Backends: Opengl3: Support GLSL 410 shader when GLSL version is auto-detected.#9427
Backends: Opengl3: Support GLSL 410 shader when GLSL version is auto-detected.#9427perminovVS wants to merge 1 commit into
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…detected. Add the GLSL 410 shader and ensure it is selected when the GLSL version is auto-detected (i.e. when glsl_version is nullptr). Previously the GLSL 410 shader was only used if a GLSL version string was passed manually to ImGui_ImplOpenGL3_Init. Now the backend detects the GL/GLSL version at runtime and will pick the GLSL 410 shader when the context supports it. ocornut@fc737d2
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Thank you very much Vladimir. Can you suggest how to amend your examples/xxxx_opengl3/main.cpp file? As current code is the example does: #elif defined(__APPLE__)
// GL 3.2 + GLSL 150
const char* glsl_version = "#version 150";
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Required on Mac
#else
// GL 3.0 + GLSL 130
const char* glsl_version = "#version 130";
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
//glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
//glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 3.0+ only
#endifTherefore your code path won't run. Can you report the detected GlVersion
Thank you. |
Thank you — glad to see the change merged (7950c96). A bit of context about my environment and how I initialize GL in production:
What I do in production (relevant snippet) // For cocos2d-x: GLViewImpl::initWithRect used to create the highest available GL context on macOS/Wine
if (IsRunWine())
{
// Minimum target is OpenGL 4.1
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 1);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
Configuration::getInstance()->setCoreProfile(true);
}
_mainWindow = glfwCreateWindow(neededWidth, neededHeight, _viewName.c_str(), _monitor, nullptr);
if (_mainWindow == nullptr && IsRunWine())
{
Configuration::getInstance()->setCoreProfile(false);
// Create default fallback
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 1);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_ANY_PROFILE);
_mainWindow = glfwCreateWindow(neededWidth, neededHeight, _viewName.c_str(), _monitor, nullptr);
}Why this: on macOS (Intel or Apple Silicon) the system GL implementation exposes up to GL 4.1. When running under Wine I try to request the highest desktop profile available (4.1 core) so the runtime and drivers give me the best feature set possible. If that fails I fall back to a very conservative context for auto select max in driver. As far as I recall, I experienced initialization issues on Apple Silicon, so I explicitly request an OpenGL 4.1 core context; if that fails, I fall back to the default (more conservative) context. |
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I tested my app by requesting a GL 3.0 context (the branch shown in the example). The problem remained and several of my 3D shaders would not compile under that context, which indicates the runtime/driver on macOS (under Wine on macOS) does not provide the features I need when only GL 3.0 is requested. For that reason GLViewImpl::initWithRect first requests an OpenGL 4.1 core context (the maximum desktop GL Apple exposes); the driver/runtime ultimately decides the exact version returned. If creating a 4.1 context fails, the code falls back to a conservative default context. |
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If your app explicitly try to request varying GL context version, then surely you can select a GLSL version manually too? So to clarify, this fix doesn't strictly fix #6577 because the example have explicit GL version. |
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If, for work need set glsl_version = nullptr I build example_glfw_opengl3 no change: set nullptr: 
Now need remove const char* glsl_version // Decide GL+GLSL versions
#if defined(IMGUI_IMPL_OPENGL_ES2)
// GL ES 2.0 + GLSL 100 (WebGL 1.0)
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 2);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
#elif defined(IMGUI_IMPL_OPENGL_ES3)
// GL ES 3.0 + GLSL 300 es (WebGL 2.0)
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
glfwWindowHint(GLFW_CLIENT_API, GLFW_OPENGL_ES_API);
#elif defined(__APPLE__)
// GL 3.2 + GLSL 150
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 2);
glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // Required on Mac
#else
// GL 3.0 + GLSL 130
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 0);
//glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE); // 3.2+ only
//glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // 3.0+ only
#endif
// And call as nullptr or empty
ImGui_ImplOpenGL3_Init(nullptr); // set glsl_version auto |
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For real PC Windows 11 no change: set nullptr: |
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What I tested Observed behavior
Please consider one of the following changes to the example:
Additionally, I tested modifying the example to create a modern context (create a temporary legacy context, load bool CreateDeviceWGL(HWND hWnd, WGL_WindowData* data)
{
HDC hDc = ::GetDC(hWnd);
PIXELFORMATDESCRIPTOR pfd = { 0 };
pfd.nSize = sizeof(pfd);
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 32;
const int pf = ::ChoosePixelFormat(hDc, &pfd);
if (pf == 0)
return false;
if (::SetPixelFormat(hDc, pf, &pfd) == FALSE)
return false;
::ReleaseDC(hWnd, hDc);
data->hDC = ::GetDC(hWnd);
if (!g_hRC)
{
HGLRC tempRC = wglCreateContext(data->hDC);
if (!tempRC) { ::ReleaseDC(hWnd, data->hDC); return false; }
if (!wglMakeCurrent(data->hDC, tempRC))
{
wglDeleteContext(tempRC);
::ReleaseDC(hWnd, data->hDC);
return false;
}
// get version context
GLint major = 0;
GLint minor = 0;
glGetIntegerv(0x821B, &major); // GL_MAJOR_VERSION
glGetIntegerv(0x821C, &minor); // GL_MINOR_VERSION
const char* gl_version_str = (const char*)glGetString(GL_VERSION);
if (major == 0 && minor == 0)
sscanf(gl_version_str, "%d.%d", &major, &minor); // Query GL_VERSION in desktop GL 2.x, the string will start with "<major>.<minor>"
GLuint GlVersion = (GLuint)(major * 100 + minor * 10);
if (GlVersion < 300)
{
typedef HGLRC(WINAPI* PFNWGLCREATECONTEXTATTRIBSARBPROC)(HDC, HGLRC, const int*);
PFNWGLCREATECONTEXTATTRIBSARBPROC wglCreateContextAttribsARB =
(PFNWGLCREATECONTEXTATTRIBSARBPROC)wglGetProcAddress("wglCreateContextAttribsARB");
HGLRC newRC = nullptr;
if (wglCreateContextAttribsARB)
{
// GL 3.0
int attribs[] = {
0x2091, 3, // WGL_CONTEXT_MAJOR_VERSION_ARB
0x2092, 0, // WGL_CONTEXT_MINOR_VERSION_ARB
0x9126, 0x00000001, // WGL_CONTEXT_PROFILE_MASK_ARB, WGL_CONTEXT_CORE_PROFILE_BIT_ARB
0
};
newRC = wglCreateContextAttribsARB(data->hDC, 0, attribs);
}
if (newRC)
{
wglMakeCurrent(nullptr, nullptr);
wglDeleteContext(tempRC);
g_hRC = newRC;
wglMakeCurrent(data->hDC, g_hRC);
}
else
{
// Could not create a 3.0+ context: keep the temporary OpenGL 2.x compatibility context as fallback.
g_hRC = tempRC;
}
}
else
{
// Keep temporary context: already OpenGL 3.0+.
g_hRC = tempRC;
}
}
return true;
}
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2 participants
Add the GLSL 410 shader and ensure it is selected when the GLSL version is auto-detected (i.e. when glsl_version is nullptr). Previously the GLSL 410 shader was only used if a GLSL version string was passed manually to ImGui_ImplOpenGL3_Init. Now the backend detects the GL/GLSL version at runtime and will pick the GLSL 410 shader when the context supports it.
fc737d2