Using renderer on MacOS

[StarSugar]

I have a problem, please help me! I tried to draw a graph with the renderer on my MacBook, but nothing shows up on the window, even though I've used SDL_RenderPresent.
Here is my code.

//
//  main.c
//  test
//
//  Created by *** on 2022/1/15.
//

#include <stdio.h>
#include "SDL2/SDL.h"
SDL_Texture* loadBMP(char* filePath,SDL_Renderer* renderer){
    SDL_Surface* bmp = NULL;
    SDL_Texture* texture = NULL;
    bmp = SDL_LoadBMP(filePath);
    if(bmp == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return (SDL_Texture*)-1;
    }
    texture = SDL_CreateTextureFromSurface(renderer, bmp);
    SDL_FreeSurface(bmp);
    if(texture == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return (SDL_Texture*)-1;
    }
    return texture;
}

void drawTextrue(int x,int y,SDL_Texture* texture,SDL_Renderer* renderer){
    SDL_Rect rectangle;
    rectangle.x = x;
    rectangle.y = y;
    SDL_QueryTexture(texture, NULL, NULL, &rectangle.x, &rectangle.y);
    SDL_RenderCopy(renderer, texture, NULL, &rectangle);
}

int main(int argc, const char * argv[]) {
    // insert code here...
    SDL_Window* window = NULL;
    SDL_Renderer* renderer = NULL;
    
    if(SDL_Init(SDL_Init(SDL_INIT_EVERYTHING)) < 0){
        printf("\nThere is a error:%s\n",SDL_GetError());
    }
    
    window = SDL_CreateWindow("test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN);
    if(window == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return 1;
    }
    
    renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
    if(renderer == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return 1;
    }
    
    SDL_Texture* background = NULL;
    background = loadBMP("/Users/gaoyuzhuo/Desktop/background.bmp", renderer);
    if(background == (SDL_Texture*)-1){
        printf("\n The error is %s\n",SDL_GetError());
        return 1;
    }
    
    SDL_Texture* image = NULL;
    image = loadBMP("/Users/gaoyuzhuo/Desktop/image.bmp", renderer);
    if(image == (SDL_Texture*)-1){
        printf("\n The error is %s\n",SDL_GetError());
        return 1;
    }
    
    int bx = 0;
    int by = 0;
    SDL_RenderClear(renderer);
    SDL_QueryTexture(background, NULL, NULL, &bx, &by);
    drawTextrue(0, 0, background, renderer);
    drawTextrue(0, by, background, renderer);
    drawTextrue(bx, 0, background, renderer);
    drawTextrue(bx, by, background, renderer);
    SDL_RenderPresent(renderer);
    
    drawTextrue(0, 0, image, renderer);
    SDL_RenderPresent(renderer);
    
    SDL_bool quit = SDL_FALSE;
    while(!quit){
        SDL_Event e;
        while(SDL_PollEvent(&e)){
            if(e.type == SDL_QUIT){
                quit = SDL_TRUE;
            }
        }
    }
    
    SDL_DestroyRenderer(renderer);
    SDL_DestroyTexture(image);
    SDL_DestroyTexture(background);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 0;
}

result:

I'm looking forward your reply!

[slouken]

I haven't tried to run this, but usually the drawing is done every frame, e.g.

//
//  main.c
//  test
//
//  Created by *** on 2022/1/15.
//

#include <stdio.h>
#include "SDL2/SDL.h"
SDL_Texture* loadBMP(char* filePath,SDL_Renderer* renderer){
    SDL_Surface* bmp = NULL;
    SDL_Texture* texture = NULL;
    bmp = SDL_LoadBMP(filePath);
    if(bmp == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return (SDL_Texture*)-1;
    }
    texture = SDL_CreateTextureFromSurface(renderer, bmp);
    SDL_FreeSurface(bmp);
    if(texture == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return (SDL_Texture*)-1;
    }
    return texture;
}

void drawTextrue(int x,int y,SDL_Texture* texture,SDL_Renderer* renderer){
    SDL_Rect rectangle;
    rectangle.x = x;
    rectangle.y = y;
    SDL_QueryTexture(texture, NULL, NULL, &rectangle.x, &rectangle.y);
    SDL_RenderCopy(renderer, texture, NULL, &rectangle);
}

int main(int argc, const char * argv[]) {
    // insert code here...
    SDL_Window* window = NULL;
    SDL_Renderer* renderer = NULL;
    
    if(SDL_Init(SDL_Init(SDL_INIT_EVERYTHING)) < 0){
        printf("\nThere is a error:%s\n",SDL_GetError());
    }
    
    window = SDL_CreateWindow("test", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED, 640, 480, SDL_WINDOW_SHOWN);
    if(window == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return 1;
    }
    
    renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
    if(renderer == NULL){
        printf("\nThe error is %s\n",SDL_GetError());
        return 1;
    }
    
    SDL_Texture* background = NULL;
    background = loadBMP("/Users/gaoyuzhuo/Desktop/background.bmp", renderer);
    if(background == (SDL_Texture*)-1){
        printf("\n The error is %s\n",SDL_GetError());
        return 1;
    }
    
    SDL_Texture* image = NULL;
    image = loadBMP("/Users/gaoyuzhuo/Desktop/image.bmp", renderer);
    if(image == (SDL_Texture*)-1){
        printf("\n The error is %s\n",SDL_GetError());
        return 1;
    }
    
    SDL_bool quit = SDL_FALSE;
    while(!quit){
        SDL_Event e;
        while(SDL_PollEvent(&e)){
            if(e.type == SDL_QUIT){
                quit = SDL_TRUE;
            }
        }
    
        int bx = 0;
        int by = 0;
        SDL_RenderClear(renderer);
        SDL_QueryTexture(background, NULL, NULL, &bx, &by);
        drawTextrue(0, 0, background, renderer);
        drawTextrue(0, by, background, renderer);
        drawTextrue(bx, 0, background, renderer);
        drawTextrue(bx, by, background, renderer);
        SDL_RenderPresent(renderer);
    
        drawTextrue(0, 0, image, renderer);
        SDL_RenderPresent(renderer);
    }
    
    SDL_DestroyRenderer(renderer);
    SDL_DestroyTexture(image);
    SDL_DestroyTexture(background);
    SDL_DestroyWindow(window);
    SDL_Quit();
    return 0;
}

[1bsyl]

I think the drawTexture() is wrong :

• you miss to set a w / h to rectangle.
  eg
  rectangle.w = someval;
  rectangle.h = someval;
  otherwise it scales to 0 x 0

then you may want to set
rect.x = rect.y to smaller value to draw within the window size
(i didn't try with you image so this may not be needed)

So closing ..

[1bsyl]

ping @StarSugar