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Ignasi
10-08-2012, 07:21 AM
Hi,


I'm trying to paint some 2D label text in OpenGL.
I've already achieved it, but I'm having problems because I don't want the text to be always visible, I mean I would like that the DEPTH_TEST would be applied to the text rendered, but I've been unable to accomplish it.
I'm using glCallLists in order to render the text, here is a sample of more or less what I'm doing:


<CODE>

SelectObject(hDCForm, font);
wglUseFontBitmaps(hDCForm, 0, 255, IDBASELISTAFUENTETEXTO);


GLdouble modelView[16], projection[16];
GLint viewport[4];
glGetDoublev(GL_MODELVIEW_MATRIX, modelView);
glGetDoublev(GL_PROJECTION_MATRIX, projection);
glGetIntegerv(GL_VIEWPORT, viewport);


//2D mode
glMatrixMode(GL_PROJECTION);
glPushMatrix();
glLoadIdentity();
glOrtho(0.0, (GLfloat)(viewport[2] - viewport[0]), 0.0, (GLfloat)(viewport[3] - viewport[1]), -1, 1);
glMatrixMode(GL_MODELVIEW);
glPushMatrix();
glLoadIdentity();
glDisable(GL_DEPTH_TEST);

//project
double tx, ty, tz;
gluProject(position.x, position.y, position.z, modelView, projection, viewport, &tx, &ty, &tz);

//draw text
glRasterPos3d(tx, ty, tz);
glPushAttrib(GL_LIST_BIT);
glListBase(IDBASELISTAFUENTETEXTO);
glCallLists(strlen(str), GL_UNSIGNED_BYTE, str);
glPopAttrib();

//restore 3D
glMatrixMode(GL_PROJECTION);
glPopMatrix();
glMatrixMode(GL_MODELVIEW);
glPopMatrix();
glEnable(GL_DEPTH_TEST);


</CODE>


Thanks in advance

Rosario Leonardi
10-08-2012, 01:31 PM
if you want the GL_DEPTH_TEST to be enabled during the text rendering why you disable it?
Witch part of the scene should occlude your text?
From the code you posted the text is rendered with an ortho projection, usually 3d scene are rendered with perspective, how can you compare the depth of two different projections?
Can you post a picture of what you want?