// Copyright (c) 2017-2020 Xiamen Yaji Software Co., Ltd.
CCEffect %{
  temporaries:
    s1: &s1 {
      minFilter: linear,
      magFilter: linear,
      addressU: clamp,
      addressV: clamp,
    }
    s2: &s2 {
      minFilter: point,
      magFilter: point,
      addressU: clamp,
      addressV: clamp,
    }
  techniques:
  - name: smaa
    passes:
    - vert: smaa-edge-vs:vert
      frag: smaa-edge-fs:frag
      depthStencilState:
        depthTest: false
        depthWrite: false
      properties:
        u_texSampler: { sampler: *s1 }
    - vert: smaa-blend-vs:vert
      frag: smaa-blend-fs:frag
      depthStencilState:
        depthTest: false
        depthWrite: false
      properties:
        u_edgeTexSampler: { sampler: *s1 }
        u_areaTexSampler: { sampler: *s1 }
        u_searchTexSampler: { sampler: *s2 }
}%

CCProgram smaa-edge-vs %{
  precision highp float;
  #include <builtin/uniforms/cc-global>

  in vec2 a_position;
  in vec2 a_texCoord;
  out vec2 v_uv;
  out vec4 v_offsets[3];

  vec4 vert () {
    vec4 pos = vec4(a_position, 0.0, 1.0);
    v_uv = a_texCoord * cc_screenScale.xy;
    v_offsets[0] = v_uv.xyxy + cc_nativeSize.zwzw * vec4(-1.0, 0.0, 0.0, 1.0);
    v_offsets[1] = v_uv.xyxy + cc_nativeSize.zwzw * vec4( 1.0, 0.0, 0.0, -1.0);
    v_offsets[2] = v_uv.xyxy + cc_nativeSize.zwzw * vec4(-2.0, 0.0, 0.0, 2.0);

    return pos;
  }
}%

CCProgram smaa-edge-fs %{
  precision highp float;
  #include <builtin/uniforms/cc-global>
  #include <common/common-define>
  #include <common/color/gamma>
  #include <common/color/aces>

  #pragma define SMAA_THRESHOLD 0.1

  in vec2 v_uv;
  in vec4 v_offsets[3];
  uniform sampler2D u_texSampler;

  vec3 ToLDR(vec3 color) {
  #if CC_USE_HDR
    color *= cc_exposure.x * FP_SCALE_INV;
    color = ACESToneMap(color);
    color = LinearToSRGB(color);
  #endif
    return color;
  }

  vec4 frag () {
    vec2 threshold = vec2(SMAA_THRESHOLD, SMAA_THRESHOLD);
    vec4 delta;
    vec3 C = ToLDR(texture(u_texSampler, v_uv).rgb);
    vec3 Cleft = ToLDR(texture(u_texSampler, v_offsets[0].xy).rgb);
    vec3 t = abs(C - Cleft);
    delta.x = max(max(t.r, t.g), t.b);
    vec3 Ctop = ToLDR(texture(u_texSampler, v_offsets[0].zw).rgb);
    t = abs(C - Ctop);
    delta.y = max(max(t.r, t.g), t.b);
    vec2 edges = step(threshold, delta.xy);

    if (dot(edges, vec2(1.0, 1.0)) == 0.0)
      discard;

    vec3 Cright = ToLDR(texture(u_texSampler, v_offsets[1].xy).rgb);
    t = abs(C - Cright);
    delta.z = max(max(t.r, t.g), t.b);
    vec3 Cbottom = ToLDR(texture(u_texSampler, v_offsets[1].zw).rgb);
    t = abs(C - Cbottom);
    delta.w = max(max(t.r, t.g), t.b);
    float maxDelta = max(max(max(delta.x, delta.y), delta.z), delta.w);
    vec3 Cleftleft = ToLDR(texture(u_texSampler, v_offsets[2].xy).rgb);
    t = abs(C - Cleftleft);
    delta.z = max(max(t.r, t.g), t.b);
    vec3 Ctoptop = ToLDR(texture(u_texSampler, v_offsets[2].zw).rgb);
    t = abs(C - Ctoptop);
    delta.w = max(max(t.r, t.g), t.b);
    maxDelta = max(max(maxDelta, delta.z), delta.w);
    edges.xy *= step(0.5 * maxDelta, delta.xy);

    vec4 o = vec4(edges, 0.0, 0.0);

    return o;
  }
}%

CCProgram smaa-blend-vs %{
  precision highp float;
  #include <builtin/uniforms/cc-global>

