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Fix WebGL premultiplied alpha. Fix texImage2D calls with RGB images.
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@MortimerGoro
MortimerGoro committed Apr 28, 2017
1 parent 418c3e8 commit e6d17f8
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Showing 2 changed files with 83 additions and 99 deletions.
111 changes: 83 additions & 28 deletions components/script/dom/webglrenderingcontext.rs
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Expand Up @@ -51,7 +51,7 @@ use webrender_traits;
use webrender_traits::{WebGLCommand, WebGLError, WebGLFramebufferBindingRequest, WebGLParameter};
use webrender_traits::WebGLError::*;

type ImagePixelResult = Result<(Vec<u8>, Size2D<i32>), ()>;
type ImagePixelResult = Result<(Vec<u8>, Size2D<i32>, bool), ()>;
pub const MAX_UNIFORM_AND_ATTRIBUTE_LEN: usize = 256;

macro_rules! handle_potential_webgl_error {
Expand Down Expand Up @@ -389,8 +389,17 @@ impl WebGLRenderingContext {

match (format, data_type) {
(TexFormat::RGBA, TexDataType::UnsignedByte) => pixels,
(TexFormat::RGB, TexDataType::UnsignedByte) => pixels,

(TexFormat::RGB, TexDataType::UnsignedByte) => {
// Remove alpha channel
let pixel_count = pixels.len() / 4;
let mut rgb8 = Vec::<u8>::with_capacity(pixel_count * 3);
for rgba8 in pixels.chunks(4) {
rgb8.push(rgba8[0]);
rgb8.push(rgba8[1]);
rgb8.push(rgba8[2]);
}
rgb8
},
(TexFormat::RGBA, TexDataType::UnsignedShort4444) => {
let mut rgba4 = Vec::<u8>::with_capacity(pixel_count * 2);
for rgba8 in pixels.chunks(4) {
Expand Down Expand Up @@ -443,9 +452,9 @@ impl WebGLRenderingContext {
//
// Nontheless, since it's the error case, I'm not totally sure the
// complexity is worth it.
let (pixels, size) = match source {
let (pixels, size, premultiplied) = match source {
ImageDataOrHTMLImageElementOrHTMLCanvasElementOrHTMLVideoElement::ImageData(image_data) => {
(image_data.get_data_array(), image_data.get_size())
(image_data.get_data_array(), image_data.get_size(), false)
},
ImageDataOrHTMLImageElementOrHTMLCanvasElementOrHTMLVideoElement::HTMLImageElement(image) => {
let img_url = match image.get_url() {
Expand All @@ -472,15 +481,16 @@ impl WebGLRenderingContext {

byte_swap(&mut data);

(data, size)
(data, size, false)
},
// TODO(emilio): Getting canvas data is implemented in CanvasRenderingContext2D,
// but we need to refactor it moving it to `HTMLCanvasElement` and support
// WebGLContext (probably via GetPixels()).
ImageDataOrHTMLImageElementOrHTMLCanvasElementOrHTMLVideoElement::HTMLCanvasElement(canvas) => {
if let Some((mut data, size)) = canvas.fetch_all_data() {
byte_swap(&mut data);
(data, size)
// Pixels got from Canvas have already alpha premultiplied
(data, size, true)
} else {
return Err(());
}
Expand All @@ -489,7 +499,7 @@ impl WebGLRenderingContext {
=> unimplemented!(),
};

return Ok((pixels, size));
return Ok((pixels, size, premultiplied));
}

// TODO(emilio): Move this logic to a validator.
Expand Down Expand Up @@ -644,6 +654,51 @@ impl WebGLRenderingContext {
}
}

// Remove premultiplied alpha.
// This is only called when texImage2D is called using a canvas2d source and
// UNPACK_PREMULTIPLY_ALPHA_WEBGL is disabled. Pixels got from a canvas2D source
// are always RGBA8 with premultiplied alpha, so we don't have to worry about
// additional formats as happens in the premultiply_pixels method.
fn remove_premultiplied_alpha(&self, mut pixels: Vec<u8>) -> Vec<u8> {
for rgba in pixels.chunks_mut(4) {
let a = (rgba[3] as f32) / 255.0;
rgba[0] = (rgba[0] as f32 / a) as u8;
rgba[1] = (rgba[1] as f32 / a) as u8;
rgba[2] = (rgba[2] as f32 / a) as u8;
}
pixels
}

fn prepare_pixels(&self,
internal_format: TexFormat,
data_type: TexDataType,
width: u32,
height: u32,
unpacking_alignment: u32,
source_premultiplied: bool,
source_from_image_or_canvas: bool,
mut pixels: Vec<u8>) -> Vec<u8> {
let dest_premultiply = self.texture_unpacking_settings.get().contains(PREMULTIPLY_ALPHA);
if !source_premultiplied && dest_premultiply {
if source_from_image_or_canvas {
// When the pixels come from image or canvas or imagedata, use RGBA8 format
pixels = self.premultiply_pixels(TexFormat::RGBA, TexDataType::UnsignedByte, pixels);
} else {
pixels = self.premultiply_pixels(internal_format, data_type, pixels);
}
} else if source_premultiplied && !dest_premultiply {
pixels = self.remove_premultiplied_alpha(pixels);
}

if source_from_image_or_canvas {
pixels = self.rgba8_image_to_tex_image_data(internal_format, data_type, pixels);
}

