c++ - Constant Buffer DirectX 11 -

getting frustrated cbuffer in hlsl d3d11 not updating, initial values set upon application launch updating no go, used updatesubresource, tried id3d11devicecontext::map & id3d11devicecontext::unmap.

note: cbuffer setup d3d11_usage_dynamic & d3d11_cpu_access_write.

my id3d11buffer (constant buffer) returning 4 bytes when it's size queried.... sounds part of problem

struct vs_cbuffer_data {     xmfloat4x4 world;     xmfloat4x4 view;     xmfloat4x4 projection;      vs_cbuffer_data()     {         xmstorefloat4x4(&world, directx::xmmatrixidentity());         xmstorefloat4x4(&view, directx::xmmatrixidentity());         xmstorefloat4x4(&projection, directx::xmmatrixidentity());     } };  d3d11_buffer_desc cbufferdesc; memset(&cbufferdesc, 0, sizeof(cbufferdesc));  cbufferdesc.bindflags = d3d11_bind_constant_buffer cbufferdesc.usage = d3d11_usage_dynamic; cbufferdesc.bytewidth = sizeof(m_cbufferdata); cbufferdesc.cpuaccessflags = d3d11_cpu_access_write; cbufferdesc.miscflags = 0; cbufferdesc.structurebytestride = 0;  d3d11_subresource_data subdata; memset(&subdata, 0, sizeof(subdata));  subdata.psysmem = &m_cbufferdata;  if (failed(prenderertemp->createbuffer(cbufferdesc {     outputdebugstring("failed create cbuffer!")     goto failed; }  void cube::updateviewprojection(__in const renderer* prenderer, __in const    xmfloat4x4   &view, __in const xmfloat4x4 &proj) {     d3d11_mapped_subresource mappedsubresource;     memset(&mappedsubresource, 0, sizeof(mappedsubresource));      if (succeeded(prenderer->getdevcontext()->map(m_pcbuffer, 0, d3d11_map_write_no_overwrite,  0, &mappedsubresource)))      {         primitive::updateviewprojection(null, view, proj);         vs_cbuffer_data* cbdata = (vs_cbuffer_data*)&mappedsubresource.pdata;          memcpy(cbdata, &m_cbufferdata, sizeof(cbdata));         prenderer->getdevcontext()->unmap(m_pcbuffer, 0);         setbuffers(prenderer);     } }  // shader.vsh cbuffer cbmatrixbuffer : register(b0) {     float4x4 world;     float4x4 view;     float4x4 projection; }; 

your problem in memcpy. line here:

memcpy(cbdata, &m_cbufferdata, sizeof(cbdata)); 

is copying number of bytes equal size of vs_cbuffer_data pointer, on 32 bit systems 4 bytes (8 bytes on x64). code should read:

memcpy(cbdata, &m_cbufferdata, sizeof(vs_cbuffer_data)); 

which copy 48 bytes of data opposed 4/8 (whatever sizeof(void*) evaluates to).

in general, avoid using sizeof query size of array, , avoid in regards pointers (unless have need that).