/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // Copyright (c) 2016, Intel Corporation // Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated // documentation files (the "Software"), to deal in the Software without restriction, including without limitation // the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to // permit persons to whom the Software is furnished to do so, subject to the following conditions: // The above copyright notice and this permission notice shall be included in all copies or substantial portions of // the Software. // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO // THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE // SOFTWARE. /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // File changes (yyyy-mm-dd) // 2016-09-07: filip.strugar@intel.com: first commit // 2020-12-05: clayjohn: convert to Vulkan and Godot // 2021-05-27: clayjohn: convert SSAO to SSIL /////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// #[compute] #version 450 #VERSION_DEFINES #define SSIL_MAIN_DISK_SAMPLE_COUNT (32) const vec4 sample_pattern[SSIL_MAIN_DISK_SAMPLE_COUNT] = { vec4(0.78488064, 0.56661671, 1.500000, -0.126083), vec4(0.26022232, -0.29575172, 1.500000, -1.064030), vec4(0.10459357, 0.08372527, 1.110000, -2.730563), vec4(-0.68286800, 0.04963045, 1.090000, -0.498827), vec4(-0.13570161, -0.64190155, 1.250000, -0.532765), vec4(-0.26193795, -0.08205118, 0.670000, -1.783245), vec4(-0.61177456, 0.66664219, 0.710000, -0.044234), vec4(0.43675563, 0.25119025, 0.610000, -1.167283), vec4(0.07884444, 0.86618668, 0.640000, -0.459002), vec4(-0.12790935, -0.29869005, 0.600000, -1.729424), vec4(-0.04031125, 0.02413622, 0.600000, -4.792042), vec4(0.16201244, -0.52851415, 0.790000, -1.067055), vec4(-0.70991218, 0.47301072, 0.640000, -0.335236), vec4(0.03277707, -0.22349690, 0.600000, -1.982384), vec4(0.68921727, 0.36800742, 0.630000, -0.266718), vec4(0.29251814, 0.37775412, 0.610000, -1.422520), vec4(-0.12224089, 0.96582592, 0.600000, -0.426142), vec4(0.11071457, -0.16131058, 0.600000, -2.165947), vec4(0.46562141, -0.59747696, 0.600000, -0.189760), vec4(-0.51548797, 0.11804193, 0.600000, -1.246800), vec4(0.89141309, -0.42090443, 0.600000, 0.028192), vec4(-0.32402530, -0.01591529, 0.600000, -1.543018), vec4(0.60771245, 0.41635221, 0.600000, -0.605411), vec4(0.02379565, -0.08239821, 0.600000, -3.809046), vec4(0.48951152, -0.23657045, 0.600000, -1.189011), vec4(-0.17611565, -0.81696892, 0.600000, -0.513724), vec4(-0.33930185, -0.20732205, 0.600000, -1.698047), vec4(-0.91974425, 0.05403209, 0.600000, 0.062246), vec4(-0.15064627, -0.14949332, 0.600000, -1.896062), vec4(0.53180975, -0.35210401, 0.600000, -0.758838), vec4(0.41487166, 0.81442589, 0.600000, -0.505648), vec4(-0.24106961, -0.32721516, 0.600000, -1.665244) }; // these values can be changed (up to SSIL_MAX_TAPS) with no changes required elsewhere; values for 4th and 5th preset are ignored but array needed to avoid compilation errors // the actual number of texture samples is two times this value (each "tap" has two symmetrical depth texture samples) const int num_taps[5] = { 3, 5, 12, 0, 0 }; #define SSIL_TILT_SAMPLES_ENABLE_AT_QUALITY_PRESET (99) // to disable simply set to 99 or similar #define SSIL_TILT_SAMPLES_AMOUNT (0.4) // #define SSIL_HALOING_REDUCTION_ENABLE_AT_QUALITY_PRESET (1) // to disable simply set