From 7e5a9582b3c00ade36d8c06aaa477c0750a5b3be Mon Sep 17 00:00:00 2001
From: "konstantin.matveyev" <konstantin.matveyev@eligovision.ru>
Date: Sun, 30 Jul 2017 19:58:56 +0300
Subject: [PATCH] [*] osgViewer::GraphicsWindowIOS fixes

---
 src/osgViewer/GraphicsWindowIOS.mm | 100 ++++++++++++++++-------------
 1 file changed, 56 insertions(+), 44 deletions(-)

diff --git a/src/osgViewer/GraphicsWindowIOS.mm b/src/osgViewer/GraphicsWindowIOS.mm
index 5bca620b5..0636a6d5f 100644
--- a/src/osgViewer/GraphicsWindowIOS.mm
+++ b/src/osgViewer/GraphicsWindowIOS.mm
@@ -10,7 +10,7 @@
     #import <OpenGLES/ES1/glext.h>
 #else
     #import <OpenGLES/ES2/glext.h>
-    #if defined(OSG_GLES3_FEATURES)
+    #if OSG_GLES3_FEATURES
         #import <OpenGLES/ES3/glext.h>
     #endif
 
@@ -432,9 +432,17 @@ typedef std::map<void*, unsigned int> TouchPointsIdMapping;
         glBindFramebufferOES(GL_FRAMEBUFFER_OES, _msaaFramebuffer);
         glBindRenderbufferOES(GL_RENDERBUFFER_OES, _msaaRenderBuffer);
 
-        // Samples is the amount of pixels the MSAA buffer uses to make one pixel on the render // buffer. Use a small number like 2 for the 3G and below and 4 or more for newer models
+        // Samples is the amount of pixels the MSAA buffer uses to make one pixel on the render
+		// buffer. Use a small number like 2 for the 3G and below and 4 or more for newer models
+		// NOTE: Formats of draw and read buffers must be identical
 
-        glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER_OES, _win->getTraits()->samples, GL_RGB5_A1_OES, _backingWidth, _backingHeight);
+		GLenum internalFormat = GL_RGB5_A1_OES;
+#	if OSG_GLES3_FEATURES
+		if ([_context API] == kEAGLRenderingAPIOpenGLES3)
+			internalFormat = GL_RGBA8_OES;
+#	endif
+
+        glRenderbufferStorageMultisampleAPPLE(GL_RENDERBUFFER_OES, _win->getTraits()->samples, internalFormat, _backingWidth, _backingHeight);
 
         glFramebufferRenderbufferOES(GL_FRAMEBUFFER_OES, GL_COLOR_ATTACHMENT0_OES, GL_RENDERBUFFER_OES, _msaaRenderBuffer);
         glGenRenderbuffersOES(1, &_msaaDepthBuffer);
@@ -507,64 +515,68 @@ typedef std::map<void*, unsigned int> TouchPointsIdMapping;
 
 
 #if defined(__IPHONE_4_0) && (__IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_4_0)
-    if(_msaaFramebuffer)
-    {
-        glBindFramebufferOES(GL_FRAMEBUFFER_OES, _msaaFramebuffer);
-
+	if (_msaaFramebuffer) {
+		// Resolve the contents from the multisampling buffer into the resolve (view) buffer
         glBindFramebufferOES(GL_READ_FRAMEBUFFER_APPLE, _msaaFramebuffer);
         glBindFramebufferOES(GL_DRAW_FRAMEBUFFER_APPLE, _viewFramebuffer);
 
