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Merged
nmwsharp merged 2 commits into from
Jul 19, 2025
Merged

Allow setting camera view center #350

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6f55925
introduce viewCenter, improve logic around view changes
nmwsharp Jul 19, 2025
5520195
set view center with click, ctrl/cmd fixes
nmwsharp Jul 19, 2025
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1 change: 1 addition & 0 deletions include/polyscope/context.h
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,7 @@ struct Context {
glm::mat4x4 viewMat;
double fov = view::defaultFov;
ProjectionMode projectionMode = ProjectionMode::Perspective;
glm::vec3 viewCenter;
bool midflight = false;
float flightStartTime = -1;
float flightEndTime = -1;
Expand Down
11 changes: 10 additions & 1 deletion include/polyscope/view.h
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Expand Up @@ -56,6 +56,7 @@ extern std::array<float, 4>& bgColor;
extern glm::mat4x4& viewMat;
extern double& fov; // in the y direction
extern ProjectionMode& projectionMode;
extern glm::vec3& viewCenter; // center about which view transformations are performed

// "Flying" view members
extern bool& midflight;
Expand Down Expand Up @@ -99,6 +100,13 @@ void lookAt(glm::vec3 cameraLocation, glm::vec3 target, glm::vec3 upDir, bool fl
glm::mat4 computeHomeView();
void resetCameraToHomeView();
void flyToHomeView();
void setViewCenter(glm::vec3 newCenter, bool flyTo = false);

// These both set the new value, and project the current view as-needed to conform to the new setting
void updateViewAndChangeNavigationStyle(NavigateStyle newStyle, bool flyTo = false);
void updateViewAndChangeUpDir(UpDir newUpDir, bool flyTo = false);
void updateViewAndChangeFrontDir(FrontDir newFrontDir, bool flyTo = false);
void updateViewAndChangeCenter(glm::vec3 newCenter, bool flyTo = false);

// Move the camera with a 'flight' where the camera's position is briefly animated
void startFlightTo(const CameraParameters& p, float flightLengthInSeconds = .4);
Expand Down Expand Up @@ -175,8 +183,9 @@ void ensureViewValid();
void processTranslate(glm::vec2 delta);
void processRotate(glm::vec2 startP, glm::vec2 endP);
void processClipPlaneShift(double amount);
void processZoom(double amount);
void processZoom(double amount, bool relativeToCenter = false);
void processKeyboardNavigation(ImGuiIO& io);
void processSetCenter(glm::vec2 screenCoords);

// deprecated, bad names, see variants above
glm::vec3 bufferCoordsToWorldRay(glm::vec2 bufferCoords);
Expand Down
161 changes: 93 additions & 68 deletions src/polyscope.cpp
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Expand Up @@ -338,6 +338,9 @@ float dragDistSinceLastRelease = 0.0;
void processInputEvents() {
ImGuiIO& io = ImGui::GetIO();

// RECALL: in ImGUI language, on MacOS "ctrl" == "cmd", so all the options
// below referring to ctrl really mean cmd on MacOS.

// If any mouse button is pressed, trigger a redraw
if (ImGui::IsAnyMouseDown()) {
requestRedraw();
Expand All @@ -358,90 +361,108 @@ void processInputEvents() {
}
}

// === Mouse inputs
if (!io.WantCaptureMouse && !widgetCapturedMouse) {
double xoffset = io.MouseWheelH;
double yoffset = io.MouseWheel;

if (xoffset != 0 || yoffset != 0) {
requestRedraw();
{ // Process scroll via "mouse wheel" (which might be a touchpad)
double xoffset = io.MouseWheelH;
double yoffset = io.MouseWheel;

// On some setups, shift flips the scroll direction, so take the max
// scrolling in any direction
double maxScroll = xoffset;
if (std::abs(yoffset) > std::abs(xoffset)) {
maxScroll = yoffset;
}
if (xoffset != 0 || yoffset != 0) {
requestRedraw();

// Pass camera commands to the camera
if (maxScroll != 0.0) {
bool scrollClipPlane = io.KeyShift;
// On some setups, shift flips the scroll direction, so take the max
// scrolling in any direction
double maxScroll = xoffset;
if (std::abs(yoffset) > std::abs(xoffset)) {
maxScroll = yoffset;
}

