Implement GL_OES_fbo_render_mipmap.

This enables binding any texture mipmap level as a framebuffer
attachment.

Bug swiftshader:104

Change-Id: I3d4ea637ddd38bb62ca1363fe2c69c569eea36e9
Reviewed-on: https://swiftshader-review.googlesource.com/18008
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Lingfeng Yang <lfy@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>

src/OpenGL/libGLESv2/Context.cpp

diff --git a/src/OpenGL/libGLESv2/Context.cpp b/src/OpenGL/libGLESv2/Context.cpp
index 5a5a6b3..e257174 100644
--- a/src/OpenGL/libGLESv2/Context.cpp
+++ b/src/OpenGL/libGLESv2/Context.cpp
@@ -4405,6 +4405,7 @@
 		"GL_OES_EGL_image_external",
 		"GL_OES_EGL_sync",
 		"GL_OES_element_index_uint",
+		"GL_OES_fbo_render_mipmap",
 		"GL_OES_framebuffer_object",
 		"GL_OES_packed_depth_stencil",
 		"GL_OES_rgb8_rgba8",

src/OpenGL/libGLESv2/Renderbuffer.cpp

diff --git a/src/OpenGL/libGLESv2/Renderbuffer.cpp b/src/OpenGL/libGLESv2/Renderbuffer.cpp
index a970dcf..fdbb617 100644
--- a/src/OpenGL/libGLESv2/Renderbuffer.cpp
+++ b/src/OpenGL/libGLESv2/Renderbuffer.cpp
@@ -78,7 +78,7 @@
 
 RenderbufferTexture2D::~RenderbufferTexture2D()
 {
-	mTexture2D = NULL;
+	mTexture2D = nullptr;
 }
 
 // Textures need to maintain their own reference count for references via
@@ -441,7 +441,7 @@
 
 void Renderbuffer::setStorage(RenderbufferStorage *newStorage)
 {
-	ASSERT(newStorage != NULL);
+	ASSERT(newStorage);
 
 	delete mInstance;
 	mInstance = newStorage;

src/OpenGL/libGLESv2/libGLESv2.cpp

diff --git a/src/OpenGL/libGLESv2/libGLESv2.cpp b/src/OpenGL/libGLESv2/libGLESv2.cpp
index 1577569..4be1261 100644
--- a/src/OpenGL/libGLESv2/libGLESv2.cpp
+++ b/src/OpenGL/libGLESv2/libGLESv2.cpp
@@ -6006,11 +6006,6 @@
 				return error(GL_INVALID_OPERATION);
 			}
 
-			if(tex->isCompressed(textarget, level))
-			{
-				return error(GL_INVALID_OPERATION);
-			}
-
 			switch(textarget)
 			{
 			case GL_TEXTURE_3D:
@@ -6023,10 +6018,15 @@
 				return error(GL_INVALID_ENUM);
 			}
 
-			if(level != 0)
+			if((level < 0) || (level >= es2::IMPLEMENTATION_MAX_TEXTURE_LEVELS))
 			{
 				return error(GL_INVALID_VALUE);
 			}
+
+			if(tex->isCompressed(textarget, level))
+			{
+				return error(GL_INVALID_OPERATION);
+			}
 		}
 
 		es2::Framebuffer *framebuffer = nullptr;
@@ -6049,14 +6049,14 @@
 
 		switch(attachment)
 		{
-		case GL_DEPTH_ATTACHMENT:   framebuffer->setDepthbuffer(textarget, texture);   break;
-		case GL_STENCIL_ATTACHMENT: framebuffer->setStencilbuffer(textarget, texture); break;
+		case GL_DEPTH_ATTACHMENT:   framebuffer->setDepthbuffer(textarget, texture, level);   break;
+		case GL_STENCIL_ATTACHMENT: framebuffer->setStencilbuffer(textarget, texture, level); break;
 		default:
 			if((attachment - GL_COLOR_ATTACHMENT0) >= MAX_COLOR_ATTACHMENTS)
 			{
 				return error(GL_INVALID_ENUM);
 			}
-			framebuffer->setColorbuffer(textarget, texture, attachment - GL_COLOR_ATTACHMENT0);
+			framebuffer->setColorbuffer(textarget, texture, attachment - GL_COLOR_ATTACHMENT0, level);
 			break;
 		}
 	}