opengl: Call glViewport each time when different framebuffer is set

internal/graphics/opengl/context.go

@@ -40,12 +40,28 @@ type Context struct {
 	context
 }
 
-func (c *Context) bindFramebuffer(f Framebuffer) {
+func (c *Context) bindFramebuffer(f Framebuffer) error {
 	if c.lastFramebuffer == f {
-		return
+		return nil
+	}
+	if err := c.bindFramebufferImpl(f); err != nil {
+		return err
 	}
-	c.bindFramebufferImpl(f)
 	c.lastFramebuffer = f
+	return nil
+}
+
+func (c *Context) SetViewport(f Framebuffer, width, height int) error {
+	lf := c.lastFramebuffer
+	c.bindFramebuffer(f)
+	if lf != f || c.lastViewportWidth != width || c.lastViewportHeight != height {
+		if err := c.setViewportImpl(width, height); err != nil {
+			return nil
+		}
+		c.lastViewportWidth = width
+		c.lastViewportHeight = height
+	}
+	return nil
 }
 
 func (c *Context) ScreenFramebuffer() Framebuffer {

internal/graphics/opengl/context_desktop.go

@@ -180,15 +180,26 @@ func (c *Context) NewTexture(width, height int, pixels []uint8, filter Filter) (
 	return texture, nil
 }
 
-func (c *Context) bindFramebufferImpl(f Framebuffer) {
+func (c *Context) bindFramebufferImpl(f Framebuffer) error {
-	gl.BindFramebuffer(gl.FRAMEBUFFER, uint32(f))
+	if err := c.RunOnContextThread(func() error {
+		gl.BindFramebuffer(gl.FRAMEBUFFER, uint32(f))
+		return nil
+	}); err != nil {
+		return err
+	}
+	return nil
 }
 
 func (c *Context) FramebufferPixels(f Framebuffer, width, height int) ([]uint8, error) {
 	var pixels []uint8
 	if err := c.RunOnContextThread(func() error {
 		gl.Flush()
-		c.bindFramebuffer(f)
+		return nil
+	}); err != nil {
+		return nil, err
+	}
+	c.bindFramebuffer(f)
+	if err := c.RunOnContextThread(func() error {
 		pixels = make([]uint8, 4*width*height)
 		gl.ReadPixels(0, 0, int32(width), int32(height), gl.RGBA, gl.UNSIGNED_BYTE, gl.Ptr(pixels))
 		if e := gl.GetError(); e != gl.NO_ERROR {
@@ -236,24 +247,25 @@ func (c *Context) TexSubImage2D(p []uint8, width, height int) {
 	})
 }
 
-func (c *Context) BindScreenFramebuffer() {
+func (c *Context) BindScreenFramebuffer() error {
-	c.RunOnContextThread(func() error {
+	return c.bindFramebuffer(c.screenFramebuffer)
-		c.bindFramebuffer(c.screenFramebuffer)
-		return nil
-	})
 }
 
 func (c *Context) NewFramebuffer(texture Texture) (Framebuffer, error) {
 	var framebuffer Framebuffer
+	var f uint32
 	if err := c.RunOnContextThread(func() error {
-		var f uint32
 		gl.GenFramebuffers(1, &f)
 		// TODO: Use gl.IsFramebuffer
 		if f <= 0 {
 			return errors.New("opengl: creating framebuffer failed: gl.IsFramebuffer returns false")
 		}
-		c.bindFramebuffer(Framebuffer(f))
+		return nil
-
+	}); err != nil {
+		return 0, err
+	}
+	c.bindFramebuffer(Framebuffer(f))
+	if err := c.RunOnContextThread(func() error {
 		gl.FramebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, uint32(texture), 0)
 		s := gl.CheckFramebufferStatus(gl.FRAMEBUFFER)
 		if s != gl.FRAMEBUFFER_COMPLETE {
@@ -273,14 +285,9 @@ func (c *Context) NewFramebuffer(texture Texture) (Framebuffer, error) {
 	return framebuffer, nil
 }
 
