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#define ALLEGRO_UNSTABLE
#include <allegro5/allegro.h>
#include <allegro5/allegro_opengl.h>
#include <allegro5/allegro_image.h>
#include <stdio.h>
#include "common.c"
GLhandleARB tinter;
GLhandleARB tinter_shader;
int main(int argc, char **argv)
{
float r = 0.5, g = 0.5, b = 1, ratio = 0;
int dir = 1;
ALLEGRO_DISPLAY *display;
ALLEGRO_BITMAP *mysha;
ALLEGRO_BITMAP *buffer;
const char *tinter_shader_src[] = {
"uniform sampler2D backBuffer;",
"uniform float r;",
"uniform float g;",
"uniform float b;",
"uniform float ratio;",
"void main() {",
" vec4 color;",
" float avg, dr, dg, db;",
" color = texture2D(backBuffer, gl_TexCoord[0].st);",
" avg = (color.r + color.g + color.b) / 3.0;",
" dr = avg * r;",
" dg = avg * g;",
" db = avg * b;",
" color.r = color.r - (ratio * (color.r - dr));",
" color.g = color.g - (ratio * (color.g - dg));",
" color.b = color.b - (ratio * (color.b - db));",
" gl_FragColor = color;",
"}"
};
const int TINTER_LEN = 18;
double start;
GLint loc;
(void)argc;
(void)argv;
if (!al_init()) {
abort_example("Could not init Allegro\n");
}
al_install_keyboard();
al_init_image_addon();
al_set_new_display_flags(ALLEGRO_OPENGL);
display = al_create_display(320, 200);
if (!display) {
abort_example("Error creating display\n");
}
mysha = al_load_bitmap("data/mysha.pcx");
if (!mysha) {
abort_example("Could not load image.\n");
}
buffer = al_create_bitmap(320, 200);
if (!al_have_opengl_extension("GL_EXT_framebuffer_object")
&& !al_have_opengl_extension("GL_ARB_fragment_shader")) {
abort_example("Fragment shaders not supported.\n");
}
tinter_shader = glCreateShaderObjectARB(GL_FRAGMENT_SHADER_ARB);
glShaderSourceARB(tinter_shader, TINTER_LEN, tinter_shader_src, NULL);
glCompileShaderARB(tinter_shader);
tinter = glCreateProgramObjectARB();
glAttachObjectARB(tinter, tinter_shader);
glLinkProgramARB(tinter);
loc = glGetUniformLocationARB(tinter, "backBuffer");
glUniform1iARB(loc, al_get_opengl_texture(buffer));
start = al_get_time();
while (1) {
double now, diff;
ALLEGRO_KEYBOARD_STATE state;
al_get_keyboard_state(&state);
if (al_key_down(&state, ALLEGRO_KEY_ESCAPE)) {
break;
}
now = al_get_time();
diff = now - start;
start = now;
ratio += diff * 0.5 * dir;
if (dir < 0 && ratio < 0) {
ratio = 0;
dir = -dir;
}
else if (dir > 0 && ratio > 1) {
ratio = 1;
dir = -dir;
}
al_set_target_bitmap(buffer);
glUseProgramObjectARB(tinter);
loc = glGetUniformLocationARB(tinter, "ratio");
glUniform1fARB(loc, ratio);
loc = glGetUniformLocationARB(tinter, "r");
glUniform1fARB(loc, r);
loc = glGetUniformLocationARB(tinter, "g");
glUniform1fARB(loc, g);
loc = glGetUniformLocationARB(tinter, "b");
glUniform1fARB(loc, b);
al_draw_bitmap(mysha, 0, 0, 0);
glUseProgramObjectARB(0);
al_set_target_backbuffer(display);
al_draw_bitmap(buffer, 0, 0, 0);
al_flip_display();
al_rest(0.001);
}
glDetachObjectARB(tinter, tinter_shader);
glDeleteObjectARB(tinter_shader);
al_uninstall_system();
return 0;
}
/* vim: set sts=3 sw=3 et: */
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