to 99 or similar #define SSIL_HALOING_REDUCTION_AMOUNT (0.8) // values from 0.0 - 1.0, 1.0 means max weighting (will cause artifacts, 0.8 is more reasonable) // #define SSIL_DEPTH_MIPS_ENABLE_AT_QUALITY_PRESET (2) #define SSIL_DEPTH_MIPS_GLOBAL_OFFSET (-4.3) // best noise/quality/performance tradeoff, found empirically // // !!warning!! the edge handling is hard-coded to 'disabled' on quality level 0, and enabled above, on the C++ side; while toggling it here will work for // testing purposes, it will not yield performance gains (or correct results) #define SSIL_DEPTH_BASED_EDGES_ENABLE_AT_QUALITY_PRESET (1) // #define SSIL_REDUCE_RADIUS_NEAR_SCREEN_BORDER_ENABLE_AT_QUALITY_PRESET (1) #define SSIL_MAX_TAPS 32 #define SSIL_ADAPTIVE_TAP_BASE_COUNT 5 #define SSIL_ADAPTIVE_TAP_FLEXIBLE_COUNT (SSIL_MAX_TAPS - SSIL_ADAPTIVE_TAP_BASE_COUNT) #define SSIL_DEPTH_MIP_LEVELS 4 layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in; layout(set = 0, binding = 0) uniform sampler2DArray source_depth_mipmaps; layout(rgba8, set = 0, binding = 1) uniform restrict readonly image2D source_normal; layout(set = 0, binding = 2) uniform Constants { //get into a lower set vec4 rotation_matrices[20]; } constants; #ifdef ADAPTIVE layout(rgba16, set = 1, binding = 0) uniform restrict readonly image2DArray source_ssil; layout(set = 1, binding = 1) uniform sampler2D source_importance; layout(set = 1, binding = 2, std430) buffer Counter { uint sum; } counter; #endif layout(rgba16, set = 2, binding = 0) uniform restrict writeonly image2D dest_image; layout(r8, set = 2, binding = 1) uniform image2D edges_weights_image; layout(set = 3, binding = 0) uniform sampler2D last_frame; layout(set = 3, binding = 1) uniform ProjectionConstants { mat4 reprojection; } projection_constants; layout(push_constant, std430) uniform Params { ivec2 screen_size; int pass; int quality; vec2 half_screen_pixel_size; vec2 half_screen_pixel_size_x025; vec2 NDC_to_view_mul; vec2 NDC_to_view_add; vec2 pad2; float z_near; float z_far; float radius; float intensity; int size_multiplier; int pad; float fade_out_mul; float fade_out_add; float normal_rejection_amount; float inv_radius_near_limit; bool is_orthogonal; float neg_inv_radius; float load_counter_avg_div; float adaptive_sample_limit; ivec2 pass_coord_offset; vec2 pass_uv_offset; } params; float pack_edges(vec4 p_edgesLRTB) { p_edgesLRTB = round(clamp(p_edgesLRTB, 0.0, 1.0) * 3.05); return dot(p_edgesLRTB, vec4(64.0 / 255.0, 16.0 / 255.0, 4.0 / 255.0, 1.0 / 255.0)); } vec3 NDC_to_view_space(vec2 p_pos, float p_viewspace_depth) { if (params.is_orthogonal) { return vec3((params.NDC_to_view_mul * p_pos.xy + params.NDC_to_view_add), p_viewspace_depth); } else { return vec3((params.NDC_to_view_mul * p_pos.xy + params.NDC_to_view_add) * p_viewspace_depth, p_viewspace_depth); } } // calculate effect radius and fit our screen sampling pattern inside it void calculate_radius_parameters(const float p_pix_center_length, const vec2 p_pixel_size_at_center, out float r_lookup_radius, out float r_radius, out float r_fallof_sq) { r_radius = params.radius; // when too close, on-screen sampling disk will grow beyond screen size; limit this to avoid closeup temporal artifacts const float too_close_limit = clamp(p_pix_center_length * params.inv_radius_near_limit, 0.0, 1.0) * 0.8 + 0.2; r_radius *= too_close_limit; // 0.85 