gpu: drop Framebuffer.IsComplete in favour of an error from NewFramebuffer

Signed-off-by: Elias Naur <mail@eliasnaur.com>

gpu/backend.go

@@ -20,7 +20,7 @@ type Backend interface {
 	IsTimeContinuous() bool
 	NewTexture(format TextureFormat, width, height int, minFilter, magFilter TextureFilter, bindings BufferBinding) Texture
 	DefaultFramebuffer() Framebuffer
-	NewFramebuffer(tex Texture) Framebuffer
+	NewFramebuffer(tex Texture) (Framebuffer, error)
 	NewImmutableBuffer(typ BufferBinding, data []byte) Buffer
 	NewBuffer(typ BufferBinding, size int) Buffer
 	NewProgram(vertexShader, fragmentShader ShaderSources) (Program, error)
@@ -127,7 +127,6 @@ type Framebuffer interface {
 	Bind()
 	Invalidate()
 	Release()
-	IsComplete() error
 }
 
 type Timer interface {

gpu/gl/backend.go

@@ -139,7 +139,7 @@ func NewBackend(f Functions) (*Backend, error) {
 }
 
 func (b *Backend) BeginFrame() {
-	// Assume GL state is reset.
+	// Assume GL state is reset between frames.
 	b.state = glstate{}
 }
 
@@ -162,13 +162,17 @@ func (b *Backend) IsTimeContinuous() bool {
 	return b.funcs.GetInteger(GPU_DISJOINT_EXT) == FALSE
 }
 
-func (b *Backend) NewFramebuffer(tex gpu.Texture) gpu.Framebuffer {
+func (b *Backend) NewFramebuffer(tex gpu.Texture) (gpu.Framebuffer, error) {
 	gltex := tex.(*gpuTexture)
 	fb := b.funcs.CreateFramebuffer()
 	fbo := &gpuFramebuffer{funcs: b.funcs, obj: fb}
 	fbo.Bind()
 	b.funcs.FramebufferTexture2D(FRAMEBUFFER, COLOR_ATTACHMENT0, TEXTURE_2D, gltex.obj, 0)
-	return fbo
+	if st := b.funcs.CheckFramebufferStatus(FRAMEBUFFER); st != FRAMEBUFFER_COMPLETE {
+		fbo.Release()
+		return nil, fmt.Errorf("incomplete framebuffer, status = 0x%x, err = %d", st, b.funcs.GetError())
+	}
+	return fbo, nil
 }
 
 func (b *Backend) DefaultFramebuffer() gpu.Framebuffer {
@@ -536,13 +540,6 @@ func (b *gpuBuffer) BindIndex() {
 	b.backend.funcs.BindBuffer(ELEMENT_ARRAY_BUFFER, b.obj)
 }
 
-func (f *gpuFramebuffer) IsComplete() error {
-	if st := f.funcs.CheckFramebufferStatus(FRAMEBUFFER); st != FRAMEBUFFER_COMPLETE {
-		return fmt.Errorf("incomplete framebuffer, status = 0x%x, err = %d", st, f.funcs.GetError())
-	}
-	return nil
-}
-
 func (f *gpuFramebuffer) Bind() {
 	f.funcs.BindFramebuffer(FRAMEBUFFER, f.obj)
 }

gpu/gpu.go

@@ -489,7 +489,7 @@ func (r *renderer) stencilClips(pathCache *opCache, ops []*pathOp) {
 		if fbo != p.place.Idx {
 			fbo = p.place.Idx
 			f := r.pather.stenciler.cover(fbo)
-			bindFramebuffer(f.fbo)
+			f.fbo.Bind()
 			r.ctx.Clear(BufferAttachmentColor)
 		}
 		data, _ := pathCache.get(p.pathKey)
@@ -513,7 +513,7 @@ func (r *renderer) intersect(ops []imageOp) {
 		if fbo != img.place.Idx {
 			fbo = img.place.Idx
 			f := r.pather.stenciler.intersections.fbos[fbo]
-			bindFramebuffer(f.fbo)
+			f.fbo.Bind()
 			r.ctx.Clear(BufferAttachmentColor)
 		}
 		r.ctx.Viewport(img.place.Pos.X, img.place.Pos.Y, img.clip.Dx(), img.clip.Dy())
@@ -990,13 +990,6 @@ func clipSpaceTransform(r image.Rectangle, viewport image.Point) (f32.Point, f32
 	return scale, offset
 }
 
-func bindFramebuffer(fbo Framebuffer) {
-	fbo.Bind()
-	if err := fbo.IsComplete(); err != nil {
-		panic(fmt.Errorf("AA FBO not complete: %v", err))
-	}
-}
-
 // Fill in maximal Y coordinates of the NW and NE corners.
 func fillMaxY(verts []byte) {
 	contour := 0

gpu/path.go

@@ -211,7 +211,11 @@ func (s *fboSet) resize(ctx Backend, sizes []image.Point) {
 			f.size = sz
 			f.tex = ctx.NewTexture(TextureFormatFloat, sz.X, sz.Y, FilterNearest, FilterNearest,
 				BufferBindingTexture|BufferBindingFramebuffer)
-			f.fbo = ctx.NewFramebuffer(f.tex)
+			fbo, err := ctx.NewFramebuffer(f.tex)
+			if err != nil {
+				panic(err)
+			}
+			f.fbo = fbo
 		}
 	}
 	// Delete extra fbos.