internal/graphicsdriver: remove FramebufferYDirection

internal/graphicsdriver/directx/graphics_windows.go

@@ -1149,10 +1149,6 @@ func (g *Graphics) SetVsyncEnabled(enabled bool) {
 func (g *Graphics) SetFullscreen(fullscreen bool) {
 }
 
-func (g *Graphics) FramebufferYDirection() graphicsdriver.YDirection {
-	return graphicsdriver.Downward
-}
-
 func (g *Graphics) NeedsRestoring() bool {
 	return false
 }

internal/graphicsdriver/graphics.go

@@ -43,7 +43,6 @@ type Graphics interface {
 	NewScreenFramebufferImage(width, height int) (Image, error)
 	SetVsyncEnabled(enabled bool)
 	SetFullscreen(fullscreen bool)
-	FramebufferYDirection() YDirection
 	NeedsRestoring() bool
 	NeedsClearingScreen() bool
 	IsGL() bool
@@ -77,13 +76,6 @@ type WritePixelsArgs struct {
 	Height int
 }
 
-type YDirection int
-
-const (
-	Upward YDirection = iota
-	Downward
-)
-
 type Shader interface {
 	ID() ShaderID
 	Dispose()

internal/graphicsdriver/metal/graphics_darwin.go

@@ -610,10 +610,6 @@ func (g *Graphics) SetFullscreen(fullscreen bool) {
 	g.view.setFullscreen(fullscreen)
 }
 
-func (g *Graphics) FramebufferYDirection() graphicsdriver.YDirection {
-	return graphicsdriver.Downward
-}
-
 func (g *Graphics) NeedsRestoring() bool {
 	return false
 }

internal/graphicsdriver/opengl/graphics.go

@@ -275,11 +275,20 @@ func (g *Graphics) DrawTriangles(dstID graphicsdriver.ImageID, srcIDs [graphics.
 	{
 		const idx = graphics.ProjectionMatrixUniformVariableIndex
 		g.uniformVars[idx].name = g.uniformVariableName(idx)
-		g.uniformVars[idx].value = []float32{
-			2 / float32(dw), 0, 0, 0,
-			0, 2 / float32(dh), 0, 0,
-			0, 0, 1, 0,
-			-1, -1, 0, 1,
+		if destination.screen {
+			g.uniformVars[idx].value = []float32{
+				2 / float32(dw), 0, 0, 0,
+				0, -2 / float32(dh), 0, 0,
+				0, 0, 1, 0,
+				-1, 1, 0, 1,
+			}
+		} else {
+			g.uniformVars[idx].value = []float32{
+				2 / float32(dw), 0, 0, 0,
+				0, 2 / float32(dh), 0, 0,
+				0, 0, 1, 0,
+				-1, -1, 0, 1,
+			}
 		}
 		g.uniformVars[idx].typ = shader.ir.Uniforms[idx]
 	}
@@ -334,10 +343,6 @@ func (g *Graphics) SetFullscreen(fullscreen bool) {
 	// Do nothing
 }
 
-func (g *Graphics) FramebufferYDirection() graphicsdriver.YDirection {
-	return graphicsdriver.Upward
-}
-
 func (g *Graphics) NeedsRestoring() bool {
 	return g.context.needsRestoring()
 }

internal/ui/context.go

@@ -218,35 +218,15 @@ func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) {
 		c.screen.clear()
 	}
 
-	ga := 1.0
-	gd := 1.0
-	gtx := 0.0
-	gty := 0.0
-
 	screenScale, offsetX, offsetY := c.screenScaleAndOffsets()
-	s := screenScale
-	switch y := graphicsDriver.FramebufferYDirection(); y {
-	case graphicsdriver.Upward:
-		ga *= s
-		gd *= -s
-		gty += float64(c.offscreen.height) * s
-	case graphicsdriver.Downward:
-		ga *= s
-		gd *= s
-	default:
-		panic(fmt.Sprintf("ui: invalid y-direction: %d", y))
-	}
-
-	gtx += offsetX
-	gty += offsetY
 
 	var shader *Shader
 	switch {
 	case !theGlobalState.isScreenFilterEnabled():
 		shader = NearestFilterShader
-	case math.Floor(s) == s:
+	case math.Floor(screenScale) == screenScale:
 		shader = NearestFilterShader
-	case s > 1:
+	case screenScale > 1:
 		shader = screenShader
 	default:
 		// screenShader works with >=1 scale, but does not well with <1 scale.
@@ -269,7 +249,7 @@ func (c *context) drawGame(graphicsDriver graphicsdriver.Graphics) {
 
 	vs := graphics.QuadVertices(
 		0, 0, float32(c.offscreen.width), float32(c.offscreen.height),
-		float32(ga), 0, 0, float32(gd), float32(gtx), float32(gty),
+		float32(screenScale), 0, 0, float32(screenScale), float32(offsetX), float32(offsetY),
 		1, 1, 1, 1)
 	is := graphics.QuadIndices()