main.cpp

#include <iostream>
#include <SDL.h>
#include <SDL2_gfxPrimitives.h>
#include "res_path.h"

/*
 * Lesson 1: Hello World!
 */
int main(int, char **) {
    //First we need to start up SDL, and make sure it went ok
    if (SDL_Init(SDL_INIT_VIDEO) != 0) {
        std::cout << "SDL_Init Error: " << SDL_GetError() << std::endl;
        return 1;
    }

    //Now create a window with title "Hello World" at 100, 100 on the screen with w:640 h:480 and show it
    SDL_Window *win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN);
    //Make sure creating our window went ok
    if (win == nullptr) {
        std::cout << "SDL_CreateWindow Error: " << SDL_GetError() << std::endl;
        return 1;
    }

    //Create a renderer that will draw to the window, -1 specifies that we want to load whichever
    //video driver supports the flags we're passing
    //Flags: SDL_RENDERER_ACCELERATED: We want to use hardware accelerated rendering
    //SDL_RENDERER_PRESENTVSYNC: We want the renderer's present function (update screen) to be
    //synchronized with the monitor's refresh rate
    SDL_Renderer *ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
    if (ren == nullptr) {
        SDL_DestroyWindow(win);
        std::cout << "SDL_CreateRenderer Error: " << SDL_GetError() << std::endl;
        SDL_Quit();
        return 1;
    }

    //SDL 2.0 now uses textures to draw things but SDL_LoadBMP returns a surface
    //this lets us choose when to upload or remove textures from the GPU
    std::string imagePath = getResourcePath("Lesson1") + "hello.bmp";
    SDL_Surface *bmp = SDL_LoadBMP(imagePath.c_str());
    if (bmp == nullptr) {
        SDL_DestroyRenderer(ren);
        SDL_DestroyWindow(win);
        std::cout << "SDL_LoadBMP Error: " << SDL_GetError() << std::endl;
        SDL_Quit();
        return 1;
    }

    //To use a hardware accelerated texture for rendering we can create one from
    //the surface we loaded
    SDL_Texture *tex = SDL_CreateTextureFromSurface(ren, bmp);
    //We no longer need the surface
    SDL_FreeSurface(bmp);
    if (tex == nullptr) {
        SDL_DestroyRenderer(ren);
        SDL_DestroyWindow(win);
        std::cout << "SDL_CreateTextureFromSurface Error: " << SDL_GetError() << std::endl;
        SDL_Quit();
        return 1;
    }

    //A sleepy rendering loop, wait for 3 seconds and render and present the screen each time
    for (int i = 0; i < 3; ++i) {
        //First clear the renderer
        SDL_SetRenderDrawColor(ren, 0, 0, 0, 255);
        SDL_RenderClear(ren);
        //Draw the texture
        //SDL_RenderCopy(ren, tex, NULL, NULL);
        rectangleColor( ren, 0, 0, 100, 11, 0xff0000ff );
        boxColor( ren, 0, 1, (i*10)+10, 9, 0xff00ff00 );
        //Update the screen
        SDL_RenderPresent(ren);
        //Take a quick break after all that hard work
        SDL_Delay(1000);
    }

    //Clean up our objects and quit
    SDL_DestroyTexture(tex);
    SDL_DestroyRenderer(ren);
    SDL_DestroyWindow(win);
    SDL_Quit();

    return 0;
}