From 8b3f752af50e6c700ac46db34adff36a66165223 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Branimir=20Karad=C5=BEi=C4=87?= <branimirkaradzic@gmail.com>
Date: Wed, 11 Jan 2017 20:38:38 -0800
Subject: [PATCH] Skip rendering when scissor is zero area.

---
 src/renderer_d3d11.cpp |  5 +++++
 src/renderer_d3d12.cpp |  5 +++++
 src/renderer_d3d9.cpp  |  5 +++++
 src/renderer_gl.cpp    |  5 +++++
 src/renderer_mtl.mm    | 13 ++++++++-----
 src/renderer_vk.cpp    |  5 +++++
 6 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/src/renderer_d3d11.cpp b/src/renderer_d3d11.cpp
index 984ec4b1c..41f841cfb 100644
--- a/src/renderer_d3d11.cpp
+++ b/src/renderer_d3d11.cpp
@@ -5744,6 +5744,11 @@ BX_PRAGMA_DIAGNOSTIC_POP();
 					{
 						Rect scissorRect;
 						scissorRect.intersect(viewScissorRect, _render->m_rectCache.m_cache[scissor]);
+						if (scissorRect.isZeroArea() )
+						{
+							continue;
+						}
+
 						scissorEnabled = true;
 						D3D11_RECT rc;
 						rc.left   = scissorRect.m_x;
diff --git a/src/renderer_d3d12.cpp b/src/renderer_d3d12.cpp
index e593d5ba0..401f6c59d 100644
--- a/src/renderer_d3d12.cpp
+++ b/src/renderer_d3d12.cpp
@@ -5371,6 +5371,11 @@ data.NumQualityLevels = 0;
 							restoreScissor = true;
 							Rect scissorRect;
 							scissorRect.intersect(viewScissorRect,_render->m_rectCache.m_cache[scissor]);
+							if (scissorRect.isZeroArea() )
+							{
+								continue;
+							}
+
 							D3D12_RECT rc;
 							rc.left   = scissorRect.m_x;
 							rc.top    = scissorRect.m_y;
diff --git a/src/renderer_d3d9.cpp b/src/renderer_d3d9.cpp
index 1f1adee0a..a582dba2e 100644
--- a/src/renderer_d3d9.cpp
+++ b/src/renderer_d3d9.cpp
@@ -3795,6 +3795,11 @@ namespace bgfx { namespace d3d9
 					{
 						Rect scissorRect;
 						scissorRect.intersect(viewScissorRect, _render->m_rectCache.m_cache[scissor]);
+						if (scissorRect.isZeroArea() )
+						{
+							continue;
+						}
+
 						DX_CHECK(device->SetRenderState(D3DRS_SCISSORTESTENABLE, true) );
 						RECT rc;
 						rc.left   = scissorRect.m_x;
diff --git a/src/renderer_gl.cpp b/src/renderer_gl.cpp
index 38ca1b663..91e9ef6e7 100644
--- a/src/renderer_gl.cpp
+++ b/src/renderer_gl.cpp
@@ -6601,6 +6601,11 @@ namespace bgfx { namespace gl
 					{
 						Rect scissorRect;
 						scissorRect.intersect(viewScissorRect, _render->m_rectCache.m_cache[scissor]);
+						if (scissorRect.isZeroArea() )
+						{
+							continue;
+						}
+
 						GL_CHECK(glEnable(GL_SCISSOR_TEST) );
 						GL_CHECK(glScissor(scissorRect.m_x
 							, resolutionHeight-scissorRect.m_height-scissorRect.m_y
diff --git a/src/renderer_mtl.mm b/src/renderer_mtl.mm
index 8a9958bbc..e5c13f66f 100644
--- a/src/renderer_mtl.mm
+++ b/src/renderer_mtl.mm
@@ -3406,14 +3406,17 @@ namespace bgfx { namespace mtl
 					{
 						Rect scissorRect;
 						scissorRect.intersect(viewScissorRect, _render->m_rectCache.m_cache[scissor]);
-						rc.x   = scissorRect.m_x;
-						rc.y    = scissorRect.m_y;
+						if (scissorRect.isZeroArea() )
+						{
+							continue;
+						}
+
+						rc.x      = scissorRect.m_x;
+						rc.y      = scissorRect.m_y;
 						rc.width  = scissorRect.m_width;
 						rc.height = scissorRect.m_height;
-
-						if ( rc.width == 0 || rc.height == 0 )
-							continue;
 					}
+
 					rce.setScissorRect(rc);
 				}
 
diff --git a/src/renderer_vk.cpp b/src/renderer_vk.cpp
index d03c9e565..7609b43d5 100644
--- a/src/renderer_vk.cpp
+++ b/src/renderer_vk.cpp
@@ -4262,6 +4262,11 @@ BX_UNUSED(currentSamplerStateIdx);
 							restoreScissor = true;
 							Rect scissorRect;
 							scissorRect.intersect(viewScissorRect,_render->m_rectCache.m_cache[scissor]);
+							if (scissorRect.isZeroArea() )
+							{
+								continue;
+							}
+
 							VkRect2D rc;
 							rc.offset.x      = scissorRect.m_x;
 							rc.offset.x      = scissorRect.m_y;