A lot of stuff...

Makefile

-CFLAGS = -Wno-unused-command-line-argument -Wno-missing-field-initializers  -Wall -Wextra -Wpedantic -lm
+CFLAGS = -Wno-unused-command-line-argument -Wno-missing-field-initializers  -Wall -Wextra -Wpedantic -lm -fopenmp
 DEBUG_CFLAGS = -g -DDEBUG
 
 LDLIBS = $(shell pkg-config --libs sdl2 SDL2_ttf)
@@ -9,7 +9,8 @@ CFLAGS := $(CFLAGS) $(DEBUG_CFLAGS)
 SRCDIR=src
 BIULDDIR=build
 # compiler
-CC = gcc
+#CC = gcc
+CC = clang
 
 OBJS = $(BIULDDIR)/mouse.o $(BIULDDIR)/ui.o
 

src/mandelbrot.c

 #include <SDL2/SDL_events.h>
 #include <SDL2/SDL_render.h>
+#include <SDL2/SDL_scancode.h>
 #include <SDL2/SDL_surface.h>
 #include <SDL2/SDL_timer.h>
 #include <SDL2/SDL_video.h>
 #include <stdio.h>
 #include <SDL2/SDL.h>
 #include <complex.h>
-#include <pthread.h>
+#include<omp.h>
 
 #include "mandelbrot.h"
 #include "mouse.h"
@@ -30,21 +31,22 @@ mandelbrot(Complex c) {
 } 
 
 void 
-render(SDL_Renderer* renderer, ViewInfo view, int start_x, int end_x, int start_y, int end_y) {
-    
-    SDL_SetRenderDrawColor(renderer, 0, 0, 50, 255);
-    SDL_RenderClear(renderer);
+render(App *app, ViewInfo view, int start_x, int end_x, int start_y, int end_y) {
     
+    SDL_SetRenderDrawColor(app->renderer, 0, 0, 50, 255);
+    SDL_RenderClear(app->renderer);
+
+    //#pragma omp parallel for schedule(guided)
     for (int x = start_x; x < end_x; x++) {
         for (int y = start_y; y < end_y; y++) {
-            double real = view.x_min + (x * (view.x_max - view.x_min)) / SCREEN_WIDTH;
-            double imag = view.y_min + (y * (view.y_max - view.y_min)) / SCREEN_HEIGHT;
+            double real = view.x_min + (x * (view.x_max - view.x_min)) / app->win_width;
+            double imag = view.y_min + (y * (view.y_max - view.y_min)) / app->win_height;
             Complex c = {real, imag};
             
             int iterations = mandelbrot(c);
 
             if (iterations == MAX_ITERATIONS){
-                SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255);
+                SDL_SetRenderDrawColor(app->renderer, 0, 0, 0, 255);
             } else {
                 double t = (double)iterations / MAX_ITERATIONS;
                 t = 0.5 + 0.5 * cos(log(t + 0.0001) * 3.0);
@@ -53,9 +55,9 @@ render(SDL_Renderer* renderer, ViewInfo view, int start_x, int end_x, int start_
                 int g = (int)(255 * t * 0.4);  
                 int b = (int)(255 * t * 0.2);        
                 
-                SDL_SetRenderDrawColor(renderer, r, g, b, 255);
+                SDL_SetRenderDrawColor(app->renderer, r, g, b, 255);
             }
-            SDL_RenderDrawPoint(renderer, x, y);
+            SDL_RenderDrawPoint(app->renderer, x, y);
         }
     }
 }
@@ -74,10 +76,12 @@ main(int argc, char *argv[])
         SDL_CreateWindow("Mandelbrot set exploer", 
             0, 0, 
             SCREEN_WIDTH,  SCREEN_HEIGHT, 
-            SDL_WINDOW_SHOWN), 
+            SDL_WINDOW_SHOWN | SDL_WINDOW_RESIZABLE | SDL_WINDOW_OPENGL), 
         SDL_CreateRenderer(app.window, 
                 -1, 
-                SDL_RENDERER_ACCELERATED)
+                SDL_RENDERER_ACCELERATED),
+        SCREEN_HEIGHT,
+        SCREEN_WIDTH
             };
 
