如何使用 SDL 2.0.9 创建 Direct3d 11 渲染器

在我的项目中我必须使用SDL_BLENDOPERATION_MAXIMUM via SDL_ComposeCustomBlendMode()仅在 SDL 2.0.9 中由 direct3d11 渲染器支持。我有 Windows 8.1 和 GeForce GTX750 Ti，并更新了驱动程序。我的系统应该支持 DirectX 11 渲染。

更改定义于SDL_config.h or SDL_config_windows.h (SDL_VIDEO_RENDER_D3D11到 1 和SDL_VIDEO_RENDER_D3D到 0) 没有帮助。 我尝试根据 SDL 源代码使用定义的 SDL_VIDEO_RENDER_D3D11 或 WINRT 来填充预处理器定义。但这没有帮助。

我应该如何激活 direct3d11 渲染器以便可以使用最大混合模式？

我的测试代码：

#include "SDL.h"
#include "SDL_image.h"
#include <string>

using namespace std;

int main( int argc, char *argv[] ) {
    SDL_Init( SDL_INIT_VIDEO );
    IMG_Init( IMG_INIT_PNG );
    SDL_SetHintWithPriority( SDL_HINT_RENDER_DRIVER, "direct3d11", SDL_HINT_OVERRIDE );
    SDL_Window *window = SDL_CreateWindow( "Testing", SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED,
                                             1200, 600, SDL_WINDOW_RESIZABLE );
    SDL_Renderer *renderer = SDL_CreateRenderer( window, -1, SDL_RENDERER_ACCELERATED );
    SDL_RendererInfo *rendererInfo = new SDL_RendererInfo();
    SDL_RendererInfo *driverInfo = new SDL_RendererInfo();
    SDL_GetRendererInfo( renderer, rendererInfo );
    int drivers = SDL_GetNumRenderDrivers();
    string availableDrivers = " (";
    for ( int i = 0; i < drivers; ++i ) {
        SDL_GetRenderDriverInfo( i, driverInfo );
        string driverName = driverInfo->name;
        if ( i == drivers - 1 ) {
            availableDrivers += driverName;
        }
        else {
            availableDrivers += driverName + ", ";
        }
    }
    availableDrivers += ")";
    string path = SDL_GetBasePath();
    SDL_Surface *surfRed = IMG_Load( (path + "\\Red.png").c_str() );
    SDL_Texture *textRed = SDL_CreateTextureFromSurface( renderer, surfRed );
    SDL_FreeSurface( surfRed );
    SDL_Surface *surfBlue = IMG_Load( ( path + "\\Blue.png" ).c_str() );
    SDL_Texture *textBlue = SDL_CreateTextureFromSurface( renderer, surfBlue );
    SDL_FreeSurface( surfBlue );
    SDL_Rect destRed, destBlue;
    destRed.x = 128;
    destRed.y = 128;
    destBlue.x = 196;
    destBlue.y = 196;
    SDL_QueryTexture( textRed, NULL, NULL, &destRed.w, &destRed.h );
    SDL_QueryTexture( textBlue, NULL, NULL, &destBlue.w, &destBlue.h );
    SDL_BlendMode blendMode = SDL_ComposeCustomBlendMode( SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_MAXIMUM,
        SDL_BLENDFACTOR_ONE, SDL_BLENDFACTOR_ONE, SDL_BLENDOPERATION_MAXIMUM );         
    SDL_SetTextureBlendMode( textRed, blendMode );
    SDL_SetTextureBlendMode( textBlue, blendMode );
//  SDL_SetRenderDrawBlendMode( renderer, blendMode );
    string info = rendererInfo->name + availableDrivers + " " + SDL_GetError();
    SDL_SetWindowTitle( window, info.c_str() );
    SDL_SetRenderDrawColor( renderer, 0, 0, 0, 255 );
    SDL_Event event;
    bool isRunning = true;
    while ( isRunning ) {
        if ( SDL_PollEvent( &event ) ) {
            if ( event.type == SDL_QUIT ) {
                isRunning = false;
            }
        }
        SDL_RenderClear( renderer );
        SDL_RenderCopy( renderer, textRed, NULL, &destRed );
        SDL_RenderCopy( renderer, textBlue, NULL, &destBlue );
        SDL_RenderPresent( renderer );
    }
    delete driverInfo;
    delete rendererInfo;
    SDL_DestroyTexture( textRed );
    SDL_DestroyTexture( textBlue );
    SDL_DestroyRenderer( renderer );
    SDL_DestroyWindow( window );
    IMG_Quit();
    SDL_Quit();
    return 0;
}

窗口标题为“direct3d（direct3d、opengl、opengles2、软件）不支持此操作”。当我更改为 SDL_BLENDOPERATION_ADD 时它工作正常，但这不是我想要的。如果我取消注释渲染器混合模式，它也没有帮助。

1. 通过枚举支持的渲染器后端SDL_GetNumRenderDrivers() and SDL_GetRenderDriverInfo().
2. 请注意索引direct3d11驱动程序（如果存在）。
3. 将索引传递到SDL_CreateRenderer().

全部一起：

SDL_Init( SDL_INIT_VIDEO );
SDL_Window* window = SDL_CreateWindow( "SDL2", 0, 0, 640, 480, SDL_WINDOW_SHOWN );

SDL_Renderer* renderer = nullptr;
for( int i = 0; i < SDL_GetNumRenderDrivers(); ++i )
{
    SDL_RendererInfo rendererInfo = {};
    SDL_GetRenderDriverInfo( i, &rendererInfo );
    if( rendererInfo.name != std::string( "direct3d11" ) )
    {
        continue;
    }

    renderer = SDL_CreateRenderer( window, i, 0 );
    break;
}