diff options
Diffstat (limited to 'source/blender/draw/engines/workbench/shaders/workbench_cavity_lib.glsl')
-rw-r--r-- | source/blender/draw/engines/workbench/shaders/workbench_cavity_lib.glsl | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/source/blender/draw/engines/workbench/shaders/workbench_cavity_lib.glsl b/source/blender/draw/engines/workbench/shaders/workbench_cavity_lib.glsl new file mode 100644 index 00000000000..7b77139fb6c --- /dev/null +++ b/source/blender/draw/engines/workbench/shaders/workbench_cavity_lib.glsl @@ -0,0 +1,84 @@ + + +/* from The Alchemy screen-space ambient obscurance algorithm + * http://graphics.cs.williams.edu/papers/AlchemyHPG11/VV11AlchemyAO.pdf */ + +void ssao_factors( + in float depth, in vec3 normal, in vec3 position, in vec2 screenco, + out float cavities, out float edges) +{ + cavities = edges = 0.0; + /* early out if there is no need for SSAO */ + if (ssao_factor_cavity == 0.0 && ssao_factor_edge == 0.0) + return; + + /* take the normalized ray direction here */ + vec3 noise = texture(ssao_jitter, screenco.xy * jitter_tilling).rgb; + + /* find the offset in screen space by multiplying a point + * in camera space at the depth of the point by the projection matrix. */ + vec2 offset; + float homcoord = WinMatrix[2][3] * position.z + WinMatrix[3][3]; + offset.x = WinMatrix[0][0] * ssao_distance / homcoord; + offset.y = WinMatrix[1][1] * ssao_distance / homcoord; + /* convert from -1.0...1.0 range to 0.0..1.0 for easy use with texture coordinates */ + offset *= 0.5; + + + int num_samples = int(ssao_samples_num); + + /* Note. Putting noise usage here to put some ALU after texture fetch. */ + vec2 rotX = noise.rg; + vec2 rotY = vec2(-rotX.y, rotX.x); + + for (int x = 0; x < num_samples; x++) { + int sample_index = x + (int(ssao_iteration) * num_samples); + if (sample_index > 500) { + continue; + } + /* ssao_samples[x].xy is sample direction (normalized). + * ssao_samples[x].z is sample distance from disk center. */ + + /* Rotate with random direction to get jittered result. */ + vec2 dir_jittered = vec2(dot(ssao_samples[sample_index].xy, rotX), dot(ssao_samples[sample_index].xy, rotY)); + dir_jittered.xy *= ssao_samples[sample_index].z + noise.b; + + vec2 uvcoords = screenco.xy + dir_jittered * offset; + + if (uvcoords.x > 1.0 || uvcoords.x < 0.0 || uvcoords.y > 1.0 || uvcoords.y < 0.0) + continue; + + float depth_new = texture(depthBuffer, uvcoords).r; + + /* Handle Background case */ + bool is_background = (depth_new == 1.0); + + /* This trick provide good edge effect even if no neighboor is found. */ + vec3 pos_new = get_view_space_from_depth(uvcoords, (is_background) ? depth : depth_new); + + if (is_background) + pos_new.z -= ssao_distance; + + vec3 dir = pos_new - position; + float len = length(dir); + float f_cavities = dot(dir, normal); + float f_edge = -f_cavities; + float f_bias = 0.05 * len + 0.0001; + + float attenuation = 1.0 / (len * (1.0 + len * len * ssao_attenuation)); + + /* use minor bias here to avoid self shadowing */ + if (f_cavities > -f_bias) + cavities += f_cavities * attenuation; + + if (f_edge > f_bias) + edges += f_edge * attenuation; + } + + cavities /= ssao_samples_num; + edges /= ssao_samples_num; + + /* don't let cavity wash out the surface appearance */ + cavities = clamp(cavities * ssao_factor_cavity, 0.0, 1.0); + edges = edges * ssao_factor_edge; +} |