     ViewInfo view = {
@@ -95,10 +99,7 @@ main(int argc, char *argv[])
         .original_view = view
     };
 
-    const int FPS = 60;
-    const int FRAME_DELAY = 1000 / FPS;
     Uint32 frame_start;
-    int frame_time;
 
     UI ui;
     init_ui(&ui);
@@ -119,13 +120,32 @@ main(int argc, char *argv[])
                 case SDL_QUIT:
                     running = 0;
                     break;
-                 case SDL_KEYDOWN:
+                case SDL_WINDOWEVENT:
+                    if(event.window.event == SDL_WINDOWEVENT_RESIZED){
+                        SDL_GetWindowSize(app.window, &app.win_width, &app.win_height);
+                    } 
+                    break;
+                case SDL_KEYDOWN:
                         switch (event.key.keysym.scancode)
                         {
                             case SDL_SCANCODE_Q:
                             case SDL_SCANCODE_ESCAPE:
                                 running = 0;
                                 break;
+                            case SDL_SCANCODE_MINUS:
+                                view.x_min = view.x_min * 1.1;
+                                view.x_max = view.x_max * 1.1;
+                                view.y_min= view.y_min * 1.1;
+                                view.y_max = view.y_max * 1.1;
+                                view.zoom = view.zoom * 1.1;
+                                break;
+                            case SDL_SCANCODE_EQUALS:
+                                view.x_min = view.x_min * 0.9;
+                                view.x_max = view.x_max * 0.9;
+                                view.y_min= view.y_min * 0.9;
+                                view.y_max = view.y_max * 0.9;
+                                view.zoom = view.zoom * 0.9;
+                                break;
                         }
                 default:
                     handle_mouse(event, &mouse, &view);
@@ -136,13 +156,10 @@ main(int argc, char *argv[])
         SDL_RenderClear(app.renderer);
 
         //drawing happens here
-        pthread_t threads[THREADS];
-        int thread = 0;
-
-        render(app.renderer, 
+        render(&app, 
                 view, 
-                0, SCREEN_WIDTH, 
-                0,SCREEN_HEIGHT);
+                0, app.win_width, 
+                0,app.win_height);
 
         int msec = SDL_GetTicks() - frame_start;
         float fps = 0;
@@ -153,9 +170,6 @@ main(int argc, char *argv[])
 
         SDL_RenderPresent(app.renderer);
 
-        frame_time = SDL_GetTicks() - frame_start;
-        if (frame_time < FRAME_DELAY)
-            SDL_Delay(FRAME_DELAY - frame_time);
     }
         //SDL_FreeSurface(app.surfaceA);
         SDL_DestroyRenderer(app.renderer);

src/mandelbrot.h

@@ -5,8 +5,8 @@
 
 #define SCREEN_WIDTH 640
 #define SCREEN_HEIGHT 480
-#define MAX_ITERATIONS 300
-#define THREADS 4
+#define MAX_ITERATIONS 200
+#define FRAMES_TO_CALCULATE_FPS 10 
 
 typedef struct {
     double real;
@@ -16,6 +16,8 @@ typedef struct {
 typedef struct{
     SDL_Window *window;
     SDL_Renderer *renderer;
+    int win_height;
+    int win_width;
 } App ;
 
 typedef struct{
@@ -33,7 +35,6 @@ typedef struct{
     ViewInfo original_view;
 } Mouse ;
 
-void render(SDL_Renderer* renderer, ViewInfo view, int start_x, int end_x, int start_y, int end_y);
-
+void render(App *app, ViewInfo view, int start_x, int end_x, int start_y, int end_y);
 
 #endif