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use pixels in setBackgroundImagePosition and add argument for clamp

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This commit is contained in:
Nick Fisher
2022-09-07 17:40:18 +10:00
parent a5cf61f410
commit fd90bae53f
6 changed files with 68 additions and 47 deletions
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97
ios/src/FilamentViewer.cpp
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@@ -389,13 +389,11 @@ void FilamentViewer::setBackgroundImage(const char *resourcePath) {
_imageTexture->setImage(*_engine, 0, std::move(buffer));
_imageTexture->generateMipmaps(*_engine);
// This currently just centers the image in the viewport at its original size
// This currently just acnhors the image at the bottom left of the viewport at its original size
// TODO - implement stretch/etc
const Viewport& vp = _view->getViewport();
Log("Image width %d height %d vp width %d height %d", _imageWidth, _imageHeight, vp.width, vp.height);
_imageScale = mat4f { float(vp.width) / float(_imageWidth) , 0.0f, 0.0f, 1.0f, 0.0f, float(vp.height) / float(_imageHeight), 0.0f, 1.0f, 0.0f, 0.0f, 1.0f,1.0f, 0.0f, 0.0f, 0.0f, 1.0f };
// _imageScale = mat4f { 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f,1.0f, 0.0f, 0.0f, 0.0f, 1.0f };
_imageScale = mat4f { float(vp.width) / float(_imageWidth) , 0.0f, 0.0f, 0.0f, 0.0f, float(vp.height) / float(_imageHeight), 0.0f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 0.0f, 0.0f, 1.0f };
_imageMaterial->setDefaultParameter("transform", _imageScale);
_imageMaterial->setDefaultParameter("image", _imageTexture, _imageSampler);
@@ -408,52 +406,75 @@ void FilamentViewer::setBackgroundImage(const char *resourcePath) {
///
/// Translates the background image by the specified x/y NDC units (i.e. between -1 and 1).
/// Clamps both values so that the left/top and right/bottom sides of the background image are
/// positioned at a max/min of -1/1 respectively (i.e. you cannot set a position where the left/top or right/bottom sides would be "inside" the screen coordinate space.
/// Translates the background image by (x,y) pixels.
/// If clamp is true, x/y are both clamped so that the left/top and right/bottom sides of the background image
/// are positioned at a max/min of -1/1 respectively
/// (i.e. you cannot set a position where the left/top or right/bottom sides would be "inside" the screen coordinate space).
///
void FilamentViewer::setBackgroundImagePosition(float x, float y) {
void FilamentViewer::setBackgroundImagePosition(float x, float y, bool clamp=false) {
// first, clamp x/y
auto xScale = float(_imageWidth) / _view->getViewport().width;
auto yScale = float(_imageHeight) / _view->getViewport().height;
// to translate the background image, we apply a transform to the UV coordinates of the quad texture, not the quad itself (see image.mat).
// this allows us to set a background colour for the quad when the texture has been translated outside the quad's bounds.
// so we need to munge the coordinates appropriately (and take into consideration the scale transform applied when the image was loaded).
float xMin = 0;
float xMax = 0;
float yMin = 0;
float yMax = 0;
// first, convert x/y to a percentage of the original image size
x /= _imageWidth;
y /= _imageHeight;
// we need to clamp x so that it can only be translated between (left side touching viewport left) and (right side touching viewport right)
// if width is less than viewport, these values are 0/1-xScale respectively
if(xScale < 1) {
xMin = 0;
xMax = 1-xScale;
// otherwise, these value are (xScale-1 and 1-xScale)
} else {
xMin = 1-xScale;
xMax = 0;
// now scale these by the viewport dimensions so they can be incorporated directly into the UV transform matrix.
// x *= _imageScale[0][0];
// y *= _imageScale[1][1];
// TODO - I haven't updated the clamp calculations to work with scaled image width/height percentages so the below code is probably wrong, don't use it until it's fixed.
if(clamp) {
Log("Clamping background image translation");
// first, clamp x/y
auto xScale = float(_imageWidth) / _view->getViewport().width;
auto yScale = float(_imageHeight) / _view->getViewport().height;
float xMin = 0;
float xMax = 0;
float yMin = 0;
float yMax = 0;
// we need to clamp x so that it can only be translated between (left side touching viewport left) and (right side touching viewport right)
// if width is less than viewport, these values are 0/1-xScale respectively
if(xScale < 1) {
xMin = 0;
xMax = 1-xScale;
// otherwise, these value are (xScale-1 and 1-xScale)
} else {
xMin = 1-xScale;
xMax = 0;
}
// do the same for y
if(yScale < 1) {
yMin = 0;
yMax = 1-yScale;
} else {
yMin = 1-yScale;
yMax = 0;
}
x = std::max(xMin, std::min(x,xMax));
y = std::max(yMin, std::min(y,yMax));
}
// do the same for y
if(yScale < 1) {
yMin = 0;
yMax = 1-yScale;
} else {
yMin = 1-yScale;
yMax = 0;
}
x = std::max(xMin, std::min(x,xMax));
y = std::max(yMin, std::min(y,yMax));
// these values are then negated to account for the fact that the transform is applied to the UV coordinates, not the vertices (see image.mat).
// i.e. translating the image right by 0.5 units means translating the UV coordinates left by 0.5 units.
x = -x;
y = -y;
Log("x %f y %f", x, y);
auto transform = _imageScale * math::mat4f::translation(math::float3(x, y, 0.0f));
Log("imageScale %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f ", _imageScale[0][0],_imageScale[0][1],_imageScale[0][2], _imageScale[0][3], \
_imageScale[1][0],_imageScale[1][1],_imageScale[1][2], _imageScale[1][3],\
_imageScale[2][0],_imageScale[2][1],_imageScale[2][2], _imageScale[2][3], \
_imageScale[3][0],_imageScale[3][1],_imageScale[3][2], _imageScale[3][3]);
auto transform = math::mat4f::translation(math::float3(x, y, 0.0f)) * _imageScale;
Log("transform %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f %f ", transform[0][0],transform[0][1],transform[0][2], transform[0][3], \
transform[1][0],transform[1][1],transform[1][2], transform[1][3],\
transform[2][0],transform[2][1],transform[2][2], transform[2][3], \