killocan
Hi there! I'm trying to implement bloom effect w/o shaders and proceed to use allegro+ogl to archive this. As i read in someplaces i need to render my scene to a texture and apply some blur and stuff. The problem is that when i copy the backbuffer to another BITMAP it's taking a LOT of time. Is anything very wrong in my code or my computer is very bad on this?
1#include <stdio.h>
2
3#include "allegro5/allegro.h"
4#include "allegro5/allegro_image.h"
5#include "allegro5/allegro_opengl.h"
6#include "allegro5/allegro_font.h"
7#include "allegro5/allegro_primitives.h"
8
9#include <GL/glu.h>
10
11#include "common.c"
12
13struct camera {
14 double xangle, yangle, zangle;
15 double dist;
16};
17
18struct camera camera = {
19 0.0, 0.0, 0.0,
20 20.0
21};
22
23double angle_speed = 5.0;
24double dist_speed = 1.0;
25
26GLuint tex;
27ALLEGRO_BITMAP *bmp,*buffer;
28bool key[ALLEGRO_KEY_MAX];
29
30GLUquadricObj * quadratic;
31
32static void set_camera_position(void)
33{
34 glMatrixMode(GL_PROJECTION);
35 glLoadIdentity();
36 //glFrustum(-1.0, 1.0, -1.0, 1.0, 1.0, 90.0);
37 gluPerspective(45.0f,(GLfloat)1024.0/(GLfloat)768.0,0.1f,100.0f);
38 glTranslatef(0, 0, -camera.dist);
39 glRotatef(camera.xangle, 1, 0, 0);
40 glRotatef(camera.yangle, 0, 1, 0);
41 glRotatef(camera.zangle, 0, 0, 1);
42 glMatrixMode(GL_MODELVIEW);
43}
44
45
46
47static void keyboard(void)
48{
49 if(key[ALLEGRO_KEY_LEFT]) camera.yangle += angle_speed;
50 if(key[ALLEGRO_KEY_RIGHT]) camera.yangle -= angle_speed;
51
52 if(key[ALLEGRO_KEY_UP]) camera.xangle += angle_speed;
53 if(key[ALLEGRO_KEY_DOWN]) camera.xangle -= angle_speed;
54
55 if(key[ALLEGRO_KEY_PGUP]) camera.dist -= dist_speed;
56 if(key[ALLEGRO_KEY_PGDN]) camera.dist += dist_speed;
57}
58
59
60static void draw(void)
61{
62 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
63
64 glLoadIdentity();
65
66 glBindTexture(GL_TEXTURE_2D, tex);
67
68 glRotatef(45.0f,0.0f,1.0f,0.0f);
69 glTranslatef(14.0f,8.0f,0.0f);
70
71 gluSphere(quadratic,3.f,64,64);
72}
73
74static void map(void)
75{
76 glMatrixMode(GL_PROJECTION);
77 glLoadIdentity();
78 glOrtho(0.0f, 1024 - 1.0, 768 - 1.0, 0.0, -1.0, 1.0);
79 glMatrixMode(GL_MODELVIEW);
80 glLoadIdentity();
81
82 al_draw_filled_rectangle(0, 640, 1024, 768, al_map_rgba_f(1,0,0,1));
83}
84
85static void setup_textures(ALLEGRO_DISPLAY *display)
86{
87 ALLEGRO_BITMAP *tmp_bmp;
88// ALLEGRO_FONT *font;
89 int w, h;//, depth;
90
91// font = al_load_font("data/fixed_font.tga", 0, 0);
92// if(!font) {
93// abort_example("Error loading `data/fixed_font.tga'\n");
94// exit(1);
95// }
96
97 glViewport(0,0,1024,768);
98 gluPerspective(45.0f,(GLfloat)1024.0/(GLfloat)768.0,0.1f,100.0f);
99
100 tmp_bmp = al_load_bitmap("data/moon.bmp");
101 if(!tmp_bmp) {
102 abort_example("Error loading `data/moon.bmp'\n");
103 exit(1);
104 }
105
106 w = 512;
107 h = 512;
108 bmp = al_create_bitmap(w, h);
109
110 al_set_new_bitmap_flags(ALLEGRO_VIDEO_BITMAP);
111 buffer = al_create_bitmap(1024, 1024);
112
113 al_set_target_bitmap(bmp);
114 al_draw_bitmap(tmp_bmp,0,0,0);
115
116// depth = al_get_display_option(display, ALLEGRO_DEPTH_SIZE);
117// if (!depth)
118// al_draw_textf(font, al_map_rgb(255, 0, 0), 0, 5, 0, "No Z-buffer!");
119// else
