Color Quantities

Visualize color data at the nodes or cells of a sparse volume grid.

Example: adding color quantities to a sparse volume grid

#include "polyscope/polyscope.h"
#include "polyscope/sparse_volume_grid.h"

polyscope::init();

glm::vec3 origin{0., 0., 0.};
glm::vec3 cellWidth{0.1, 0.1, 0.1};

std::vector<glm::ivec3> occupiedCells = {
    {0, 0, 0}, {1, 0, 0}, {0, 1, 0}, {1, 1, 0},
};

polyscope::SparseVolumeGrid* psGrid = polyscope::registerSparseVolumeGrid(
        "sample sparse grid", origin, cellWidth, occupiedCells);

// === Cell color: one RGB color per occupied cell ===
std::vector<glm::vec3> cellColors = {
    {1.f, 0.f, 0.f}, {0.f, 1.f, 0.f}, {0.f, 0.f, 1.f}, {1.f, 1.f, 0.f},
};
psGrid->addCellColorQuantity("cell color", cellColors);

// === Node color: colors at node indices ===
std::vector<glm::ivec3> nodeIndices = { /* all unique corner nodes */ };
std::vector<glm::vec3> nodeColors = { /* one RGB color per node index */ };
psGrid->addNodeColorQuantity("node color", nodeIndices, nodeColors);

polyscope::show();

Add cell colors

SparseVolumeGridCellColorQuantity* SparseVolumeGrid::addCellColorQuantity(std::string name, const T& colors)

Add a color quantity defined at the cells of the grid.

• name the name of the quantity
• colors an array of RGB colors, one per occupied cell in the same order as the occupiedCells array used at registration. The type should be adaptable to an array of glm::vec3. Colors are RGB floats in [0, 1].

Add node colors

SparseVolumeGridNodeColorQuantity* SparseVolumeGrid::addNodeColorQuantity(std::string name, const TI& nodeIndices, const TC& nodeColors)

Add a color quantity defined at the nodes of the grid.

Node colors are passed as paired arrays of node indices and colors. For a cell with grid indices (i, j, k), its corner nodes have indices (i+dx, j+dy, k+dz) for dx, dy, dz in {0, 1}. The node indices may be passed in any order, and extra entries (for nodes not required by any occupied cell) are ignored. However, all required node values must be present.

• name the name of the quantity
• nodeIndices an array of glm::ivec3 node grid indices. The type should be adaptable to an array of glm::ivec3.
• nodeColors an array of RGB colors, one per entry in nodeIndices. The type should be adaptable to an array of glm::vec3. Colors are RGB floats in [0, 1].