/
ex_projection2.c
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/
ex_projection2.c
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#include <allegro5/allegro.h>
#include <allegro5/allegro_image.h>
#include <allegro5/allegro_font.h>
#include <allegro5/allegro_primitives.h>
#include <math.h>
#include "common.c"
static void draw_pyramid(ALLEGRO_BITMAP* texture, float x, float y, float z, float theta)
{
ALLEGRO_COLOR c = al_map_rgb_f(1, 1, 1);
ALLEGRO_TRANSFORM t;
ALLEGRO_VERTEX vtx[5] = {
/* x y z u v c */
{ 0, 1, 0, 0, 64, c},
{-1, -1, -1, 0, 0, c},
{ 1, -1, -1, 64, 64, c},
{ 1, -1, 1, 64, 0, c},
{-1, -1, 1, 64, 64, c},
};
int indices[12] = {
0, 1, 2,
0, 2, 3,
0, 3, 4,
0, 4, 1
};
al_identity_transform(&t);
al_rotate_transform_3d(&t, 0, 1, 0, theta);
al_translate_transform_3d(&t, x, y, z);
al_use_transform(&t);
al_draw_indexed_prim(vtx, NULL, texture, indices, 12, ALLEGRO_PRIM_TRIANGLE_LIST);
}
static void set_perspective_transform(ALLEGRO_BITMAP* bmp)
{
ALLEGRO_TRANSFORM p;
float aspect_ratio = (float)al_get_bitmap_height(bmp) / al_get_bitmap_width(bmp);
al_set_target_bitmap(bmp);
al_identity_transform(&p);
al_perspective_transform(&p, -1, aspect_ratio, 1, 1, -aspect_ratio, 1000);
al_use_projection_transform(&p);
}
int main(int argc, char **argv)
{
ALLEGRO_DISPLAY *display;
ALLEGRO_TIMER *timer;
ALLEGRO_EVENT_QUEUE *queue;
ALLEGRO_BITMAP *texture;
ALLEGRO_BITMAP *display_sub_persp;
ALLEGRO_BITMAP *display_sub_ortho;
ALLEGRO_BITMAP *buffer;
ALLEGRO_FONT *font;
bool redraw = false;
bool quit = false;
bool fullscreen = false;
bool background = false;
int display_flags = ALLEGRO_RESIZABLE;
float theta = 0;
if (argc > 1) {
if(strcmp(argv[1], "--use-shaders") == 0) {
display_flags |= ALLEGRO_PROGRAMMABLE_PIPELINE;
}
else {
abort_example("Unknown command line argument: %s\n", argv[1]);
}
}
if (!al_init()) {
abort_example("Could not init Allegro.\n");
}
al_init_image_addon();
al_init_primitives_addon();
al_init_font_addon();
init_platform_specific();
al_install_keyboard();
al_set_new_display_flags(display_flags);
al_set_new_display_option(ALLEGRO_DEPTH_SIZE, 16, ALLEGRO_SUGGEST);
/* Load everything as a POT bitmap to make sure the projection stuff works
* with mismatched backing texture and bitmap sizes. */
al_set_new_display_option(ALLEGRO_SUPPORT_NPOT_BITMAP, 0, ALLEGRO_REQUIRE);
display = al_create_display(800, 600);
if (!display) {
abort_example("Error creating display\n");
}
al_set_window_constraints(display, 256, 512, 0, 0);
al_apply_window_constraints(display, true);
set_perspective_transform(al_get_backbuffer(display));
/* This bitmap is a sub-bitmap of the display, and has a perspective transformation. */
display_sub_persp = al_create_sub_bitmap(al_get_backbuffer(display), 0, 0, 256, 256);
set_perspective_transform(display_sub_persp);
/* This bitmap is a sub-bitmap of the display, and has a orthographic transformation. */
display_sub_ortho = al_create_sub_bitmap(al_get_backbuffer(display), 0, 0, 256, 512);
/* This bitmap has a perspective transformation, purposefully non-POT */
buffer = al_create_bitmap(200, 200);
set_perspective_transform(buffer);
timer = al_create_timer(1.0 / 60);
font = al_create_builtin_font();
queue = al_create_event_queue();
al_register_event_source(queue, al_get_keyboard_event_source());
al_register_event_source(queue, al_get_display_event_source(display));
al_register_event_source(queue, al_get_timer_event_source(timer));
al_set_new_bitmap_flags(ALLEGRO_MIN_LINEAR | ALLEGRO_MAG_LINEAR |
ALLEGRO_MIPMAP);
texture = al_load_bitmap("data/bkg.png");
if (!texture) {
abort_example("Could not load data/bkg.png");
}
al_start_timer(timer);
while (!quit) {
ALLEGRO_EVENT event;
al_wait_for_event(queue, &event);
switch (event.type) {
case ALLEGRO_EVENT_DISPLAY_CLOSE:
quit = true;
break;
case ALLEGRO_EVENT_DISPLAY_RESIZE:
al_acknowledge_resize(display);
set_perspective_transform(al_get_backbuffer(display));
break;
case ALLEGRO_EVENT_KEY_DOWN:
switch (event.keyboard.keycode) {
case ALLEGRO_KEY_ESCAPE:
quit = true;
break;
case ALLEGRO_KEY_SPACE:
fullscreen = !fullscreen;
al_set_display_flag(display, ALLEGRO_FULLSCREEN_WINDOW, fullscreen);
set_perspective_transform(al_get_backbuffer(display));
break;
}
break;
case ALLEGRO_EVENT_TIMER:
redraw = true;
theta = fmod(theta + 0.05, 2 * ALLEGRO_PI);
break;
case ALLEGRO_EVENT_DISPLAY_HALT_DRAWING:
background = true;
al_acknowledge_drawing_halt(display);
al_stop_timer(timer);
break;
case ALLEGRO_EVENT_DISPLAY_RESUME_DRAWING:
background = false;
al_acknowledge_drawing_resume(display);
al_start_timer(timer);
break;
}
if (!background && redraw && al_is_event_queue_empty(queue)) {
al_set_target_backbuffer(display);
al_set_render_state(ALLEGRO_DEPTH_TEST, 1);
al_clear_to_color(al_map_rgb_f(0, 0, 0));
al_clear_depth_buffer(1000);
draw_pyramid(texture, 0, 0, -4, theta);
al_set_target_bitmap(buffer);
al_set_render_state(ALLEGRO_DEPTH_TEST, 1);
al_clear_to_color(al_map_rgb_f(0, 0.1, 0.1));
al_clear_depth_buffer(1000);
draw_pyramid(texture, 0, 0, -4, theta);
al_set_target_bitmap(display_sub_persp);
al_set_render_state(ALLEGRO_DEPTH_TEST, 1);
al_clear_to_color(al_map_rgb_f(0, 0, 0.25));
al_clear_depth_buffer(1000);
draw_pyramid(texture, 0, 0, -4, theta);
al_set_target_bitmap(display_sub_ortho);
al_set_render_state(ALLEGRO_DEPTH_TEST, 0);
al_draw_text(font, al_map_rgb_f(1, 1, 1), 128, 16, ALLEGRO_ALIGN_CENTER,
"Press Space to toggle fullscreen");
al_draw_bitmap(buffer, 0, 256, 0);
al_flip_display();
redraw = false;
}
}
return 0;
}