OpenGL ES text rendering as a block

[QuantumDoja]

Hi, I am trying just to draw some text on the screen with opengl es, I always however end up with the text as a huge green box...any ideas?

code:

- (void)drawView {

[EAGLContext setCurrentContext:context];

_textures[0] = [[Texture2D alloc] initWithString:@"hello" dimensions:CGSizeMake(1, 1) alignment:UITextAlignmentLeft fontName:@"Arial" fontSize:14];

//Set up OpenGL projection matrix
glMatrixMode(GL_PROJECTION);
glMatrixMode(GL_MODELVIEW);

//Initialize OpenGL states
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_TEXTURE_2D);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);


glClearDepthf(1.0f);

glBindFramebufferOES(GL_FRAMEBUFFER_OES, viewFramebuffer);
glViewport(0, 0, backingWidth, backingHeight);

glLoadIdentity();

glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

GLfloat line[] = {
-0.5f, -0.5f, //point A
0.5f, -0.5f, //point B
};
GLfloat xxx[] = {
-0.0f, -0.5f, //point A
-0.5f, -0.2f, //point B
};

GLfloat spinline[] = {
-0.5f, 0.0f, //point A
0.5f, 0.0f, //point B
};

glColor4f(0.0f,1.0f,0.0f,1.0f);//Change the object color to green

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
[_textures[0] drawAtPoint:CGPointMake(0, 0)];
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);

glColor4f(1.0f,0.0f,0.0f,1.0f);

glEnableClientState( GL_VERTEX_ARRAY );
glEnableClientState( GL_TEXTURE_COORD_ARRAY );

glVertexPointer(2, GL_FLOAT, 0, line);
glDrawArrays(GL_LINES, 0, 2);

glVertexPointer(2, GL_FLOAT, 0, xxx);
glDrawArrays(GL_LINES, 0, 2);

glVertexPointer(2, GL_FLOAT, 0, spinline);
glDrawArrays(GL_LINES, 0, 2);


glBindRenderbufferOES(GL_RENDERBUFFER_OES, viewRenderbuffer);
[context presentRenderbuffer:GL_RENDERBUFFER_OES];
}

[QuantumDoja]

*bump* - anyone have any ideas?

[scottiphone]

Try drawing a simple shape first to make sure your codes working as expect. Next load an image into a texture and use that. If you get those working then double check your usage of the text in texture calls.

[papillon68]

Did anyone solve this ? I'm stuck exactly with that green box, and no text showing ...

[tophat02]

Try adding:

glDisableClientState(GL_COLOR_ARRAY);

To Texture2D's drawAtRect and drawAtPoint functions, that ended up working for me.

[ME_IS_NSFW]

The thread is now a little bit old, but I came across it while searching to solve the same problem. No luck finding info but I did manage to solve it anyway.

For me I ended up fixing it by figuring out that the GL renderstate was wrong...basically, texturing and blending states were the issues and solved by the first three lines of the following...

	glEnable(GL_BLEND);
	glEnable(GL_TEXTURE_2D );
	glEnableClientState( GL_TEXTURE_COORD_ARRAY );	
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	glColor4f( 0.0f, 1.0f, 0.5f, 1.0f );
	[texture drawAtPoint:CGPointMake( 0, 0 )];

[Proxus]

Originally Posted by tophat02

Try adding:

glDisableClientState(GL_COLOR_ARRAY);

To Texture2D's drawAtRect and drawAtPoint functions, that ended up working for me.

I am having the same problem. My string texture is rendering as a solid color block.

I have the correct blend mode enabled (glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)) and I have added glDisableClientState(GL_COLOR_ARRAY); to my drawAtPoint function yet it continues to be a solid block of color

Any ideas on how to fix?

[EDIT]: hahahahahaha oh man, I was just missing glEnable(GL_BLEND); Thanks ME_IS, your post made me double check haha.

[lokidil]

lBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA);

Texture2D *text=[[Texture2D alloc] initWithString:@"Hello" dimensions:CGSizeMake(256, 256) alignment:UITextAlignmentLeft fontName:@"Arial" fontSize:14];

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

To display the text above code is ok.Then how to rotate the text using the texture2d class!!!