internal/graphicsdriver/opengl: Remove unused code using PBO

Updates #1678

internal/graphicsdriver/opengl/context_desktop.go

@@ -496,10 +496,6 @@ func (c *context) needsRestoring() bool {
 	return false
 }
 
-func (c *context) canUsePBO() bool {
-	return false
-}
-
 func (c *context) texSubImage2D(t textureNative, args []*driver.ReplacePixelsArgs) {
 	c.bindTexture(t)
 	for _, a := range args {
@@ -507,39 +503,6 @@ func (c *context) texSubImage2D(t textureNative, args []*driver.ReplacePixelsArg
 	}
 }
 
-func (c *context) newPixelBufferObject(width, height int) buffer {
-	var b uint32
-	gl.GenBuffers(1, &b)
-	gl.BindBuffer(gl.PIXEL_UNPACK_BUFFER, b)
-	gl.BufferData(gl.PIXEL_UNPACK_BUFFER, 4*width*height, nil, gl.STREAM_DRAW)
-	gl.BindBuffer(gl.PIXEL_UNPACK_BUFFER, 0)
-	return buffer(b)
-}
-
-func (c *context) replacePixelsWithPBO(buffer buffer, t textureNative, width, height int, args []*driver.ReplacePixelsArgs) {
-	c.bindTexture(t)
-	gl.BindBuffer(gl.PIXEL_UNPACK_BUFFER, uint32(buffer))
-
-	stride := 4 * width
-	for _, a := range args {
-		offset := 4 * (a.Y*width + a.X)
-		for j := 0; j < a.Height; j++ {
-			gl.BufferSubData(gl.PIXEL_UNPACK_BUFFER, offset+stride*j, 4*a.Width, gl.Ptr(a.Pixels[4*a.Width*j:4*a.Width*(j+1)]))
-		}
-	}
-
-	gl.TexSubImage2D(gl.TEXTURE_2D, 0, 0, 0, int32(width), int32(height), gl.RGBA, gl.UNSIGNED_BYTE, nil)
-	gl.BindBuffer(gl.PIXEL_UNPACK_BUFFER, 0)
-}
-
-func (c *context) getBufferSubData(buffer buffer, width, height int) []byte {
-	gl.BindBuffer(gl.PIXEL_UNPACK_BUFFER, uint32(buffer))
-	pixels := make([]byte, 4*width*height)
-	gl.GetBufferSubData(gl.PIXEL_UNPACK_BUFFER, 0, 4*width*height, gl.Ptr(pixels))
-	gl.BindBuffer(gl.PIXEL_UNPACK_BUFFER, 0)
-	return pixels
-}
-
 func (c *context) enableStencilTest() {
 	gl.Enable(gl.STENCIL_TEST)
 }

internal/graphicsdriver/opengl/context_js.go

@@ -599,54 +599,6 @@ func (c *context) texSubImage2D(t textureNative, args []*driver.ReplacePixelsArg
 	}
 }
 
