House Shooter Recreation with SDL2 and Odin – Half 2 – Render Participant

Rendering a picture requires initialization of the SDL Picture library.

Steps to Render an Picture

1. Initialize SDL_Image for the asset file sorts you wish to use.
2. Load a Texture
3. Hold that Texture in an Entity struct that additionally tracks the entity’s place.
4. SDL.RenderCopy() to attract the entity to the scene earlier than SDL.RenderPresent()

SDL_Image.Init()

The Picture library extends the core library to permit for utilizing .png photographs once we use the SDL_Image.INIT_PNG flag.

SDL_Image.LoadTexture()

In instances the place you are rendering for 2d and also you do NOT have to control a picture (aside from resizing and altering place), LoadTexture() is probably the most environment friendly option to load a picture asset. See https://wiki.libsdl.org/SDL_image/IMG_LoadTexture.

player_texture := SDL_Image.LoadTexture(recreation.renderer, "property/participant.png")
assert(player_texture != nil, SDL.GetErrorString())

SDL_Image.LoadTexture() will return nil on an error, so it’s a good suggestion to test that earlier than persevering with with our code.

There’s a mistake within the code under, and chances are you’ll not perceive why your participant.png is not loading should you did not use an assert() right here:

// strive utilizing an assert right here to see the issue:
player_texture := SDL_Image.LoadTexture(recreation.renderer, "/property/participant.png")

Entity :: struct

Entity structs are a easy option to maintain observe of entity positions and their loaded textures which you want for subsequent calls to SDL.RenderCopy().

Entity :: struct
{
    tex: ^SDL.Texture,
    dest: SDL.Rect,
}

Should you’re utilizing a sprite sheet with many sprites, additionally, you will must maintain observe of the supply place of the picture on the sprite sheet:

Entity :: struct
{
    tex: ^SDL.Texture,
    supply: SDL.Rect,
    dest: SDL.Rect,
}

At this level in our code we don’t want to trace a supply as a result of we’re loading the complete picture.

SDL.RenderCopy()

As a result of we’re loading the complete picture, we are able to go nil to the SDL.RenderCopy() perform rather than the supply SDL.Rect struct:

SDL.RenderCopy(recreation.renderer, recreation.participant.tex, nil, &recreation.participant.dest)

SDL.RenderCopy() is named in spite of everything inputs are dealt with and any updates are made to the participant struct’s place.