如何使用SDL_CreateTexture
如何使用SDL_CreateTexture
提问于 2014-11-02 10:36:28
我想知道ho如何使用 SDL 函数.
我只想创造纹理，给它一个颜色，并画在屏幕的某处。我不想在里面放任何照片。
我想我可以按照这个顺序使用SDL_CreateTexture, SDL_SetTextureColorMod, SDL_RenderCopy, SDL_RenderPresent，但是总是得到一个黑色的矩形，而不是红色的。
#include <SDL.h>
int main(int argc, char* argv[]) {
SDL_Init(SDL_INIT_EVERYTHING);
SDL_Window *MainWindow = SDL_CreateWindow("My Game Window",
SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED,
1024, 768,
SDL_WINDOW_SHOWN
);
SDL_Renderer *renderer = SDL_CreateRenderer(MainWindow, -1, 0);
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
SDL_RenderClear(renderer);
SDL_Texture *Tile = SDL_CreateTexture(renderer,SDL_PIXELFORMAT_RGBA8888,SDL_TEXTUREACCESS_TARGET,8,8);
//I want my texture to be red
SDL_SetTextureColorMod(Tile,255,0,0);
//I just try this i dont know if I have to do that
SDL_SetTextureAlphaMod(Tile,255);
SDL_Rect destination = {320,240,8,8};
SDL_RenderCopy(renderer,Tile,NULL,&destination);
SDL_RenderPresent(renderer);
SDL_Delay(3000);
//Clean up
SDL_DestroyTexture(Tile);
SDL_DestroyWindow(MainWindow);
SDL_Quit();
return 0;
}我也不知道我是否在SDL_CreateTexture中使用正确的格式(SDL_CreateTexture)值。他们很多，我不明白他们是什么意思。我可以用哪一种形式来表达这个目的？
回答 1
Stack Overflow用户
回答已采纳
发布于 2014-11-02 11:06:27
SetTextureColorMod将确保后续的呈现复制操作将考虑到指定的乘数。它不会改变颜色的纹理纹理。
您最好要么加载位图，要么用红色初始化纹理，如下面的示例所示
int main(int argc, char* argv[]) {
SDL_Init(SDL_INIT_EVERYTHING);
SDL_Window *MainWindow = SDL_CreateWindow("My Game Window",
SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED,
1024, 768,
SDL_WINDOW_SHOWN
);
SDL_Renderer *renderer = SDL_CreateRenderer(MainWindow, -1, 0);
SDL_SetRenderDrawColor(renderer, 255, 255, 255, 255);
SDL_RenderClear(renderer);
SDL_Texture *Tile = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888,
SDL_TEXTUREACCESS_STREAMING, 8, 8);
// Initialize texture pixels to a red opaque RGBA value
unsigned char* bytes = nullptr;
int pitch = 0;
SDL_LockTexture(Tile, nullptr, reinterpret_cast<void**>(&bytes), &pitch);
unsigned char rgba[4] = { 255, 0, 0, 255 };
for(int y = 0; y < 8; ++y) {
for (int x = 0; x < 8; ++x) {
memcpy(&bytes[(y * 8 + x)*sizeof(rgba)], rgba, sizeof(rgba));
}
}
SDL_UnlockTexture(Tile);
SDL_Rect destination = { 320, 240, 8, 8 };
SDL_RenderCopy(renderer, Tile, NULL, &destination);
SDL_RenderPresent(renderer);
SDL_Delay(3000);
//Clean up
SDL_DestroyTexture(Tile);
SDL_DestroyWindow(MainWindow);
SDL_Quit();
return 0;
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/26698378
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