Skip to content
Permalink
Browse files

[c-host] dxgi: don't stall the GPU pipeline to map textures to ram

ID3D11DeviceContext_Map by default will force a CPU sync if the prior call to
CopyResource has not completed, this change defers the mapping and sets the
D3D11_MAP_FLAG_DO_NOT_WAIT when attempting to map the texture allowing the
capture to continue without incurring an expensive CPU/GPU sync.

A new tuneable has also been added

  * dxgi:maxTextures
  • Loading branch information...
gnif committed May 26, 2019
1 parent d07aa4b commit 21b02efb4d6f2be70352b464eff21e78bbebd920
Showing with 65 additions and 24 deletions.
  1. +1 −1 VERSION
  2. +64 −23 c-host/platform/Windows/capture/DXGI/src/dxgi.c
@@ -1 +1 @@
B1-rc2-1-g9f33043d17+1
B1-rc2-2-gd07aa4b29e+1
@@ -30,10 +30,16 @@ Place, Suite 330, Boston, MA 02111-1307 USA

#include "dxgi_extra.h"

#define MAX_TEXTURES 2
enum TextureState
{
TEXTURE_STATE_UNUSED,
TEXTURE_STATE_PENDING_MAP,
TEXTURE_STATE_MAPPED
};

typedef struct Texture
{
enum TextureState state;
ID3D11Texture2D * tex;
D3D11_MAPPED_SUBRESOURCE map;
osEventHandle * evt;
@@ -64,7 +70,8 @@ struct iface
ID3D11DeviceContext * deviceContext;
D3D_FEATURE_LEVEL featureLevel;
IDXGIOutputDuplication * dup;
Texture texture[MAX_TEXTURES];
int maxTextures;
Texture * texture;
int texRIndex;
int texWIndex;
bool needsRelease;
@@ -120,6 +127,13 @@ static void dxgi_initOptions()
.type = OPTION_TYPE_STRING,
.value.x_string = NULL
},
{
.module = "dxgi",
.name = "maxTextures",
.description = "The maximum number of frames to buffer before skipping",
.type = OPTION_TYPE_INT,
.value.x_int = 1
},
{0}
};

@@ -153,6 +167,11 @@ static bool dxgi_create()
return false;
}

this->maxTextures = option_get_int("dxgi", "maxTextures");
if (this->maxTextures <= 0)
this->maxTextures = 1;

this->texture = calloc(sizeof(struct Texture), this->maxTextures);
return true;
}

@@ -434,7 +453,7 @@ static bool dxgi_init(void * pointerShape, const unsigned int pointerSize)
texDesc.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
texDesc.MiscFlags = 0;

for(int i = 0; i < MAX_TEXTURES; ++i)
for(int i = 0; i < this->maxTextures; ++i)
{
status = ID3D11Device_CreateTexture2D(this->device, &texDesc, NULL, &this->texture[i].tex);
if (FAILED(status))
@@ -485,8 +504,10 @@ static bool dxgi_deinit()
{
assert(this);

for(int i = 0; i < MAX_TEXTURES; ++i)
for(int i = 0; i < this->maxTextures; ++i)
{
this->texture[i].state = TEXTURE_STATE_UNUSED;

if (this->texture[i].map.pData)
{
ID3D11DeviceContext_Unmap(this->deviceContext, (ID3D11Resource*)this->texture[i].tex, 0);
@@ -563,6 +584,7 @@ static void dxgi_free()

os_freeEvent(this->frameEvent );
os_freeEvent(this->pointerEvent);
free(this->texture);

free(this);
this = NULL;
@@ -586,11 +608,35 @@ static CaptureResult dxgi_capture()
DXGI_OUTDUPL_FRAME_INFO frameInfo;
IDXGIResource * res;

// if the read texture is pending a mapping
if (this->texture[this->texRIndex].state == TEXTURE_STATE_PENDING_MAP)
{
Texture * tex = &this->texture[this->texRIndex];

// try to map the resource, but don't wait for it
status = ID3D11DeviceContext_Map(this->deviceContext, (ID3D11Resource*)tex->tex, 0, D3D11_MAP_READ, 0x100000L, &tex->map);

if (status != DXGI_ERROR_WAS_STILL_DRAWING)
{
if (FAILED(status))
{
DEBUG_WINERROR("Failed to map the texture", status);
IDXGIResource_Release(res);
return CAPTURE_RESULT_ERROR;
}

// successful map, set the state and signal that there is a frame available
tex->state = TEXTURE_STATE_MAPPED;
os_signalEvent(this->frameEvent);
}
}

// release the prior frame
result = dxgi_releaseFrame();
if (result != CAPTURE_RESULT_OK)
return result;

status = IDXGIOutputDuplication_AcquireNextFrame(this->dup, 1000, &frameInfo, &res);
status = IDXGIOutputDuplication_AcquireNextFrame(this->dup, 1, &frameInfo, &res);
switch(status)
{
case S_OK:
@@ -616,7 +662,12 @@ static CaptureResult dxgi_capture()
// check if the texture is free, if not skip the frame to keep up
if (!os_waitEvent(tex->evt, 0))
{
DEBUG_WARN("Frame skipped");
/*
NOTE: This is only informational for when debugging, skipping frames is
OK as we are likely getting frames faster then the client can render
them (ie, vsync off in a title)
*/
//DEBUG_WARN("Frame skipped");
}
else
{
@@ -630,33 +681,23 @@ static CaptureResult dxgi_capture()
}

// if the texture was mapped, unmap it
if (tex->map.pData)
if (tex->state == TEXTURE_STATE_MAPPED)
{
ID3D11DeviceContext_Unmap(this->deviceContext, (ID3D11Resource*)tex->tex, 0);
tex->map.pData = NULL;
}

// issue the copy from GPU to CPU RAM
// issue the copy from GPU to CPU RAM and release the src
ID3D11DeviceContext_CopyResource(this->deviceContext,
(ID3D11Resource *)tex->tex, (ID3D11Resource *)src);
ID3D11Texture2D_Release(src);

// map the resource (this must be done here as ID3D11DeviceContext is not thread safe)
status = ID3D11DeviceContext_Map(this->deviceContext, (ID3D11Resource*)tex->tex, 0, D3D11_MAP_READ, 0, &tex->map);
if (FAILED(status))
{
DEBUG_WINERROR("Failed to map the texture", status);
IDXGIResource_Release(res);
return CAPTURE_RESULT_ERROR;
}

// signal that a frame is available
os_signalEvent(this->frameEvent);
// pending map
tex->state = TEXTURE_STATE_PENDING_MAP;

// advance our write pointer
if (++this->texWIndex == MAX_TEXTURES)
if (++this->texWIndex == this->maxTextures)
this->texWIndex = 0;

ID3D11Texture2D_Release(src);
}
}

@@ -745,7 +786,7 @@ static CaptureResult dxgi_getFrame(CaptureFrame * frame)
memcpy(frame->data, tex->map.pData, this->pitch * this->height);
os_signalEvent(tex->evt);

if (++this->texRIndex == MAX_TEXTURES)
if (++this->texRIndex == this->maxTextures)
this->texRIndex = 0;

return CAPTURE_RESULT_OK;

0 comments on commit 21b02ef

Please sign in to comment.
You can’t perform that action at this time.