-        glResolveMultisampleFramebufferAPPLE();
-
-        GLenum attachments[] = {GL_DEPTH_ATTACHMENT_OES, GL_COLOR_ATTACHMENT0_OES};
-    #ifdef OSG_GLES3_FEATURES
-        switch ([_context API])
-        {
-            case kEAGLRenderingAPIOpenGLES3:
-                glBlitFramebuffer(0, 0, _backingWidth, _backingHeight,
-                                  0, 0, _backingWidth, _backingHeight,
-                                  GL_COLOR_BUFFER_BIT, GL_LINEAR);
-                glInvalidateFramebuffer(GL_READ_FRAMEBUFFER_APPLE, 2, attachments);
-                break;
-
-            default:
-                glResolveMultisampleFramebufferAPPLE();
-                glDiscardFramebufferEXT(GL_READ_FRAMEBUFFER_APPLE, 2, attachments);
-                break;
-        }
-    #else
-        glDiscardFramebufferEXT(GL_READ_FRAMEBUFFER_APPLE, 2, attachments);
-    #endif
+#	if OSG_GLES3_FEATURES
+        if ([_context API] == kEAGLRenderingAPIOpenGLES3) {
+			glBlitFramebuffer(0, 0, _backingWidth, _backingHeight,
+							  0, 0, _backingWidth, _backingHeight,
+							  GL_COLOR_BUFFER_BIT, GL_LINEAR);
+		}
+		else
+			glResolveMultisampleFramebufferAPPLE();
+#	else
+		glResolveMultisampleFramebufferAPPLE();
+#	endif
     }
 #endif
 
-
-      //swap buffers (sort of i think?)
+	// Present Results step
     glBindRenderbufferOES(GL_RENDERBUFFER_OES, _viewRenderbuffer);
-
-    //display render in context
     [_context presentRenderbuffer:GL_RENDERBUFFER_OES];
 
-    //re bind the frame buffer for next frames renders
-    glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);
-
 #if defined(__IPHONE_4_0) && (__IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_4_0)
-    if (_msaaFramebuffer)
-        glBindFramebufferOES(GL_FRAMEBUFFER_OES, _msaaFramebuffer);;
+	if (_msaaFramebuffer) {
+		// Invalidate (discard) step (must be after present step)
+		GLenum attachments[] = {GL_DEPTH_ATTACHMENT_OES, GL_COLOR_ATTACHMENT0_OES};
+#	if OSG_GLES3_FEATURES
+		if ([_context API] == kEAGLRenderingAPIOpenGLES3)
+			glInvalidateFramebuffer(GL_READ_FRAMEBUFFER_APPLE, 2, attachments);
+		else
+			glDiscardFramebufferEXT(GL_READ_FRAMEBUFFER_APPLE, 2, attachments);
+#	else
+		glDiscardFramebufferEXT(GL_READ_FRAMEBUFFER_APPLE, 2, attachments);
+#	endif
+	}
 #endif
+
+	[self bindFrameBuffer];
 }
 
 //
 //bind view buffer as current for new render pass
 //
 - (void)bindFrameBuffer {
-
-    //bind the frame buffer
-    glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);
-
 #if defined(__IPHONE_4_0) && (__IPHONE_OS_VERSION_MIN_REQUIRED >= __IPHONE_4_0)
-    if (_msaaFramebuffer)
-        glBindFramebufferOES(GL_READ_FRAMEBUFFER_APPLE, _msaaFramebuffer);
+    if (_msaaFramebuffer) {
+#	if OSG_GLES3_FEATURES
+		if ([_context API] == kEAGLRenderingAPIOpenGLES3) {
+			glBindFramebufferOES(GL_DRAW_FRAMEBUFFER_APPLE, _msaaFramebuffer);
+			glBindFramebufferOES(GL_READ_FRAMEBUFFER_APPLE, _viewFramebuffer);
+		}
+		else
+			glBindFramebufferOES(GL_FRAMEBUFFER_OES, _msaaFramebuffer);
+#	else
+		glBindFramebufferOES(GL_FRAMEBUFFER_OES, _msaaFramebuffer);
+#	endif
+	}
+	else
+		glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);
+#else
+	glBindFramebufferOES(GL_FRAMEBUFFER_OES, _viewFramebuffer);
 #endif
 }
 
@@ -1016,7 +1028,7 @@ bool GraphicsWindowIOS:: makeCurrentImplementation()
         _updateContext = false;
     }
     //i think we also want to bind the frame buffer here
-    //[_view bindFrameBuffer];
+//    [_view bindFrameBuffer];
 
     return true;
 }