# SDL_CreateSoftwareRenderer

Create a 2D software rendering context for a surface.

## Header File

Defined in [<SDL3/SDL_render.h>](https://github.com/libsdl-org/SDL/blob/main/include/SDL3/SDL_render.h)

## Syntax

```c
SDL_Renderer * SDL_CreateSoftwareRenderer(SDL_Surface *surface);
```

## Function Parameters

|                              |             |                                                                                            |
| ---------------------------- | ----------- | ------------------------------------------------------------------------------------------ |
| [SDL_Surface](SDL_Surface) * | **surface** | the [SDL_Surface](SDL_Surface) structure representing the surface where rendering is done. |

## Return Value

([SDL_Renderer](SDL_Renderer) *) Returns a valid rendering context or NULL
if there was an error; call [SDL_GetError](SDL_GetError)() for more
information.

## Remarks

Two other API which can be used to create [SDL_Renderer](SDL_Renderer):
[SDL_CreateRenderer](SDL_CreateRenderer)() and
[SDL_CreateWindowAndRenderer](SDL_CreateWindowAndRenderer)(). These can
_also_ create a software renderer, but they are intended to be used with an
[SDL_Window](SDL_Window) as the final destination and not an
[SDL_Surface](SDL_Surface).

## Thread Safety

It is safe to call this function from any thread.

## Version

This function is available since SDL 3.2.0.

## Code Examples

```c
#include <SDL3/SDL.h>
#include <SDL3/SDL_main.h>

SDL_Window *window;
SDL_Renderer *renderer;
int done;

void DrawChessBoard(SDL_Renderer *renderer)
{
    int row = 0, column = 0, x = 0;
    SDL_FRect rect;
    SDL_Rect darea;

    /* Get the Size of drawing surface */
    SDL_GetRenderViewport(renderer, &darea);

    SDL_SetRenderDrawColor(renderer, 0xFF, 0xFF, 0xFF, 0xFF);
    SDL_RenderClear(renderer);

    for (; row < 8; row++) {
        column = row % 2;
        x = column;
        for (; column < 4 + (row % 2); column++) {
            SDL_SetRenderDrawColor(renderer, 0, 0, 0, 0xFF);

            rect.w = (float)darea.w / 8;
            rect.h = (float)darea.h / 8;
            rect.x = x * rect.w;
            rect.y = row * rect.h;
            x = x + 2;
            SDL_RenderFillRect(renderer, &rect);
        }
    }
    SDL_RenderPresent(renderer);
}

void loop()
{
    SDL_Event e;
    while (SDL_PollEvent(&e)) {
        if (e.type == SDL_EVENT_QUIT) {
            done = 1;
            return;
        }

        if ((e.type == SDL_EVENT_KEY_DOWN) && (e.key.key == SDLK_ESCAPE)) {
            done = 1;
            return;
        }
    }

    DrawChessBoard(renderer);

    /* Got everything on rendering surface,
       now Update the drawing image on window screen */
    SDL_UpdateWindowSurface(window);
}

int main(int argc, char *argv[])
{
    SDL_Surface *surface;

    /* Initialize SDL */
    if (!SDL_Init(SDL_INIT_VIDEO)) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_Init fail : %s\n", SDL_GetError());
        return 1;
    }

    /* Create window and renderer for given surface */
    window = SDL_CreateWindow("Chess Board", 640, 480, 0);
    if (!window) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Window creation fail : %s\n", SDL_GetError());
        return 1;
    }
    surface = SDL_GetWindowSurface(window);
    renderer = SDL_CreateSoftwareRenderer(surface);
    if (!renderer) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Render creation for surface fail : %s\n", SDL_GetError());
        return 1;
    }

    /* Draw the Image on rendering surface */
    done = 0;

    while (!done) {
        loop();
    }

    SDL_Quit();
    return 0;
}

```

## See Also

- [SDL_DestroyRenderer](SDL_DestroyRenderer)

----
[CategoryAPI](CategoryAPI), [CategoryAPIFunction](CategoryAPIFunction), [CategoryRender](CategoryRender)

