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Diffstat (limited to 'servers/rendering/renderer_rd/shaders/ssao.glsl')
| -rw-r--r-- | servers/rendering/renderer_rd/shaders/ssao.glsl | 601 |
1 files changed, 419 insertions, 182 deletions
diff --git a/servers/rendering/renderer_rd/shaders/ssao.glsl b/servers/rendering/renderer_rd/shaders/ssao.glsl index 346338181a..315ef8fa13 100644 --- a/servers/rendering/renderer_rd/shaders/ssao.glsl +++ b/servers/rendering/renderer_rd/shaders/ssao.glsl @@ -1,249 +1,486 @@ +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// +// 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 +/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// + #[compute] #version 450 VERSION_DEFINES -layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in; +#define SSAO_ADAPTIVE_TAP_BASE_COUNT 5 + +#define INTELSSAO_MAIN_DISK_SAMPLE_COUNT (32) +const vec4 sample_pattern[INTELSSAO_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 SSAO_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 SSAO_TILT_SAMPLES_ENABLE_AT_QUALITY_PRESET (99) // to disable simply set to 99 or similar +#define SSAO_TILT_SAMPLES_AMOUNT (0.4) +// +#define SSAO_HALOING_REDUCTION_ENABLE_AT_QUALITY_PRESET (1) // to disable simply set to 99 or similar +#define SSAO_HALOING_REDUCTION_AMOUNT (0.6) // values from 0.0 - 1.0, 1.0 means max weighting (will cause artifacts, 0.8 is more reasonable) +// +#define SSAO_NORMAL_BASED_EDGES_ENABLE_AT_QUALITY_PRESET (2) // to disable simply set to 99 or similar +#define SSAO_NORMAL_BASED_EDGES_DOT_THRESHOLD (0.5) // use 0-0.1 for super-sharp normal-based edges +// +#define SSAO_DETAIL_AO_ENABLE_AT_QUALITY_PRESET (1) // whether to use detail; to disable simply set to 99 or similar +// +#define SSAO_DEPTH_MIPS_ENABLE_AT_QUALITY_PRESET (2) // !!warning!! the MIP generation on the C++ side will be enabled on quality preset 2 regardless of this value, so if changing here, change the C++ side too +#define SSAO_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 SSAO_DEPTH_BASED_EDGES_ENABLE_AT_QUALITY_PRESET (1) +// +#define SSAO_REDUCE_RADIUS_NEAR_SCREEN_BORDER_ENABLE_AT_QUALITY_PRESET (1) + +#define SSAO_MAX_TAPS 32 +#define SSAO_MAX_REF_TAPS 512 +#define SSAO_ADAPTIVE_TAP_BASE_COUNT 5 +#define SSAO_ADAPTIVE_TAP_FLEXIBLE_COUNT (SSAO_MAX_TAPS - SSAO_ADAPTIVE_TAP_BASE_COUNT) +#define SSAO_DEPTH_MIP_LEVELS 4 -#define TWO_PI 6.283185307179586476925286766559 +layout(local_size_x = 8, local_size_y = 8, local_size_z = 1) in; -#ifdef SSAO_QUALITY_HIGH -#define NUM_SAMPLES (20) -#endif +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 SSAO_QUALITY_ULTRA -#define NUM_SAMPLES (48) +#ifdef ADAPTIVE +layout(rg8, set = 1, binding = 0) uniform restrict readonly image2DArray source_ssao; +layout(set = 1, binding = 1) uniform sampler2D source_importance; +layout(set = 1, binding = 2, std430) buffer Counter { + uint sum; +} +counter; #endif -#ifdef SSAO_QUALITY_LOW -#define NUM_SAMPLES (8) -#endif +layout(rg8, set = 2, binding = 0) uniform restrict writeonly image2D dest_image; -#if !defined(SSAO_QUALITY_LOW) && !defined(SSAO_QUALITY_HIGH) && !defined(SSAO_QUALITY_ULTRA) -#define NUM_SAMPLES (12) -#endif +// This push_constant is full - 128 bytes - if you need to add more data, consider adding to the uniform buffer instead +layout(push_constant, binding = 1, std430) uniform Params { + ivec2 screen_size; + int pass; + int quality; -// If using depth mip levels, the log of the maximum pixel offset before we need to switch to a lower -// miplevel to maintain reasonable spatial locality in the cache -// If this number is too small (< 3), too many taps will land in the same pixel, and we'll get bad variance that manifests as flashing. -// If it is too high (> 5), we'll get bad performance because we're not using the MIP levels effectively -#define LOG_MAX_OFFSET (3) - -// This must be less than or equal to the MAX_MIP_LEVEL defined in SSAO.cpp -#define MAX_MIP_LEVEL (4) - -// This is the number of turns around the circle that the spiral pattern makes. This should be prime to prevent -// taps from lining up. This particular choice was tuned for NUM_SAMPLES == 9 - -const int ROTATIONS[] = int[]( - 1, 1, 2, 3, 2, 5, 2, 3, 2, - 3, 3, 5, 5, 3, 4, 7, 5, 5, 7, - 9, 8, 5, 5, 7, 7, 7, 8, 5, 8, - 11, 12, 7, 10, 13, 8, 11, 8, 7, 14, - 11, 11, 13, 12, 13, 19, 17, 13, 11, 18, - 19, 11, 11, 14, 17, 21, 15, 16, 17, 18, - 13, 17, 11, 17, 19, 18, 25, 18, 19, 19, - 29, 21, 19, 27, 31, 29, 21, 18, 17, 29, - 31, 31, 23, 18, 25, 26, 25, 23, 19, 34, - 19, 27, 21, 25, 39, 29, 17, 21, 27); - -//#define NUM_SPIRAL_TURNS (7) -const int NUM_SPIRAL_TURNS = ROTATIONS[NUM_SAMPLES - 1]; - -layout(set = 0, binding = 0) uniform sampler2D source_depth_mipmaps; -layout(r8, set = 1, binding = 0) uniform restrict writeonly image2D dest_image; - -#ifndef USE_HALF_SIZE -layout(set = 2, binding = 0) uniform sampler2D source_depth; -#endif + vec2 half_screen_pixel_size; + int size_multiplier; + float detail_intensity; -layout(set = 3, binding = 0) uniform sampler2D source_normal; + vec2 NDC_to_view_mul; + vec2 NDC_to_view_add; -layout(push_constant, binding = 1, std430) uniform Params { - ivec2 screen_size; - float z_far; - float z_near; + vec2 pad2; + vec2 half_screen_pixel_size_x025; - bool orthogonal; - float intensity_div_r6; float radius; - float bias; - - vec4 proj_info; - vec2 pixel_size; - float proj_scale; - uint pad; + float intensity; + float shadow_power; + float shadow_clamp; + + float fade_out_mul; + float fade_out_add; + float horizon_angle_threshold; + 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; -vec3 reconstructCSPosition(vec2 S, float z) { - if (params.orthogonal) { - return vec3((S.xy * params.proj_info.xy + params.proj_info.zw), z); +// packing/unpacking for edges; 2 bits per edge mean 4 gradient values (0, 0.33, 0.66, 1) for smoother transitions! +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((S.xy * params.proj_info.xy + params.proj_info.zw) * z, z); + return vec3((params.NDC_to_view_mul * p_pos.xy + params.NDC_to_view_add) * p_viewspace_depth, p_viewspace_depth); } } -vec3 getPosition(ivec2 ssP) { - vec3 P; -#ifdef USE_HALF_SIZE - P.z = texelFetch(source_depth_mipmaps, ssP, 0).r; - P.z = -P.z; -#else - P.z = texelFetch(source_depth, ssP, 0).r; +// 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; - P.z = P.z * 2.0 - 1.0; - if (params.orthogonal) { - P.z = ((P.z + (params.z_far + params.z_near) / (params.z_far - params.z_near)) * (params.z_far - params.z_near)) / 2.0; - } else { - P.z = 2.0 * params.z_near * params.z_far / (params.z_far + params.z_near - P.z * (params.z_far - params.z_near)); - } - P.z = -P.z; -#endif - // Offset to pixel center - P = reconstructCSPosition(vec2(ssP) + vec2(0.5), P.z); - return P; + // 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); } -/** Returns a unit vector and a screen-space radius for the tap on a unit disk (the caller should scale by the actual disk radius) */ -vec2 tapLocation(int sampleNumber, float spinAngle, out float ssR) { - // Radius relative to ssR - float alpha = (float(sampleNumber) + 0.5) * (1.0 / float(NUM_SAMPLES)); - float angle = alpha * (float(NUM_SPIRAL_TURNS) * 6.28) + spinAngle; +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); +} - ssR = alpha; - return vec2(cos(angle), sin(angle)); +vec3 decode_normal(vec3 p_encoded_normal) { + vec3 normal = p_encoded_normal * 2.0 - 1.0; + return normal; } -/** Read the camera-space position of the point at screen-space pixel ssP + unitOffset * ssR. Assumes length(unitOffset) == 1 */ -vec3 getOffsetPosition(ivec2 ssP, float ssR) { - // Derivation: - // mipLevel = floor(log(ssR / MAX_OFFSET)); +vec3 load_normal(ivec2 p_pos) { + vec3 encoded_normal = imageLoad(source_normal, p_pos).xyz; + encoded_normal.z = 1.0 - encoded_normal.z; + return decode_normal(encoded_normal); +} - int mipLevel = clamp(int(floor(log2(ssR))) - LOG_MAX_OFFSET, 0, MAX_MIP_LEVEL); +vec3 load_normal(ivec2 p_pos, ivec2 p_offset) { + vec3 encoded_normal = imageLoad(source_normal, p_pos + p_offset).xyz; + encoded_normal.z = 1.0 - encoded_normal.z; + return decode_normal(encoded_normal); +} - vec3 