MapLibreParticleLab/src/mbgl/programs/symbol_program.cpp

#include <mbgl/programs/symbol_program.hpp>
#include <mbgl/renderer/render_tile.hpp>
#include <mbgl/map/transform_state.hpp>
#include <mbgl/style/layers/symbol_layer_impl.hpp>
#include <mbgl/layout/symbol_projection.hpp>
#include <mbgl/tile/tile.hpp>
#include <mbgl/util/enum.hpp>
#include <mbgl/math/clamp.hpp>

namespace mbgl {

using namespace style;

static_assert(sizeof(SymbolLayoutVertex) == 24, "expected SymbolLayoutVertex size");

std::unique_ptr<SymbolSizeBinder> SymbolSizeBinder::create(const float tileZoom,
                                                           const style::PropertyValue<float>& sizeProperty,
                                                           const float defaultValue) {
    return sizeProperty.match(
        [&](const Undefined& value) -> std::unique_ptr<SymbolSizeBinder> {
            return std::make_unique<ConstantSymbolSizeBinder>(tileZoom, value, defaultValue);
        },
        [&](float value) -> std::unique_ptr<SymbolSizeBinder> {
            return std::make_unique<ConstantSymbolSizeBinder>(tileZoom, value, defaultValue);
        },
        [&](const style::PropertyExpression<float>& expression) -> std::unique_ptr<SymbolSizeBinder> {
            if (expression.isFeatureConstant()) {
                return std::make_unique<ConstantSymbolSizeBinder>(tileZoom, expression, defaultValue);
            } else if (expression.isZoomConstant()) {
                return std::make_unique<SourceFunctionSymbolSizeBinder>(tileZoom, expression, defaultValue);
            } else {
                return std::make_unique<CompositeFunctionSymbolSizeBinder>(tileZoom, expression, defaultValue);
            }
        });
}

template <class Values, class... Args>
Values makeValues(const bool isText,
                  const bool hasVariablePacement,
                  const style::SymbolPropertyValues& values,
                  const Size& texsize,
                  const std::array<float, 2>& pixelsToGLUnits,
                  const bool alongLine,
                  const RenderTile& tile,
                  const TransformState& state,
                  const float symbolFadeChange,
                  Args&&... args) {
    std::array<float, 2> extrudeScale;

    if (values.pitchAlignment == AlignmentType::Map) {
        extrudeScale.fill(tile.id.pixelsToTileUnits(1.f, static_cast<float>(state.getZoom())));
    } else {
        extrudeScale = {{pixelsToGLUnits[0] * state.getCameraToCenterDistance(),
                         pixelsToGLUnits[1] * state.getCameraToCenterDistance()}};
    }

    const float pixelsToTileUnits = tile.id.pixelsToTileUnits(1.f, static_cast<float>(state.getZoom()));
    const bool pitchWithMap = values.pitchAlignment == style::AlignmentType::Map;
    const bool rotateWithMap = values.rotationAlignment == style::AlignmentType::Map;

    // Line label rotation happens in `updateLineLabels`/`reprojectLineLabels``
    // Pitched point labels are automatically rotated by the labelPlaneMatrix projection
    // Unpitched point labels need to have their rotation applied after projection
    const bool rotateInShader = rotateWithMap && !pitchWithMap && !alongLine;

    mat4 labelPlaneMatrix;
    if (alongLine || hasVariablePacement) {
        // For labels that follow lines the first part of the projection is
        // handled on the cpu. Pass an identity matrix because no transformation
        // needs to be done in the vertex shader.
        matrix::identity(labelPlaneMatrix);
    } else {
        labelPlaneMatrix = getLabelPlaneMatrix(tile.matrix, pitchWithMap, rotateWithMap, state, pixelsToTileUnits);
    }

    mat4 glCoordMatrix = getGlCoordMatrix(tile.matrix, pitchWithMap, rotateWithMap, state, pixelsToTileUnits);

