SDL progress bar from https://forums.libsdl.org/viewtopic.php?p=46932

SDL_UI_PBar.hpp

/*
   
   Render a Horizontal Percentage Bar
   Drains left to right normally, if width is negative it will drain right to left.
   Percent is clamped 0.0f - 1.0f

*/

void RenderHPBar(int x, int y, int w, int h, float Percent, SDL_Color FGColor, SDL_Color BGColor) {
   Percent = Percent > 1.f ? 1.f : Percent < 0.f ? 0.f : Percent;
   SDL_Color old;
   SDL_GetRenderDrawColor(Renderer, &old.r, &old.g, &old.g, &old.a);
   SDL_Rect bgrect = { x, y, w, h };
   SDL_SetRenderDrawColor(Renderer, BGColor.r, BGColor.g, BGColor.b, BGColor.a);
   SDL_RenderFillRect(Renderer, &bgrect);
   SDL_SetRenderDrawColor(Renderer, FGColor.r, FGColor.g, FGColor.b, FGColor.a);
   int pw = (int)((float)w * Percent);
   int px = x + (w - pw);
   SDL_Rect fgrect = { px, y, pw, h };
   SDL_RenderFillRect(Renderer, &fgrect);
   SDL_SetRenderDrawColor(Renderer, old.r, old.g, old.b, old.a);
}

/*
   
   Render a Vertical Percentage Bar
   Drains top to bottom normally, if height is negative it will drain bottom to top
   Percent is clamped 0.0f - 1.0f

*/

void RenderVPBar(int x, int y, int w, int h, float Percent, SDL_Color FGColor, SDL_Color BGColor) {
   Percent = Percent > 1.f ? 1.f : Percent < 0.f ? 0.f : Percent;
   SDL_Color old;
   SDL_GetRenderDrawColor(Renderer, &old.r, &old.g, &old.g, &old.a);
   SDL_Rect bgrect = { x, y, w, h };
   SDL_SetRenderDrawColor(Renderer, BGColor.r, BGColor.g, BGColor.b, BGColor.a);
   SDL_RenderFillRect(Renderer, &bgrect);
   SDL_SetRenderDrawColor(Renderer, FGColor.r, FGColor.g, FGColor.b, FGColor.a);
   int ph = (int)((float)h * Percent);
   int py = y + (h - ph);
   SDL_Rect fgrect = { x, py, w, ph };
   SDL_RenderFillRect(Renderer, &fgrect);
   SDL_SetRenderDrawColor(Renderer, old.r, old.g, old.b, old.a);
}

SDL_Util.hpp

/*

   color - Returns an SDL_Color with the appropriate values

*/

SDL_Color color(Uint8 r, Uint8 g, Uint8 b, Uint8 a) {
   SDL_Color col = {r,g,b,a};
   return col;
}