// Pass camera commands to the camera
if (maxScroll != 0.0) {
bool scrollClipPlane = io.KeyShift && !io.KeyCtrl;
bool relativeZoom = io.KeyShift && io.KeyCtrl;

if (scrollClipPlane) {
view::processClipPlaneShift(maxScroll);
} else {
view::processZoom(maxScroll);
if (scrollClipPlane) {
view::processClipPlaneShift(maxScroll);
} else {
view::processZoom(maxScroll, relativeZoom);
}
}
}
}
}

// === Mouse inputs
if (!io.WantCaptureMouse && !widgetCapturedMouse) {

// Process drags
bool dragLeft = ImGui::IsMouseDragging(0);
bool dragRight = !dragLeft && ImGui::IsMouseDragging(1); // left takes priority, so only one can be true
if (dragLeft || dragRight) {
{ // Process drags
bool dragLeft = ImGui::IsMouseDragging(0);
bool dragRight = !dragLeft && ImGui::IsMouseDragging(1); // left takes priority, so only one can be true
if (dragLeft || dragRight) {

glm::vec2 dragDelta{io.MouseDelta.x / view::windowWidth, -io.MouseDelta.y / view::windowHeight};
dragDistSinceLastRelease += std::abs(dragDelta.x);
dragDistSinceLastRelease += std::abs(dragDelta.y);
glm::vec2 dragDelta{io.MouseDelta.x / view::windowWidth, -io.MouseDelta.y / view::windowHeight};
dragDistSinceLastRelease += std::abs(dragDelta.x);
dragDistSinceLastRelease += std::abs(dragDelta.y);

// exactly one of these will be true
bool isRotate = dragLeft && !io.KeyShift && !io.KeyCtrl;
bool isTranslate = (dragLeft && io.KeyShift && !io.KeyCtrl) || dragRight;
bool isDragZoom = dragLeft && io.KeyShift && io.KeyCtrl;
// exactly one of these will be true
bool isRotate = dragLeft && !io.KeyShift && !io.KeyCtrl;
bool isTranslate = (dragLeft && io.KeyShift && !io.KeyCtrl) || dragRight;
bool isDragZoom = dragLeft && io.KeyShift && io.KeyCtrl;

if (isDragZoom) {
view::processZoom(dragDelta.y * 5);
}
if (isRotate) {
glm::vec2 currPos{io.MousePos.x / view::windowWidth,
(view::windowHeight - io.MousePos.y) / view::windowHeight};
currPos = (currPos * 2.0f) - glm::vec2{1.0, 1.0};
if (std::abs(currPos.x) <= 1.0 && std::abs(currPos.y) <= 1.0) {
view::processRotate(currPos - 2.0f * dragDelta, currPos);
if (isDragZoom) {
view::processZoom(dragDelta.y * 5, true);
}
if (isRotate) {
glm::vec2 currPos{io.MousePos.x / view::windowWidth,
(view::windowHeight - io.MousePos.y) / view::windowHeight};
currPos = (currPos * 2.0f) - glm::vec2{1.0, 1.0};
if (std::abs(currPos.x) <= 1.0 && std::abs(currPos.y) <= 1.0) {
view::processRotate(currPos - 2.0f * dragDelta, currPos);
}
}
if (isTranslate) {
view::processTranslate(dragDelta);
}
}
if (isTranslate) {
view::processTranslate(dragDelta);
}
}

// Click picks
float dragIgnoreThreshold = 0.01;
if (ImGui::IsMouseReleased(0)) {
{ // Click picks
float dragIgnoreThreshold = 0.01;
bool anyModifierHeld = io.KeyShift || io.KeyCtrl || io.KeyAlt;
bool ctrlShiftHeld = io.KeyShift && io.KeyCtrl;

if (!anyModifierHeld && io.MouseReleased[0]) {

// Don't pick at the end of a long drag
if (dragDistSinceLastRelease < dragIgnoreThreshold) {
ImVec2 p = ImGui::GetMousePos();
PickResult pickResult = pickAtScreenCoords(glm::vec2{p.x, p.y});
setSelection(pickResult);
// Don't pick at the end of a long drag
if (dragDistSinceLastRelease < dragIgnoreThreshold) {
glm::vec2 screenCoords{io.MousePos.x, io.MousePos.y};
PickResult pickResult = pickAtScreenCoords(screenCoords);
setSelection(pickResult);
}
}

