Using RingLibSDL

Ring

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Using RingLibSDL

In this chapter we will learn about using RingLibSDL to create games based on the LibSDL, SDLImage, SDLTTF and SDLMixer libraries.

Tip

RingLibSDL is not distributed with the binary releases for desktop which uses RingAllegro

Note

To use RingLibSDL, Check ring/android/ringlibsdl folder.

Create Window

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)
SDL_Delay(2000)
SDL_DestroyWindow(win)
SDL_Quit()

Display Image

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)
ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC )
bmp = SDL_LoadBMP("hello.bmp")
tex = SDL_CreateTextureFromSurface(ren,bmp)
SDL_FreeSurface(bmp)
SDL_RenderClear(ren)
SDL_RenderCopy2(ren,tex)
SDL_RenderPresent(ren)
SDL_Delay(2000)
SDL_DestroyTexture(tex)
SDL_DestroyRenderer(ren)
SDL_DestroyWindow(win)
SDL_Quit()

Switch between two images

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)
ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC )
bmp = SDL_LoadBMP("hello.bmp")
tex = SDL_CreateTextureFromSurface(ren,bmp)
SDL_FreeSurface(bmp)
bmp = SDL_LoadBMP("hello2.bmp")
tex2 = SDL_CreateTextureFromSurface(ren,bmp)
SDL_FreeSurface(bmp)

for x = 1 to 10 showtex(tex) showtex(tex2) next

SDL_DestroyTexture(tex)
SDL_DestroyTexture(tex2)
SDL_DestroyRenderer(ren)
SDL_DestroyWindow(win)
SDL_Quit()

func showtex oTex
        SDL_RenderClear(ren)
        SDL_RenderCopy2(ren,oTex)
        SDL_RenderPresent(ren)
        SDL_Delay(200)

Draw Rectangle

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)
ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC )
SDL_RenderClear(ren)
rect = sdl_new_sdl_rect()
sdl_set_sdl_rect_x(rect,10)
sdl_set_sdl_rect_y(rect,10)
sdl_set_sdl_rect_w(rect,100)
sdl_set_sdl_rect_h(rect,100)
SDL_SetRenderDrawColor(ren,255,255,255,255)
SDL_RenderDrawRect(ren,rect)
sdl_destroy_sdl_rect(rect)
SDL_RenderPresent(ren)
SDL_Delay(2000)
SDL_DestroyRenderer(ren)
SDL_DestroyWindow(win)
SDL_Quit()

Display PNG Images

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)
ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC )
bmp = IMG_Load("hello3.png")
tex = SDL_CreateTextureFromSurface(ren,bmp)
SDL_FreeSurface(bmp)
SDL_RenderClear(ren)
SDL_RenderCopy2(ren,tex)
SDL_RenderPresent(ren)
SDL_Delay(2000)
SDL_DestroyTexture(tex)
SDL_DestroyRenderer(ren)
SDL_DestroyWindow(win)
SDL_Quit()

Use TTF Fonts

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)
ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC )
SDL_RenderClear(ren)

TTF_Init()
font = TTF_OpenFont("pirulen.ttf", 16)
color = sdl_new_sdl_color()
sdl_set_sdl_color_r(color,0)
sdl_set_sdl_color_g(color,255)
sdl_set_sdl_color_b(color,0)
text = TTF_RenderText_Solid(font,"Welcome to the Ring language",color)
surface = SDL_GetWindowSurface(win)
SDL_BlitSurface(text, nullpointer(), surface, nullpointer())
SDL_UpdateWindowSurface(win)
SDL_Delay(2000)

SDL_Destroy_SDL_Color(color)
SDL_FreeSurface(text)
TTF_CloseFont(font)
SDL_DestroyRenderer(ren)
SDL_DestroyWindow(win)
SDL_Quit()

Display Transparent Images

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)

flags = IMG_INIT_JPG | IMG_INIT_PNG
IMG_Init(flags)

win = SDL_CreateWindow("Hello World!", 100, 100, 800, 600, SDL_WINDOW_SHOWN)
ren = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC )

bmp = IMG_Load("stars.jpg")
tex = SDL_CreateTextureFromSurface(ren,bmp)
SDL_FreeSurface(bmp)
SDL_RenderClear(ren)
SDL_RenderCopy(ren,tex,nullpointer(),nullpointer())
SDL_DestroyTexture(tex)

bmp = IMG_Load("player.png")
# Image - Set Transparent color (white)
myformat = sdl_get_sdl_surface_format(bmp)
white = SDL_MapRGB(myformat, 255, 255, 255)
SDL_SetColorKey(bmp, SDL_True, white)

tex = SDL_CreateTextureFromSurface(ren,bmp)
SDL_FreeSurface(bmp)
rect = sdl_new_sdl_rect()
sdl_set_sdl_rect_x(rect,0)
sdl_set_sdl_rect_y(rect,0)
sdl_set_sdl_rect_w(rect,100)
sdl_set_sdl_rect_h(rect,100)
SDL_RenderCopy(ren,tex,nullpointer(),rect)

