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gapir/cc/windows: Don't kill the context if the backbuffer changes.
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Fixes: google#834
Fixes: google#825
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@ben-clayton
ben-clayton committed Aug 1, 2017
1 parent f806947 commit 49c4a3f
Showing 1 changed file with 121 additions and 72 deletions.
193 changes: 121 additions & 72 deletions gapir/cc/windows/gles_renderer.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -61,14 +61,20 @@ class WGL {
public:
class PBuffer {
public:
PBuffer(HPBUFFERARB pbuf, HGLRC ctx, HDC hdc);
~PBuffer();

static std::shared_ptr<PBuffer> create(const GlesRenderer::Backbuffer& backbuffer, PBuffer* shared_ctx);

void bind();
void unbind();
void set_backbuffer(const GlesRenderer::Backbuffer& backbuffer);

private:
friend class WGL;
PBuffer(const GlesRenderer::Backbuffer& backbuffer, PBuffer* shared_ctx);

void create_buffer(const GlesRenderer::Backbuffer& backbuffer);
void release_buffer();

HPBUFFERARB mPBuf;
HGLRC mCtx;
HDC mHDC;
Expand All @@ -78,8 +84,6 @@ class WGL {

static const WGL& get();

std::shared_ptr<PBuffer> create_pbuffer(GlesRenderer::Backbuffer backbuffer, PBuffer* shared_ctx) const;

private:
HWND mWindow;
HDC mHDC;
Expand All @@ -93,22 +97,102 @@ class WGL {
PFNWGLQUERYPBUFFERARB QueryPbufferARB;
};

WGL::PBuffer::PBuffer(const GlesRenderer::Backbuffer& backbuffer, PBuffer* shared_ctx)
: mPBuf(nullptr)
, mCtx(nullptr)
, mHDC(nullptr) {

WGL::PBuffer::PBuffer(HPBUFFERARB pbuf, HGLRC ctx, HDC hdc) : mPBuf(pbuf), mCtx(ctx), mHDC(hdc) {}
create_buffer(backbuffer);

WGL::PBuffer::~PBuffer() {
auto wgl = WGL::get();
if (!wgl.ReleasePbufferDCARB(mPBuf, mHDC)) {
GAPID_ERROR("Failed to release HDC. Error: 0x%x", GetLastError());
}
if (!wgl.DestroyPbufferARB(mPBuf)) {
GAPID_ERROR("Failed to destroy pbuffer. Error: 0x%x", GetLastError());
for (auto gl_version : core::gl::sVersionSearchOrder) {
std::vector<int> attribs;
attribs.push_back(WGL_CONTEXT_MAJOR_VERSION_ARB);
attribs.push_back(gl_version.major);
attribs.push_back(WGL_CONTEXT_MINOR_VERSION_ARB);
attribs.push_back(gl_version.minor);
// https://www.khronos.org/registry/OpenGL/extensions/KHR/KHR_context_flush_control.txt
// These are disabled as they don't seem to improve performance.
// attribs.push_back(WGL_CONTEXT_RELEASE_BEHAVIOR_ARB);
// attribs.push_back(WGL_CONTEXT_RELEASE_BEHAVIOR_NONE_ARB);
attribs.push_back(0);
auto ctx = wgl.CreateContextAttribsARB(mHDC, (shared_ctx != nullptr) ? shared_ctx->mCtx : nullptr, attribs.data());
if (ctx != nullptr) {
mCtx = ctx;
return;
}
}
GAPID_FATAL("Failed to create GL context using wglCreateContextAttribsARB. Error: 0x%x", GetLastError());
}

