imGui bindings

rrraptor · August 2020

antix said:
@rrraptor That's a great idea but personally I don't think it's worthwhile. I say that because I don't see Gideros ever being able to make apps that need a user interfaces as complex as that since Gideros is really a gaming platform, not a utility platform.

You dont have to create apps. What if I want to create a city building simulator or something like Factorio or maybe a strategy game? In all cases, the UI will be pretty complex.
Check this out.

antix said:
Also.. your little GUI framework is very good and more than Gideros needs I'd say

No, it is missing a lot of stuff, like drop downs, popups, text input dialogs (single line and nultiline) and e.t.c.

As I said, I can try to create a binding, but I dont know where to start. It sounds not that hard:

Integrating Dear ImGui within your custom engine is a matter of
1) wiring mouse/keyboard/gamepad inputs
2) uploading one texture to your GPU/render engine
3) providing a render function that can bind textures and render textured triangles.

But the only thing that I can do by my self is mouse and keyboard inputs, but not the drawing stuff.

hgy29 · August 2020

I can help with the drawing stuff, luckily gideros has internal apis usable by plugins for that.

rrraptor · August 2020

hgy29 said:
I can help with the drawing stuff, luckily gideros has internal apis usable by plugins for that.

It look like this, right?

static Application* application;
static lua_State *L;
 
class ImGuiSprite {
public:
	ImGuiSprite(LuaApplication* application, lua_State *L);
	virtual ~ImGuiSprite();
	SpriteProxy *proxy_;
	void doDraw(const CurrentTransform&, float sx, float sy, float ex, float ey);
private:
	void drawMesh();
	LuaApplication* application_;
 
	// declare vertex and color arrays to be able to draw triangles?
};
 
static void b2PSS_Draw(void *c, const CurrentTransform&t, float sx, float sy,
		float ex, float ey) {
	((ImGuiSprite *) c)->doDraw(t, sx, sy, ex, ey);
}
 
static void b2PSS_Destroy(void *c) {
	delete ((ImGuiSprite *) c);
}
 
ImGuiSprite::ImGuiSprite(LuaApplication* application, lua_State *L)
{
	application_ = application;	
	proxy_ = gtexture_get_spritefactory()->createProxy(application->getApplication(), this, b2PSS_Draw, b2PSS_Destroy);
}
 
ImGuiSprite::~ImGuiSprite() {
	delete proxy_;
	// gevent_RemoveEventsWithGid(gid);
}
 
int createSpineSprite(lua_State *L) {
	LuaApplication* application = static_cast<LuaApplication*>(luaL_getdata(L));
	::application = application->getApplication();
	Binder binder(L);
	ImGuiSprite *ps = new ImGuiSprite(application, L);
 
	binder.pushInstance("SpineSprite", ps->proxy_);
 
	luaL_rawgetptr(L, LUA_REGISTRYINDEX, &keyWeak);
	lua_pushvalue(L, -2);
	luaL_rawsetptr(L, -2, ps);
	lua_pop(L, 1);
 
	return 1;
}

I tried to compile this, but got an error... I dont realy remember what kind of error, but it was related to "binder.pushInstance".

hgy29 · August 2020

Yes, something like that. It is more complex than for other plugins as you need full Gideros source tree, but you are on the right track.

hgy29 · August 2020

I think the issue was that 'binder' class isn't actually visible from plugins, so you have to compile it inside the plugin by including "luabinding/binder.cpp" inside your plugin

keszegh · August 2020

Thanks @rrraptor for working on this, it will be an awesome addition.

rrraptor · August 2020

hgy29 said:
I think the issue was that 'binder' class isn't actually visible from plugins, so you have to compile it inside the plugin by including "luabinding/binder.cpp" inside your plugin

Ty, that worked

~~Btw, can I setup qt so it will put the dll to "plugins" folder ?~~
Solved

DESTDIR = ../../../plugins/

rrraptor · August 2020

Finally I figured out how to get ImGui to work

It successfully generated a default font and seems like mouse inputs also works.

MoKaLux · August 2020

Wonderful rrraptor, with this addition gideros will be number 1

rrraptor · August 2020

@hgy29 how can I redefine a ImGui assertion macro to get error messages ?