// Reset the drag distance after any release
dragDistSinceLastRelease = 0.0;
}
// Clear pick
if (ImGui::IsMouseReleased(1)) {
if (dragDistSinceLastRelease < dragIgnoreThreshold) {
resetSelection();
// Clear pick
if (!anyModifierHeld && io.MouseReleased[1]) {
if (dragDistSinceLastRelease < dragIgnoreThreshold) {
resetSelection();
}
dragDistSinceLastRelease = 0.0;
}

// Ctrl-shift left-click to set new center
if (ctrlShiftHeld && io.MouseReleased[0]) {
if (dragDistSinceLastRelease < dragIgnoreThreshold) {
glm::vec2 screenCoords{io.MousePos.x, io.MousePos.y};
view::processSetCenter(screenCoords);
}
}
dragDistSinceLastRelease = 0.0;
}
}
}

// Reset the drag distance after any release
if (io.MouseReleased[0]) {
dragDistSinceLastRelease = 0.0;
}

// === Key-press inputs
if (!io.WantCaptureKeyboard) {
view::processKeyboardNavigation(io);
Expand Down Expand Up @@ -634,15 +655,18 @@ void buildPolyscopeGui() {

// clang-format off
ImGui::Begin("Controls", NULL, ImGuiWindowFlags_NoTitleBar);
ImGui::TextUnformatted("View Navigation:");
ImGui::TextUnformatted(" Rotate: [left click drag]");
ImGui::TextUnformatted(" Translate: [shift] + [left click drag] OR [right click drag]");
ImGui::TextUnformatted(" Zoom: [scroll] OR [ctrl] + [shift] + [left click drag]");
ImGui::TextUnformatted(" Use [ctrl-c] and [ctrl-v] to save and restore camera poses");
ImGui::TextUnformatted("View Navigation:");
ImGui::TextUnformatted(" Rotate: [left click drag]");
ImGui::TextUnformatted(" Translate: [shift] + [left click drag] OR [right click drag]");
ImGui::TextUnformatted(" Zoom: [scroll] OR [ctrl/cmd] + [shift] + [left click drag]");
ImGui::TextUnformatted(" Use [ctrl/cmd-c] and [ctrl/cmd-v] to save and restore camera poses");
ImGui::TextUnformatted(" via the clipboard.");
ImGui::TextUnformatted("\nMenu Navigation:");
ImGui::TextUnformatted(" Hold [ctrl/cmd] + [shift] and [left click] in the scene to set the");
ImGui::TextUnformatted(" orbit center.");
ImGui::TextUnformatted(" Hold [ctrl/cmd] + [shift] and scroll to zoom towards the center.");
ImGui::TextUnformatted("\nMenu Navigation:");
ImGui::TextUnformatted(" Menu headers with a '>' can be clicked to collapse and expand.");
ImGui::TextUnformatted(" Use [ctrl] + [left click] to manually enter any numeric value");
ImGui::TextUnformatted(" Use [ctrl/cmd] + [left click] to manually enter any numeric value");
ImGui::TextUnformatted(" via the keyboard.");
ImGui::TextUnformatted(" Press [space] to dismiss popup dialogs.");
ImGui::TextUnformatted("\nSelection:");
Expand Down Expand Up @@ -1095,8 +1119,9 @@ bool hasStructure(std::string type, std::string name) {
// Special automatic case, return any
if (name == "") {
if (sMap.size() != 1) {
exception("Cannot use automatic has-structure test with empty name unless there is exactly one structure of that type "
"registered");
exception(
"Cannot use automatic has-structure test with empty name unless there is exactly one structure of that type "
"registered");
}
return true;
}
Expand Down
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