GL: Scissor always enabled.

src/glimports.h

@@ -515,6 +515,7 @@ GL_IMPORT_OES__(true,  PFNGLBINDVERTEXARRAYPROC,                   glBindVertexA
 GL_IMPORT_OES__(true,  PFNGLDELETEVERTEXARRAYSPROC,                glDeleteVertexArrays);
 GL_IMPORT_OES__(true,  PFNGLGENVERTEXARRAYSPROC,                   glGenVertexArrays);
 
+GL_IMPORT_____x(true,  PFNGLCLIPCONTROLPROC,                       glClipControl);
 GL_IMPORT_____x(true,  PFNGLENABLEIPROC,                           glEnablei);
 GL_IMPORT_____x(true,  PFNGLDISABLEIPROC,                          glDisablei);
 GL_IMPORT_____x(true,  PFNGLBLENDEQUATIONIPROC,                    glBlendEquationi);

src/renderer_gl.cpp

@@ -5473,6 +5473,8 @@ namespace bgfx { namespace gl
 		viewScissorRect.clear();
 		uint16_t discardFlags = BGFX_CLEAR_NONE;
 
+		GL_CHECK(glEnable(GL_SCISSOR_TEST) );
+
 		const bool blendIndependentSupported = s_extension[Extension::ARB_draw_buffers_blend].m_supported;
 		const bool computeSupported = (BX_ENABLED(BGFX_CONFIG_RENDERER_OPENGL) && s_extension[Extension::ARB_compute_shader].m_supported)
 									|| BX_ENABLED(BGFX_CONFIG_RENDERER_OPENGLES >= 31)
@@ -5595,7 +5597,7 @@ namespace bgfx { namespace gl
 					}
 
 					const Rect& scissorRect = _render->m_scissor[view];
-					viewHasScissor = !scissorRect.isZero();
+					viewHasScissor  = !scissorRect.isZero();
 					viewScissorRect = viewHasScissor ? scissorRect : viewState.m_rect;
 
 					GL_CHECK(glViewport(viewState.m_rect.m_x
@@ -5822,25 +5824,16 @@ namespace bgfx { namespace gl
 
 					if (UINT16_MAX == scissor)
 					{
-						if (viewHasScissor)
-						{
-							GL_CHECK(glEnable(GL_SCISSOR_TEST) );
-							GL_CHECK(glScissor(viewScissorRect.m_x
-								, resolutionHeight-viewScissorRect.m_height-viewScissorRect.m_y
-								, viewScissorRect.m_width
-								, viewScissorRect.m_height
-								) );
-						}
-						else
-						{
-							GL_CHECK(glDisable(GL_SCISSOR_TEST) );
-						}
+						GL_CHECK(glScissor(viewScissorRect.m_x
+							, resolutionHeight-viewScissorRect.m_height-viewScissorRect.m_y
+							, viewScissorRect.m_width
+							, viewScissorRect.m_height
+							) );
 					}
 					else
 					{
 						Rect scissorRect;
 						scissorRect.intersect(viewScissorRect, _render->m_rectCache.m_cache[scissor]);
-						GL_CHECK(glEnable(GL_SCISSOR_TEST) );
 						GL_CHECK(glScissor(scissorRect.m_x
 							, resolutionHeight-scissorRect.m_height-scissorRect.m_y
 							, scissorRect.m_width