gl.Finish() before drawing image in a window (#94)

Solves #93
elgopher · Mar 15, 2020 · b83f669 · b83f669
1 parent acfbbbc
commit b83f669
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Showing 7 changed files with 83 additions and 30 deletions.
diff --git a/gl/api.go b/gl/api.go
@@ -114,6 +114,8 @@ type API interface {
 	GetError() uint32
 	// ReadPixels reads a block of pixels from the frame buffer
 	ReadPixels(x int32, y int32, width int32, height int32, format uint32, xtype uint32, pixels unsafe.Pointer)
+	// Finish blocks until all GL execution is complete
+	Finish()
 	// Ptr takes a slice or pointer (to a singular scalar value or the first
 	// element of an array or slice) and returns its GL-compatible address.
 	//

diff --git a/gl/command.go b/gl/command.go
@@ -199,18 +199,30 @@ func (c *AcceleratedCommand) Run(output image.AcceleratedImageSelection, selecti
 		panic("output image created in a different OpenGL context than program")
 	}
 
-	c.program.use()
-	c.api.Enable(scissorTest)
-	c.api.BindFramebuffer(framebuffer, img.frameBufferID)
 	loc := output.Location
-	locHeight := loc.Height
-	if locHeight > img.height {
-		locHeight = img.height
+	if loc.X >= img.width {
+		return
+	}
+	if loc.Y >= img.height {
+		return
 	}
 	x := int32(loc.X)
-	y := int32(img.height - locHeight - loc.Y)
+	y := int32(loc.Y)
 	w := int32(loc.Width)
-	h := int32(locHeight)
+	h := int32(loc.Height)
+	if x < 0 {
+		w += x
+		x = 0
+	}
+	if y < 0 {
+		h += y
+		y = 0
+	}
+	y = int32(img.height) - h - y
+
+	c.program.use()
+	c.api.Enable(scissorTest)
+	c.api.BindFramebuffer(framebuffer, img.frameBufferID)
 	c.api.Scissor(x, y, w, h)
 	c.api.Viewport(x, y, w, h)
 

diff --git a/gl/gl_test.go b/gl/gl_test.go
@@ -535,5 +535,6 @@ func (a apiStub) GetTexImage(target uint32, level int32, format uint32, xtype ui
 func (a apiStub) GetError() uint32 { return 0 }
 func (a apiStub) ReadPixels(x int32, y int32, width int32, height int32, format uint32, xtype uint32, pixels unsafe.Pointer) {
 }
+func (a apiStub) Finish()                             {}
 func (a apiStub) Ptr(data interface{}) unsafe.Pointer { return nil }
 func (a apiStub) PtrOffset(offset int) unsafe.Pointer { return nil }
diff --git a/gl/integration/glfw/opengl_integration_test.go b/gl/integration/glfw/opengl_integration_test.go
@@ -510,16 +510,46 @@ func TestAcceleratedCommand_Run(t *testing.T) {
 					location:       image.AcceleratedImageLocation{},
 					expectedColors: []image.Color{image.Transparent},
 				},
-				"x out of bounds": {
+				"x equal image width": {
 					width: 1, height: 1,
 					location:       image.AcceleratedImageLocation{X: 1, Width: 1, Height: 1},
 					expectedColors: []image.Color{image.Transparent},
 				},
-				"y out of bounds": {
+				"x higher than image width": {
+					width: 1, height: 1,
+					location:       image.AcceleratedImageLocation{X: 2, Width: 1, Height: 1},
+					expectedColors: []image.Color{image.Transparent},
+				},
+				"negative x": {
+					width: 1, height: 1,
+					location:       image.AcceleratedImageLocation{X: -1, Width: 1, Height: 1},
+					expectedColors: []image.Color{image.Transparent},
+				},
+				"negative x, width 2": {
+					width: 1, height: 1,
+					location:       image.AcceleratedImageLocation{X: -1, Width: 2, Height: 1},
+					expectedColors: []image.Color{color},
+				},
+				"y equal image height": {
 					width: 1, height: 1,
 					location:       image.AcceleratedImageLocation{Y: 1, Width: 1, Height: 1},
 					expectedColors: []image.Color{image.Transparent},
 				},
+				"y higher than image height": {
+					width: 1, height: 1,
+					location:       image.AcceleratedImageLocation{Y: 2, Width: 1, Height: 1},
+					expectedColors: []image.Color{image.Transparent},
+				},
+				"negative y": {
+					width: 1, height: 1,
+					location:       image.AcceleratedImageLocation{Y: -1, Width: 1, Height: 1},
+					expectedColors: []image.Color{image.Transparent},
+				},
+				"negative y, height 2": {
+					width: 1, height: 1,
+					location:       image.AcceleratedImageLocation{Y: -1, Width: 1, Height: 2},
+					expectedColors: []image.Color{color},
+				},
 				"whole image": {
 					width: 1, height: 1,
 					location:       image.AcceleratedImageLocation{Width: 1, Height: 1},

