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2D TTF Text Rendering with SDL & OpenGL Issues


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#1 Jevi   Members   -  Reputation: 127

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Posted 15 July 2012 - 08:19 PM

So I have looked around and I haven't found the best way to actually implement this in SDL & OpenGL. At this moment I can display text to the screen with a TTF but its not really displaying the text the way it should be. Attached is a screen shot of how the engine looks like when displaying text. Basically from what I can see in my code, I think what is happening is that I am not blitting my text texture with the my main SDL_Surface that I am using as my window. I say that because in the picture my character who has a red collision box around him is being covered up my the text texture I'm rendering my text with. Any ideas of what I can do?

All the engine code can be found here: https://github.com/Jevi/SDL_GL_ENGINE

In my game loop I call beginDraw() and endDraw() before and after I draw everything to the screen.

void graphics::SDL_GL_RenderText(float x1, float y1, int width, int height, const char* text, int ptsize, const char* ttfLoc, int r, int g, int b){
SDL_Surface* temp;
SDL_Surface* temp2;
SDL_Rect rect;
TTF_Font* font;
SDL_Color textColor;
unsigned int texture;
font = TTF_OpenFont( ttfLoc , ptsize );
textColor.r = r;
textColor.g = g;
textColor.b = b;
temp = TTF_RenderText_Blended( font, text, textColor );
// width = nextpoweroftwo(width);
// height = nextpoweroftwo(height);
temp2 = SDL_CreateRGBSurface(0, width, height, 32, r, g, b, 0);
SDL_BlitSurface(temp, 0, temp2, 0);
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, temp2->w, temp2->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, temp2->pixels);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
/* prepare to render our texture */
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, texture);
glColor3f(1.0f, 1.0f, 1.0f);
/* Draw a quad at location */
glBegin(GL_QUADS);
glTexCoord2d(0,0);
glVertex2f(x1, y1);
glTexCoord2d(1,0);
glVertex2f(x1 + temp2->w, y1);
glTexCoord2d(1,1);
glVertex2f(x1 + temp2->w, y1 + temp2->h);
glTexCoord2d(0,1);
glVertex2f(x1, y1 + temp2->h);
glEnd();
glFinish();
glDisable(GL_BLEND);
glDisable(GL_TEXTURE_2D);
SDL_FreeSurface(temp);
SDL_FreeSurface(temp2);
TTF_CloseFont(font);
glDeleteTextures(1, &texture);
}


void graphics::GL_BeginDraw(){
glClear(GL_COLOR_BUFFER_BIT);
glPushMatrix(); //Start rendering phase
glOrtho(0,width,height,0,-1,1); //Set the matrix
}

void graphics::GL_EndDraw(){
glPopMatrix(); //End rendering phase
SDL_GL_SwapBuffers();
glFinish();
}

P.S: I'm going to make another post for this but I might as well ask this also if you guys are already looking at my code. I have been noticing some memory issues with the engine. In task manager the memory allocated to my program is constantly climbing since its starts at around 11000 K. Help with that would also be appreciated. Thanks

Attached Thumbnails

  • engineExample.png

Edited by Jevi, 16 July 2012 - 04:23 PM.


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