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This thread is locked; no one can reply to it.
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| I need help with my text drawing function |
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ISDcaptain
Member #15,087
May 2013
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Okay Im making a Zelda clone, and Im trying to implement that iconic Zelda text box style. You know where it makes a small beep with each letter? 1
2//Draw text function
3void drawText(char text[], int x, int y)
4{
5 //Get the size of the text
6 int n = strlen(text);
7
8 //Should the program draw the text on screen?
9 if(drawingtext)
10 {
11 //Now draw each letter in the char array
12 for(int i = 0; i < n; i++)
13 {
14 //Draw the letter
15 al_draw_text(font, al_map_rgb(255, 255, 255), x, y, NULL, text);
16
17 //Play the beep
18 al_play_sample_instance(beepInstance);
19
20 //Rest the program
21 al_rest(10);
22 }
23 }
24 else
25 return;
26}
My problem is in the function al_draw_text(), how do I draw each piece of char array at a time, rather than all of it? I want use text[i] as my parameter instead of just text. What should I do? |
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DanielH
Member #934
January 2001
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1 //Draw text function
2 void drawText(char text[], int x, int y)
3 {
4 //Get the size of the text
5 int n = strlen(text);
6
7 //Should the program draw the text on screen?
8 if(drawingtext)
9 {
10 char s[2]={0,0};
11 int px = x;
12
13 //Now draw each letter in the char array
14 for(int i = 0; i < n; i++)
15 {
16 //Draw the letter
17 //al_draw_text(font, al_map_rgb(255, 255, 255), x, y, NULL, text);
18 s[0]=text[i];
19
20 al_draw_text(font, al_map_rgb(255, 255, 255), px, y, NULL, s);
21
22 px += al_get_text_width(font,s);
23
24 //Play the beep
25 al_play_sample_instance(beepInstance);
26
27 //Rest the program
28 al_rest(10);
29 }
30 }
31 else
32 return;
33}
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SiegeLord
Member #7,827
October 2006
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I'm not sure that will respect glyph kerning... I'd personally use ALLEGRO_USTR for this: ALLEGRO_USTR_INFO info; const ALLEGRO_USTR* ustr = al_ref_buffer(&info, text, (size_t)i); al_draw_ustr(font, al_map_rgb(255, 255, 255), x, y, 0, ustr); Note that that will redraw the initial letters every time, so you need to clear the textbox every frame. I certainly would not use al_rest like that. Instead, I would increment i every 10 ticks or something (and not use a loop). Or, alternatively, I'd pass the start tick and the current tick to the drawText function and have it figure out the value of i from that. "For in much wisdom is much grief: and he that increases knowledge increases sorrow."-Ecclesiastes 1:18 |
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ISDcaptain
Member #15,087
May 2013
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Yeah im running into problems. The beep keeps on going on, and it doesn't draw each letter one at a time, I don't know what to do. |
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Kris Asick
Member #1,424
July 2001
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al_draw_textf(font, al_map_rgb(255, 255, 255), x, y, NULL, "%c", text[i]); --- Kris Asick (Gemini) |
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Edgar Reynaldo
Major Reynaldo
May 2007
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Kris - see what SiegeLord said about kerning. ISDcaptain said: Yeah im running into problems. The beep keeps on going on, and it doesn't draw each letter one at a time, I don't know what to do. Create a timer that beats as often as you want your letters to appear. Each time you get a timer event you increment a counter like n. Then when you draw, you draw n out of the total number of letters where n is the number of timer ticks passed since you started it. Each time you get a timer event play the sound. That should solve your problems. Draw it like SiegeLord suggested, with al_ref_buffer or al_ref_ustr. My Website! | EAGLE GUI Library Demos | My Deviant Art Gallery | Spiraloid Preview | A4 FontMaker | Skyline! (Missile Defense) Eagle and Allegro 5 binaries | Older Allegro 4 and 5 binaries | Allegro 5 compile guide |
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Kris Asick
Member #1,424
July 2001
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Edgar Reynaldo said: Kris - see what SiegeLord said about kerning.
*nods* Yeah, for variable width fonts, simply looping through all the characters isn't going to work very nicely without some extra code, though I thought I'd inject that little bit of code into the conversation as a quick "make it work right now" approach. Refinements can come afterwards. --- Kris Asick (Gemini) |
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ISDcaptain
Member #15,087
May 2013
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Okay how would I go about doing that with a timer? I don't know much about them other than how to use them to regulate the FPS. |
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Edgar Reynaldo
Major Reynaldo
May 2007
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These should get you started : You just need to wait for a timer event, then increment n and play a beep every time you get one. My Website! | EAGLE GUI Library Demos | My Deviant Art Gallery | Spiraloid Preview | A4 FontMaker | Skyline! (Missile Defense) Eagle and Allegro 5 binaries | Older Allegro 4 and 5 binaries | Allegro 5 compile guide |
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ISDcaptain
Member #15,087
May 2013
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K I created a timer: ALLEGRO_TIMER *textTimer = NULL How do I get it to tick with each letter: textTimer = al_create_timer(?/?); ?? I don't know what to do here. |
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Edgar Reynaldo
Major Reynaldo
May 2007
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The manual said: al_create_timer ALLEGRO_TIMER* al_create_timer(double speed_secs) Introduced in 5.0.0 Install a new timer. If successful, a pointer to a new timer object is returned, otherwise NULL is returned. speed_secs is in seconds per "tick", and must be positive. The new timer is initially stopped. The system driver must be installed before this function can be called. Usage note: typical granularity is on the order of microseconds, but with some drivers might only be milliseconds. See also: al_start_timer, al_destroy_timer Waiting on an event queue for a timer event : 1int letterCount = 0;
2ALLEGRO_TIMER* textTimer = al_create_timer(seconds_per_letter);
3ALLEGRO_EVENT_QUEUE* queue = al_create_event_queue();
4
5if (!textTimer || !queue) {Fail();}
6
7al_register_event_source(queue , al_get_timer_event_source(textTimer));
8
9// When you start writing your text :
10letterCount = 0;
11al_start_timer(textTimer);
12
13// In your program loop
14do {
15
16 ALLEGRO_EVENT ev;
17 al_wait_for_event(queue , &ev);
18
19 if (ev.type == ALLEGRO_EVENT_TIMER) {
20 ++letterCount;
21 PlayBeep();
22 redraw = true;
23 }
24} while(!al_is_event_queue_empty());
25
26if (redraw) {
27 // draw your text here
28}
My Website! | EAGLE GUI Library Demos | My Deviant Art Gallery | Spiraloid Preview | A4 FontMaker | Skyline! (Missile Defense) Eagle and Allegro 5 binaries | Older Allegro 4 and 5 binaries | Allegro 5 compile guide |
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