diff --git a/glfw/gl_api.go b/glfw/gl_api.go
@@ -404,6 +404,13 @@ func (g *context) ReadPixels(x int32, y int32, width int32, height int32, format
 	})
 }
 
+// Finish blocks until all GL execution is complete
+func (g *context) Finish() {
+	g.run(func() {
+		gl.Finish()
+	})
+}
+
 // Ptr takes a slice or pointer (to a singular scalar value or the first
 // element of an array or slice) and returns its GL-compatible address.
 //

diff --git a/glfw/glfw.go b/glfw/glfw.go
@@ -197,13 +197,13 @@ func (g *OpenGL) OpenWindow(width, height int, options ...WindowOption) (*Window
 	screenAcceleratedImage := g.context.NewAcceleratedImage(width, height)
 	screenImage := image.New(width, height, screenAcceleratedImage)
 	win := &Window{
-		mainThreadLoop:         g.mainThreadLoop,
-		keyboardEvents:         keyboardEvents,
-		requestedWidth:         width,
-		requestedHeight:        height,
-		screenAcceleratedImage: screenAcceleratedImage,
-		screenImage:            screenImage,
-		zoom:                   1,
+		mainThreadLoop:   g.mainThreadLoop,
+		keyboardEvents:   keyboardEvents,
+		requestedWidth:   width,
+		requestedHeight:  height,
+		screenImage:      screenImage,
+		screenContextAPI: g.context.API(),
+		zoom:             1,
 	}
 	var err error
 	g.mainThreadLoop.Execute(func() {
@@ -247,7 +247,7 @@ func (g *OpenGL) OpenWindow(width, height int, options ...WindowOption) (*Window
 	}
 	// in this window context there is only one program used with one texture
 	win.api.UseProgram(win.program.ID())
-	win.api.BindTexture(gl33.TEXTURE_2D, win.screenAcceleratedImage.TextureID())
+	win.api.BindTexture(gl33.TEXTURE_2D, screenAcceleratedImage.TextureID())
 	return win, nil
 }
 

diff --git a/glfw/window.go b/glfw/window.go
@@ -11,24 +11,25 @@ import (
 
 // Window is an implementation of loop.Screen and keyboard.EventSource
 type Window struct {
-	glfwWindow             *glfw.Window
-	mainThreadLoop         *MainThreadLoop
-	screenPolygon          *screenPolygon
-	keyboardEvents         *internal.KeyboardEvents
-	requestedWidth         int
-	requestedHeight        int
-	zoom                   int
-	screenImage            *image.Image
-	screenAcceleratedImage *gl.AcceleratedImage
-	api                    gl.API
-	context                *gl.Context
-	program                *gl.Program
+	glfwWindow       *glfw.Window
+	mainThreadLoop   *MainThreadLoop
+	screenPolygon    *screenPolygon
+	keyboardEvents   *internal.KeyboardEvents
+	requestedWidth   int
+	requestedHeight  int
+	zoom             int
+	screenImage      *image.Image
+	screenContextAPI gl.API
+	api              gl.API
+	context          *gl.Context
+	program          *gl.Program
 }
 
 // Draw draws a screen image to the invisible buffer. It will be shown in window
 // after SwapImages is called.
 func (w *Window) Draw() {
 	w.screenImage.Upload()
+	w.screenContextAPI.Finish()
 	var width, height int
 	w.mainThreadLoop.Execute(func() {
 		width, height = w.glfwWindow.GetFramebufferSize()