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| A5 can't get load_bitmap to find image |
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kyle motherwell
Member #11,111
July 2009
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Hey people, I was here a while ago learning A4 then I took a short break, I came back just a few days ago and A5 appears to have been out for a bit, I had a look at it and looked at some examples and such, I wanted to see if I could load an image and draw it to the screen so I created a bitmap object and set it to NULL then I tried to assign it an image from my HDD called bob, which is a bitmap image. The problem is when the program runs I get an exception : First-chance exception at 0x00000000 in AllegroProject.exe: 0xC0000005: Access violation. Unhandled exception at 0x00000000 in AllegroProject.exe: 0xC0000005: Access violation. I presume this is because the image assign fails because it can't find my image, I tried quite a few things to get this working, first I tried an absolute path, which did not work, then I put it in the same folder as the .exe that also did not work, I also tried something using the path "hack" someone was calling it although I only partially understood what it was doing and it kept failing at compile so I left it. So I would really appreciate it if someone could tell me whats wrong with my program. Line that is the main culprit: al_load_bitmap("bob.bmp"); |
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Trent Gamblin
Member #261
April 2000
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Please post some source code. Use <code></code> tags.
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Matthew Leverton
Supreme Loser
January 1999
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Call al_init_image_addon() first. |
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kyle motherwell
Member #11,111
July 2009
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To mat, I just put it in now and it still seems to give exceptions. 1#include "stdafx.h"
2#include <stdio.h>
3#include <allegro5/allegro.h>
4#include <allegro5/allegro_image.h>
5
6int main(int argc, char **argv)
7{
8
9//Create a display and an event queue
10 ALLEGRO_DISPLAY *display = NULL;
11 ALLEGRO_EVENT_QUEUE *event_queue = NULL;
12 ALLEGRO_BITMAP * testBMP = NULL;
13
14 al_init_image_addon();
15
16al_load_bitmap("bob.bmp");
17
18 if(!testBMP)
19 {
20 fprintf(stderr,"failed to initialize testBMP!\n");
21 return -1;
22
23 }
24
25
26 if(!al_init_image_addon())
27 {
28 fprintf(stderr,"failed to initialize image addon!\n");
29 return -1;
30
31 }
32
33
34
35
36 //Test if allegro failed to initiliaze, if it did print a message to the console and leave with error code -1
37 if(!al_init()) {
38 fprintf(stderr, "failed to initialize allegro!\n");
39 return -1;
40 }
41 //Set the display by assisnging it the properties returned from the function al_create_display(640, 480) this sets the display to a resoloution of 640x480
42 display = al_create_display(640, 480);
43
44 //check to see if the display was properly set
45 if(!display) {
46 fprintf(stderr, "failed to create display!\n");
47 return -1;
48 }
49
50 //Create an even queue, event queues can be filled with different evens that happen from sources, sources include keyboard, mouse and display, we will use display
51 event_queue = al_create_event_queue();
52
53 //We check if the queue was set properly
54 if(!event_queue) {
55 fprintf(stderr, "failed to create event_queue!\n");
56 al_destroy_display(display);
57 return -1;
58 }
59
60 //We set the queue to watch all the events from the source, our source is the display, so resizing or closing the window would be an event for the display
61 al_register_event_source(event_queue, al_get_display_event_source(display));
62
63 //We clear the screen to the colour black
64 al_clear_to_color(al_map_rgb(0,0,0));
65
66 //We swap the drawing buffer to show our changes since we last swapped buffers, search up double buffering to find out more about what this means
67 al_flip_display();
68
69
70 while(1)
71 {
72 //We createa an event to hold the event
73 ALLEGRO_EVENT ev;
74 //A timeout to be initiliased
75 ALLEGRO_TIMEOUT timeout;
76 //Here we initliase timeout and set it to 0.06, or 60 miliseconds
77 al_init_timeout(&timeout, 0.06);
78
79 //Here the bool is assigned either true of false depending if the event queue is updated with an event or it gets set to false if the timeout occurs before the event finishes.