SDL_SetTextureBlendMode(tex,2)
SDL_SetTextureAlphaMod(tex,255)
sdl_set_sdl_rect_x(rect,200)
sdl_set_sdl_rect_y(rect,200)
sdl_set_sdl_rect_w(rect,100)
sdl_set_sdl_rect_h(rect,100)
SDL_RenderCopy(ren,tex,nullpointer(),rect)

SDL_DestroyTexture(tex)
SDL_Destroy_SDL_Rect(rect)

SDL_RenderPresent(ren)
SDL_Delay(2000)
SDL_DestroyRenderer(ren)
SDL_DestroyWindow(win)
SDL_Quit()

Close Window Event

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)

myevent = sdl_new_sdl_event()
while true
        thevent = sdl_pollevent(myevent)
        switch sdl_get_sdl_event_type(myevent)
                on sdl_get_sdl_quit()
                        exit
                on sdl_get_sdl_keydown()
                        Key = SDL_GET_SDL_Event_key_keysym_sym(myevent)
                        if key = 27 exit ok

        off
end

SDL_DestroyWindow(win)
SDL_Quit()

Mouse Events

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)

win = SDL_CreateWindow("Mouse Events ", 100, 100, 640, 480, SDL_WINDOW_SHOWN)

TTF_Init()
font = TTF_OpenFont("pirulen.ttf", 16)
color = sdl_new_sdl_color()
sdl_set_sdl_color_r(color,0)
sdl_set_sdl_color_g(color,255)
sdl_set_sdl_color_b(color,0)

surface = SDL_GetWindowSurface(win)

myevent = sdl_new_sdl_event()
while true
        cMsg = ""
        sdl_pollevent(myevent)
        switch sdl_get_sdl_event_type(myevent)
                on SDL_QUIT
                        exit
                on SDL_KEYDOWN
                        Key = SDL_GET_SDL_Event_key_keysym_sym(myevent)
                        if key = 27 exit ok
                on SDL_MOUSEBUTTONDOWN
                        if sdl_get_Sdl_Event_button_button(myevent) = SDL_BUTTON_LEFT
                                SDL_SETWINDOWTITLE(win, " Button_Left_Down " )
                        but sdl_get_Sdl_Event_button_button(myevent) = SDL_BUTTON_MIDDLE
                                SDL_SETWINDOWTITLE(win,  " Button_Middle_Down " )
                        but sdl_get_Sdl_Event_button_button(myevent) = SDL_BUTTON_RIGHT
                                SDL_SETWINDOWTITLE(win,  " Button_Right_Down " )
                        ok
                on SDL_MOUSEMOTION
                        sdl_fillrect(surface,nullpointer(),0)
                        if sdl_get_sdl_event_motion_xrel(myevent) < 0
                                cMsg += " Left "
                        else
                                cMsg += " Right "
                        ok
                        if sdl_get_sdl_event_motion_yrel(myevent) < 0
                                cMsg += " Up "
                        else
                                cMsg += " Down "
                        ok
                        cMsg += " x = " + sdl_get_sdl_event_motion_x(myevent)
                        cMsg += " y = " + sdl_get_sdl_event_motion_y(myevent)
                        showmsg(cMsg)
        off
end

SDL_Destroy_SDL_Color(Color)
TTF_CloseFont(font)
SDL_DestroyWindow(win)
SDL_Quit()

func showmsg mymsg
        text = TTF_RenderText_Solid(font,mymsg,color)
        SDL_BlitSurface(text, nullpointer(), surface, nullpointer())
        SDL_UpdateWindowSurface(win)
        SDL_FreeSurface(text)

Play Sound

Example:

Load "libsdl.ring"

SDL_Init(SDL_INIT_EVERYTHING)
win = SDL_CreateWindow("Hello World!", 100, 100, 640, 480, SDL_WINDOW_SHOWN)
Mix_OpenAudio( 44100, MIX_DEFAULT_FORMAT , 2, 10000)
Mix_AllocateChannels(4)
sound = Mix_LoadWav( "sound.wav" )
Mix_VolumeChunk(sound,1)
Mix_PlayChannel(1,sound,0)

myevent = sdl_new_sdl_event()
while true
        thevent = sdl_pollevent(myevent)
        switch sdl_get_sdl_event_type(myevent)
                on sdl_get_sdl_quit()
                        exit
                on sdl_get_sdl_keydown()
                        Key = SDL_GET_SDL_Event_key_keysym_sym(myevent)
                        if key = 27 exit ok
        off
end

Mix_FreeChunk( sound )
Mix_CloseAudio()
Mix_Quit()
SDL_DestroyWindow(win)
SDL_Quit()

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