#include <mbgl/renderer/painter.hpp>
#include <mbgl/platform/gl.hpp>
#include <mbgl/renderer/raster_bucket.hpp>
#include <mbgl/style/style_layer.hpp>
#include <mbgl/style/style_layer_group.hpp>
#include <mbgl/util/std.hpp>
#include <mbgl/map/map.hpp>
#include <mbgl/map/transform.hpp>

using namespace mbgl;

void Painter::renderRaster(RasterBucket& bucket, util::ptr<StyleLayer> layer_desc, const Tile::ID&, const mat4 &matrix) {
    if (pass != RenderPass::Translucent) return;

    const RasterProperties &properties = layer_desc->getProperties<RasterProperties>();

    if (bucket.hasData()) {
        depthMask(false);

        useProgram(rasterShader->program);
        rasterShader->u_matrix = matrix;
        rasterShader->u_buffer = 0;
        rasterShader->u_opacity = properties.opacity;
        rasterShader->u_brightness_low = properties.brightness[0];
        rasterShader->u_brightness_high = properties.brightness[1];
        rasterShader->u_saturation_factor = saturationFactor(properties.saturation);
        rasterShader->u_contrast_factor = contrastFactor(properties.contrast);
        rasterShader->u_spin_weights = spinWeights(properties.hue_rotate);

        depthRange(strata + strata_epsilon, 1.0f);

        bucket.drawRaster(*rasterShader, tileStencilBuffer, coveringRasterArray);

        depthMask(true);
    }
}

float Painter::saturationFactor(float saturation) {
    if (saturation > 0) {
        return 1 - 1 / (1.001 - saturation);
    } else {
        return -saturation;
    }
}

float Painter::contrastFactor(float contrast) {
    if (contrast > 0) {
        return 1 / (1 - contrast);
    } else {
        return 1 + contrast;
    }
}

std::array<float, 3> Painter::spinWeights(float spin) {
    spin *= M_PI / 180;
    float s = std::sin(spin);
    float c = std::cos(spin);
    std::array<float, 3> spin_weights = {{
        (2 * c + 1) / 3,
        (-std::sqrt(3.0f) * s - c + 1) / 3,
        (std::sqrt(3.0f) * s - c + 1) / 3
    }};
    return spin_weights;
}