80 bool got_event = al_wait_for_event_until(event_queue, &ev, &timeout);
81
82 //We check if the event was close
83 if(got_event && ev.type == ALLEGRO_EVENT_DISPLAY_CLOSE) {
84
85 //This ends the program loop, closing the program
86 break;
87 }
88
89 //Clear to black and swap buffers
90 al_clear_to_color(al_map_rgb(0,0,0));
91 al_flip_display();
92 }
93
94 //Destroy display object and queue object
95 al_destroy_display(display);
96 al_destroy_event_queue(event_queue);
97
98
99 return 0;
100}
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Trent Gamblin
Member #261
April 2000
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You've got it in there twice now, both in the wrong place. Before you use any other allegro functions, call al_init.
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Matthew Leverton
Supreme Loser
January 1999
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Call load bitmap after initializing Allegro, after initializing the image addon, and after creating the display. Use an absolute path until you know for sure it is working. Also, your test is bogus because you never assign the value of load_bitmap to anything. |
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kyle motherwell
Member #11,111
July 2009
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Forgive me for how messy and badly done it all is, I done it pretty quickly and didn't see what I had done wrong. I fixed the mistakes (not all of them I'm sure) and now my test code runs and tells me that it cannot initiliaze the image. I used a absolute path too. 1#include "stdafx.h"
2#include <stdio.h>
3#include <allegro5/allegro.h>
4#include <allegro5/allegro_image.h>
5
6int main(int argc, char **argv)
7{
8
9//Create a display and an event queue
10 ALLEGRO_DISPLAY *display = NULL;
11 ALLEGRO_EVENT_QUEUE *event_queue = NULL;
12 ALLEGRO_BITMAP * testBMP = NULL;
13
14//Test if allegro failed to initiliaze, if it did print a message to the console and leave with error code -1
15 if(!al_init()) {
16 fprintf(stderr, "failed to initialize allegro!\n");
17 return -1;
18 }
19 //Set the display by assisnging it the properties returned from the function al_create_display(640, 480) this sets the display to a resoloution of 640x480
20 display = al_create_display(640, 480);
21
22 //check to see if the display was properly set
23 if(!display) {
24 fprintf(stderr, "failed to create display!\n");
25 return -1;
26 }
27
28 testBMP = al_load_bitmap("C:\Users\Kyle\Desktop\kyle-and-liams-project\AllegroProject\bob.bmp");
29
30 if(!testBMP)
31 {
32 fprintf(stderr,"failed to initialize testBMP!\n");
33 return -1;
34
35 }
36
37 //Create an even queue, event queues can be filled with different evens that happen from sources, sources include keyboard, mouse and display, we will use display
38 event_queue = al_create_event_queue();
39
40 //We check if the queue was set properly
41 if(!event_queue) {
42 fprintf(stderr, "failed to create event_queue!\n");
43 al_destroy_display(display);
44 return -1;
45 }
46
47
48 //We set the queue to watch all the events from the source, our source is the display, so resizing or closing the window would be an event for the display
49 al_register_event_source(event_queue, al_get_display_event_source(display));
50
51 //We clear the screen to the colour black
52 al_clear_to_color(al_map_rgb(0,0,0));
53
54 //We swap the drawing buffer to show our changes since we last swapped buffers, search up double buffering to find out more about what this means
55 al_flip_display();
56
57
58 while(1)
59 {
60 //We createa an event to hold the event
61 ALLEGRO_EVENT ev;
62 //A timeout to be initiliased
63 ALLEGRO_TIMEOUT timeout;
64 //Here we initliase timeout and set it to 0.06, or 60 miliseconds
65 al_init_timeout(&timeout, 0.06);
66
67 //Here the bool is assigned either true of false depending if the event queue is updated with an event or it gets set to false if the timeout occurs before the event finishes.
68 bool got_event = al_wait_for_event_until(event_queue, &ev, &timeout);
69
70 //We check if the event was close
71 if(got_event && ev.type == ALLEGRO_EVENT_DISPLAY_CLOSE) {
72
73 //This ends the program loop, closing the program
74 break;
75 }
76
77 //Clear to black and swap buffers
78 al_clear_to_color(al_map_rgb(0,0,0));
79 al_flip_display();
80 }
81
82 //Destroy display object and queue object
83 al_destroy_display(display);
84 al_destroy_event_queue(event_queue);
85
86
87 return 0;
88}
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Matthew Leverton
Supreme Loser
January 1999
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The answer is in my previous post. Edit: And use '/' or '\\' for path separators. A single backslash will cause problems. |
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kyle motherwell
Member #11,111
July 2009
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Thanks, it was the slashes that were causing the problem. |
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