  #pragma define SMAA_MAX_SEARCH_STEPS 8

  in vec2 a_position;
  in vec2 a_texCoord;
  out vec2 v_uv;
  out vec4 v_offsets[3];
  out vec2 v_pixCoord;

  vec4 vert () {
    vec4 pos = vec4(a_position, 0.0, 1.0);
    v_uv = a_texCoord * cc_screenScale.xy;
    v_pixCoord = v_uv * cc_nativeSize.xy;
    v_offsets[0] = v_uv.xyxy + cc_nativeSize.zwzw * vec4(-0.25, 0.125, 1.25, 0.125);
    v_offsets[1] = v_uv.xyxy + cc_nativeSize.zwzw * vec4(-0.125, 0.25, -0.125, -1.25);
    v_offsets[2] = vec4(v_offsets[0].xz, v_offsets[1].yw) + vec4(-2.0, 2.0, -2.0, 2.0) * cc_nativeSize.zzww * float(SMAA_MAX_SEARCH_STEPS);

    return pos;
  }
}%

CCProgram smaa-blend-fs %{
  precision highp float;
  #include <builtin/uniforms/cc-global>

  #pragma define SMAA_MAX_SEARCH_STEPS 8
  #pragma define SMAA_AREATEX_MAX_DISTANCE 16
  #pragma define SMAA_AREATEX_PIXEL_SIZE (1.0 / vec2(160.0, 560.0))
  #pragma define SMAA_AREATEX_SUBTEX_SIZE (1.0 / 7.0)

  in vec2 v_uv;
  in vec4 v_offsets[3];
  in vec2 v_pixCoord;

  uniform sampler2D u_edgeTexSampler;
  uniform sampler2D u_areaTexSampler;
  uniform sampler2D u_searchTexSampler;

  float SMAASearchLength(vec2 e, float bias, float scale) {
    e.r = bias + e.r * scale;
    return 255.0 * texture(u_searchTexSampler, e).r;
  }
  float SMAASearchXLeft(vec2 texcoord, float end) {
    vec2 e = vec2(0.0, 1.0);
    for (int i = 0; i < SMAA_MAX_SEARCH_STEPS; ++i) {
        e = texture(u_edgeTexSampler, texcoord).rg;
        texcoord -= vec2( 2.0, 0.0 ) * cc_nativeSize.zw;
        if (!(texcoord.x > end && e.g > 0.8281 && e.r == 0.0))
          break;
    }
    texcoord.x += 0.25 * cc_nativeSize.z;
    texcoord.x += cc_nativeSize.z;
    texcoord.x += 2.0 * cc_nativeSize.z;
    texcoord.x -= cc_nativeSize.z * SMAASearchLength(e, 0.0, 0.5);
    return texcoord.x;
  }
  float SMAASearchXRight(vec2 texcoord, float end) {
    vec2 e = vec2(0.0, 1.0);
    for (int i = 0; i < SMAA_MAX_SEARCH_STEPS; ++i) {
        e = texture(u_edgeTexSampler, texcoord).rg;
        texcoord += vec2( 2.0, 0.0 ) * cc_nativeSize.zw;
        if (!(texcoord.x < end && e.g > 0.8281 && e.r == 0.0))
          break;
    }
    texcoord.x -= 0.25 * cc_nativeSize.z;
    texcoord.x -= cc_nativeSize.z;
    texcoord.x -= 2.0 * cc_nativeSize.z;
    texcoord.x += cc_nativeSize.z * SMAASearchLength(e, 0.5, 0.5);
    return texcoord.x;
  }
  float SMAASearchYUp(vec2 texcoord, float end) {
      vec2 e = vec2(1.0, 0.0);
      for (int i = 0; i < SMAA_MAX_SEARCH_STEPS; ++i) {
          e = texture(u_edgeTexSampler, texcoord).rg;
          texcoord += vec2( 0.0, 2.0 ) * cc_nativeSize.zw;
          if (!(texcoord.y > end && e.r > 0.8281 && e.g == 0.0))
            break;
      }
      texcoord.y -= 0.25 * cc_nativeSize.w;
      texcoord.y -= cc_nativeSize.w;
      texcoord.y -= 2.0 * cc_nativeSize.w;
      texcoord.y += cc_nativeSize.w * SMAASearchLength(e.gr, 0.0, 0.5);
      return texcoord.y;
  }
  float SMAASearchYDown(vec2 texcoord, float end) {
      vec2 e = vec2(1.0, 0.0);
      for (int i = 0; i < SMAA_MAX_SEARCH_STEPS; ++i) {
          e = texture(u_edgeTexSampler, texcoord).rg;
          texcoord -= vec2( 0.0, 2.0 ) * cc_nativeSize.zw;
          if (!(texcoord.y < end && e.r > 0.8281 && e.g == 0.0))
            break;
      }
      texcoord.y += 0.25 * cc_nativeSize.w;
      texcoord.y += cc_nativeSize.w;
      texcoord.y += 2.0 * cc_nativeSize.w;
      texcoord.y -= cc_nativeSize.w * SMAASearchLength(e.gr, 0.5, 0.5);
      return texcoord.y;
  }

