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#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#define ALLEGRO_UNSTABLE
#include "allegro5/allegro.h"
#include "allegro5/allegro_primitives.h"
#include "common.c"
typedef struct
{
float x, y;
float nx, ny, nz;
} CUSTOM_VERTEX;
#define RING_SIZE 25
#define SPHERE_RADIUS 150.1
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480
#define NUM_RINGS (SCREEN_WIDTH / RING_SIZE + 1)
#define NUM_SEGMENTS 64
#define NUM_VERTICES (NUM_RINGS * NUM_SEGMENTS * 6)
#define FIRST_OUTSIDE_RING ((int)(SPHERE_RADIUS / RING_SIZE))
static void setup_vertex(CUSTOM_VERTEX* vtx, int ring, int segment, bool inside)
{
float len;
float x, y, z;
x = ring * RING_SIZE * cosf(2 * ALLEGRO_PI * segment / NUM_SEGMENTS);
y = ring * RING_SIZE * sinf(2 * ALLEGRO_PI * segment / NUM_SEGMENTS);
vtx->x = x + SCREEN_WIDTH / 2;
vtx->y = y + SCREEN_HEIGHT / 2;
if (inside) {
/* This comes from the definition of the normal vector as the
* gradient of the 3D surface. */
z = sqrtf(SPHERE_RADIUS * SPHERE_RADIUS - x * x - y * y);
vtx->nx = x / z;
vtx->ny = y / z;
}
else {
vtx->nx = 0;
vtx->ny = 0;
}
vtx->nz = 1.0;
len = sqrtf(vtx->nx * vtx->nx + vtx->ny * vtx->ny + vtx->nz * vtx->nz);
vtx->nx /= len;
vtx->ny /= len;
vtx->nz /= len;
}
int main(int argc, char **argv)
{
ALLEGRO_DISPLAY *display;
ALLEGRO_TIMER *timer;
ALLEGRO_EVENT_QUEUE *queue;
bool redraw = true;
ALLEGRO_SHADER *shader;
ALLEGRO_VERTEX_DECL *vertex_decl;
ALLEGRO_VERTEX_ELEMENT vertex_elems[] = {
{ALLEGRO_PRIM_POSITION, ALLEGRO_PRIM_FLOAT_2, offsetof(CUSTOM_VERTEX, x)},
{ALLEGRO_PRIM_USER_ATTR, ALLEGRO_PRIM_FLOAT_3, offsetof(CUSTOM_VERTEX, nx)},
{0, 0, 0}
};
CUSTOM_VERTEX vertices[NUM_VERTICES];
bool quit = false;
const char* vertex_shader_file;
const char* pixel_shader_file;
int vertex_idx = 0;
int ring, segment;
float diffuse_color[4] = {0.1, 0.1, 0.7, 1.0};
float light_position[3] = {0, 0, 100};
(void)argc;
(void)argv;
if (!al_init()) {
abort_example("Could not init Allegro.\n");
}
al_install_mouse();
al_install_keyboard();
al_install_touch_input();
if (!al_init_primitives_addon()) {
abort_example("Could not init primitives addon.\n");
}
init_platform_specific();
al_set_new_display_flags(ALLEGRO_PROGRAMMABLE_PIPELINE);
display = al_create_display(SCREEN_WIDTH, SCREEN_HEIGHT);
if (!display) {
abort_example("Error creating display.\n");
}
vertex_decl = al_create_vertex_decl(vertex_elems, sizeof(CUSTOM_VERTEX));
if (!vertex_decl) {
abort_example("Error creating vertex declaration.\n");
}
/* Computes a "spherical" bump ring. The z coordinate is not actually set
* appropriately as this is a 2D example, but the normal vectors are computed
* correctly for the light shading effect. */
for (ring = 0; ring < NUM_RINGS; ring++) {
for (segment = 0; segment < NUM_SEGMENTS; segment++) {
bool inside = ring < FIRST_OUTSIDE_RING;
setup_vertex(&vertices[vertex_idx + 0], ring + 0, segment + 0, inside);
setup_vertex(&vertices[vertex_idx + 1], ring + 0, segment + 1, inside);
setup_vertex(&vertices[vertex_idx + 2], ring + 1, segment + 0, inside);
setup_vertex(&vertices[vertex_idx + 3], ring + 1, segment + 0, inside);
setup_vertex(&vertices[vertex_idx + 4], ring + 0, segment + 1, inside);
setup_vertex(&vertices[vertex_idx + 5], ring + 1, segment + 1, inside);
vertex_idx += 6;
}
}
shader = al_create_shader(ALLEGRO_SHADER_AUTO);
if (!shader) {
abort_example("Failed to create shader.");
}
if (al_get_shader_platform(shader) == ALLEGRO_SHADER_GLSL) {
vertex_shader_file = "data/ex_prim_shader_vertex.glsl";
pixel_shader_file = "data/ex_prim_shader_pixel.glsl";
}
else {
vertex_shader_file = "data/ex_prim_shader_vertex.hlsl";
pixel_shader_file = "data/ex_prim_shader_pixel.hlsl";
}
if (!al_attach_shader_source_file(shader, ALLEGRO_VERTEX_SHADER, vertex_shader_file)) {
abort_example("al_attach_shader_source_file for vertex shader failed: %s\n",
al_get_shader_log(shader));
}
if (!al_attach_shader_source_file(shader, ALLEGRO_PIXEL_SHADER, pixel_shader_file)) {
abort_example("al_attach_shader_source_file for pixel shader failed: %s\n",
al_get_shader_log(shader));
}
if (!al_build_shader(shader)) {
abort_example("al_build_shader for link failed: %s\n", al_get_shader_log(shader));
}
al_use_shader(shader);
al_set_shader_float_vector("diffuse_color", 4, diffuse_color, 1);
/* alpha controls shininess, and 25 is very shiny */
al_set_shader_float("alpha", 25);
timer = al_create_timer(1.0 / 60);
queue = al_create_event_queue();
al_register_event_source(queue, al_get_keyboard_event_source());
al_register_event_source(queue, al_get_mouse_event_source());
if (al_is_touch_input_installed()) {
al_register_event_source(queue,
al_get_touch_input_mouse_emulation_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_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_MOUSE_AXES:
light_position[0] = event.mouse.x;
light_position[1] = event.mouse.y;
break;
case ALLEGRO_EVENT_KEY_CHAR:
if (event.keyboard.keycode == ALLEGRO_KEY_ESCAPE)
quit = true;
break;
case ALLEGRO_EVENT_TIMER:
redraw = true;
break;
}
if (redraw && al_is_event_queue_empty(queue)) {
al_clear_to_color(al_map_rgb_f(0, 0, 0));
al_set_shader_float_vector("light_position", 3, light_position, 1);
al_draw_prim(vertices, vertex_decl, NULL, 0, NUM_VERTICES, ALLEGRO_PRIM_TRIANGLE_LIST);
al_flip_display();
redraw = false;
}
}
al_use_shader(NULL);
al_destroy_shader(shader);
al_destroy_vertex_decl(vertex_decl);
return 0;
}
/* vim: set sts=3 sw=3 et: */
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