    return Values{uniforms::matrix::Value(tile.translatedMatrix(values.translate, values.translateAnchor, state)),
                  uniforms::label_plane_matrix::Value(labelPlaneMatrix),
                  uniforms::coord_matrix::Value(
                      tile.translateVtxMatrix(glCoordMatrix, values.translate, values.translateAnchor, state, true)),
                  uniforms::extrude_scale::Value(extrudeScale),
                  uniforms::texsize::Value(texsize),
                  uniforms::fade_change::Value(symbolFadeChange),
                  uniforms::is_text::Value(isText),
                  uniforms::camera_to_center_distance::Value(state.getCameraToCenterDistance()),
                  uniforms::pitch::Value(state.getPitch()),
                  uniforms::pitch_with_map::Value(pitchWithMap),
                  uniforms::rotate_symbol::Value(rotateInShader),
                  uniforms::aspect_ratio::Value(state.getSize().aspectRatio()),
                  std::forward<Args>(args)...};
}

SymbolIconProgram::LayoutUniformValues SymbolIconProgram::layoutUniformValues(
    const bool isText,
    const bool hasVariablePacement,
    const style::SymbolPropertyValues& values,
    const Size& texsize,
    const std::array<float, 2>& pixelsToGLUnits,
    const bool alongLine,
    const RenderTile& tile,
    const TransformState& state,
    const float symbolFadeChange) {
    return makeValues<SymbolIconProgram::LayoutUniformValues>(
        isText, hasVariablePacement, values, texsize, pixelsToGLUnits, alongLine, tile, state, symbolFadeChange);
}

template <class Name, shaders::BuiltIn ShaderSource, class PaintProperties>
typename SymbolSDFProgram<Name, ShaderSource, PaintProperties>::LayoutUniformValues
SymbolSDFProgram<Name, ShaderSource, PaintProperties>::layoutUniformValues(const bool isText,
                                                                           const bool hasVariablePacement,
                                                                           const style::SymbolPropertyValues& values,
                                                                           const Size& texsize,
                                                                           const std::array<float, 2>& pixelsToGLUnits,
                                                                           const float pixelRatio,
                                                                           const bool alongLine,
                                                                           const RenderTile& tile,
                                                                           const TransformState& state,
                                                                           const float symbolFadeChange,
                                                                           const SymbolSDFPart part) {
    const float gammaScale = (values.pitchAlignment == AlignmentType::Map
                                  ? static_cast<float>(std::cos(state.getPitch())) * state.getCameraToCenterDistance()
                                  : 1.0f);

    return makeValues<SymbolSDFProgram<Name, ShaderSource, PaintProperties>::LayoutUniformValues>(
        isText,
        hasVariablePacement,
        values,
        texsize,
        pixelsToGLUnits,
        alongLine,
        tile,
        state,
        symbolFadeChange,
        uniforms::gamma_scale::Value(gammaScale),
        uniforms::device_pixel_ratio::Value(pixelRatio),
        uniforms::is_halo::Value(part == SymbolSDFPart::Halo));
}

SymbolTextAndIconProgram::LayoutUniformValues SymbolTextAndIconProgram::layoutUniformValues(
    const bool hasVariablePacement,
    const style::SymbolPropertyValues& values,
    const Size& texsize,
    const Size& texsize_icon,
    const std::array<float, 2>& pixelsToGLUnits,
    const float pixelRatio,
    const bool alongLine,
    const RenderTile& tile,
    const TransformState& state,
    const float symbolFadeChange,
    const SymbolSDFPart part) {
    return {SymbolSDFProgram<SymbolSDFTextProgram,
                             shaders::BuiltIn::SymbolSDFTextProgram,
                             style::TextPaintProperties>::layoutUniformValues(true,
                                                                              hasVariablePacement,
                                                                              values,
                                                                              texsize,
                                                                              pixelsToGLUnits,
                                                                              pixelRatio,
                                                                              alongLine,
                                                                              tile,
                                                                              state,
                                                                              symbolFadeChange,
                                                                              part)
                .concat(gfx::UniformValues<SymbolTextAndIconProgramUniforms>(uniforms::texsize::Value(texsize_icon)))};
}

template class SymbolSDFProgram<SymbolSDFIconProgram,
                                shaders::BuiltIn::SymbolSDFIconProgram,
                                style::IconPaintProperties>;
template class SymbolSDFProgram<SymbolSDFTextProgram,
                                shaders::BuiltIn::SymbolSDFTextProgram,
                                style::TextPaintProperties>;

} // namespace mbgl