1 files changed, 86 insertions, 0 deletions
diff --git a/source/blender/draw/engines/overlay/shaders/outline_detect_frag.glsl b/source/blender/draw/engines/overlay/shaders/outline_detect_frag.glsl
new file mode 100644
index 00000000000..79c970adfe0
--- /dev/null
+++ b/source/blender/draw/engines/overlay/shaders/outline_detect_frag.glsl
@@ -0,0 +1,86 @@
+
+in vec4 uvcoordsvar;
+
+out vec4 FragColor;
+
+uniform usampler2D outlineId;
+uniform sampler2D outlineDepth;
+uniform sampler2D sceneDepth;
+
+uniform float alphaOcclu;
+
+void main()
+{
+  ivec2 texel = ivec2(gl_FragCoord.xy);
+
+#ifdef GPU_ARB_texture_gather
+  vec2 texel_size = 1.0 / vec2(textureSize(outlineId, 0).xy);
+  vec2 uv = ceil(gl_FragCoord.xy) * texel_size;
+
+  /* Samples order is CW starting from top left. */
+  uvec4 tmp1 = textureGather(outlineId, uv - texel_size);
+  uvec4 tmp2 = textureGather(outlineId, uv);
+
+  uint ref_id = tmp1.y;
+  uvec4 id = uvec4(tmp1.xz, tmp2.xz);
+#else
+  uvec4 id;
+  uint ref_id = texelFetch(outlineId, texel, 0).r;
+  id.x = texelFetchOffset(outlineId, texel, 0, ivec2(-1, 0)).r;
+  id.y = texelFetchOffset(outlineId, texel, 0, ivec2(0, -1)).r;
+  id.z = texelFetchOffset(outlineId, texel, 0, ivec2(0, 1)).r;
+  id.w = texelFetchOffset(outlineId, texel, 0, ivec2(1, 0)).r;
+#endif
+
+#ifdef WIRE
+  /* We want only 2px outlines. */
+  /* TODO optimize, don't sample if we don't need to. */
+  id.xy = uvec2(ref_id);
+#endif
+
+  bool outline = any(notEqual(id, uvec4(ref_id)));
+
+  ivec2 depth_texel = texel;
+  /* If texel is an outline but has no valid id ...
+   * replace id and depth texel by a valid one.
+   * This keeps the outline thickness consistent everywhere. */
+  if (ref_id == 0u && outline) {
+    depth_texel = (id.x != 0u) ? texel + ivec2(-1, 0) : depth_texel;
+    depth_texel = (id.y != 0u) ? texel + ivec2(0, -1) : depth_texel;
+    depth_texel = (id.z != 0u) ? texel + ivec2(0, 1) : depth_texel;
+    depth_texel = (id.w != 0u) ? texel + ivec2(1, 0) : depth_texel;
+
+    ref_id = (id.x != 0u) ? id.x : ref_id;
+    ref_id = (id.y != 0u) ? id.y : ref_id;
+    ref_id = (id.z != 0u) ? id.z : ref_id;
+    ref_id = (id.w != 0u) ? id.w : ref_id;
+  }
+
+  float ref_depth = texelFetch(outlineDepth, depth_texel, 0).r;
+  float scene_depth = texelFetch(sceneDepth, depth_texel, 0).r;
+
+  /* Avoid bad cases of zfighting for occlusion only. */
+  const float epsilon = 3.0 / 8388608.0;
+  bool occluded = (ref_depth > scene_depth + epsilon);
+
+  /* WATCH: Keep in sync with outlineId of the prepass. */
+  uint color_id = ref_id >> 14u;
+  if (ref_id == 0u) {
+    FragColor = vec4(0.0);
+  }
+  else if (color_id == 1u) {
+    FragColor = colorSelect;
+  }
+  else if (color_id == 2u) {
+    FragColor = colorDupliSelect;
+  }
+  else if (color_id == 3u) {
+    FragColor = colorActive;
+  }
+  else {
+    FragColor = colorTransform;
+  }
+
+  FragColor.a *= (occluded) ? alphaOcclu : 1.0;
+  FragColor.a = (outline) ? FragColor.a : 0.0;
+}