--label:アニメーション効果
--information:DVD Bounce

--group:動作設定
--track@speed:速度,0.0,5000.0,400.0,1.0
--track@angle:移動角度,-360.0,360.0,45.0,0.1
--track@zoom_pct:サイズ(%),1.0,1000.0,100.0,1.0
--track@seed:乱数シード,0,10000,0,1
--group:

--group:領域設定
--track@box_w:領域幅(0=自動),0,8000,0,1
--track@box_h:領域高さ(0=自動),0,8000,0,1
--trackgroup@box_w,box_h:領域サイズ
--group:

--group:色設定
--check@use_original:元の色を使用,0
--track@saturation:彩度,0.0,100.0,80.0,0.1
--track@brightness:明度,0.0,100.0,100.0,0.1
--track@color_mix:着色強度(%),0.0,100.0,100.0,0.1
--hide@saturation:use_original==1
--hide@brightness:use_original==1
--hide@color_mix:use_original==1
--group:

--[[pixelshader@ps_dvd_bounce:
cbuffer Params : register(b0) {
    float4 target_color; // rgb: target_rgb, w: mix_ratio
};

Texture2D tex : register(t0);
SamplerState samp : register(s0);

float4 ps_dvd_bounce(float4 pos : SV_Position, float2 uv : TEXCOORD0) : SV_Target {
    float4 c = tex.Sample(samp, uv);
    if (c.a <= 0.0) {
        return float4(0.0, 0.0, 0.0, 0.0);
    }

    // Straight RGB に変換してカラーブレンド
    float3 straight_rgb = c.rgb / c.a;
    float3 blended_rgb = lerp(straight_rgb, target_color.rgb, target_color.w);

    // Premultiplied Alpha 適用
    return float4(blended_rgb * c.a, c.a);
}
]]

do
    local cos = math.cos
    local sin = math.sin
    local rad = math.rad
    local floor = math.floor
    local max = math.max

    local function bounce_position(distance, range)
        if range <= 0.0 then
            return 0.0, 0
        end

        local period = range * 2.0
        local normalized = distance % period
        local position = (normalized > range) and (period - normalized) or normalized

        return position, floor(distance / range)
    end

    local w = obj.w
    local h = obj.h
    if w <= 0 or h <= 0 then
        return
    end

    -- 1. 解像度および境界ボックスの取得
    local screen_w = (obj.screen_w and obj.screen_w > 0) and obj.screen_w or 1920
    local screen_h = (obj.screen_h and obj.screen_h > 0) and obj.screen_h or 1080

    local bounds_w = (box_w <= 0) and screen_w or box_w
    local bounds_h = (box_h <= 0) and screen_h or box_h

    -- 2. 拡大率の適用と実寸の計算
    local cur_zoom = obj.zoom or 1.0
    local scale_factor = zoom_pct * 0.01
    obj.zoom = cur_zoom * scale_factor

    local obj_w = w * obj.zoom
    local obj_h = h * obj.zoom

    -- 3. 移動ベクトルの算出と三角波バウンス計算
    local rad_val = rad(angle)
    local vx = cos(rad_val) * speed
    local vy = sin(rad_val) * speed

    local range_x = max(0.0, bounds_w - obj_w)
    local range_y = max(0.0, bounds_h - obj_h)

    local initial_phase_x = (seed * 123.45) % 10000.0
    local initial_phase_y = (seed * 678.91) % 10000.0

    local dist_x = obj.time * vx + initial_phase_x
    local dist_y = obj.time * vy + initial_phase_y

    local pos_x, bounce_count_x = bounce_position(dist_x, range_x)
    local pos_y, bounce_count_y = bounce_position(dist_y, range_y)
    local total_bounces = bounce_count_x + bounce_count_y

    -- 中心原点の相対座標へ加算
    obj.ox = (obj.ox or 0.0) + (pos_x - range_x * 0.5)
    obj.oy = (obj.oy or 0.0) + (pos_y - range_y * 0.5)

    -- 4. 着色シェーダー処理 (バウンス回数に応じた色相変化)
    if use_original == 0 and color_mix > 0.0 then
        local hue = obj.rand1(seed * 1000 + total_bounces * 17, 0) * 360.0
        local col_hex = HSV(hue, saturation, brightness)
        local r, g, b = RGB(col_hex)

        obj.pixelshader(
            "ps_dvd_bounce",
            "object",
            { "object" },
            {
                r / 255.0,
                g / 255.0,
                b / 255.0,
                color_mix * 0.01
            },
            "copy",
            "clamp"
        )
    end
end