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/* main.c
* Created: 2023-09-02
* Author: Aryadev Chavali
* Description: Entrypoint of program
*/
#include <math.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
#include <raylib.h>
#include <raymath.h>
#include <stb/stb_image_write.h>
#define WIDTH 1024
#define HEIGHT 1024
#define MAX_THREADS 4
uint64_t MAX_ITER = 1 << 2;
Color cells[WIDTH * HEIGHT];
pthread_t threads[MAX_THREADS];
#define SQUARE(a) (a * a)
Color iter_to_colour(size_t iterations)
{
if (iterations == MAX_ITER)
return BLACK;
// quadratic ratio
float ratio = Remap(iterations * (MAX_ITER - iterations), 0,
SQUARE(MAX_ITER) / 4, 0, 1);
return (Color){255 * SQUARE(ratio), 255 * SQUARE(SQUARE(ratio)), 255 * ratio,
255};
}
struct ThreadArg
{
size_t x_0, x_t;
size_t y_0, y_t;
bool done;
};
void *generate_colours(void *state)
{
struct ThreadArg *ptr = (struct ThreadArg *)state;
ptr->done = false;
for (size_t i = ptr->x_0; i < ptr->x_t; ++i)
for (size_t j = ptr->y_0; j < ptr->y_t; ++j)
{
Vector2 init = {Remap(i, 0, WIDTH, -1.5, 0.5),
Remap(j, 0, HEIGHT, -1, 1)};
Vector2 update = {0};
size_t iterations;
for (iterations = 0;
iterations < MAX_ITER && Vector2LengthSqr(update) <= 4; ++iterations)
{
double new_x = SQUARE(update.x) - SQUARE(update.y) + init.x;
update.y = (2 * update.x * update.y) + init.y;
update.x = new_x;
}
cells[(i * WIDTH) + j] = iter_to_colour(iterations);
}
ptr->done = true;
return NULL;
}
void threads_start_render(struct ThreadArg *args)
{
for (size_t i = 0; i < MAX_THREADS; ++i)
pthread_create(&threads[i], NULL, &generate_colours, &args[i]);
}
bool threads_done(struct ThreadArg *args)
{
for (size_t i = 0; i < MAX_THREADS; ++i)
if (!args[i].done)
return false;
return true;
}
void threads_cancel_render(void)
{
for (size_t i = 0; i < MAX_THREADS; ++i)
pthread_join(threads[i], NULL);
}
bool write_to_png(const char *filepath)
{
unsigned char *image_data = calloc(3 * WIDTH * HEIGHT, sizeof(*image_data));
size_t image_ptr = 0;
for (size_t i = 0; i < HEIGHT; ++i)
for (size_t j = 0; j < WIDTH; ++j, image_ptr += 3)
{
Color c = cells[(j * WIDTH) + i];
unsigned char colour[3] = {c.r, c.g, c.b};
memcpy(image_data + image_ptr, colour, sizeof(*colour) * 3);
}
stbi_write_png(filepath, WIDTH, HEIGHT, 3, image_data, 3 * WIDTH);
free(image_data);
return true;
}
#define ZOOM_INC 0.3f
#define MOVE_INC WIDTH / 50
int main(void)
{
InitWindow(WIDTH, HEIGHT, "Mandelbrot simulation");
Camera2D camera = {0};
camera.zoom = 1.0f;
Image img = {.data = cells,
.width = WIDTH,
.height = HEIGHT,
.format = PIXELFORMAT_UNCOMPRESSED_R8G8B8A8,
.mipmaps = 1};
Texture2D texture = LoadTextureFromImage(img);
SetTargetFPS(60);
struct ThreadArg args[] = {{0, WIDTH / 2, 0, HEIGHT, false},
{WIDTH / 2, WIDTH, 0, HEIGHT / 4, false},
{WIDTH / 2, WIDTH, HEIGHT / 4, HEIGHT / 2, false},
{WIDTH / 2, WIDTH, HEIGHT / 2, HEIGHT, false}};
threads_start_render(args);
const size_t delta = 10;
bool rendered = false;
for (size_t prev = 0, ticks = 0; !WindowShouldClose(); ++ticks)
{
if (IsKeyPressed(KEY_UP) || IsKeyDown(KEY_UP))
camera.target.y -= MOVE_INC;
else if (IsKeyPressed(KEY_DOWN) || IsKeyDown(KEY_DOWN))
camera.target.y += MOVE_INC;
else if (IsKeyPressed(KEY_RIGHT) || IsKeyDown(KEY_RIGHT))
camera.target.x += MOVE_INC;
else if (IsKeyPressed(KEY_LEFT) || IsKeyDown(KEY_LEFT))
camera.target.x -= MOVE_INC;
else if (IsKeyPressed(KEY_N) || IsKeyDown(KEY_N))
{
camera.zoom += ZOOM_INC;
if (camera.zoom > 3.0f)
camera.zoom = 3.0f;
}
else if (IsKeyPressed(KEY_M) || IsKeyDown(KEY_M))
{
camera.zoom -= ZOOM_INC;
if (camera.zoom < 0.1f)
camera.zoom = 0.1f;
}
else if (IsKeyPressed(KEY_SPACE))
{
threads_cancel_render();
memset(cells, 0, WIDTH * HEIGHT);
MAX_ITER *= 2;
rendered = false;
threads_start_render(args);
}
if (ticks - prev > delta)
{
prev = ticks;
bool done = threads_done(args);
if (!done || !rendered)
UpdateTexture(texture, cells);
else if (done)
rendered = true;
}
char iters[128];
sprintf(iters, "iterations=%lu", MAX_ITER);
BeginDrawing();
BeginMode2D(camera);
ClearBackground(BLACK);
DrawTexturePro(texture, (Rectangle){0, 0, WIDTH, HEIGHT},
(Rectangle){WIDTH / 2, HEIGHT / 2, WIDTH, HEIGHT},
(Vector2){WIDTH / 2, HEIGHT / 2}, -90, WHITE);
DrawText(iters, 200, 200, 50, RAYWHITE);
EndMode2D();
EndDrawing();
}
write_to_png("test.png");
threads_cancel_render();
UnloadTexture(texture);
CloseWindow();
return 0;
}
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