is to reduce the radius to allow for more samples on a slope to still stay within influence r_lookup_radius = (0.85 * r_radius) / p_pixel_size_at_center.x; // used to calculate falloff (both for AO samples and per-sample weights) r_fallof_sq = -1.0 / (r_radius * r_radius); } vec4 calculate_edges(const float p_center_z, const float p_left_z, const float p_right_z, const float p_top_z, const float p_bottom_z) { // slope-sensitive depth-based edge detection vec4 edgesLRTB = vec4(p_left_z, p_right_z, p_top_z, p_bottom_z) - p_center_z; vec4 edgesLRTB_slope_adjusted = edgesLRTB + edgesLRTB.yxwz; edgesLRTB = min(abs(edgesLRTB), abs(edgesLRTB_slope_adjusted)); return clamp((1.3 - edgesLRTB / (p_center_z * 0.040)), 0.0, 1.0); } vec3 load_normal(ivec2 p_pos) { vec3 encoded_normal = normalize(imageLoad(source_normal, p_pos).xyz * 2.0 - 1.0); encoded_normal.z = -encoded_normal.z; return encoded_normal; } vec3 load_normal(ivec2 p_pos, ivec2 p_offset) { vec3 encoded_normal = normalize(imageLoad(source_normal, p_pos + p_offset).xyz * 2.0 - 1.0); encoded_normal.z = -encoded_normal.z; return encoded_normal; } // all vectors in viewspace float calculate_pixel_obscurance(vec3 p_pixel_normal, vec3 p_hit_delta, float p_fallof_sq) { float length_sq = dot(p_hit_delta, p_hit_delta); float NdotD = dot(p_pixel_normal, p_hit_delta) / sqrt(length_sq); float falloff_mult = max(0.0, length_sq * p_fallof_sq + 1.0); return max(0, NdotD - 0.05) * falloff_mult; } void SSIL_tap_inner(const int p_quality_level, inout vec3 r_color_sum, inout float r_obscurance_sum, inout float r_weight_sum, const vec2 p_sampling_uv, const float p_mip_level, const vec3 p_pix_center_pos, vec3 p_pixel_normal, const float p_fallof_sq, const float p_weight_mod) { // get depth at sample float viewspace_sample_z = textureLod(source_depth_mipmaps, vec3(p_sampling_uv, params.pass), p_mip_level).x; vec3 sample_normal = load_normal(ivec2(p_sampling_uv * vec2(params.screen_size))); // convert to viewspace vec3 hit_pos = NDC_to_view_space(p_sampling_uv.xy, viewspace_sample_z); vec3 hit_delta = hit_pos - p_pix_center_pos; float obscurance = calculate_pixel_obscurance(p_pixel_normal, hit_delta, p_fallof_sq); float weight = 1.0; if (p_quality_level >= SSIL_HALOING_REDUCTION_ENABLE_AT_QUALITY_PRESET) { float reduct = max(0, -hit_delta.z); reduct = clamp(reduct * params.neg_inv_radius + 2.0, 0.0, 1.0); weight = SSIL_HALOING_REDUCTION_AMOUNT * reduct + (1.0 - SSIL_HALOING_REDUCTION_AMOUNT); } // Translate sampling_uv to last screen's coordinates const vec4 sample_pos = projection_constants.reprojection * vec4(p_sampling_uv * 2.0 - 1.0, (viewspace_sample_z - params.z_near) / (params.z_far - params.z_near) * 2.0 - 1.0, 1.0); vec2 reprojected_sampling_uv = (sample_pos.xy / sample_pos.w) * 0.5 + 0.5; weight *= p_weight_mod; r_obscurance_sum += obscurance * weight; vec3 sample_color = textureLod(last_frame, reprojected_sampling_uv, 5.0).rgb; // Reduce impact of fireflies by tonemapping before averaging: http://graphicrants.blogspot.com/2013/12/tone-mapping.html sample_color /= (1.0 + dot(sample_color, vec3(0.299, 0.587, 0.114))); r_color_sum += sample_color * obscurance * weight * mix(1.0, smoothstep(0.0, 0.1, -dot(sample_normal, normalize(hit_delta))), params.normal_rejection_amount); r_weight_sum += weight; } void SSILTap(const int p_quality_level, inout vec3 r_color_sum, inout