WGL::PBuffer::~PBuffer() {
release_buffer();
if (!wglDeleteContext(mCtx)) {
GAPID_ERROR("Failed to delete GL context. Error: 0x%x", GetLastError());
}
}

void WGL::PBuffer::create_buffer(const GlesRenderer::Backbuffer& backbuffer) {
release_buffer();

int r = 8, g = 8, b = 8, a = 8, d = 24, s = 8;
core::gl::getColorBits(backbuffer.format.color, r, g, b, a);
core::gl::getDepthBits(backbuffer.format.depth, d);
core::gl::getStencilBits(backbuffer.format.stencil, s);

const unsigned int MAX_FORMATS = 32;

int formats[MAX_FORMATS];
unsigned int num_formats;
const int fmt_attribs[] = {
WGL_DRAW_TO_PBUFFER_ARB, 1,
WGL_SUPPORT_OPENGL_ARB, 1,
WGL_DEPTH_BITS_ARB, d,
WGL_STENCIL_BITS_ARB, s,
WGL_RED_BITS_ARB, r,
WGL_GREEN_BITS_ARB, g,
WGL_BLUE_BITS_ARB, b,
WGL_ALPHA_BITS_ARB, a,
0, // terminator
};

auto wgl = WGL::get();

if (!wgl.ChoosePixelFormatARB(wgl.mHDC, fmt_attribs, nullptr, MAX_FORMATS, formats, &num_formats)) {
GAPID_FATAL("wglChoosePixelFormatARB failed. Error: 0x%x", GetLastError());
}
if (num_formats == 0) {
GAPID_FATAL("wglChoosePixelFormatARB returned no compatibile formats");
}
auto format = formats[0]; // TODO: Examine returned formats?
const int create_attribs[] = { 0 };
mPBuf = wgl.CreatePbufferARB(wgl.mHDC, format, backbuffer.width, backbuffer.height, create_attribs);
if (mPBuf == nullptr) {
GAPID_FATAL("wglCreatePbufferARB failed. Error: 0x%x", GetLastError());
}

mHDC = wgl.GetPbufferDCARB(mPBuf);
if (mHDC == nullptr) {
GAPID_FATAL("wglGetPbufferDCARB failed. Error: 0x%x", GetLastError());
}
}

void WGL::PBuffer::release_buffer() {
auto wgl = WGL::get();
if (mHDC != nullptr) {
if (!wgl.ReleasePbufferDCARB(mPBuf, mHDC)) {
GAPID_ERROR("Failed to release HDC. Error: 0x%x", GetLastError());
}
mHDC = nullptr;
}
if (mPBuf != nullptr) {
if (!wgl.DestroyPbufferARB(mPBuf)) {
GAPID_ERROR("Failed to destroy pbuffer. Error: 0x%x", GetLastError());
}
mPBuf = nullptr;
}
}

void WGL::PBuffer::bind() {
if (!wglMakeCurrent(mHDC, mCtx)) {
GAPID_FATAL("Failed to bind GL context. Error: 0x%x", GetLastError());
Expand All @@ -121,6 +205,23 @@ void WGL::PBuffer::unbind() {
}
}

void WGL::PBuffer::set_backbuffer(const GlesRenderer::Backbuffer& backbuffer) {
// Kill the pbuffer, and create a new one with the new backbuffer settings.
//
// Note - according to the MSDN documentation of wglMakeCurrent:
// "It need not be the same hdc that was passed to wglCreateContext when
// hglrc was created, but it must be on the same device and have the same
// pixel format."
//
// This means pixel format changes should error. If this happens, we're
// going to have to come up with a different approach.
create_buffer(backbuffer);
}

std::shared_ptr<WGL::PBuffer> WGL::PBuffer::create(const GlesRenderer::Backbuffer& backbuffer, PBuffer* shared_ctx) {
return std::shared_ptr<PBuffer>(new PBuffer(backbuffer, shared_ctx));
}