It says that you need to change macro in imgui.h:

//---- Define assertion handler. Defaults to calling assert().
// If your macro uses multiple statements, make sure is enclosed in a 'do { .. } while (0)' block so it can be used as a single statement.
//#define IM_ASSERT(_EXPR)  MyAssert(_EXPR)
//#define IM_ASSERT(_EXPR)  ((void)(_EXPR))     // Disable asserts

But in order to use lua_error(lua_State *L) I need a lua_State. But idk how to get/use it in macro.

Example use of IM_ASSERT:

 IM_ASSERT(g.Initialized);
IM_ASSERT((g.IO.DeltaTime > 0.0f || g.FrameCount == 0)              && "Need a positive DeltaTime!");
...
IM_ASSERT(text != NULL);

hgy29 · August 2020

Something like:

#include "glog.h" //From gideros SDK
#define IM_ASSERT( exp ) \
    ( (exp) ? (void)0 : glog_v("Failed assertion at %s:%d %s\n",  __FILE__,__LINE__, #exp))

Log will be sent to the debugger. If you are on windows, you can use DebugView to see them without a debugger.

rrraptor · August 2020

@hgy29 I'll try. I made simpliest version, and seems like it works. Now its time to create drawing stuff?

Plugin source is attached. There is a "MyImGuiRenderFunction" function that handles the drawing stuff. ImGui initialization in "initImGui" function.

Demo code:

require "ImGui"
 
local imgui = ImGui.new()
stage:addChild(imgui)
 
function enterFrame(e)
	imgui:NewFrame(e)
 
	imgui:Begin("My window")
	imgui:Text("Hello world")
	imgui:End()
 
	imgui:EndFrame()
	imgui:Render()
end
 
stage:addEventListener("mouseDown", function(e) imgui:onMouseDown(e) end)
stage:addEventListener("mouseUp", function(e) imgui:onMouseUp(e) end)
stage:addEventListener("mouseHover", function(e) imgui:onMouseHover(e) end)
stage:addEventListener("enterFrame", enterFrame)

Result shoud be something like this:

P.S. I forgot about screen resolution

Its 200x200 by default

keszegh · August 2020

i see imGui is not following the sprite hierarchy philosophy, instead the 'redraw on each frame' philosophy. that's a bit inconvenient, in gideros code it will look strange, but i guess we can live with it.

rrraptor · August 2020

keszegh said:
i see imGui is not following the sprite hierarchy philosophy, instead the 'redraw on each frame' philosophy. that's a bit inconvenient, in gideros code it will look strange, but i guess we can live with it.

It is called "Immediate" mode.

http://forum.giderosmobile.com/discussion/comment/63638/#Comment_63638

Anyways, I think it is easier to create a binding of existing GUI library rather than trying to create you own solution from scratch. Also, I will coninue working on my "retained" lib

hgy29 · August 2020

@rraptor, here is your main.cpp modified for rendering.
New init code from lua: wpre lang="lua">
local imgui = ImGui.new(application:getContentWidth(),application:getContentHeight())

Result:

rrraptor · August 2020

hgy29 said:
@rraptor, here is your main.cpp modified for rendering.

Whoa, amazing

rrraptor · August 2020

Something went wrong

~~Light theme does not work corectly~~ (is just me, nevermind

). Clipping does not work corectly.

P.S. Fixed mouse.

hgy29 · August 2020

rrraptor said:
Clipping does not work corectly.

Now you say that, I didn't pay much attention to clipping values, and assumed they were x,y,w,h while they seem to be x1,y1,x2,y2 instead.
Try to change

engine->pushClip((int)(pcmd->ClipRect.x - pos.x), (int)(pcmd->ClipRect.y - pos.y), (int)(pcmd->ClipRect.z - pos.x), (int)(pcmd->ClipRect.w - pos.y));

into

engine->pushClip((int)(pcmd->ClipRect.x - pos.x), (int)(pcmd->ClipRect.y - pos.y), (int)(1+pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(1+pcmd->ClipRect.w - pcmd->ClipRect.y));

(I am not sure about the '1+')

rrraptor · August 2020

hgy29 said:
rrraptor said:
Clipping does not work corectly.
Now you say that, I didn't pay much attention to clipping values, and assumed they were x,y,w,h while they seem to be x1,y1,x2,y2 instead.
Try to change
engine->pushClip((int)(pcmd->ClipRect.x - pos.x), (int)(pcmd->ClipRect.y - pos.y), (int)(pcmd->ClipRect.z - pos.x), (int)(pcmd->ClipRect.w - pos.y));
into
engine->pushClip((int)(pcmd->ClipRect.x - pos.x), (int)(pcmd->ClipRect.y - pos.y), (int)(1+pcmd->ClipRect.z - pcmd->ClipRect.x), (int)(1+pcmd->ClipRect.w - pcmd->ClipRect.y));
(I am not sure about the '1+')

Ok, that works, ty.

