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perf(camera): use getViewMatrix output parameter to avoid copy #3549

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Merged
finetjul merged 3 commits into from
Jul 13, 2026
+21 −30
Merged

perf(camera): use getViewMatrix output parameter to avoid copy #3549

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63fa428
perf(camera): use getViewMatrix output parameter to avoid copy
finetjul Jul 13, 2026
a70c01d
perf(camera): build view matrix directly into out buffer
PaulHax Jul 13, 2026
d8aba91
Merge pull request #3 from PaulHax/getviewmatrix-out-buffer
finetjul Jul 13, 2026
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3 changes: 1 addition & 2 deletions Sources/Interaction/Manipulators/MouseCameraTrackballPanManipulatorAutoCenter/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -71,8 +71,7 @@ function computeNewCenterOfRotation(
function getCameraMatrix(renderer, tempMatrix) {
const cam = renderer.getActiveCamera();
if (cam) {
mat4.copy(tempMatrix, cam.getViewMatrix());
return tempMatrix;
return cam.getViewMatrix(tempMatrix);
}
return null;
}
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38 changes: 17 additions & 21 deletions Sources/Rendering/Core/Camera/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -49,10 +49,10 @@ function vtkCamera(publicAPI, model) {
}

publicAPI.orthogonalizeViewUp = () => {
const vt = publicAPI.getViewMatrix();
model.viewUp[0] = vt[4];
model.viewUp[1] = vt[5];
model.viewUp[2] = vt[6];
publicAPI.getViewMatrix(tmpMatrix);
model.viewUp[0] = tmpMatrix[4];
model.viewUp[1] = tmpMatrix[5];
model.viewUp[2] = tmpMatrix[6];

publicAPI.modified();
};
Expand Down Expand Up @@ -231,8 +231,8 @@ function vtkCamera(publicAPI, model) {
const fp = model.focalPoint;

// get the eye / camera position from the viewMatrix
const vt = publicAPI.getViewMatrix();
const axis = [-vt[0], -vt[1], -vt[2]];
publicAPI.getViewMatrix(tmpMatrix);
const axis = [-tmpMatrix[0], -tmpMatrix[1], -tmpMatrix[2]];

mat4.identity(trans);

Expand All @@ -251,8 +251,8 @@ function vtkCamera(publicAPI, model) {
publicAPI.pitch = (angle) => {
const position = model.position;

const vt = publicAPI.getViewMatrix();
const axis = [vt[0], vt[1], vt[2]];
publicAPI.getViewMatrix(tmpMatrix);
const axis = [tmpMatrix[0], tmpMatrix[1], tmpMatrix[2]];

mat4.identity(trans);

Expand Down Expand Up @@ -388,7 +388,7 @@ function vtkCamera(publicAPI, model) {

publicAPI.computeCameraLightTransform = () => {
// not sure if this is the correct transformation, based on the same funciton in VTK
mat4.copy(tmpMatrix, publicAPI.getViewMatrix());
publicAPI.getViewMatrix(tmpMatrix);
mat4.invert(tmpMatrix, tmpMatrix);

mat4.fromScaling(tmpMatrix2, [
Expand Down Expand Up @@ -506,33 +506,29 @@ function vtkCamera(publicAPI, model) {
}
};

publicAPI.getViewMatrix = (out = undefined) => {
const result = out ?? new Float64Array(16);

publicAPI.getViewMatrix = (out = new Float64Array(16)) => {
if (model.viewMatrix) {
if (model.modelTransformMatrix) {
mat4.multiply(result, model.modelTransformMatrix, model.viewMatrix);
mat4.multiply(out, model.modelTransformMatrix, model.viewMatrix);
} else {
mat4.copy(result, model.viewMatrix);
mat4.copy(out, model.viewMatrix);
}
return result;
return out;
}

mat4.lookAt(
tmpMatrix,
out,
model.position, // eye
model.focalPoint, // at
model.viewUp // up
);

mat4.transpose(tmpMatrix, tmpMatrix);
mat4.transpose(out, out);

if (model.modelTransformMatrix) {
mat4.multiply(result, model.modelTransformMatrix, tmpMatrix);
} else {
mat4.copy(result, tmpMatrix);
mat4.multiply(out, model.modelTransformMatrix, out);
}
return result;
return out;
};

publicAPI.setProjectionMatrix = (mat) => {
Expand Down
2 changes: 1 addition & 1 deletion Sources/Rendering/OpenGL/Camera/index.js
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Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@ function vtkOpenGLCamera(publicAPI, model) {
ren.getMTime() > model.keyMatrixTime.getMTime() ||
model.renderable.getMTime() > model.keyMatrixTime.getMTime()
) {
mat4.copy(model.keyMatrices.wcvc, model.renderable.getViewMatrix());
model.renderable.getViewMatrix(model.keyMatrices.wcvc);

mat3.fromMat4(model.keyMatrices.normalMatrix, model.keyMatrices.wcvc);
mat3.invert(
Expand Down
8 changes: 2 additions & 6 deletions Sources/Widgets/Widgets3D/LineWidget/behavior.js
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Original file line number Diff line number Diff line change
Expand Up @@ -130,12 +130,8 @@ export default function widgetBehavior(publicAPI, model) {
};

publicAPI.rotateHandlesToFaceCamera = () => {
model.representations[0].setViewMatrix(
Array.from(model._camera.getViewMatrix())
);
model.representations[1].setViewMatrix(
Array.from(model._camera.getViewMatrix())
);
model.representations[0].setViewMatrix(model._camera.getViewMatrix());
model.representations[1].setViewMatrix(model._camera.getViewMatrix());
};

// Handles visibility ---------------------------------------------------------
Expand Down
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