WGL::WGL() {
class registerWindowClass {
public:
Expand Down Expand Up @@ -211,64 +312,6 @@ const WGL& WGL::get() {
return instance;
}

std::shared_ptr<WGL::PBuffer> WGL::create_pbuffer(GlesRenderer::Backbuffer backbuffer, PBuffer* shared_ctx) const {
int r = 8, g = 8, b = 8, a = 8, d = 24, s = 8;
core::gl::getColorBits(backbuffer.format.color, r, g, b, a);
core::gl::getDepthBits(backbuffer.format.depth, d);
core::gl::getStencilBits(backbuffer.format.stencil, s);

const unsigned int MAX_FORMATS = 32;

int formats[MAX_FORMATS];
unsigned int num_formats;
const int fmt_attribs[] = {
WGL_DRAW_TO_PBUFFER_ARB, 1,
WGL_SUPPORT_OPENGL_ARB, 1,
WGL_DEPTH_BITS_ARB, d,
WGL_STENCIL_BITS_ARB, s,
WGL_RED_BITS_ARB, r,
WGL_GREEN_BITS_ARB, g,
WGL_BLUE_BITS_ARB, b,
WGL_ALPHA_BITS_ARB, a,
0, // terminator
};
if (!ChoosePixelFormatARB(mHDC, fmt_attribs, nullptr, MAX_FORMATS, formats, &num_formats)) {
GAPID_FATAL("wglChoosePixelFormatARB failed. Error: 0x%x", GetLastError());
}
if (num_formats == 0) {
GAPID_FATAL("wglChoosePixelFormatARB returned no compatibile formats");
}
auto format = formats[0]; // TODO: Examine returned formats?
const int create_attribs[] = { 0 };
auto pbuffer = CreatePbufferARB(mHDC, format, backbuffer.width, backbuffer.height, create_attribs);
if (pbuffer == nullptr) {
GAPID_FATAL("wglCreatePbufferARB failed. Error: 0x%x", GetLastError());
}
auto hdc = GetPbufferDCARB(pbuffer);
if (hdc == nullptr) {
GAPID_FATAL("wglGetPbufferDCARB failed. Error: 0x%x", GetLastError());
}
for (auto gl_version : core::gl::sVersionSearchOrder) {
std::vector<int> attribs;
attribs.push_back(WGL_CONTEXT_MAJOR_VERSION_ARB);
attribs.push_back(gl_version.major);
attribs.push_back(WGL_CONTEXT_MINOR_VERSION_ARB);
attribs.push_back(gl_version.minor);
// https://www.khronos.org/registry/OpenGL/extensions/KHR/KHR_context_flush_control.txt
// These are disabled as they don't seem to improve performance.
// attribs.push_back(WGL_CONTEXT_RELEASE_BEHAVIOR_ARB);
// attribs.push_back(WGL_CONTEXT_RELEASE_BEHAVIOR_NONE_ARB);
attribs.push_back(0);
auto ctx = CreateContextAttribsARB(hdc, (shared_ctx != nullptr) ? shared_ctx->mCtx : nullptr, attribs.data());
if (ctx != nullptr) {
return std::shared_ptr<PBuffer>(new PBuffer(pbuffer, ctx, hdc));
}
}
GAPID_FATAL("Failed to create GL context using wglCreateContextAttribsARB. Error: 0x%x", GetLastError());
return nullptr;
}


class GlesRendererImpl : public GlesRenderer {
public:
GlesRendererImpl(GlesRendererImpl* shared_context);
Expand Down Expand Up @@ -333,11 +376,17 @@ void GlesRendererImpl::setBackbuffer(Backbuffer backbuffer) {

auto wasBound = tlsBound == this;

reset();
if (mContext == nullptr) {
mContext = WGL::PBuffer::create(backbuffer, mSharedContext.get());
} else {
if (wasBound) {
unbind();
}
mContext->set_backbuffer(backbuffer);
}

mContext = WGL::get().create_pbuffer(backbuffer, mSharedContext.get());
mBackbuffer = backbuffer;
mNeedsResolve = true;
mBackbuffer = backbuffer;

if (wasBound) {
bind();
Expand Down

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