#include <mbgl/renderer/render_tile.hpp>
#include <mbgl/renderer/painter.hpp>
#include <mbgl/map/transform_state.hpp>
#include <mbgl/tile/tile.hpp>
#include <mbgl/util/math.hpp>

namespace mbgl {

using namespace style;

mat4 RenderTile::translateVtxMatrix(const mat4& tileMatrix,
                                    const std::array<float, 2>& translation,
                                    TranslateAnchorType anchor,
                                    const TransformState& state,
                                    const bool inViewportPixelUnits) const {
    if (translation[0] == 0 && translation[1] == 0) {
        return tileMatrix;
    }

    mat4 vtxMatrix;

    const float angle = inViewportPixelUnits ?
        (anchor == TranslateAnchorType::Map ? state.getAngle() : 0) :
        (anchor == TranslateAnchorType::Viewport ? -state.getAngle() : 0);

    Point<float> translate = util::rotate(Point<float>{ translation[0], translation[1] }, angle);

    if (inViewportPixelUnits) {
        matrix::translate(vtxMatrix, tileMatrix, translate.x, translate.y, 0);
    } else {
        matrix::translate(vtxMatrix, tileMatrix,
                          id.pixelsToTileUnits(translate.x, state.getZoom()),
                          id.pixelsToTileUnits(translate.y, state.getZoom()),
                          0);
    }

    return vtxMatrix;
}

mat4 RenderTile::translatedMatrix(const std::array<float, 2>& translation,
                                  TranslateAnchorType anchor,
                                  const TransformState& state) const {
    return translateVtxMatrix(matrix, translation, anchor, state, false);
}

mat4 RenderTile::translatedClipMatrix(const std::array<float, 2>& translation,
                                      TranslateAnchorType anchor,
                                      const TransformState& state) const {
    return translateVtxMatrix(nearClippedMatrix, translation, anchor, state, false);
}

void RenderTile::startRender(Painter& painter) {
    tile.upload(painter.context);

    // Calculate two matrices for this tile: matrix is the standard tile matrix; nearClippedMatrix
    // clips the near plane to 100 to save depth buffer precision
    painter.state.matrixFor(matrix, id);
    painter.state.matrixFor(nearClippedMatrix, id);
    matrix::multiply(matrix, painter.projMatrix, matrix);
    matrix::multiply(nearClippedMatrix, painter.nearClippedProjMatrix, nearClippedMatrix);
}

} // namespace mbgl