  vec2 Round(vec2 x) {
    return sign(x) * floor(abs(x) + 0.5);
  }

  vec2 SMAAArea(vec2 dist, float e1, float e2) {
      vec2 texcoord = float(SMAA_AREATEX_MAX_DISTANCE) * Round(4.0 * vec2(e1, e2)) + dist;
      texcoord = SMAA_AREATEX_PIXEL_SIZE * texcoord + 0.5 * SMAA_AREATEX_PIXEL_SIZE;
      return texture(u_areaTexSampler, texcoord).rg;
  }

  vec4 frag () {
    vec4 weights = vec4(0.0);
    vec2 e = texture(u_edgeTexSampler, v_uv).rg;
    vec2 d;
    vec2 coords;

    if ( e.g > 0.0 ) {
        coords.x = SMAASearchXLeft(v_offsets[0].xy, v_offsets[2].x);
        coords.y = v_offsets[1].y;
        d.x = coords.x;
        float e1 = texture(u_edgeTexSampler, coords).r;
        coords.x = SMAASearchXRight(v_offsets[0].zw, v_offsets[2].y);
        d.y = coords.x;
        d = d / cc_nativeSize.z - v_pixCoord.x;
        vec2 sqrt_d = sqrt(abs(d));
        coords.y -= 1.0 * cc_nativeSize.w;
        float e2 = texture(u_edgeTexSampler, coords + vec2(cc_nativeSize.z, 0.0)).r;
        weights.rg = SMAAArea(sqrt_d, e1, e2);
    }
    if ( e.r > 0.0 ) {
        coords.y = SMAASearchYUp(v_offsets[1].xy, v_offsets[2].z);
        coords.x = v_offsets[0].x;
        d.x = coords.y;
        float e1 = texture(u_edgeTexSampler, coords).g;
        coords.y = SMAASearchYDown(v_offsets[1].zw, v_offsets[2].w);
        d.y = coords.y;
        d = d / cc_nativeSize.w - v_pixCoord.y;
        vec2 sqrt_d = sqrt(abs(d));
        coords.y -= 1.0 * cc_nativeSize.w;
        float e2 = texture(u_edgeTexSampler, coords + vec2(0.0, cc_nativeSize.w)).g;
        weights.ba = SMAAArea(sqrt_d, e1, e2);
    }

    return weights;
  }
}%