Windows 上的 OpenCL/OpenGL 纹理互操作：调整 OpenGL 纹理的大小

Posted 2023-02-17

【中文标题】Windows 上的 OpenCL/OpenGL 纹理互操作：调整 OpenGL 纹理的大小

【英文标题】：OpenCL/OpenGL Texture interop on windows: resizing OpenGL textures

【发布时间】：2016-08-19 13:23:34

【问题描述】：

跟进这个问题Problems with OpenCL/OpenGL Texture interop / windows：

我们有：

渲染到 FBO，纹理附加为 COLOR_ATTACHMENT0，这是inTex OpenCL 中的可分离降频器，使用inTex，通过tempTex 在三步过程中生成outTex

现在出现了一个新问题，因为这是一个编辑器实现。如果inTex 的大小改变或outTex 的大小改变，首先使用glTexImage2d 调整OpenGL 纹理的大小。然后释放三个内核对象，最后使用clReleaseMemObj( XTex ) 释放所有三个纹理的cl_mem 对象。最后一步只是使用与初始化时相同的代码重新创建所有必要的对象，然后循环继续。

在使用clCreateFromGLTexture2D 为这些纹理重新创建 cl_mem 对象期间，我收到了CL_OUT_OF_RESOURCES。因此，不再执行缩减，因为设置纹理内核参数会产生CL_INVALID_MEM_OBJECT。

也许一些伪代码有助于理解这个问题：

// OBJECTS //
////////////
cl_kernel   k_x, k_y, k_clear;
cl_mem      textureObjects[3];
int         src_width, src_height, dst_width, dst_height;
size_t      rngClr[3], offsClr[3], range_x[3], range_y[3];
float       clrCol[4]

// MAIN ENTRY POINT //
/////////////////////
if ( ( fbo ) && calculate() )

    glFinish();

    if ( CL_recreate )  recreateCLstuff();

    CLmgr->acquireGLObjects( 3, textureObjects );
    CLmgr->callKernel( k_clear, rngClr, offsClr, "clear" );
    CLmgr->setSimpleKernelArg( k_x, 3, 8, &convertXY, "horizontal::convert" );
    CLmgr->setSimpleKernelArg( k_x, 4, 16, &offsets_X, "horizontal::offset" );
    CLmgr->callKernel( k_x, range_x, "horizontal downsample" );
    CLmgr->setSimpleKernelArg( k_y, 3, 8, &convertXY.m128_f32[ 2 ], "vertical::convert" );
    CLmgr->setSimpleKernelArg( k_y, 4, 16, &offsets_Y, "vertical::offset" );
    CLmgr->callKernel( k_y, range_y, "vertical downsample" );
    CLmgr->releaseGLObjects( 3, textureObjects );
    clFinish();


bool calculate()

    // check if a resize of the "inTex" happened or a resize of
    // "outTex" or "tempTex" is necessary
    int srcw, srch, dstw, dsth;
    // acquire above values
    if ( ( srcw != src_width ) || ( srch != src_height ) || ( dstw != dst_width ) || ( dsth != dst_height ) )
    
        CL_recreate = true;

        // rebuild temporary texture
        if ( ( dst_width != dstw ) || ( src_height != srch ) )
            resizeTemporaryOpenGLTexture();
        // rebuild target texture
        if ( ( dst_width != dstw ) || ( dst_height != dsth ) )
            resizeOutputOpenGLTexture();

        // finally copy new values to the non-temporary objects
    
    //  produce all necessary parameters:
    //  - ranges (rngClr, offsClr, range_x, range_y)
    //  - convertXY
    //  - offsets_X
    //  - offsets_Y


void recreateCLstuff()

    releaseCLstuff();
    cerr << name() << ": recreating CL-stuff...\n";
    k_x             = CLmgr->newKernelInstance( className(), "separable" );
    k_y             = CLmgr->newKernelInstance( className(), "separable" );
    k_clearEmpty    = CLmgr->newKernelInstance( className(), "clearEmpty" );
    k_clear         = CLmgr->newKernelInstance( className(), "clear" );
    // [...]
    textureObjects[ 0 ] = CLmgr->createTexture( sourceTexID, WI_CL_TEXTURE_USE::sourceTexture, "source FBO texture" );
    CLmgr->setMemKernelArg( k_x, 0, textureObjects[ 0 ], "horizontal::src" );
    textureObjects[ 1 ] = CLmgr->createTexture( tempTexID, WI_CL_TEXTURE_USE::tempTexture, "separable downscaler buffer" );
    CLmgr->setMemKernelArg( k_x, 1, textureObjects[ 1 ], "horizontal::dst" );
    CLmgr->setMemKernelArg( k_y, 0, textureObjects[ 1 ], "vertical::src" );
    textureObjects[ 2 ] = CLmgr->createTexture( textureID, WI_CL_TEXTURE_USE::targetTexture, "WI_CLtexture target" );
    CLmgr->setMemKernelArg( k_y, 1, textureObjects[ 2 ], "vertical::dst" );
    CLmgr->setMemKernelArg( k_clear, 1, textureObjects[ 2 ], "clear::dst" );

    CLmgr->setSimpleKernelArg( k_clear, 0, 16, clrCol, "clear::clearColor" );

    CL_recreate = false;


void releaseCLstuff()

    cerr << name() << ": releasing CL stuff...\n";
    cl_int err;
    #define releaseKernel( obj ) if ( obj ) if ( err = clReleaseKernel( obj ) ) cerr << "release kernel object \""##obj##"\" failed! (" << clErrorString( err ) << ")\n"

    releaseKernel( k_x );
    releaseKernel( k_y );
    releaseKernel( k_clear );

    for ( int i = 0; i < 3; ++i )
    
        if ( textureObjects[ i ] )
            if ( err = clReleaseMemObject( textureObjects[ i ] ) )
                cerr << "release texture object #" << i << " failed! (" << clErrorString( err ) << ")\n";
            else
                textureObjects[ i ] = nullptr;
    

【参考方案1】：

简单的答案：显然 OpenCL 不喜欢重用 OpenGL 纹理。如果共享纹理的大小发生变化，则需要处理以下步骤：

glDeleteTextures( 1, &id );
glGenTextures( 1, &id );
glBindTexture( GL_TEXTURE_2D, id );
// set texture parameters, so it becomes complete in the eyes of OpenCL and OpenGL
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE );
// allocate texture storage in the GPU
glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA, w, h, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr );
glBindTexture( GL_TEXTURE_2D, 0 );
glFinish();

object = clCreateFromGLTexture2D( context, flags[ usage ], GL_TEXTURE_2D, 0, &id, nullptr );
clSetKernelArg( kernel, argPos, sizeof( cl_mem ), &object );