From e5965d7771abd445f5ada5a24409ef2a7dae1410 Mon Sep 17 00:00:00 2001
From: Hajime Hoshi <hajimehoshi@gmail.com>
Date: Sun, 5 Jun 2016 03:16:54 +0900
Subject: [PATCH] opengl: Reduce calls of glSetViewport

---
 internal/graphics/opengl/context.go         | 4 +++-
 internal/graphics/opengl/context_desktop.go | 5 +++--
 internal/graphics/opengl/context_js.go      | 7 ++++---
 internal/graphics/opengl/context_mobile.go  | 7 ++++---
 4 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/internal/graphics/opengl/context.go b/internal/graphics/opengl/context.go
index 4fefa5ed4..f32a28f29 100644
--- a/internal/graphics/opengl/context.go
+++ b/internal/graphics/opengl/context.go
@@ -39,9 +39,11 @@ type Context struct {
 	context
 }
 
-func (c *Context) bindFramebuffer(f Framebuffer) {
+func (c *Context) bindFramebuffer(f Framebuffer) bool {
 	if c.lastFramebuffer != f {
 		c.bindFramebufferImpl(f)
 		c.lastFramebuffer = f
+		return true
 	}
+	return false
 }
diff --git a/internal/graphics/opengl/context_desktop.go b/internal/graphics/opengl/context_desktop.go
index 30316149a..b87da67f6 100644
--- a/internal/graphics/opengl/context_desktop.go
+++ b/internal/graphics/opengl/context_desktop.go
@@ -228,8 +228,9 @@ func (c *Context) NewFramebuffer(texture Texture) (Framebuffer, error) {
 
 func (c *Context) SetViewport(f Framebuffer, width, height int) error {
 	return c.RunOnContextThread(func() error {
-		c.bindFramebuffer(f)
-		gl.Viewport(0, 0, int32(width), int32(height))
+		if c.bindFramebuffer(f) {
+			gl.Viewport(0, 0, int32(width), int32(height))
+		}
 		return nil
 	})
 }
diff --git a/internal/graphics/opengl/context_js.go b/internal/graphics/opengl/context_js.go
index 0da88f3da..348720fd4 100644
--- a/internal/graphics/opengl/context_js.go
+++ b/internal/graphics/opengl/context_js.go
@@ -205,9 +205,10 @@ func (c *Context) NewFramebuffer(t Texture) (Framebuffer, error) {
 }
 
 func (c *Context) SetViewport(f Framebuffer, width, height int) error {
-	c.bindFramebuffer(f)
-	gl := c.gl
-	gl.Viewport(0, 0, width, height)
+	if c.bindFramebuffer(f) {
+		gl := c.gl
+		gl.Viewport(0, 0, width, height)
+	}
 	return nil
 }
 
diff --git a/internal/graphics/opengl/context_mobile.go b/internal/graphics/opengl/context_mobile.go
index 1a1b0b5bd..04f9ba39a 100644
--- a/internal/graphics/opengl/context_mobile.go
+++ b/internal/graphics/opengl/context_mobile.go
@@ -182,9 +182,10 @@ func (c *Context) NewFramebuffer(texture Texture) (Framebuffer, error) {
 }
 
 func (c *Context) SetViewport(f Framebuffer, width, height int) error {
-	gl := c.gl
-	c.bindFramebuffer(f)
-	gl.Viewport(0, 0, width, height)
+	if c.bindFramebuffer(f) {
+		gl := c.gl
+		gl.Viewport(0, 0, width, height)
+	}
 	return nil
 }