Re: R: [Plib-users] Grrr.... I only get a black screen

[Peter P. <pet...@st...>]

Paolo Leoncini wrote:
> Peter,
> 
> try these:
> 
> 1. disable lighting (state->disable(GL_LIGHTING));
> 2. add the fourth vertex color (just three colors set for four
> vertices), or just add a single color, single normal (flat shading);
> 3. move the sgSetCoord/setCamera to the draw() section and use rotate_
> as azimuth (4th param in sgSetCoord) in order to look around.
> 
> Alternatively try loading a 3D model (get whatever 3DS model in
> internet) instead of creating the leaf internally.
> 
> Let's hope and see...
> 
> Paolo
> 
> 
> 
>>-----Messaggio originale-----
>>Da: pli...@li... 
>>[mailto:pli...@li...] Per conto di 
>>Peter Poulsen
>>Inviato: giovedì 26 agosto 2004 10.09
>>A: pli...@li...
>>Oggetto: [Plib-users] Grrr.... I only get a black screen
>>
>>
>>I have been playing around with wxWindow and ssg and I simply 
>>cannot get it 
>>working properly.
>>
>>My program can be found here: 
>>http://rafb.net/paste/results/TcxCwP78.html 
>>It shows to 
>>windows. One is drawn using ssg and _should_ show a white 
>>rectangle, but only shows a black screen. The other window is 
>>drawn using 
>>direct opengl calls, and shows (and should show) a spinning 
>>red rectangle.
>>
>>It can be compiled with this command:
>>g++ wxssg.cc -o wxssg `wx-config --cxxflags --libs --gl-libs` 
>>-lplibssg
>>-lplibul -lplibsg
>>
>>Can anybody explain to me why only the red rectangle works?
>>
>>PS. considering that it works with direct opengl calls, I 
>>don't think the 
>>problem is in wxWindow.
>>
Thanks alot! I finally got it working. I'm posting it here just for the 
archive.


#include <iostream>
#include <string>
#include <cassert>
#include <cmath>

#include <wx/wx.h>
#include <wx/glcanvas.h>
#include <wx/notebook.h>

#include <plib/ssg.h>

bool ssg_init = false;

class GL_Window : public wxGLCanvas
{
public:
	GL_Window(float c, wxWindow* parent, wxWindowID id, const wxPoint& pos, 
const wxSize& size,
			  long style=0, const wxString& name="GLCanvas", int* attribList = 0,
			  const wxPalette& palette = wxNullPalette)
		: wxGLCanvas(parent, id, pos, size, style, name, attribList, palette), 
c_(c), rotate_(c)
		{
		}
	virtual ~GL_Window() {}

	void init(int color) {
		SetCurrent();
		if(!ssg_init) {
			ssgInit();
			ssg_init = true;
		}
		ssgGetCurrentContext()->setNearFar(0.1, 10000.0);
		ssgGetCurrentContext()->setCullface(false);
			
		sgVec3 sunposn ;
		sgSetVec3(sunposn, 0.0f, -10.0f, 0.0f) ;
		ssgGetLight(0)->setPosition(sunposn) ;

		root_ = new ssgRoot;
		ssgVertexArray* vertices = new ssgVertexArray;
		sgVec3 x = { -0.5, 0.0f, -0.5 };
		sgVec3 y = { -0.5, 0.0f, 0.5 };
		sgVec3 z = { 0.5, 0.0f, 0.5 };
		sgVec3 w = { 0.5, 0.0f, -0.5 };
		
		vertices->add(z);
		vertices->add(y);
		vertices->add(x);
		vertices->add(w);

		sgVec4 white = { 1.0f, color, color, 1.0f};
		ssgColourArray* colours = new ssgColourArray;
		colours->add(white);
		ssgNormalArray* normals = new ssgNormalArray;
		sgVec3 normal = { 0, -1.0f, 0 };
		normals->add(normal);

		ssgVtxTable* n = new ssgVtxTable(GL_QUADS, vertices, normals, NULL, colours);
		ssgSimpleState* state = new ssgSimpleState () ;
		state->disable(GL_TEXTURE_2D);
		state->disable(GL_COLOR_MATERIAL);
		state->disable(GL_LIGHTING);
		n->setState(state);
		n->setCullFace(false);

		root_->addKid(n);
	}
	
	void draw() {
		rotate_ += 0.01;

		glClearColor(0.0, 0.0, 0.0, 0.0);
		glClear(GL_COLOR_BUFFER_BIT);

		SetCurrent();
		glViewport(0, 0, (GLint)200, (GLint)200);
		if(root_) {
			sgCoord coord;
			sgSetCoord(&coord, 0.0f, -2.0f, 0.0f, 5*cos(rotate_), 0.0f, 0.0f);
			ssgGetCurrentContext()->setCamera(&coord);
			ssgCullAndDraw(root_);
		}
		SwapBuffers();
	}

	void OnIdle(wxIdleEvent& event)	{
		draw();
		event.RequestMore();
	}
private:
	float c_;
	float rotate_;
	ssgRoot* root_;
	
	DECLARE_EVENT_TABLE();
};

class MyApp: public wxApp
{
	virtual bool OnInit();
};

IMPLEMENT_APP(MyApp)

bool MyApp::OnInit()
{
	wxFrame* frame = new wxFrame((wxFrame *)NULL, -1,  "Hello GL World",
								 wxPoint(50,50), wxSize(450,340) );
	frame->Show(TRUE);
	wxNotebook* book = new wxNotebook(frame, -1, wxPoint(-1,-1), wxSize(450,340));

	GL_Window* MyGLCanvas = new GL_Window(1, book, -1, wxPoint(-1,-1),
										  wxSize(200,200), wxSUNKEN_BORDER, "some text");
	book->AddPage(MyGLCanvas, "One");
	MyGLCanvas->init(1);
	
	MyGLCanvas = new GL_Window(0, book, -1, wxPoint(-1,-1),
							   wxSize(200,200), wxSUNKEN_BORDER, "some text");
	book->AddPage(MyGLCanvas, "Two");
	MyGLCanvas->init(0);
	return TRUE;
}

BEGIN_EVENT_TABLE(GL_Window, wxGLCanvas)
     EVT_IDLE(GL_Window::OnIdle)
END_EVENT_TABLE()


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