float r_obscurance_sum, inout float r_weight_sum, const int p_tap_index, const mat2 p_rot_scale, const vec3 p_pix_center_pos, vec3 p_pixel_normal, const vec2 p_normalized_screen_pos, const float p_mip_offset, const float p_fallof_sq, float p_weight_mod, vec2 p_norm_xy, float p_norm_xy_length) { vec2 sample_offset; float sample_pow_2_len; // patterns { vec4 new_sample = sample_pattern[p_tap_index]; sample_offset = new_sample.xy * p_rot_scale; sample_pow_2_len = new_sample.w; // precalculated, same as: sample_pow_2_len = log2( length( new_sample.xy ) ); p_weight_mod *= new_sample.z; } // snap to pixel center (more correct obscurance math, avoids artifacts) sample_offset = round(sample_offset); // calculate MIP based on the sample distance from the center, similar to as described // in http://graphics.cs.williams.edu/papers/SAOHPG12/. float mip_level = (p_quality_level < SSIL_DEPTH_MIPS_ENABLE_AT_QUALITY_PRESET) ? (0) : (sample_pow_2_len + p_mip_offset); vec2 sampling_uv = sample_offset * params.half_screen_pixel_size + p_normalized_screen_pos; SSIL_tap_inner(p_quality_level, r_color_sum, r_obscurance_sum, r_weight_sum, sampling_uv, mip_level, p_pix_center_pos, p_pixel_normal, p_fallof_sq, p_weight_mod); // for the second tap, just use the mirrored offset vec2 sample_offset_mirrored_uv = -sample_offset; // tilt the second set of samples so that the disk is effectively rotated by the normal // effective at removing one set of artifacts, but too expensive for lower quality settings if (p_quality_level >= SSIL_TILT_SAMPLES_ENABLE_AT_QUALITY_PRESET) { float dot_norm = dot(sample_offset_mirrored_uv, p_norm_xy); sample_offset_mirrored_uv -= dot_norm * p_norm_xy_length * p_norm_xy; sample_offset_mirrored_uv = round(sample_offset_mirrored_uv); } // snap to pixel center (more correct obscurance math, avoids artifacts) vec2 sampling_mirrored_uv = sample_offset_mirrored_uv * params.half_screen_pixel_size + p_normalized_screen_pos; SSIL_tap_inner(p_quality_level, r_color_sum, r_obscurance_sum, r_weight_sum, sampling_mirrored_uv, mip_level, p_pix_center_pos, p_pixel_normal, p_fallof_sq, p_weight_mod); } void generate_SSIL(out vec3 r_color, out vec4 r_edges, out float r_obscurance, out float r_weight, const vec2 p_pos, int p_quality_level, bool p_adaptive_base) { vec2 pos_rounded = trunc(p_pos); uvec2 upos = uvec2(pos_rounded); const int number_of_taps = (p_adaptive_base) ? (SSIL_ADAPTIVE_TAP_BASE_COUNT) : (num_taps[p_quality_level]); float pix_z, pix_left_z, pix_top_z, pix_right_z, pix_bottom_z; vec4 valuesUL = textureGather(source_depth_mipmaps, vec3(pos_rounded * params.half_screen_pixel_size, params.pass)); vec4 valuesBR = textureGather(source_depth_mipmaps, vec3((pos_rounded + vec2(1.0)) * params.half_screen_pixel_size, params.pass)); // get this pixel's viewspace depth pix_z = valuesUL.y; // get left right top bottom neighboring pixels for edge detection (gets compiled out on quality_level == 0) pix_left_z = valuesUL.x; pix_top_z = valuesUL.z; pix_right_z = valuesBR.z; pix_bottom_z = valuesBR.x; vec2 normalized_screen_pos = pos_rounded * params.half_screen_pixel_size + params.half_screen_pixel_size_x025; vec3 pix_center_pos = NDC_to_view_space(normalized_screen_pos, pix_z); // Load this pixel's viewspace normal uvec2 full_res_coord = upos * 2 * params.size_multiplier + params.pass_coord_offset.xy; vec3 