120// al_draw_textf(font, al_map_rgb(255, 0, 0), 0, 5, 0, "Z-buffer: %i bits", depth);
121
122 al_set_target_backbuffer(display);
123 al_destroy_bitmap(tmp_bmp);
124
125// al_destroy_font(font);
126
127 glShadeModel(GL_SMOOTH);
128
129 glEnable(GL_TEXTURE_2D);
130 glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
131
132 tex = al_get_opengl_texture(bmp);
133
134 quadratic=gluNewQuadric();
135 gluQuadricNormals(quadratic, GLU_SMOOTH);
136 gluQuadricTexture(quadratic, GL_TRUE);
137}
138
139
140
141int main(void)
142{
143 ALLEGRO_DISPLAY *display;
144 ALLEGRO_EVENT_QUEUE *queue;
145 ALLEGRO_TIMER *timer;
146 ALLEGRO_EVENT event;
147
148 if(!al_init()) {
149 abort_example("Could not init Allegro.\n");
150 return 1;
151 }
152
153 al_init_image_addon();
154 al_init_font_addon();
155 al_init_primitives_addon();
156
157 al_install_keyboard();
158
159 al_set_new_display_flags(ALLEGRO_OPENGL);
160 al_set_new_display_option(ALLEGRO_DEPTH_SIZE, 16, ALLEGRO_SUGGEST);
161 display = al_create_display(1024, 768);
162 if(!display) {
163 abort_example("Could not create display.\n");
164 }
165
166 timer = al_create_timer(1. / 60.);
167
168 queue = al_create_event_queue();
169 al_register_event_source(queue,al_get_keyboard_event_source());
170 al_register_event_source(queue,al_get_display_event_source(display));
171 al_register_event_source(queue,al_get_timer_event_source(timer));
172
173 glEnable(GL_DEPTH_TEST);
174 ///glDisable(GL_CULL_FACE);
175
176// printf("%s\n",glGetString(GL_EXTENSIONS));
177
178 setup_textures(display);
179 al_start_timer(timer);
180int test = 1;
181 while(true) {
182 al_wait_for_event(queue, &event);
183 switch(event.type) {
184 case ALLEGRO_EVENT_DISPLAY_CLOSE:
185 goto done;
186
187 case ALLEGRO_EVENT_KEY_DOWN:
188 if(event.keyboard.keycode == ALLEGRO_KEY_ESCAPE)
189 goto done;
190 key[event.keyboard.keycode] = true;
191 break;
192
193 case ALLEGRO_EVENT_KEY_UP:
194 key[event.keyboard.keycode] = false;
195 break;
196
197 case ALLEGRO_EVENT_TIMER:
198 keyboard();
199 if(al_is_event_queue_empty(queue)) {
200 set_camera_position();
201 draw();
202 glDisable(GL_DEPTH_TEST);
203 map();
204 glEnable(GL_DEPTH_TEST);
205
206 al_set_target_bitmap(buffer);
207 al_draw_bitmap(al_get_backbuffer(display), 0, 0, NULL);
208 al_set_target_backbuffer(display);
209
210 //printf("teste\n");
211 //if (test){al_save_bitmap("./saveme.png", buffer);test=0;}
212
213 al_flip_display();
214 }
215 break;
216 }
217 }
218
219done:
220 al_destroy_bitmap(bmp);
221
222 return 0;
223}
Yes, i use the ex_gldepth as my base code 
Thanks all!
William Labbett
Did you know if you call
al_set_target_bitmap() before ogl calls the opengl commands will get drawn on the target bitmap... ?
ie - you don't have to render to the backbuffer.
gnolam
killocan said:
Hi there! I'm trying to implement bloom effect w/o shaders
Then it's going to be slow, no matter what you do. 
Why are you even attempting it? This is a problem that GPUs are built to solve.
Quote:
The problem is that when i copy the backbuffer to another BITMAP it's taking a LOT of time.
And reading back data from video memory is also slow.
Mark Oates
Ugh. I hate bloom. People use it like McDonald's uses salt. 
It's right up there next to the programmer's idea of a color palette.