1
2/*
3 * Copyright 2011 Google Inc.
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8#include "GpuTimer.h"
9#include "gl/SkGLContextHelper.h"
10#include "gl/GrGLUtil.h"
11
12GpuTimer::GpuTimer(const SkGLContextHelper* glctx) : fContext(glctx) {
13    if (fContext) {
14        fContext->ref();
15        fContext->makeCurrent();
16        fStarted = false;
17        fSupported = GrGLGetVersion(fContext->gl()) > GR_GL_VER(3,3) ||
18                     fContext->hasExtension("GL_ARB_timer_query") ||
19                     fContext->hasExtension("GL_EXT_timer_query");
20
21        if (fSupported) {
22            SK_GL(*fContext, GenQueries(1, &fQuery));
23        }
24    }
25}
26
27GpuTimer::~GpuTimer() {
28    if (fContext) {
29        if (fSupported) {
30            fContext->makeCurrent();
31            SK_GL(*fContext, DeleteQueries(1, &fQuery));
32        }
33        fContext->unref();
34    }
35}
36
37void GpuTimer::start() {
38    if (fContext && fSupported) {
39        fContext->makeCurrent();
40        fStarted = true;
41        SK_GL(*fContext, BeginQuery(GR_GL_TIME_ELAPSED, fQuery));
42    }
43}
44
45/**
46 * It is important to stop the cpu clocks first,
47 * as this will cpu wait for the gpu to finish.
48 */
49double GpuTimer::end() {
50    if (fContext && fSupported) {
51        fStarted = false;
52        fContext->makeCurrent();
53        SK_GL(*fContext, EndQuery(GR_GL_TIME_ELAPSED));
54
55        GrGLint available = 0;
56        while (!available) {
57            SK_GL_NOERRCHECK(*fContext, GetQueryObjectiv(fQuery,
58                                                         GR_GL_QUERY_RESULT_AVAILABLE,
59                                                         &available));
60            // If GetQueryObjectiv is erroring out we need some alternative
61            // means of breaking out of this loop
62            GrGLenum error;
63            SK_GL_RET_NOERRCHECK(*fContext, error, GetError());
64            if (GR_GL_NO_ERROR != error) {
65                break;
66            }
67        }
68        GrGLuint64 totalGPUTimeElapsed = 0;
69        SK_GL(*fContext, GetQueryObjectui64v(fQuery,
70                                             GR_GL_QUERY_RESULT,
71                                             &totalGPUTimeElapsed));
72
73        return totalGPUTimeElapsed / 1000000.0;
74    } else {
75        return 0;
76    }
77}
78