// FINISHME: Consider doing premultiply and flip in a single mutable Vec.
self.flip_teximage_y(pixels, internal_format, data_type,
width as usize, height as usize, unpacking_alignment as usize)
}

fn tex_image_2d(&self,
texture: Root<WebGLTexture>,
target: TexImageTarget,
Expand All @@ -655,11 +710,6 @@ impl WebGLRenderingContext {
_border: u32,
unpacking_alignment: u32,
pixels: Vec<u8>) { // NB: pixels should NOT be premultipied
// FINISHME: Consider doing premultiply and flip in a single mutable Vec.
let pixels = self.premultiply_pixels(internal_format, data_type, pixels);

let pixels = self.flip_teximage_y(pixels, internal_format, data_type,
width as usize, height as usize, unpacking_alignment as usize);

// TexImage2D depth is always equal to 1
handle_potential_webgl_error!(self, texture.initialize(target,
Expand Down Expand Up @@ -705,7 +755,7 @@ impl WebGLRenderingContext {
format: TexFormat,
data_type: TexDataType,
unpacking_alignment: u32,
pixels: Vec<u8>) { // NB: pixels should NOT be premultipied
pixels: Vec<u8>) {
// We have already validated level
let image_info = texture.image_info_for_target(&target, level);

Expand All @@ -724,12 +774,6 @@ impl WebGLRenderingContext {
return self.webgl_error(InvalidOperation);
}

// FINISHME: Consider doing premultiply and flip in a single mutable Vec.
let pixels = self.premultiply_pixels(format, data_type, pixels);

let pixels = self.flip_teximage_y(pixels, format, data_type,
width as usize, height as usize, unpacking_alignment as usize);

// Set the unpack alignment. For textures coming from arrays,
// this will be the current value of the context's
// GL_UNPACK_ALIGNMENT, while for textures from images or
Expand Down Expand Up @@ -2841,8 +2885,11 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
return Ok(self.webgl_error(InvalidOperation));
}

let pixels = self.prepare_pixels(format, data_type, width, height,
unpacking_alignment, false, false, buff);

self.tex_image_2d(texture, target, data_type, format,
level, width, height, border, unpacking_alignment, buff);
level, width, height, border, unpacking_alignment, pixels);

Ok(())
}
Expand All @@ -2856,8 +2903,8 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
data_type: u32,
source: Option<ImageDataOrHTMLImageElementOrHTMLCanvasElementOrHTMLVideoElement>) -> Fallible<()> {
// Get pixels from image source
let (pixels, size) = match self.get_image_pixels(source) {
Ok((pixels, size)) => (pixels, size),
let (pixels, size, premultiplied) = match self.get_image_pixels(source) {
Ok((pixels, size, premultiplied)) => (pixels, size, premultiplied),
Err(_) => return Ok(()),
};

Expand All @@ -2880,7 +2927,9 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
Err(_) => return Ok(()), // NB: The validator sets the correct error for us.
};

let pixels = self.rgba8_image_to_tex_image_data(format, data_type, pixels);
let unpacking_alignment = 1;
let pixels = self.prepare_pixels(format, data_type, width, height,
unpacking_alignment, premultiplied, true, pixels);

self.tex_image_2d(texture, target, data_type, format,
level, width, height, border, 1, pixels);
Expand Down Expand Up @@ -2951,8 +3000,12 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
return Ok(self.webgl_error(InvalidOperation));
}

let unpacking_alignment = self.texture_unpacking_alignment.get();
let pixels = self.prepare_pixels(format, data_type, width, height,
unpacking_alignment, false, false, buff);

self.tex_sub_image_2d(texture, target, level, xoffset, yoffset,
width, height, format, data_type, unpacking_alignment, buff);
width, height, format, data_type, unpacking_alignment, pixels);
Ok(())
}

Expand All @@ -2966,8 +3019,8 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
data_type: u32,
source: Option<ImageDataOrHTMLImageElementOrHTMLCanvasElementOrHTMLVideoElement>)
-> Fallible<()> {
let (pixels, size) = match self.get_image_pixels(source) {
Ok((pixels, size)) => (pixels, size),
let (pixels, size, premultiplied) = match self.get_image_pixels(source) {
Ok((pixels, size, premultiplied)) => (pixels, size, premultiplied),
Err(_) => return Ok(()),
};

Expand All @@ -2988,7 +3041,9 @@ impl WebGLRenderingContextMethods for WebGLRenderingContext {
Err(_) => return Ok(()), // NB: The validator sets the correct error for us.
};

let pixels = self.rgba8_image_to_tex_image_data(format, data_type, pixels);
let unpacking_alignment = 1;
let pixels = self.prepare_pixels(format, data_type, width, height,
unpacking_alignment, premultiplied, true, pixels);

self.tex_sub_image_2d(texture, target, level, xoffset, yoffset,
width, height, format, data_type, 1, pixels);
Expand Down
71 changes: 0 additions & 71 deletions tests/wpt/metadata/webgl/conformance-1.0.3/conformance/textures/gl-teximage.html.ini
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