pixel_normal = load_normal(ivec2(full_res_coord)); const vec2 pixel_size_at_center = NDC_to_view_space(normalized_screen_pos.xy + params.half_screen_pixel_size, pix_center_pos.z).xy - pix_center_pos.xy; float pixel_lookup_radius; float fallof_sq; // calculate effect radius and fit our screen sampling pattern inside it float viewspace_radius; calculate_radius_parameters(length(pix_center_pos), pixel_size_at_center, pixel_lookup_radius, viewspace_radius, fallof_sq); // calculate samples rotation/scaling mat2 rot_scale_matrix; uint pseudo_random_index; { vec4 rotation_scale; // reduce effect radius near the screen edges slightly; ideally, one would render a larger depth buffer (5% on each side) instead if (!p_adaptive_base && (p_quality_level >= SSIL_REDUCE_RADIUS_NEAR_SCREEN_BORDER_ENABLE_AT_QUALITY_PRESET)) { float near_screen_border = min(min(normalized_screen_pos.x, 1.0 - normalized_screen_pos.x), min(normalized_screen_pos.y, 1.0 - normalized_screen_pos.y)); near_screen_border = clamp(10.0 * near_screen_border + 0.6, 0.0, 1.0); pixel_lookup_radius *= near_screen_border; } // load & update pseudo-random rotation matrix pseudo_random_index = uint(pos_rounded.y * 2 + pos_rounded.x) % 5; rotation_scale = constants.rotation_matrices[params.pass * 5 + pseudo_random_index]; rot_scale_matrix = mat2(rotation_scale.x * pixel_lookup_radius, rotation_scale.y * pixel_lookup_radius, rotation_scale.z * pixel_lookup_radius, rotation_scale.w * pixel_lookup_radius); } // the main obscurance & sample weight storage vec3 color_sum = vec3(0.0); float obscurance_sum = 0.0; float weight_sum = 0.0; // edge mask for between this and left/right/top/bottom neighbor pixels - not used in quality level 0 so initialize to "no edge" (1 is no edge, 0 is edge) vec4 edgesLRTB = vec4(1.0, 1.0, 1.0, 1.0); // Move center pixel slightly towards camera to avoid imprecision artifacts due to using of 16bit depth buffer. pix_center_pos *= 0.99; if (!p_adaptive_base && (p_quality_level >= SSIL_DEPTH_BASED_EDGES_ENABLE_AT_QUALITY_PRESET)) { edgesLRTB = calculate_edges(pix_z, pix_left_z, pix_right_z, pix_top_z, pix_bottom_z); } const float global_mip_offset = SSIL_DEPTH_MIPS_GLOBAL_OFFSET; float mip_offset = (p_quality_level < SSIL_DEPTH_MIPS_ENABLE_AT_QUALITY_PRESET) ? (0) : (log2(pixel_lookup_radius) + global_mip_offset); // Used to tilt the second set of samples so that the disk is effectively rotated by the normal // effective at removing one set of artifacts, but too expensive for lower quality settings vec2 norm_xy = vec2(pixel_normal.x, pixel_normal.y); float norm_xy_length = length(norm_xy); norm_xy /= vec2(norm_xy_length, -norm_xy_length); norm_xy_length *= SSIL_TILT_SAMPLES_AMOUNT; // standard, non-adaptive approach if ((p_quality_level != 3) || p_adaptive_base) { for (int i = 0; i < number_of_taps; i++) { SSILTap(p_quality_level, color_sum, obscurance_sum, weight_sum, i, rot_scale_matrix, pix_center_pos, pixel_normal, normalized_screen_pos, mip_offset, fallof_sq, 1.0, norm_xy, norm_xy_length); } } #ifdef ADAPTIVE else { // add new ones if needed vec2 full_res_uv = normalized_screen_pos + params.pass_uv_offset.xy; float importance = textureLod(source_importance, full_res_uv, 0.0).x; //Need to store obscurance from base pass // load existing base values vec4 base_values = imageLoad(source_ssil, ivec3(upos, params.pass)); weight_sum += imageLoad(edges_weights_image, ivec2(upos)).r * float(SSIL_ADAPTIVE_TAP_BASE_COUNT * 4.0); color_sum += (base_values.rgb) * weight_sum; obscurance_sum += (base_values.a) * weight_sum; // increase importance around edges float edge_count = dot(1.0 - edgesLRTB, vec4(1.0, 1.0, 1.0, 1.0)); float avg_total_importance = float(counter.sum) * params.load_counter_avg_div; float importance_limiter = clamp(params.adaptive_sample_limit / avg_total_importance, 0.0, 1.0); importance *= importance_limiter; float additional_sample_count = SSIL_ADAPTIVE_TAP_FLEXIBLE_COUNT * importance; const float blend_range = 3.0; const float blend_range_inv = 1.0 / blend_range; additional_sample_count += 0.5; uint additional_samples = uint(additional_sample_count); uint additional_samples_to = min(SSIL_MAX_TAPS, additional_samples + SSIL_ADAPTIVE_TAP_BASE_COUNT); for (uint i = SSIL_ADAPTIVE_TAP_BASE_COUNT; i < additional_samples_to; i++) { additional_sample_count -= 1.0f; float weight_mod = clamp(additional_sample_count * blend_range_inv, 0.0, 1.0); SSILTap(p_quality_level, color_sum, obscurance_sum, weight_sum, int(i), rot_scale_matrix, pix_center_pos, pixel_normal, normalized_screen_pos, mip_offset, fallof_sq, weight_mod, norm_xy, norm_xy_length); } } #endif // Early out for adaptive base if (p_adaptive_base) { vec3 color = color_sum / weight_sum; r_color = color; r_edges = vec4(0.0); r_obscurance = obscurance_sum / weight_sum; r_weight = weight_sum; return; } // Calculate weighted average vec3 color = color_sum / weight_sum; color /= 1.0 - dot(color, vec3(0.299, 0.587, 0.114)); // Calculate fadeout (1 close, gradient, 0 far) float fade_out = clamp(pix_center_pos.z * params.fade_out_mul + params.fade_out_add, 0.0, 1.0); // Reduce the SSIL if we're on the edge to remove artifacts on edges (we don't care for the lower quality one) if (!p_adaptive_base && (p_quality_level >= SSIL_DEPTH_BASED_EDGES_ENABLE_AT_QUALITY_PRESET)) { // when there's more than 2 opposite edges, start fading out the occlusion to reduce aliasing artifacts float edge_fadeout_factor = clamp((1.0 - edgesLRTB.x - edgesLRTB.y) * 0.35, 0.0, 1.0) + clamp((1.0 - edgesLRTB.z - edgesLRTB.w) * 0.35, 0.0, 1.0); fade_out *= clamp(1.0 - edge_fadeout_factor, 0.0, 1.0); } color = params.intensity * color; color *= fade_out; // outputs! r_color = color; r_edges = edgesLRTB; // These are used to prevent blurring across edges, 1 means no edge, 0 means edge, 0.5 means half way there, etc. r_obscurance = clamp((obscurance_sum / weight_sum) * params.intensity, 0.0, 1.0); r_weight = weight_sum; } void main() { vec3 out_color; float out_obscurance; float out_weight; vec4 out_edges; ivec2 ssC = ivec2(gl_GlobalInvocationID.xy); if (any(greaterThanEqual(ssC, params.screen_size))) { //too large, do nothing return; } vec2 uv = vec2(gl_GlobalInvocationID) + vec2(0.5); #ifdef SSIL_BASE generate_SSIL(out_color, out_edges, out_obscurance, out_weight, uv, params.quality, true); imageStore(dest_image, ssC, vec4(out_color, out_obscurance)); imageStore(edges_weights_image, ssC, vec4(out_weight / (float(SSIL_ADAPTIVE_TAP_BASE_COUNT) * 4.0))); #else generate_SSIL(out_color, out_edges, out_obscurance, out_weight, uv, params.quality, false); // pass in quality levels imageStore(dest_image, ssC, vec4(out_color, out_obscurance)); imageStore(edges_weights_image, ssC, vec4(pack_edges(out_edges))); #endif }