Method scaleTextureNaturally

radiantcore/patch/Patch.cpp:806–893

}

void Patch::scaleTextureNaturally()
{
    // Save the undo memento
    undoSave();

    // Retrieve the default scale from the registry
    auto defaultScale = registry::getValue<float>("user/ui/textures/defaultTextureScale");

    // Cycles through all the patch columns and assigns s/t coordinates.
    // During each column or row cycle, the highest world distance between columns or rows
    // determines the distance in UV space (longest distance is taken).
    // World distances are scaled to UV space with the actual texture width/height,
    // scaled by the value in the registry.

    auto horizScale = 1.0f / (static_cast<float>(_shader.getWidth()) * defaultScale);

    double texcoordX = 0;

    // Cycle through the patch width,
    for (std::size_t w = 0; w < _width; w++)
    {
        // Apply the currently active <tex> value to the control point texture coordinates.
        for (std::size_t h = 0; h < _height; h++)
        {
            // Set the x-coord (or better s-coord?) of the texture to tex.
            // For the first width cycle this is tex=0, so the texture is not shifted at the first vertex
            ctrlAt(h, w).texcoord[0] = texcoordX;
        }

        // If we reached the last row (_width - 1) we are finished (all coordinates are applied)
        if (w + 1 == _width) break;

        // Determine the texcoord of the next column
        double highestNextTexCoord = 0;

        // Determine the longest distance to the next column.
        // Again, cycle through the current column
        for (std::size_t h = 0; h < _height; h++)
        {
            // v is the vector pointing from one control point to the next neighbour
            auto worldDistance = ctrlAt(h, w).vertex - ctrlAt(h, w + 1).vertex;

            // Scale the distance in world coordinates into texture coords
            double nextTexcoordX = texcoordX + worldDistance.getLength() * horizScale;

            // Use the farthest extrapolated texture cooord
            highestNextTexCoord = std::max(highestNextTexCoord, nextTexcoordX);
        }

        // Remember the highest found texcoord, assign it to the next column
        texcoordX = highestNextTexCoord;
    }

    // Now the same goes for the texture height, cycle through all the rows
    // and calculate the longest distances, convert them to texture coordinates
    // and apply them to the according texture coordinates.
    auto vertScale = 1.0f / (static_cast<float>(_shader.getHeight()) * defaultScale);