utilizes Box2d, so I require a debug renderer. I have found someone’s implementation months ago, but I was not comfortable with the fact that it draws each primitive with a separate draw call. So I’ve rewritten the renderer and now it uses CCDrawNode and draws all primitives with a single draw call. And you know what? It takes more than 50 ms on my Android device to push triangles into the buffer (if your profiler shows correct information; anyways, fps is around 15). With the previous version of debug renderer which uses a separate draw call per primitive the framerate is bound to v-sync frequency. I understand that CCDrawNode was not designed to be dynamically changed every frame, but actually there are no sane reasons that updating the buffer is SO slow.
I have fixed several issues in Cocos2d-x, but currently I have no time for this one. So I hope the developers will pay attention on it someday.


No one again??


The same poor performance in v.3.


Do you have some code which shows that CCDrawNode is slower than drawing primitives like before?


Surely I have the code, but it’s integrated in the other codebase of the game.

Actually it’s quite easy to reproduce:

  1. create a DrawNode
  2. on each frame clear the DrawNode and fill it with the new primitives.

When I met this problem first I started to profile the corresponding code and as far as I remember the majority of time is spent in this part (DrawNode::drawPolygon):

for (int i = 0; i < count; i++)
	Vertex2F v0 = __v2f(verts[(i-1+count)%count]);
	Vertex2F v1 = __v2f(verts[i]);
	Vertex2F v2 = __v2f(verts[(i+1)%count]);
	Vertex2F n1 = v2fnormalize(v2fperp(v2fsub(v1, v0)));
	Vertex2F n2 = v2fnormalize(v2fperp(v2fsub(v2, v1)));
	Vertex2F offset = v2fmult(v2fadd(n1, n2), 1.0/(v2fdot(n1, n2) + 1.0));
    struct ExtrudeVerts tmp = {offset, n2};
	extrude[i] = tmp;


Vertex2F v0 = __v2f(verts[(i-1+count)%count]);
Vertex2F v1 = __v2f(verts[i]);
Vertex2F v2 = __v2f(verts[(i+1)%count]);


Well, at least it seems to be a CPU problem, not a GPU one (much easier to fix :stuck_out_tongue: ).

For my game i’m thinking about subclassing DrawNode and rewriting DrawNode::drawX methods to avoid this type of problems (and adding some new functionality).

Are you drawing polygons with borders? If not, you should try to copy DrawNode::drawTriangle to create a method for drawing polygons without a border. A LOT of DrawNode::drawPolygon code it’s not needed if you draw them without borders :wink: .


Yeah, I don’t need borders. This stuff is not for the game itself, it’s for physics debug drawing.


If you try my idea please post the result :slight_smile:


there is a class called physics debug node


@Wuhao wrote:

there is a class called physics debug node

Sorry, but your comment is not helpful at all.

  1. PhysicsDebugNode supports Chipmunk only. If you read my first post carefully, you’d see that I use Box2d.
  2. PhysicsDebugNode utilizes DrawNode. If you read my first and third posts carefully, you’d see that I already tried using DrawNode (even the title of the topic says the same).


@dotsquid I faced same issue recently.

Do you think draw with opengl directly will be fast?

here is my github project for how to use opengl in cocos2d-x



Yes, my current dumb implementation which draws each shape with a separate draw call is faster .
I’d wish to write a single draw call solution, by I have no time for this non-priority task.