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#include <stdbool.h>
#include <complex.h>
#include <SDL2/SDL.h>
#include "header.h"
#define WINDOW_TITLE "Mandelbrot"
#define WINDOW_X 20
#define WINDOW_Y 20
#define WINDOW_W 300
#define WINDOW_H 300
#define REFRESH_RATE 1
#define MOVE_RATIO 10
#define ZOOM_RATIO 1.1
#define REAL_LO(state) (state->center.x - state->real_range / 2)
#define REAL_HI(state) (state->center.x + state->real_range / 2)
#define IMAG_LO(state) (state->center.y - state->imag_range / 2)
#define IMAG_HI(state) (state->center.y + state->imag_range / 2)
#define IN_SET_COLOR 0x000000
#define PALETTE_START 0x000022
#define PALETTE_END 0xd62f2f
#define SET_DRAW_COLOR(renderer, c) ( \
SDL_SetRenderDrawColor(renderer, c.rgb.r, c.rgb.g, c.rgb.b, SDL_ALPHA_OPAQUE));
static void update(GState *state);
static void event_handler(GState *state);
static Color *create_palette(Color start, Color end);
static void destroy_state(GState *state);
static void error_exit_state(GState *state, const char *msg);
static void error_exit(const char *msg);
GState *graphics_init(void)
{
Color start, end;
if (SDL_Init(SDL_INIT_VIDEO) < 0)
error_exit("unable to init SDL");
GState *state = (GState*)malloc(sizeof(GState));
if (state == NULL)
error_exit("state allocation failed");
state->window = SDL_CreateWindow(WINDOW_TITLE, WINDOW_X, WINDOW_Y,
WINDOW_W, WINDOW_H, 0);
if (state->window == NULL)
error_exit_state(state, "unable to create window");
state->renderer = SDL_CreateRenderer(state->window, -1, 0);
if (state->renderer == NULL)
error_exit_state(state, "unable to create renderer");
start.hexcode = PALETTE_START;
end.hexcode = PALETTE_END;
state->palette = create_palette(start, end);
if (state->palette == NULL)
error_exit_state(state, "unable to create color palette");
state->in_set_color.hexcode = IN_SET_COLOR;
state->running = true;
state->window_w = WINDOW_W;
state->window_h = WINDOW_H;
state->real_range = REAL_RANGE;
state->imag_range = IMAG_RANGE;
state->center.x = CENTER_X;
state->center.y = CENTER_Y;
return state;
}
void graphics_quit(GState *state)
{
destroy_state(state);
SDL_Quit();
}
void graphics_run(GState *state)
{
while (state->running)
{
event_handler(state);
update(state);
SDL_Delay(REFRESH_RATE);
}
}
static void update(GState *state)
{
double a, b;
Color color;
SET_DRAW_COLOR(state->renderer, state->in_set_color);
SDL_RenderClear(state->renderer);
for (int x = 0; x < state->window_w; x++)
{
for (int y = 0; y < state->window_h; y++)
{
a = map_range((double)x, 0, state->window_w, REAL_LO(state), REAL_HI(state));
b = map_range((double)y, 0, state->window_h, IMAG_LO(state), IMAG_HI(state));
int steps = mandelbrot_in_set(a + b * I);
if (steps == -1)
continue;
color = state->palette[steps];
SET_DRAW_COLOR(state->renderer, color);
SDL_RenderDrawPoint(state->renderer, x, y);
}
}
SDL_RenderPresent(state->renderer);
}
static void event_handler(GState *state)
{
SDL_Event e;
while (SDL_PollEvent(&e))
{
switch (e.type)
{
case SDL_QUIT:
state->running = false;
break;
case SDL_KEYDOWN:
switch (e.key.keysym.sym)
{
case SDLK_UP:
case SDLK_k:
state->center.y -= state->imag_range / MOVE_RATIO;
break;
case SDLK_DOWN:
case SDLK_j:
state->center.y += state->imag_range / MOVE_RATIO;
break;
case SDLK_LEFT:
case SDLK_h:
state->center.x -= state->real_range / MOVE_RATIO;
break;
case SDLK_RIGHT:
case SDLK_l:
state->center.x += state->real_range / MOVE_RATIO;
break;
case SDLK_PLUS:
case SDLK_p:
state->real_range /= ZOOM_RATIO;
state->imag_range /= ZOOM_RATIO;
break;
case SDLK_MINUS:
case SDLK_m:
state->real_range *= ZOOM_RATIO;
state->imag_range *= ZOOM_RATIO;
break;
case SDLK_q:
state->running = false;
}
}
}
}
static Color *create_palette(Color start, Color end)
{
int red_step = abs(end.rgb.r - start.rgb.r) / MAX_ITERATION;
int green_step = abs(end.rgb.g - start.rgb.g) / MAX_ITERATION;
int blue_step = abs(end.rgb.b - start.rgb.b) / MAX_ITERATION;
Color *palette = (Color*)malloc(sizeof(Color) * MAX_ITERATION);
if (palette == NULL)
return NULL;
for (int i = 0; i < MAX_ITERATION; i++)
{
palette[i].rgb.r = i * red_step + start.rgb.r;
palette[i].rgb.g = i * green_step + start.rgb.g;
palette[i].rgb.b = i * blue_step + start.rgb.b;
}
return palette;
}
static void destroy_state(GState *state)
{
if (state == NULL)
return;
free(state->palette);
SDL_DestroyRenderer(state->renderer);
SDL_DestroyWindow(state->window);
free(state);
}
static void error_exit_state(GState *state, const char *msg)
{
destroy_state(state);
error_exit(msg);
}
static void error_exit(const char *msg)
{
SDL_Log("ERROR: %s: %s", SDL_GetError(), msg);
SDL_Quit();
exit(EXIT_FAILURE);
}
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