-func (c *context) newPixelBufferObject(width, height int) buffer {
-	gl := c.gl
-	b := gl.createBuffer.Invoke()
-	gl.bindBuffer.Invoke(gles.PIXEL_UNPACK_BUFFER, js.Value(b))
-	gl.bufferData.Invoke(gles.PIXEL_UNPACK_BUFFER, 4*width*height, gles.STREAM_DRAW)
-	gl.bindBuffer.Invoke(gles.PIXEL_UNPACK_BUFFER, nil)
-	return buffer(b)
-}
-
-func (c *context) replacePixelsWithPBO(buffer buffer, t textureNative, width, height int, args []*driver.ReplacePixelsArgs) {
-	if !isWebGL2Available {
-		panic("opengl: WebGL2 must be available when replacePixelsWithPBO is called")
-	}
-
-	c.bindTexture(t)
-	gl := c.gl
-	gl.bindBuffer.Invoke(gles.PIXEL_UNPACK_BUFFER, js.Value(buffer))
-
-	stride := 4 * width
-	for _, a := range args {
-		arr := jsutil.TemporaryUint8Array(len(a.Pixels), a.Pixels)
-		offset := 4 * (a.Y*width + a.X)
-		for j := 0; j < a.Height; j++ {
-			gl.bufferSubData.Invoke(gles.PIXEL_UNPACK_BUFFER, offset+stride*j, arr, 4*a.Width*j, 4*a.Width)
-		}
-	}
-
-	// void texSubImage2D(GLenum target, GLint level, GLint xoffset, GLint yoffset,
-	//                    GLsizei width, GLsizei height,
-	//                    GLenum format, GLenum type, GLintptr offset);
-	gl.texSubImage2D.Invoke(gles.TEXTURE_2D, 0, 0, 0, width, height, gles.RGBA, gles.UNSIGNED_BYTE, 0)
-	gl.bindBuffer.Invoke(gles.PIXEL_UNPACK_BUFFER, nil)
-}
-
-func (c *context) getBufferSubData(buffer buffer, width, height int) []byte {
-	if !isWebGL2Available {
-		panic("opengl: WebGL2 must be available when getBufferSubData is called")
-	}
-
-	gl := c.gl
-	gl.bindBuffer.Invoke(gles.PIXEL_UNPACK_BUFFER, js.Value(buffer))
-	l := 4 * width * height
-	arr := jsutil.TemporaryUint8Array(l, nil)
-	gl.getBufferSubData.Invoke(gles.PIXEL_UNPACK_BUFFER, 0, arr, 0, l)
-	gl.bindBuffer.Invoke(gles.PIXEL_UNPACK_BUFFER, nil)
-	return jsutil.Uint8ArrayToSlice(arr, l)
-}
-
 func (c *context) enableStencilTest() {
 	gl := c.gl
 	gl.enable.Invoke(gles.STENCIL_TEST)

internal/graphicsdriver/opengl/context_mobile.go

@@ -469,38 +469,6 @@ func (c *context) texSubImage2D(t textureNative, args []*driver.ReplacePixelsArg
 	}
 }
 
-func (c *context) newPixelBufferObject(width, height int) buffer {
-	b := c.ctx.GenBuffers(1)[0]
-	c.ctx.BindBuffer(gles.PIXEL_UNPACK_BUFFER, b)
-	c.ctx.BufferData(gles.PIXEL_UNPACK_BUFFER, 4*width*height, nil, gles.STREAM_DRAW)
-	c.ctx.BindBuffer(gles.PIXEL_UNPACK_BUFFER, 0)
-	return buffer(b)
-}
-
-func (c *context) replacePixelsWithPBO(buffer buffer, t textureNative, width, height int, args []*driver.ReplacePixelsArgs) {
-	// This implementation is not used yet so far. See the comment at canUsePBO.
-
-	c.bindTexture(t)
-	c.ctx.BindBuffer(gles.PIXEL_UNPACK_BUFFER, uint32(buffer))
-
-	stride := 4 * width
-	for _, a := range args {
-		offset := 4 * (a.Y*width + a.X)
-		for j := 0; j < a.Height; j++ {
-			c.ctx.BufferSubData(gles.PIXEL_UNPACK_BUFFER, offset+stride*j, a.Pixels[4*a.Width*j:4*a.Width*(j+1)])
-		}
-	}
-
-	c.ctx.TexSubImage2D(gles.TEXTURE_2D, 0, 0, 0, int32(width), int32(height), gles.RGBA, gles.UNSIGNED_BYTE, nil)
-	c.ctx.BindBuffer(gles.PIXEL_UNPACK_BUFFER, 0)
-}
-
-func (c *context) getBufferSubData(buffer buffer, width, height int) []byte {
-	// gl.GetBufferSubData doesn't exist on OpenGL ES 2 and 3.
-	// As PBO is not used in mobiles, leave this unimplemented so far.
-	panic("opengl: getBufferSubData is not implemented for mobiles")
-}
-
 func (c *context) enableStencilTest() {
 	c.ctx.Enable(gles.STENCIL_TEST)
 }