1 more question. Lines are sharp, but in original they are smooth.

hgy29 · August 2020

rrraptor said:

1 more question. Lines are sharp, but in original they are smooth.

I don't know for that one

rrraptor · August 2020

hgy29 said:

rrraptor said:

1 more question. Lines are sharp, but in original they are smooth.
I don't know for that one

Premultiplied alpha maybe?

hgy29 · August 2020

Yes, it looks better when premultiplying with alpha.
I changed render code for colors with

           uint32_t c=vtx_buffer[i].col;
           uint32_t a=(c&0xFF000000)>>24;
           uint32_t b=(c&0xFF0000)>>16;
           uint32_t g=(c&0xFF00)>>8;
           uint32_t r=(c&0xFF)>>0;
           colors[i].b=(b*a)>>8;
           colors[i].g=(g*a)>>8;
           colors[i].r=(r*a)>>8;
           colors[i].a=a;

instead of just

colors[i]=vtx_buffer[i].col;

and changed the definitions of the colors buffer too:

    struct _Color {
        uint8_t r,g,b,a;
    };
    VertexBuffer<_Color> colors;

rrraptor · August 2020

Yay, so much better

SinisterSoft · August 2020

Wow!

keszegh · August 2020

@SinisterSoft, i knew that adding this cannot be that hard, finally we are lucky to have @rrraptor around to do the dirty job with the help of @hgy29. thanks for you all.

keszegh · August 2020

btw guys, how does this 'immediate' mode affect performance? there is a lot of lua code that needs to be run at each enterframe.

rrraptor · August 2020

keszegh said:
btw guys, how does this 'immediate' mode affect performance? there is a lot of lua code that needs to be run at each enterframe.

I cant tell you right now, because the entire lua code looks like that:

require "ImGui"
 
local imgui = ImGui.new()
stage:addChild(imgui)
 
function enterFrame(e)
	imgui:NewFrame(e)
 
	imgui:ShowDemoWindow()
 
	imgui:EndFrame()
	imgui:Render()
end
 
stage:addEventListener("mouseDown", function(e) imgui:onMouseDown(e) end)
stage:addEventListener("mouseUp", function(e) imgui:onMouseUp(e) end)
stage:addEventListener("mouseHover", function(e) imgui:onMouseHover(e) end)
stage:addEventListener("mouseMove", function(e) imgui:onMouseMove(e) end)
stage:addEventListener("enterFrame", enterFrame)

"ShowDemoWindow" uses built-in function.

But I just looked at CPU usage in windows task manager and its about 2-4%

rrraptor · August 2020

@hgy29 how can I get keyboard modifiers? I dont see any method in "LuaApplication" or "Application" that can help me. Also, can I add callback to detect if window is resized/lose focus without using lua?

rrraptor · August 2020

Is it problem from my side or renderer side? Texture is streched on the edges.

Code:

void* getTexture(lua_State *L, int idx = 1)
{
    Binder binder(L);
 
    if (binder.isInstanceOf("TextureBase", idx))
    {
        TextureBase* textureBase = static_cast<TextureBase*>(binder.getInstance("TextureBase", idx));
        return (void *)textureBase->data->gid;
    }
    else if (binder.isInstanceOf("TextureRegion", idx))
    {
        BitmapData* bitmapData = static_cast<BitmapData*>(binder.getInstance("TextureRegion", idx));
        return (void *)bitmapData->texture()->data->gid;
    }
    else
    {
        lua_pushstring(L, "Type mismatch. 'TextureBase' or 'TextureRegion' expected.");
        lua_error(L);
    }
}

int ImGui_impl_Image(lua_State *L)
{
    void *tex = getTexture(L, 2);
    float w = luaL_checknumber(L, 3);
    float h = luaL_checknumber(L, 4);
    const ImVec2& size = ImVec2(w, h);
    ImGui::Image(tex, size);
    return 0;
}

hgy29 · August 2020

I think this is a NPOT texture size issue. Gideros makes textures power of two, expending your 320 to 512 internally, but of course that changes the uv mappings and Imgui won’t know.

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