问题描述

SDL 在iOS下使用的问题，求解

刚开始接触SDL，看到sdl_drawline.h里有画线的方法

  int SDL_DrawLine(SDL_Surface * dst, int x1, int y1, int x2, int y2, Uint32 color);

然后我就用来试着拿来画线，没法画出，你们是用sdl是怎么画线的，求个栗子

解决方案

是不是SDL依赖的库等在你的IOS上能不能正确工作，代码本身应该没啥问题，估计还是环境依赖

解决方案二：

上次问题加载背景图的正确做法是

 //
//  loadBackgroundBMP.c
//  text
//
//  Created by liu on 15/9/7.
//  Copyright (c) 2015年 Fcar. All rights reserved.
//

#include "loadBackgroundBMP.h"
#include "common.h"

static SDL_Texture *texture = 0;
///更新界面
void render(SDL_Renderer *renderer) {
    /* fill background in with black */
    SDL_RenderClear(renderer);
    SDL_RenderCopy(renderer, texture, NULL, NULL);
    /* update screen */
    SDL_RenderPresent(renderer);
}
///初始化纹理
void initializeTexture(SDL_Renderer *renderer) {
    SDL_Surface *bmp_surface;
    /* load the bmp */
    bmp_surface = SDL_LoadBMP("space.bmp");
    if (bmp_surface == NULL) {
        fatalError("could not load bmp");
    }
    texture = SDL_CreateTextureFromSurface(renderer, bmp_surface);
    if (texture == 0) {
        fatalError("could not create texture");
    }
    SDL_SetColorKey(bmp_surface, 1,
                    SDL_MapRGB(bmp_surface->format, 0, 0, 255));
    SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
    /* free up allocated memory */
    SDL_FreeSurface(bmp_surface);
}

void loadBMP(void) {
    SDL_Window *window;
    SDL_Renderer *renderer;

    /* 初始化 SDL */
    if (SDL_Init(SDL_INIT_VIDEO) < 0) {
        fatalError("Could not initialize SDL");
    }
    /* 创建window */
    window = SDL_CreateWindow("加载背景图", 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_OPENGL | SDL_WINDOW_BORDERLESS);

    /* 设置渲染器 */
    renderer = SDL_CreateRenderer(window, -1, 0);

    initializeTexture(renderer);

    int done = 0;
    while (!done) {
        SDL_Event event;
        while (SDL_PollEvent(&event)) {
            if (event.type == SDL_QUIT) {
                done = 1;
            }
        }
        render(renderer);
        SDL_Delay(1000);
    }
    /* cleanup */
    SDL_DestroyTexture(texture);
    /* shutdown SDL */
    SDL_Quit();
}