layout (location = 0) in vec2 a_pos;
layout (location = 1) in vec2 a_decimals_ed;
layout (location = 2) in vec2 a_normal2d;

out vec2 v_pos_a;
out vec2 v_pos_b;
out vec4 v_lighting;

layout (std140) uniform GlobalPaintParamsUBO {
    highp vec2 u_pattern_atlas_texsize;
    highp vec2 u_units_to_pixels;
    highp vec2 u_world_size;
    highp float u_camera_to_center_distance;
    highp float u_symbol_fade_change;
    highp float u_aspect_ratio;
    highp float u_pixel_ratio;
    highp float u_map_zoom;
    lowp float global_pad1;
};

layout (std140) uniform FillExtrusionDrawableUBO {
    highp mat4 u_matrix;
    highp vec2 u_pixel_coord_upper;
    highp vec2 u_pixel_coord_lower;
    highp float u_height_factor;
    highp float u_tile_ratio;
    // Interpolations
    highp float u_base_t;
    highp float u_height_t;
    highp float u_color_t;
    highp float u_pattern_from_t;
    highp float u_pattern_to_t;
    lowp float drawable_pad1;
};

layout (std140) uniform FillExtrusionTilePropsUBO {
    highp vec4 u_pattern_from;
    highp vec4 u_pattern_to;
    highp vec2 u_texsize;
    lowp float tileprops_pad1;
    lowp float tileprops_pad2;
};

layout (std140) uniform FillExtrusionPropsUBO {
    highp vec4 u_color;
    highp vec3 u_lightcolor;
    lowp float props_pad1;
    highp vec3 u_lightpos;
    highp float u_base;
    highp float u_height;
    highp float u_lightintensity;
    highp float u_vertical_gradient;
    highp float u_opacity;
    highp float u_fade;
    highp float u_from_scale;
    highp float u_to_scale;
    lowp float props_pad2;
};

#pragma mapbox: define lowp float base
#pragma mapbox: define lowp float height
#pragma mapbox: define mediump vec4 pattern_from
#pragma mapbox: define mediump vec4 pattern_to

void main() {
    #pragma mapbox: initialize lowp float base
    #pragma mapbox: initialize lowp float height
    #pragma mapbox: initialize mediump vec4 pattern_from
    #pragma mapbox: initialize mediump vec4 pattern_to

    vec2 pattern_tl_a = pattern_from.xy;
    vec2 pattern_br_a = pattern_from.zw;
    vec2 pattern_tl_b = pattern_to.xy;
    vec2 pattern_br_b = pattern_to.zw;

    float pixelRatio = u_pixel_ratio;
    float tileRatio = u_tile_ratio;
    float fromScale = u_from_scale;
    float toScale = u_to_scale;

    vec3 normal = vec3(a_normal2d / 16384.0, a_normal2d.x == 0.0 && a_normal2d.y == 0.0 ? 1.0 : 0.0);
    float edgedistance = a_decimals_ed.y;

    vec2 display_size_a = vec2((pattern_br_a.x - pattern_tl_a.x) / pixelRatio, (pattern_br_a.y - pattern_tl_a.y) / pixelRatio);
    vec2 display_size_b = vec2((pattern_br_b.x - pattern_tl_b.x) / pixelRatio, (pattern_br_b.y - pattern_tl_b.y) / pixelRatio);

    base = max(0.0, base);
    height = max(0.0, height);

    float t = mod(a_decimals_ed.x, 2.0);
    float z = t > 0.0 ? height : base;
    vec2 decimals = unpack_float(floor(a_decimals_ed.x / 2.0)) / 128.0;

    gl_Position = u_matrix * vec4(a_pos + decimals, z, 1);

    // extrusion top or side
    vec2 pos = normal.z == 1.0 ? a_pos : vec2(edgedistance, z * u_height_factor);

    v_pos_a = get_pattern_pos(u_pixel_coord_upper, u_pixel_coord_lower, fromScale * display_size_a, tileRatio, pos);
    v_pos_b = get_pattern_pos(u_pixel_coord_upper, u_pixel_coord_lower, toScale * display_size_b, tileRatio, pos);

    v_lighting = vec4(0.0, 0.0, 0.0, 1.0);
    float directional = clamp(dot(normal, u_lightpos), 0.0, 1.0);
    directional = mix((1.0 - u_lightintensity), max((0.5 + u_lightintensity), 1.0), directional);

    if (normal.z == 0.0) {
        // This avoids another branching statement, but multiplies by a constant of 0.84 if no vertical gradient,
        // and otherwise calculates the gradient based on base + height
        float fMin = mix(0.7, 0.98, 1.0 - u_lightintensity);
        float factor = clamp((t + base) * pow(height / 150.0, 0.5), fMin, 1.0);
        directional *= (1.0 - u_vertical_gradient) + (u_vertical_gradient * factor);
    }

    v_lighting.rgb += clamp(directional * u_lightcolor, mix(vec3(0.0), vec3(0.3), 1.0 - u_lightcolor), vec3(1.0));
    v_lighting *= u_opacity;
}