From 3d460e04453be503a26cd21a92924243ee15df49 Mon Sep 17 00:00:00 2001
From: Vladimir Vukicevic <vladimir@pobox.com>
Date: Mon, 17 Jun 2019 20:28:52 +0200
Subject: [PATCH] Work around emscripten double-reporting GL error

---
 src/renderer_gl.cpp | 47 ++++++++++++++++++++++++++-------------------
 1 file changed, 27 insertions(+), 20 deletions(-)

diff --git a/src/renderer_gl.cpp b/src/renderer_gl.cpp
index 0677580e1..a3f72e02b 100644
--- a/src/renderer_gl.cpp
+++ b/src/renderer_gl.cpp
@@ -1055,10 +1055,22 @@ namespace bgfx { namespace gl
 
 	typedef void (*PostSwapBuffersFn)(uint32_t _width, uint32_t _height);
 
+	void flushGlError()
+	{
+		for (GLenum err = glGetError(); err != 0; err = glGetError() );
+	}
+
+	GLenum getGlError()
+	{
+		GLenum err = glGetError();
+		flushGlError();
+		return err;
+	}
+
 	static const char* getGLString(GLenum _name)
 	{
 		const char* str = (const char*)glGetString(_name);
-		glGetError(); // ignore error if glGetString returns NULL.
+		getGlError(); // ignore error if glGetString returns NULL.
 		if (NULL != str)
 		{
 			return str;
@@ -1070,7 +1082,7 @@ namespace bgfx { namespace gl
 	static uint32_t getGLStringHash(GLenum _name)
 	{
 		const char* str = (const char*)glGetString(_name);
-		glGetError(); // ignore error if glGetString returns NULL.
+		getGlError(); // ignore error if glGetString returns NULL.
 		if (NULL != str)
 		{
 			return bx::hash<bx::HashMurmur2A>(str, (uint32_t)bx::strLen(str) );
@@ -1155,7 +1167,7 @@ namespace bgfx { namespace gl
 	{
 		GLint result = 0;
 		glGetIntegerv(_pname, &result);
-		GLenum err = glGetError();
+		GLenum err = getGlError();
 		BX_WARN(0 == err, "glGetIntegerv(0x%04x, ...) failed with GL error: 0x%04x.", _pname, err);
 		return 0 == err ? result : 0;
 	}
@@ -1168,11 +1180,6 @@ namespace bgfx { namespace gl
 		tfi.m_type        = _type;
 	}
 
-	void flushGlError()
-	{
-		for (GLenum err = glGetError(); err != 0; err = glGetError() );
-	}
-
 	static void texSubImage(
 		  GLenum _target
 		, GLint _level
@@ -1457,7 +1464,7 @@ namespace bgfx { namespace gl
 				uint32_t block = bx::uint32_max(4, dim);
 				size = (block*block*bpp)/8;
 				compressedTexImage(target, ii, internalFmt, dim, dim, 0, 0, size, data);
-				err |= glGetError();
+				err |= getGlError();
 			}
 		}
 		else
@@ -1467,7 +1474,7 @@ namespace bgfx { namespace gl
 				dim = bx::uint32_max(1, dim);
 				size = (dim*dim*bpp)/8;
 				texImage(target, 0, ii, internalFmt, dim, dim, 0, 0, tfi.m_fmt, tfi.m_type, data);
-				err |= glGetError();
+				err |= getGlError();
 			}
 		}
 
@@ -1513,7 +1520,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 				, _dim
 				, _dim
 				);
-			err = glGetError();
+			err = getGlError();
 		}
 
 		if (0 == err)
@@ -1532,7 +1539,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 			&&  _mipAutogen)
 			{
 				glGenerateMipmap(target);
-				err = glGetError();
+				err = getGlError();
 			}
 		}
 
@@ -1556,7 +1563,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 		GLenum err = 0;
 
 		glTexStorage2D(GL_TEXTURE_2D, 1, s_imageFormat[_format], _dim, _dim);
-		err |= glGetError();
+		err |= getGlError();
 		if (0 == err)
 		{
 			glBindImageTexture(0
@@ -1567,7 +1574,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 				, GL_READ_WRITE
 				, s_imageFormat[_format]
 				);
-			err |= glGetError();
+			err |= getGlError();
 		}
 
 		GL_CHECK(glDeleteTextures(1, &id) );
@@ -1606,7 +1613,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 			glBindRenderbuffer(GL_RENDERBUFFER, 0);
 			glDeleteRenderbuffers(1, &rbo);
 
-			GLenum err = glGetError();
+			GLenum err = getGlError();
 			return 0 == err;
 		}
 
@@ -1648,7 +1655,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 				, id
 				, 0
 				);
-		err = glGetError();
+		err = getGlError();
 
 		if (0 == err)
 		{
@@ -1892,7 +1899,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 			if (BX_ENABLED(BGFX_CONFIG_RENDERER_USE_EXTENSIONS) )
 			{
 				const char* extensions = (const char*)glGetString(GL_EXTENSIONS);
-				glGetError(); // ignore error if glGetString returns NULL.
+				getGlError(); // ignore error if glGetString returns NULL.
 				if (NULL != extensions)
 				{
 					bx::StringView ext(extensions);
@@ -1912,7 +1919,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 				{
 					GLint numExtensions = 0;
 					glGetIntegerv(GL_NUM_EXTENSIONS, &numExtensions);
-					glGetError(); // ignore error if glGetIntegerv returns NULL.
+					getGlError(); // ignore error if glGetIntegerv returns NULL.
 
 					for (GLint index = 0; index < numExtensions; ++index)
 					{
@@ -2205,7 +2212,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 							, 1
 							, &maxSamples
 							);
-						GLenum err = glGetError();
+						GLenum err = getGlError();
 						supported |= 0 == err && maxSamples > 0
 							? BGFX_CAPS_FORMAT_TEXTURE_FRAMEBUFFER_MSAA
 							: BGFX_CAPS_FORMAT_TEXTURE_NONE
@@ -2217,7 +2224,7 @@ BX_TRACE("%d, %d, %d, %s", _array, _srgb, _mipAutogen, getName(_format) );
 							, 1
 							, &maxSamples
 							);
-						err = glGetError();
+						err = getGlError();
 						supported |= 0 == err && maxSamples > 0
 							? BGFX_CAPS_FORMAT_TEXTURE_MSAA
 							: BGFX_CAPS_FORMAT_TEXTURE_NONE