program: time each part of the frame, cap fps instead of fixed sleep

4 files changed, 33 insertions, 2 deletions

diff --git a/kon/kondebug.c b/kon/kondebug.c
index a68ebcf..54e8d13 100644
--- a/kon/kondebug.c
+++ b/kon/kondebug.c
@@ -91,6 +91,7 @@ struct kon_debug {
 	double accumTime;
 	int accumFrames;
 	float fps;
+	double times[4]; /* update, draw, present, blit */
 	float graph[KON_DEBUG_GRAPH];
 	int graphHead;
 };
@@ -607,6 +608,16 @@ void kon_debugFrame(kon_debug_t *d)
 	d->graphHead = (d->graphHead + 1) % KON_DEBUG_GRAPH;
 }
 
+void kon_debugTimes(kon_debug_t *d, double update, double draw, double present, double blit)
+{
+	double in[4];
+	int i;
+
+	if (!d) return;
+	in[0] = update; in[1] = draw; in[2] = present; in[3] = blit;
+	for (i = 0; i < 4; i++) d->times[i] += (in[i] - d->times[i]) * 0.1;
+}
+
 static void kon_debugBox_(const kon_debug_t *d, kon_framebuffer_t *fb, int x, int y, const char *s, uint32_t color)
 {
 	int w = 0;
@@ -628,6 +639,9 @@ static void kon_debugDrawOverlay_(kon_debug_t *d, kon_framebuffer_t *fb)
 	y += d->lineH + 3;
 
 	if (d->overlay >= 1) {
+		snprintf(line, sizeof(line), "upd %.1f  draw %.1f  scale %.1f  blit %.1f", d->times[0] * 1000.0, d->times[1] * 1000.0, d->times[2] * 1000.0, d->times[3] * 1000.0);
+		kon_debugBox_(d, fb, x, y, line, dim);
+		y += d->lineH + 3;
 		kon_fillRectangle(fb, x - 2, y - 2, KON_DEBUG_GRAPH + 4, 34, 0xB0000000);
 		for (i = 0; i < KON_DEBUG_GRAPH; i++) {
 			float ms = d->graph[(d->graphHead + i) % KON_DEBUG_GRAPH];
diff --git a/kon/kondebug.h b/kon/kondebug.h
index f17f0c2..0f32a0f 100644
--- a/kon/kondebug.h
+++ b/kon/kondebug.h
@@ -69,6 +69,9 @@ int kon_debugConsoleOpen(const kon_debug_t *debug);
 void kon_debugFrame(kon_debug_t *debug);
 void kon_debugDraw(kon_debug_t *debug, kon_framebuffer_t *fb);
 
+/* where the frame went, in seconds. shown under the fps when the overlay is on */
+void kon_debugTimes(kon_debug_t *debug, double update, double draw, double present, double blit);
+
 float kon_debugFps(const kon_debug_t *debug);
 
 /* set by the quit and exit commands, the game decides what to do with it */
@@ -87,6 +90,7 @@ static inline int kon_debugFeedEvent(kon_debug_t *debug, const kon_event_t *even
 static inline int kon_debugConsoleOpen(const kon_debug_t *debug) { (void)debug; return 0; }
 static inline void kon_debugFrame(kon_debug_t *debug) { (void)debug; }
 static inline void kon_debugDraw(kon_debug_t *debug, kon_framebuffer_t *fb) { (void)debug; (void)fb; }
+static inline void kon_debugTimes(kon_debug_t *debug, double update, double draw, double present, double blit) { (void)debug; (void)update; (void)draw; (void)present; (void)blit; }
 static inline float kon_debugFps(const kon_debug_t *debug) { (void)debug; return 0.0f; }
 static inline int kon_debugQuitRequested(const kon_debug_t *debug) { (void)debug; return 0; }
 
diff --git a/kon/konprogram.c b/kon/konprogram.c
index 31fe7b6..a87aee8 100644
--- a/kon/konprogram.c
+++ b/kon/konprogram.c
@@ -110,7 +110,7 @@ static void kon_frame_(void *data) {
 	const kon_programConfig_t *config = &state->config;
 	kon_display_t *display = program->display;
 	kon_event_t ev;
-	kon_time now, dt;
+	kon_time now, dt, t0, t1, t2, t3, t4, cap;
 
 	while (kon_pollEvent(program->window, &ev)) {
 		if (kon_debugFeedEvent(program->debug, &ev)) continue;
@@ -131,17 +131,29 @@ static void kon_frame_(void *data) {
 		else kon_setWindowPos(program->window, state->shakeX, state->shakeY);
 	}
 
+	t0 = kon_getTime();
 	if (config->update) config->update(program, dt, config->user);
+	t1 = kon_getTime();
 	kon_clearFramebuffer(display->game, KON_BACKGROUND_COLOR);
 	if (config->draw) config->draw(program, display->game, config->user);
+	t2 = kon_getTime();
 
 	kon_presentDisplay(display);
+	t3 = kon_getTime();
 	if (config->drawScreen) config->drawScreen(program, display->screen, config->user);
 	kon_debugFrame(program->debug);
 	if (kon_debugQuitRequested(program->debug)) kon_setShouldClose(program->window, true);
 	kon_debugDraw(program->debug, display->screen);
+	t4 = kon_getTime();
 	kon_blitPixels(program->window, display->screen->data, display->screen->width, display->screen->height);
-	kon_sleep(0.008);
+	kon_debugTimes(program->debug, t1 - t0, t2 - t1, t3 - t2, kon_getTime() - t4);
+
+	/* only wait out what is left of the frame, a fixed sleep eats time the frame could use */
+	if (config->maxFps >= 0) {
+		cap = 1.0 / (config->maxFps > 0 ? config->maxFps : 120);
+		dt = kon_getTime() - now;
+		if (dt < cap) kon_sleep(cap - dt);
+	}
 }
 
 void kon_programQuit(kon_program_t *program) {
diff --git a/kon/konprogram.h b/kon/konprogram.h
index f0a29b3..04aef18 100644
--- a/kon/konprogram.h
+++ b/kon/konprogram.h
@@ -46,6 +46,7 @@ typedef struct kon_programConfig {
 	int windowWidth, windowHeight; /* 3 times the game size */
 	const char *assetDir;          /* folder with loose files, "assets". only used with KON_DEVELOPER */
 	const char *packPath;          /* pack file to read assets from, none if NULL */
+	int maxFps;                    /* frame cap, 120. -1 for none */
 	void *user;                    /* given back to every callback */
 
 	/* return 0 to quit before the loop starts */