Functions to dynamically draw individual pixels in C using SDL2. Is this the fastest way? Is this the simplest way? Is it the most elegant way? You'll be the judge.

sdl2_pixel_drawing.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdbool.h>
#include <SDL.h>

typedef int rgb;

#define SCR_W		360
#define SCR_H 		200
#define BUFLEN		SCR_W * SCR_H * sizeof(rgb)
#define WND_ZOOM	3
#define WND_W		SCR_W * WND_ZOOM
#define WND_H		SCR_H * WND_ZOOM

SDL_Window* wnd = NULL;
SDL_Renderer* rend = NULL;
SDL_Texture* tex = NULL;
rgb scrbuf[BUFLEN] = { 0 };
bool fullscreen = false;

void open_window(const char* title)
{
	SDL_SetHint(SDL_HINT_RENDER_DRIVER, "direct3d");
	SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, "nearest");

	fullscreen = false;

	wnd = SDL_CreateWindow(title, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, WND_W, WND_H, fullscreen ? SDL_WINDOW_FULLSCREEN_DESKTOP : 0);
	rend = SDL_CreateRenderer(wnd, -1, SDL_RENDERER_PRESENTVSYNC | SDL_RENDERER_ACCELERATED | SDL_RENDERER_TARGETTEXTURE);
	tex = SDL_CreateTexture(rend, SDL_PIXELFORMAT_ARGB8888, SDL_TEXTUREACCESS_STREAMING, SCR_W, SCR_H);

	SDL_SetRenderDrawBlendMode(rend, SDL_BLENDMODE_NONE);
	SDL_SetTextureBlendMode(tex, SDL_BLENDMODE_NONE);
	SDL_RenderSetLogicalSize(rend, SCR_W, SCR_H);
	SDL_SetWindowPosition(wnd, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
	SDL_RaiseWindow(wnd);
}

void update_window()
{
	static int pitch;
	static void* pixels;

	SDL_LockTexture(tex, NULL, &pixels, &pitch);
	SDL_memcpy(pixels, scrbuf, BUFLEN);
	SDL_UnlockTexture(tex);
	SDL_RenderCopy(rend, tex, NULL, NULL);
	SDL_RenderPresent(rend);
}

void set_pixel(int x, int y, rgb color)
{
	if (x >= 0 && y >= 0 && x < SCR_W && y < SCR_H) {
		scrbuf[y * SCR_W + x] = color;
	}
}