internal/graphicsdriver/opengl/graphics.go

@@ -149,11 +149,6 @@ func (g *Graphics) SetVertices(vertices []float32, indices []uint16) {
 func (g *Graphics) DrawTriangles(dstID driver.ImageID, srcIDs [graphics.ShaderImageNum]driver.ImageID, offsets [graphics.ShaderImageNum - 1][2]float32, shaderID driver.ShaderID, indexLen int, indexOffset int, mode driver.CompositeMode, colorM *affine.ColorM, filter driver.Filter, address driver.Address, dstRegion, srcRegion driver.Region, uniforms []interface{}, evenOdd bool) error {
 	destination := g.images[dstID]
 
-	if !destination.pbo.equal(*new(buffer)) {
-		g.context.deleteBuffer(destination.pbo)
-		destination.pbo = *new(buffer)
-	}
-
 	g.drawCalled = true
 
 	if err := destination.setViewport(); err != nil {

internal/graphicsdriver/opengl/image.go

@@ -25,7 +25,6 @@ type Image struct {
 	texture     textureNative
 	stencil     renderbufferNative
 	framebuffer *framebuffer
-	pbo         buffer
 	width       int
 	height      int
 	screen      bool
@@ -40,9 +39,6 @@ func (i *Image) IsInvalidated() bool {
 }
 
 func (i *Image) Dispose() {
-	if !i.pbo.equal(*new(buffer)) {
-		i.graphics.context.deleteBuffer(i.pbo)
-	}
 	if i.framebuffer != nil {
 		i.framebuffer.delete(&i.graphics.context)
 	}
@@ -69,18 +65,10 @@ func (i *Image) Pixels() ([]byte, error) {
 		return nil, err
 	}
 
-	// PBO is created only when PBO is enabled AND ReplacePixels is called.
-	// If PBO is enabled but the buffer doesn't exist, this means either ReplacePixels is not called or
-	// different draw calls than ReplacePixels were called.
-	if !i.graphics.context.canUsePBO() || i.pbo.equal(*new(buffer)) {
 	p := i.graphics.context.framebufferPixels(i.framebuffer, i.width, i.height)
 	return p, nil
 }
 
-	p := i.graphics.context.getBufferSubData(i.pbo, i.width, i.height)
-	return p, nil
-}
-
 func (i *Image) framebufferSize() (int, int) {
 	if i.screen {
 		// The (default) framebuffer size can't be converted to a power of 2.
@@ -144,25 +132,5 @@ func (i *Image) ReplacePixels(args []*driver.ReplacePixelsArgs) {
 		i.graphics.context.flush()
 	}
 	i.graphics.drawCalled = false
-
-	// TODO: Now canUsePBO always returns false (#1678). Remove the code for PBO.
-	if !i.graphics.context.canUsePBO() {
 	i.graphics.context.texSubImage2D(i.texture, args)
-		return
-	}
-
-	w, h := i.width, i.height
-	if i.pbo.equal(*new(buffer)) {
-		i.pbo = i.graphics.context.newPixelBufferObject(w, h)
-		if i.pbo.equal(*new(buffer)) {
-			panic("opengl: newPixelBufferObject failed")
-		}
-		if i.framebuffer != nil {
-			i.graphics.context.framebufferPixelsToBuffer(i.framebuffer, i.pbo, i.width, i.height)
-		}
-	}
-	if i.pbo.equal(*new(buffer)) {
-		panic("opengl: newPixelBufferObject failed")
-	}
-	i.graphics.context.replacePixelsWithPBO(i.pbo, i.texture, w, h, args)
 }