-func (c *Context) SetViewport(f Framebuffer, width, height int) error {
+func (c *Context) setViewportImpl(width, height int) error {
 	return c.RunOnContextThread(func() error {
-		c.bindFramebuffer(f)
+		gl.Viewport(0, 0, int32(width), int32(height))
-		if c.lastViewportWidth != width || c.lastViewportHeight != height {
-			gl.Viewport(0, 0, int32(width), int32(height))
-			c.lastViewportWidth = width
-			c.lastViewportHeight = height
-		}
 		return nil
 	})
 }

internal/graphics/opengl/context_js.go

@@ -172,9 +172,10 @@ func (c *Context) NewTexture(width, height int, pixels []uint8, filter Filter) (
 	return Texture{t}, nil
 }
 
-func (c *Context) bindFramebufferImpl(f Framebuffer) {
+func (c *Context) bindFramebufferImpl(f Framebuffer) error {
 	gl := c.gl
 	gl.BindFramebuffer(gl.FRAMEBUFFER, f.Object)
+	return nil
 }
 
 func (c *Context) FramebufferPixels(f Framebuffer, width, height int) ([]uint8, error) {
@@ -230,14 +231,9 @@ func (c *Context) NewFramebuffer(t Texture) (Framebuffer, error) {
 	return Framebuffer{f}, nil
 }
 
-func (c *Context) SetViewport(f Framebuffer, width, height int) error {
+func (c *Context) setViewportImpl(width, height int) error {
-	c.bindFramebuffer(f)
+	gl := c.gl
-	if c.lastViewportWidth != width || c.lastViewportHeight != height {
+	gl.Viewport(0, 0, width, height)
-		gl := c.gl
-		gl.Viewport(0, 0, width, height)
-		c.lastViewportWidth = width
-		c.lastViewportHeight = height
-	}
 	return nil
 }
 

internal/graphics/opengl/context_mobile.go

@@ -192,8 +192,8 @@ func (c *Context) TexSubImage2D(p []uint8, width, height int) {
 	gl.TexSubImage2D(mgl.TEXTURE_2D, 0, 0, 0, width, height, mgl.RGBA, mgl.UNSIGNED_BYTE, p)
 }
 
-func (c *Context) BindScreenFramebuffer() {
+func (c *Context) BindScreenFramebuffer() error {
-	c.bindFramebuffer(c.screenFramebuffer)
+	return c.bindFramebuffer(c.screenFramebuffer)
 }
 
 func (c *Context) NewFramebuffer(texture Texture) (Framebuffer, error) {
@@ -215,18 +215,12 @@ func (c *Context) NewFramebuffer(texture Texture) (Framebuffer, error) {
 		}
 		return Framebuffer{}, fmt.Errorf("opengl: creating framebuffer failed: unknown error")
 	}
-
 	return Framebuffer(f), nil
 }
 
-func (c *Context) SetViewport(f Framebuffer, width, height int) error {
+func (c *Context) setViewportImpl(width, height int) error {
-	c.bindFramebuffer(f)
+	gl := c.gl
-	if c.lastViewportWidth != width || c.lastViewportHeight != height {
+	gl.Viewport(0, 0, width, height)
-		gl := c.gl
-		gl.Viewport(0, 0, width, height)
-		c.lastViewportWidth = width
-		c.lastViewportHeight = height
-	}
 	return nil
 }
 

internal/ui/ui_glfw.go

@@ -247,19 +247,23 @@ func (u *userInterface) Terminate() error {
 }
 
 func (u *userInterface) SwapBuffers() error {
+	var err error
 	u.runOnMainThread(func() {
-		u.swapBuffers()
+		err = u.swapBuffers()
 	})
-	return nil
+	return err
 }
 
-func (u *userInterface) swapBuffers() {
+func (u *userInterface) swapBuffers() error {
 	// The bound framebuffer must be the default one (0) before swapping buffers.
-	u.context.BindScreenFramebuffer()
+	if err := u.context.BindScreenFramebuffer(); err != nil {
+		return err
+	}
 	u.context.RunOnContextThread(func() error {
 		u.window.SwapBuffers()
 		return nil
 	})
+	return nil
 }
 
 func (u *userInterface) FinishRendering() error {