From bb6b19c4100067d369a7bd984a78ec08fdb35db2 Mon Sep 17 00:00:00 2001
From: Doug Binks <doug@enkisoftware.com>
Date: Tue, 18 Feb 2014 12:26:41 +0100
Subject: [PATCH] Added GPU timer and fixed up formatting.

---
 example/demo.c        | 42 ++++++++++++++++++++----------------------
 example/example_gl3.c | 41 ++++++++++++++++++++++++++++++++++++++---
 2 files changed, 58 insertions(+), 25 deletions(-)

diff --git a/example/demo.c b/example/demo.c
index 41f5882..9c8b40e 100644
--- a/example/demo.c
+++ b/example/demo.c
@@ -911,28 +911,26 @@ void renderFPS(struct NVGcontext* vg, float x, float y, struct FPScounter* fps,
 	nvgFill(vg);
 
 	nvgFontFace(vg, "sans");
-    if( RENDER_FPS == style )
-    {
-	    nvgFontSize(vg, 18.0f);
-	    nvgTextAlign(vg,NVG_ALIGN_RIGHT|NVG_ALIGN_MIDDLE);
-	    nvgFillColor(vg, nvgRGBA(240,240,240,255));
-	    sprintf(str, "%.2f FPS", 1.0f / avg);
-	    nvgText(vg, x+w-5,y+h/2, str, NULL);
-
-        nvgFontSize(vg, 15.0f);
-	    nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
-	    nvgFillColor(vg, nvgRGBA(240,240,240,160));
-	    sprintf(str, "%.2f ms", avg * 1000.0f);
-	    nvgText(vg, x+5,y+h/2, str, NULL);
-    }
-    else
-    {
-	    nvgFontSize(vg, 18.0f);
-	    nvgTextAlign(vg,NVG_ALIGN_RIGHT|NVG_ALIGN_MIDDLE);
-	    nvgFillColor(vg, nvgRGBA(240,240,240,255));
-	    sprintf(str, "%.2f ms", avg * 1000.0f);
-	    nvgText(vg, x+w-5,y+h/2, str, NULL);
-    }
+	if( RENDER_FPS == style ) {
+		nvgFontSize(vg, 18.0f);
+		nvgTextAlign(vg,NVG_ALIGN_RIGHT|NVG_ALIGN_MIDDLE);
+		nvgFillColor(vg, nvgRGBA(240,240,240,255));
+		sprintf(str, "%.2f FPS", 1.0f / avg);
+		nvgText(vg, x+w-5,y+h/2, str, NULL);
+		
+		nvgFontSize(vg, 15.0f);
+		nvgTextAlign(vg,NVG_ALIGN_LEFT|NVG_ALIGN_MIDDLE);
+		nvgFillColor(vg, nvgRGBA(240,240,240,160));
+		sprintf(str, "%.2f ms", avg * 1000.0f);
+		nvgText(vg, x+5,y+h/2, str, NULL);
+	}
+    else {
+		nvgFontSize(vg, 18.0f);
+		nvgTextAlign(vg,NVG_ALIGN_RIGHT|NVG_ALIGN_MIDDLE);
+		nvgFillColor(vg, nvgRGBA(240,240,240,255));
+		sprintf(str, "%.2f ms", avg * 1000.0f);
+		nvgText(vg, x+w-5,y+h/2, str, NULL);
+	}
 
 
 }
diff --git a/example/example_gl3.c b/example/example_gl3.c
index 6b9d192..f1f69e4 100644
--- a/example/example_gl3.c
+++ b/example/example_gl3.c
@@ -31,7 +31,6 @@
 #include "nanovg_gl3buf.h"
 #include "demo.h"
 
-
 void errorcb(int error, const char* desc)
 {
 	printf("GLFW error %d: %s\n", error, desc);
@@ -49,14 +48,19 @@ static void key(GLFWwindow* window, int key, int scancode, int action, int mods)
 		blowup = !blowup;
 }
 
+enum numqueries {
+    NUM_QUERIES = 5
+};
+
 int main()
 {
 	GLFWwindow* window;
 	struct DemoData data;
 	struct NVGcontext* vg = NULL;
-	struct FPScounter fps;
-	struct FPScounter cpuTimes;
+	struct FPScounter fps, cpuTimes, gpuTimes;
 	double prevt = 0, cpuTime = 0;
+    int timerquery = GL_FALSE, currquery = 0, retquery = 0;
+    GLuint timerqueryid[NUM_QUERIES];
 
 	if (!glfwInit()) {
 		printf("Failed to init GLFW.");
@@ -65,6 +69,7 @@ int main()
 
 	initFPS(&fps);
 	initFPS(&cpuTimes);
+	initFPS(&gpuTimes);
 
 	glfwSetErrorCallback(errorcb);
 #ifndef _WIN32 // don't require this on win32, and works with more cards
@@ -110,6 +115,11 @@ int main()
 
 	glfwSwapInterval(0);
 
+	timerquery = glfwExtensionSupported("GL_ARB_timer_query");
+	if( timerquery ) {
+		glGenQueries(NUM_QUERIES, timerqueryid);
+	}
+
 	glfwSetTime(0);
 	prevt = glfwGetTime();
 
@@ -125,6 +135,10 @@ int main()
 		prevt = t;
 		updateFPS(&fps, dt);
         updateFPS(&cpuTimes, cpuTime);
+		if( timerquery ) {
+            glBeginQuery(GL_TIME_ELAPSED, timerqueryid[currquery % NUM_QUERIES] );
+			currquery = ++currquery;
+		}
 
 		glfwGetCursorPos(window, &mx, &my);
 		glfwGetWindowSize(window, &winWidth, &winHeight);
@@ -147,11 +161,32 @@ int main()
 		renderDemo(vg, mx,my, winWidth,winHeight, t, blowup, &data);
 		renderFPS(vg, 5,5, &fps, RENDER_FPS);
 		renderFPS(vg, 310,5, &cpuTimes, RENDER_MS);
+		renderFPS(vg, 615,5, &gpuTimes, RENDER_MS);
 
 		nvgEndFrame(vg);
 
 		glEnable(GL_DEPTH_TEST);
+
+        // Measure the CPU time taken excluding swap buffers (as the swap may wait for GPU)
         cpuTime = glfwGetTime() - t;
+
+		if( timerquery ) {
+			GLint available = 1;
+			glEndQuery(GL_TIME_ELAPSED);
+			while( available && retquery <= currquery ) {
+				// check for results if there are any
+				glGetQueryObjectiv(timerqueryid[retquery], GL_QUERY_RESULT_AVAILABLE, &available);
+				if( available ) {
+					GLuint64 timeElapsed = 0;
+					double gpuTime;
+					glGetQueryObjectui64v(timerqueryid[retquery % NUM_QUERIES], GL_QUERY_RESULT, &timeElapsed);
+					retquery = ++retquery ;
+					gpuTime = (double)timeElapsed * 1e-9;
+					updateFPS(&gpuTimes, (float)gpuTime);
+				}
+			}
+
+		}
 		glfwSwapBuffers(window);
 		glfwPollEvents();
 	}