通过PySDL2使用SDL_QueryTexture的问题

Question

I am using PySDL2 and I am coding a little script that load a image on a windows but I am getting this error message "ctypes.ArgumentError: argument 4: : expected LP_c_int instance instead of int" when i use this function "SDL_QueryTexture". This is my code:

"""Simple example for using sdl2 directly."""
import os
import sys
import ctypes
from sdl2 import *

def run():
    SDL_Init(SDL_INIT_VIDEO)
    window = SDL_CreateWindow(b"Hello World",
                                   SDL_WINDOWPOS_CENTERED,
                                   SDL_WINDOWPOS_CENTERED,
                                   459, 536, SDL_WINDOW_SHOWN)
    render = SDL_CreateRenderer(window, -1, 0)                                   
    fname = os.path.join(os.path.dirname(os.path.abspath(__file__)),
                         "resources", "self-control.bmp")
    imageSurface = SDL_LoadBMP(fname.encode("utf-8"))
    imageTexture = SDL_CreateTextureFromSurface(render, imageSurface)
    SDL_FreeSurface(imageSurface)

    sourceRectangle = SDL_Rect()
    destinationRectangle = SDL_Rect()    
    SDL_QueryTexture(imageTexture, None, None, sourceRectangle.w, sourceRectangle.h)

    destinationRectangle.x = sourceRectangle.x = 0
    destinationRectangle.y = sourceRectangle.y = 0
    destinationRectangle.w = sourceRectangle.w
    destinationRectangle.h = sourceRectangle.h

    SDL_RenderCopy(render, imageTexture, sourceRectangle, destinationRectangle)

    running = True
    event = sdl2.SDL_Event()
    while running:
        while SDL_PollEvent(ctypes.byref(event)) != 0:
            if event.type == sdl2.SDL_QUIT:
                running = False
                break
        SDL_Delay(10)

    SDL_DestroyWindow(window)
    SDL_Quit()
    return 0    

if __name__ == "__main__":
    sys.exit(run())

I know is something related to ctypes, i hope someone can help me.

Answer 1

SDL_QueryTexture gets pointers to ints to write result to, you cannot simply pass int here. Workaround would be something like

w = ctypes.c_int()
h = ctypes.c_int()
SDL_QueryTexture(imageTexture, None, None, w, h)

And then getting result from w.value and h.value .

However you already have a surface, why not just read width and height from it?

imageSurface.contents.w, imageSurface.contents.h