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Make FPS counter more accurate

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While trying to figure a discrepancy between the FPS counter from the
overlay we've introduced in Mesa [1] and the counter in the Vulkan
demos, I figured the demos are not accounting for part of the
rendering loop but rather just the amount of time spent rendering.

This changes accounts for the total amount of time between 2 frames. I
don't think any difference is visible until you reach high frame rates
of 100s or so.

[1]: https://gitlab.freedesktop.org/mesa/mesa/merge_requests/303
This commit is contained in:
Lionel Landwerlin 2019-02-23 20:38:09 +00:00
parent cf83c1b499
commit 9db191f9a9
2 changed files with 12 additions and 12 deletions
Download patch file Download diff file Expand all files Collapse all files

21
base/vulkanexamplebase.cpp
View file

@ -250,7 +250,7 @@ void VulkanExampleBase::renderFrame()
timer -= 1.0f; timer -= 1.0f;
} }
} }
fpsTimer += (float)tDiff; float fpsTimer = std::chrono::duration<double, std::milli>(tEnd - lastTimestamp).count();
if (fpsTimer > 1000.0f) if (fpsTimer > 1000.0f)
{ {
lastFPS = static_cast<uint32_t>((float)frameCounter * (1000.0f / fpsTimer)); lastFPS = static_cast<uint32_t>((float)frameCounter * (1000.0f / fpsTimer));
@ -260,8 +260,8 @@ void VulkanExampleBase::renderFrame()
SetWindowText(window, windowTitle.c_str()); SetWindowText(window, windowTitle.c_str());
} }
#endif #endif
fpsTimer = 0.0f;
frameCounter = 0; frameCounter = 0;
lastTimestamp = tEnd;
} }
// TODO: Cap UI overlay update rates // TODO: Cap UI overlay update rates
updateOverlay(); updateOverlay();
@ -280,6 +280,7 @@ void VulkanExampleBase::renderLoop()
destWidth = width; destWidth = width;
destHeight = height; destHeight = height;
lastTimestamp = std::chrono::high_resolution_clock::now();
#if defined(_WIN32) #if defined(_WIN32)
MSG msg; MSG msg;
bool quitMessageReceived = false; bool quitMessageReceived = false;
@ -347,12 +348,12 @@ void VulkanExampleBase::renderLoop()
timer -= 1.0f; timer -= 1.0f;
} }
} }
fpsTimer += (float)tDiff; float fpsTimer = std::chrono::duration<double, std::milli>(tEnd - lastTimestamp).count();
if (fpsTimer > 1000.0f) if (fpsTimer > 1000.0f)
{ {
lastFPS = (float)frameCounter * (1000.0f / fpsTimer); lastFPS = (float)frameCounter * (1000.0f / fpsTimer);
fpsTimer = 0.0f;
frameCounter = 0; frameCounter = 0;
lastTimestamp = tEnd;
} }
// TODO: Cap UI overlay update rates/only issue when update requested // TODO: Cap UI overlay update rates/only issue when update requested
@ -437,12 +438,12 @@ void VulkanExampleBase::renderLoop()
timer -= 1.0f; timer -= 1.0f;
} }
} }
fpsTimer += (float)tDiff; float fpsTimer = std::chrono::duration<double, std::milli>(tEnd - lastTimestamp).count();
if (fpsTimer > 1000.0f) if (fpsTimer > 1000.0f)
{ {
lastFPS = (float)frameCounter * (1000.0f / fpsTimer); lastFPS = (float)frameCounter * (1000.0f / fpsTimer);
fpsTimer = 0.0f;
frameCounter = 0; frameCounter = 0;
lastTimestamp = tEnd;
} }
updateOverlay(); updateOverlay();
} }
@ -483,7 +484,7 @@ void VulkanExampleBase::renderLoop()
timer -= 1.0f; timer -= 1.0f;
} }
} }
fpsTimer += (float)tDiff; float fpsTimer = std::chrono::duration<double, std::milli>(tEnd - lastTimestamp).count();
if (fpsTimer > 1000.0f) if (fpsTimer > 1000.0f)
{ {
if (!settings.overlay) if (!settings.overlay)
@ -492,8 +493,8 @@ void VulkanExampleBase::renderLoop()
xdg_toplevel_set_title(xdg_toplevel, windowTitle.c_str()); xdg_toplevel_set_title(xdg_toplevel, windowTitle.c_str());
} }
lastFPS = (float)frameCounter * (1000.0f / fpsTimer); lastFPS = (float)frameCounter * (1000.0f / fpsTimer);
fpsTimer = 0.0f;
frameCounter = 0; frameCounter = 0;
lastTimestamp = tEnd;
} }
updateOverlay(); updateOverlay();
} }
@ -532,7 +533,7 @@ void VulkanExampleBase::renderLoop()
timer -= 1.0f; timer -= 1.0f;
} }
} }
fpsTimer += (float)tDiff; float fpsTimer = std::chrono::duration<double, std::milli>(tEnd - lastTimestamp).count();
if (fpsTimer > 1000.0f) if (fpsTimer > 1000.0f)
{ {
if (!settings.overlay) if (!settings.overlay)
@ -543,8 +544,8 @@ void VulkanExampleBase::renderLoop()
windowTitle.size(), windowTitle.c_str()); windowTitle.size(), windowTitle.c_str());
} }
lastFPS = (float)frameCounter * (1000.0f / fpsTimer); lastFPS = (float)frameCounter * (1000.0f / fpsTimer);
fpsTimer = 0.0f;
frameCounter = 0; frameCounter = 0;
lastTimestamp = tEnd;
} }
updateOverlay(); updateOverlay();
} }

3
base/vulkanexamplebase.h
View file

@ -57,8 +57,6 @@
class VulkanExampleBase class VulkanExampleBase
{ {
private: private:
// fps timer (one second interval)
float fpsTimer = 0.0f;
// Get window title with example name, device, et. // Get window title with example name, device, et.
std::string getWindowTitle(); std::string getWindowTitle();
/** brief Indicates that the view (position, rotation) has changed and buffers containing camera matrices need to be updated */ /** brief Indicates that the view (position, rotation) has changed and buffers containing camera matrices need to be updated */
@ -74,6 +72,7 @@ protected:
// Frame counter to display fps // Frame counter to display fps
uint32_t frameCounter = 0; uint32_t frameCounter = 0;
uint32_t lastFPS = 0; uint32_t lastFPS = 0;
std::chrono::time_point<std::chrono::high_resolution_clock> lastTimestamp;
// Vulkan instance, stores all per-application states // Vulkan instance, stores all per-application states
VkInstance instance; VkInstance instance;
// Physical device (GPU) that Vulkan will ise // Physical device (GPU) that Vulkan will ise