forked from Rowland/EG
86 lines
3.0 KiB
GLSL
86 lines
3.0 KiB
GLSL
/**
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*
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* RenderPipeline
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*
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* Copyright (c) 2014-2016 tobspr <tobias.springer1@gmail.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*
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*/
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const float sample_radius = GET_SETTING(ao, hbao_sample_radius);
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const int num_angles = GET_SETTING(ao, hbao_ray_count);
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const int num_ray_steps = GET_SETTING(ao, hbao_ray_steps);
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const float tangent_bias = GET_SETTING(ao, hbao_tangent_bias);
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const float max_sample_distance = GET_SETTING(ao, hbao_max_distance) * 0.3;
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float accum = 0.0;
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for (int i = 0; i < num_angles; ++i) {
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float angle = (i + 2 * noise_vec.x) / float(num_angles) * TWO_PI;
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vec2 sample_dir = vec2(cos(angle), sin(angle));
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// Find the tangent andle
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float tangent_angle = acos(dot(vec3(sample_dir, 0), pixel_view_normal)) - 0.5 * M_PI
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+ tangent_bias;
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// Assume the horizon angle is the same as the tangent angle at the beginning
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// of the ray
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float horizon_angle = tangent_angle;
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vec3 last_diff = vec3(0);
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// Raymarch in the sample direction
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for (int k = 0; k < num_ray_steps; ++k) {
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// Get new texture coordinate
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vec2 texc = texcoord +
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sample_dir * (k + 2.0 + 2 * noise_vec.y) /
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num_ray_steps * pixel_size * sample_radius * kernel_scale * 0.3;
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// Fetch view pos at that position and compare it
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vec3 view_pos = get_view_pos_at(texc);
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vec3 diff = view_pos - pixel_view_pos;
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if(length(diff) < max_sample_distance) {
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// Compute actual angle
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float sample_angle = atan(diff.z / length(diff.xy));
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// Correct horizon angle
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horizon_angle = max(horizon_angle, sample_angle);
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last_diff = diff;
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}
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}
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// Now that we know the average horizon angle, add it to the result
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// For that we simply take the angle-difference
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float occlusion = saturate(sin(horizon_angle) - sin(tangent_angle));
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occlusion *= 1.0 / (1 + length(last_diff));
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accum += occlusion;
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}
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// Normalize samples
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accum /= num_angles;
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result = 1 - accum;
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