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-rw-r--r--src/core/hw/gpu.cpp63
-rw-r--r--src/core/hw/gpu.h1
-rw-r--r--src/core/settings.h1
3 files changed, 38 insertions, 27 deletions
diff --git a/src/core/hw/gpu.cpp b/src/core/hw/gpu.cpp
index 7e70b34c1..dd619cb16 100644
--- a/src/core/hw/gpu.cpp
+++ b/src/core/hw/gpu.cpp
@@ -21,10 +21,14 @@ namespace GPU {
Regs g_regs;
-static u64 frame_ticks = 0; ///< 268MHz / 60 frames per second
-static u32 cur_line = 0; ///< Current vertical screen line
-static u64 last_frame_ticks = 0; ///< CPU tick count from last frame
-static u64 last_update_tick = 0; ///< CPU ticl count from last GPU update
+bool g_skip_frame = false; ///< True if the current frame was skipped
+
+static u64 frame_ticks = 0; ///< 268MHz / gpu_refresh_rate frames per second
+static u64 line_ticks = 0; ///< Number of ticks for a screen line
+static u32 cur_line = 0; ///< Current screen line
+static u64 last_update_tick = 0; ///< CPU ticl count from last GPU update
+static u64 frame_count = 0; ///< Number of frames drawn
+static bool last_skip_frame = false; ///< True if the last frame was skipped
template <typename T>
inline void Read(T &var, const u32 raw_addr) {
@@ -178,38 +182,40 @@ template void Write<u8>(u32 addr, const u8 data);
void Update() {
auto& framebuffer_top = g_regs.framebuffer_config[0];
- // Update the frame after a certain number of CPU ticks have elapsed. This assumes that the
- // active frame in memory is always complete to render. There also may be issues with this
- // becoming out-of-synch with GSP synchrinization code (as follows). At this time, this seems to
- // be the most effective solution for both homebrew and retail applications. With retail, this
- // could be moved below (and probably would guarantee more accurate synchronization). However,
- // primitive homebrew relies on a vertical blank interrupt to happen inevitably (regardless of a
- // threading reschedule).
-
- if ((Core::g_app_core->GetTicks() - last_frame_ticks) > (GPU::frame_ticks)) {
- VideoCore::g_renderer->SwapBuffers();
- last_frame_ticks = Core::g_app_core->GetTicks();
- }
-
// Synchronize GPU on a thread reschedule: Because we cannot accurately predict a vertical
// blank, we need to simulate it. Based on testing, it seems that retail applications work more
// accurately when this is signalled between thread switches.
if (HLE::g_reschedule) {
u64 current_ticks = Core::g_app_core->GetTicks();
- u64 line_ticks = (GPU::frame_ticks / framebuffer_top.height) * 16;
+ u32 num_lines = static_cast<u32>((current_ticks - last_update_tick) / line_ticks);
- //// Synchronize line...
- if ((current_ticks - last_update_tick) >= line_ticks) {
+ // Synchronize line...
+ if (num_lines > 0) {
GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PDC0);
- cur_line++;
- last_update_tick += line_ticks;
+ cur_line += num_lines;
+ last_update_tick += (num_lines * line_ticks);
}
// Synchronize frame...
if (cur_line >= framebuffer_top.height) {
cur_line = 0;
- VideoCore::g_renderer->SwapBuffers();
+ frame_count++;
+ last_skip_frame = g_skip_frame;
+ g_skip_frame = (frame_count & Settings::values.frame_skip) != 0;
+
+ // Swap buffers based on the frameskip mode, which is a little bit tricky. When
+ // a frame is being skipped, nothing is being rendered to the internal framebuffer(s).
+ // So, we should only swap frames if the last frame was rendered. The rules are:
+ // - If frameskip == 0 (disabled), always swap buffers
+ // - If frameskip == 1, swap buffers every other frame (starting from the first frame)
+ // - If frameskip > 1, swap buffers every frameskip^n frames (starting from the second frame)
+
+ if ((((Settings::values.frame_skip != 1) ^ last_skip_frame) && last_skip_frame != g_skip_frame) ||
+ Settings::values.frame_skip == 0) {
+ VideoCore::g_renderer->SwapBuffers();
+ }
+
GSP_GPU::SignalInterrupt(GSP_GPU::InterruptId::PDC1);
}
}
@@ -217,10 +223,6 @@ void Update() {
/// Initialize hardware
void Init() {
- frame_ticks = 268123480 / Settings::values.gpu_refresh_rate;
- cur_line = 0;
- last_update_tick = last_frame_ticks = Core::g_app_core->GetTicks();
-
auto& framebuffer_top = g_regs.framebuffer_config[0];
auto& framebuffer_sub = g_regs.framebuffer_config[1];
@@ -249,6 +251,13 @@ void Init() {
framebuffer_sub.color_format = Regs::PixelFormat::RGB8;
framebuffer_sub.active_fb = 0;
+ frame_ticks = 268123480 / Settings::values.gpu_refresh_rate;
+ line_ticks = (GPU::frame_ticks / framebuffer_top.height);
+ cur_line = 0;
+ last_update_tick = Core::g_app_core->GetTicks();
+ last_skip_frame = false;
+ g_skip_frame = false;
+
LOG_DEBUG(HW_GPU, "initialized OK");
}
diff --git a/src/core/hw/gpu.h b/src/core/hw/gpu.h
index 68f11bfcb..292f496c1 100644
--- a/src/core/hw/gpu.h
+++ b/src/core/hw/gpu.h
@@ -241,6 +241,7 @@ ASSERT_REG_POSITION(command_processor_config, 0x00638);
static_assert(sizeof(Regs) == 0x1000 * sizeof(u32), "Invalid total size of register set");
extern Regs g_regs;
+extern bool g_skip_frame;
template <typename T>
void Read(T &var, const u32 addr);
diff --git a/src/core/settings.h b/src/core/settings.h
index 4808872ae..4b8928847 100644
--- a/src/core/settings.h
+++ b/src/core/settings.h
@@ -31,6 +31,7 @@ struct Values {
// Core
int cpu_core;
int gpu_refresh_rate;
+ int frame_skip;
// Data Storage
bool use_virtual_sd;