P; +// 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); - // We need to divide by 2^mipLevel to read the appropriately scaled coordinate from a MIP-map. - // Manually clamp to the texture size because texelFetch bypasses the texture unit - ivec2 mipP = clamp(ssP >> mipLevel, ivec2(0), (params.screen_size >> mipLevel) - ivec2(1)); + float falloff_mult = max(0.0, length_sq * p_fallof_sq + 1.0); -#ifdef USE_HALF_SIZE - P.z = texelFetch(source_depth_mipmaps, mipP, mipLevel).r; - P.z = -P.z; -#else - if (mipLevel < 1) { - //read from depth buffer - P.z = texelFetch(source_depth, mipP, 0).r; - P.z = P.z * 2.0 - 1.0; - if (params.orthogonal) { - P.z = ((P.z + (params.z_far + params.z_near) / (params.z_far - params.z_near)) * (params.z_far - params.z_near)) / 2.0; - } else { - P.z = 2.0 * params.z_near * params.z_far / (params.z_far + params.z_near - P.z * (params.z_far - params.z_near)); - } - P.z = -P.z; + return max(0, NdotD - params.horizon_angle_threshold) * falloff_mult; +} - } else { - //read from mipmaps - P.z = texelFetch(source_depth_mipmaps, mipP, mipLevel - 1).r; - P.z = -P.z; +void SSAO_tap_inner(const int p_quality_level, 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; + + // convert to viewspace + vec3 hit_pos = NDC_to_view_space(p_sampling_uv.xy, viewspace_sample_z).xyz; + 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 >= SSAO_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 = SSAO_HALOING_REDUCTION_AMOUNT * reduct + (1.0 - SSAO_HALOING_REDUCTION_AMOUNT); } -#endif + weight *= p_weight_mod; + r_obscurance_sum += obscurance * weight; + r_weight_sum += weight; +} + +void SSAOTap(const int p_quality_level, 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 centre, similar to as described + // in http://graphics.cs.williams.edu/papers/SAOHPG12/. + float mip_level = (p_quality_level < SSAO_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; + + SSAO_tap_inner(p_quality_level, 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; - // Offset to pixel center - P = reconstructCSPosition(vec2(ssP) + vec2(0.5), P.z); + // 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 >= SSAO_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; - return P; + SSAO_tap_inner(p_quality_level, r_obscurance_sum, r_weight_sum, sampling_mirrored_uv, mip_level, p_pix_center_pos, p_pixel_normal, p_fallof_sq, p_weight_mod); } -/** Compute the occlusion due to sample with index \a i about the pixel at \a ssC that corresponds - to camera-space point \a C with unit normal \a n_C, using maximum screen-space sampling radius \a ssDiskRadius +void generate_SSAO_shadows_internal(out float r_shadow_term, out vec4 r_edges, 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) ? (SSAO_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 neighbouring 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; - Note that units of H() in the HPG12 paper are meters, not - unitless. The whole falloff/sampling function is therefore - unitless. In this implementation, we factor out (9 / radius). + 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); - Four versions of the falloff function are implemented below -*/ -float sampleAO(in ivec2 ssC, in vec3 C, in vec3 n_C, in float ssDiskRadius, in float p_radius, in int tapIndex, in float randomPatternRotationAngle) { - // Offset on the unit disk, spun for this pixel - float ssR; - vec2 unitOffset = tapLocation(tapIndex, randomPatternRotationAngle, ssR); - ssR *= ssDiskRadius; + // 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)); - ivec2 ssP = ivec2(ssR * unitOffset) + ssC; + 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; - if (any(lessThan(ssP, ivec2(0))) || any(greaterThanEqual(ssP, params.screen_size))) { - return 0.0; + 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 >= SSAO_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 occluding point in camera space - vec3 Q = getOffsetPosition(ssP, ssR); + // the main obscurance & sample weight storage + float obscurance_sum = 0.0; + float weight_sum = 0.0; - vec3 v = Q - C; + // edge mask for between this and left/right/top/bottom neighbour 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); - float vv = dot(v, v); - float vn = dot(v, n_C); + // Move center pixel slightly towards camera to avoid imprecision artifacts due to using of 16bit depth buffer; a lot smaller offsets needed when using 32bit floats + pix_center_pos *= 0.9992; - const float epsilon = 0.01; - float radius2 = p_radius * p_radius; + if (!p_adaptive_base && (p_quality_level >= SSAO_DEPTH_BASED_EDGES_ENABLE_AT_QUALITY_PRESET)) { + edgesLRTB = calculate_edges(pix_z, pix_left_z, pix_right_z, pix_top_z, pix_bottom_z); + } - // A: From the HPG12 paper - // Note large epsilon to avoid overdarkening within cracks - //return float(vv < radius2) * max((vn - bias) / (epsilon + vv), 0.0) * radius2 * 0.6; + // adds a more high definition sharp effect, which gets blurred out (reuses left/right/top/bottom samples that we used for edge detection) + if (!p_adaptive_base && (p_quality_level >= SSAO_DETAIL_AO_ENABLE_AT_QUALITY_PRESET)) { + // disable in case of quality level 4 (reference) + if (p_quality_level != 4) { + //approximate neighbouring pixels positions (actually just deltas or "positions - pix_center_pos" ) + vec3 normalized_viewspace_dir = vec3(pix_center_pos.xy / pix_center_pos.zz, 1.0); + vec3 pixel_left_delta = vec3(-pixel_size_at_center.x, 0.0, 0.0) + normalized_viewspace_dir * (pix_left_z - pix_center_pos.z); + vec3 pixel_right_delta = vec3(+pixel_size_at_center.x, 0.0, 0.0) + normalized_viewspace_dir * (pix_right_z - pix_center_pos.z); + vec3 pixel_top_delta = vec3(0.0, -pixel_size_at_center.y, 0.0) + normalized_viewspace_dir * (pix_top_z - pix_center_pos.z); + vec3 pixel_bottom_delta = vec3(0.0, +pixel_size_at_center.y, 0.0) + normalized_viewspace_dir * (pix_bottom_z - pix_center_pos.z); + + const float range_reduction = 4.0f; // this is to avoid various artifacts + const float modified_fallof_sq = range_reduction * fallof_sq; + + vec4 additional_obscurance; + additional_obscurance.x = calculate_pixel_obscurance(pixel_normal, pixel_left_delta, modified_fallof_sq); + additional_obscurance.y = calculate_pixel_obscurance(pixel_normal, pixel_right_delta, modified_fallof_sq); + additional_obscurance.z = calculate_pixel_obscurance(pixel_normal, pixel_top_delta, modified_fallof_sq); + additional_obscurance.w = calculate_pixel_obscurance(pixel_normal, pixel_bottom_delta, modified_fallof_sq); + + obscurance_sum += params.detail_intensity * dot(additional_obscurance, edgesLRTB); + } + } - // B: Smoother transition to zero (lowers contrast, smoothing out corners). [Recommended] - float f = max(radius2 - vv, 0.0); - return f * f * f * max((vn - params.bias) / (epsilon + vv), 0.0); + // Sharp normals also create edges - but this adds to the cost as well + if (!p_adaptive_base && (p_quality_level >= SSAO_NORMAL_BASED_EDGES_ENABLE_AT_QUALITY_PRESET)) { + vec3 neighbour_normal_left = load_normal(ivec2(full_res_coord), ivec2(-2, 0)); + vec3 neighbour_normal_right = load_normal(ivec2(full_res_coord), ivec2(2, 0)); + vec3 neighbour_normal_top = load_normal(ivec2(full_res_coord), ivec2(0, -2)); + vec3 neighbour_normal_bottom = load_normal(ivec2(full_res_coord), ivec2(0, 2)); - // C: Medium contrast (which looks better at high radii), no division. Note that the - // contribution still falls off with radius^2, but we've adjusted the rate in a way that is - // more computationally efficient and happens to be aesthetically pleasing. - // return 4.0 * max(1.0 - vv * invRadius2, 0.0) * max(vn - bias, 0.0); + const float dot_threshold = SSAO_NORMAL_BASED_EDGES_DOT_THRESHOLD; - // D: Low contrast, no division operation - // return 2.0 * float(vv < radius * radius) * max(vn - bias, 0.0); -} + vec4 normal_edgesLRTB; + normal_edgesLRTB.x = clamp((dot(pixel_normal, neighbour_normal_left) + dot_threshold), 0.0, 1.0); + normal_edgesLRTB.y = clamp((dot(pixel_normal, neighbour_normal_right) + dot_threshold), 0.0, 1.0); + normal_edgesLRTB.z = clamp((dot(pixel_normal, neighbour_normal_top) + dot_threshold), 0.0, 1.0); + normal_edgesLRTB.w = clamp((dot(pixel_normal, neighbour_normal_bottom) + dot_threshold), 0.0, 1.0); -void main() { - // Pixel being shaded - ivec2 ssC = ivec2(gl_GlobalInvocationID.xy); - if (any(greaterThanEqual(ssC, params.screen_size))) { //too large, do nothing - return; + edgesLRTB *= normal_edgesLRTB; } - // World space point being shaded - vec3 C = getPosition(ssC); + const float global_mip_offset = SSAO_DEPTH_MIPS_GLOBAL_OFFSET; + float mip_offset = (p_quality_level < SSAO_DEPTH_MIPS_ENABLE_AT_QUALITY_PRESET) ? (0) : (log2(pixel_lookup_radius) + global_mip_offset); -#ifdef USE_HALF_SIZE - vec3 n_C = texelFetch(source_normal, ssC << 1, 0).xyz * 2.0 - 1.0; -#else - vec3 n_C = texelFetch(source_normal, ssC, 0).xyz * 2.0 - 1.0; + // 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 *= SSAO_TILT_SAMPLES_AMOUNT; + + // standard, non-adaptive approach + if ((p_quality_level != 3) || p_adaptive_base) { + for (int i = 0; i < number_of_taps; i++) { + SSAOTap(p_quality_level, 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; + + // this is to normalize SSAO_DETAIL_AO_AMOUNT across all pixel regardless of importance + obscurance_sum *= (SSAO_ADAPTIVE_TAP_BASE_COUNT / float(SSAO_MAX_TAPS)) + (importance * SSAO_ADAPTIVE_TAP_FLEXIBLE_COUNT / float(SSAO_MAX_TAPS)); + + // load existing base values + vec2 base_values = imageLoad(source_ssao, ivec3(upos, params.pass)).xy; + weight_sum += base_values.y * float(SSAO_ADAPTIVE_TAP_BASE_COUNT * 4.0); + obscurance_sum += (base_values.x) * 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 = SSAO_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(SSAO_MAX_TAPS, additional_samples + SSAO_ADAPTIVE_TAP_BASE_COUNT); + + for (uint i = SSAO_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); + SSAOTap(p_quality_level, 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 - n_C = normalize(n_C); - n_C.y = -n_C.y; //because this code reads flipped - // Hash function used in the HPG12 AlchemyAO paper - float randomPatternRotationAngle = mod(float((3 * ssC.x ^ ssC.y + ssC.x * ssC.y) * 10), TWO_PI); + // early out for adaptive base - just output weight (used for the next pass) + if (p_adaptive_base) { + float obscurance = obscurance_sum / weight_sum; + + r_shadow_term = obscurance; + r_edges = vec4(0.0); + r_weight = weight_sum; + return; + } + + // calculate weighted average + float obscurance = obscurance_sum / weight_sum; - // Reconstruct normals from positions. These will lead to 1-pixel black lines - // at depth discontinuities, however the blur will wipe those out so they are not visible - // in the final image. + // 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); - // Choose the screen-space sample radius - // proportional to the projected area of the sphere + // Reduce the SSAO shadowing 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 >= SSAO_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); - float ssDiskRadius = -params.proj_scale * params.radius; - if (!params.orthogonal) { - ssDiskRadius = -params.proj_scale * params.radius / C.z; + fade_out *= clamp(1.0 - edge_fadeout_factor, 0.0, 1.0); } - float sum = 0.0; - for (int i = 0; i < NUM_SAMPLES; ++i) { - sum += sampleAO(ssC, C, n_C, ssDiskRadius, params.radius, i, randomPatternRotationAngle); + + // strength + obscurance = params.intensity * obscurance; + + // clamp + obscurance = min(obscurance, params.shadow_clamp); + + // fadeout + obscurance *= fade_out; + + // conceptually switch to occlusion with the meaning being visibility (grows with visibility, occlusion == 1 implies full visibility), + // to be in line with what is more commonly used. + float occlusion = 1.0 - obscurance; + + // modify the gradient + // note: this cannot be moved to a later pass because of loss of precision after storing in the render target + occlusion = pow(clamp(occlusion, 0.0, 1.0), params.shadow_power); + + // outputs! + r_shadow_term = occlusion; // Our final 'occlusion' term (0 means fully occluded, 1 means fully lit) + 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_weight = weight_sum; +} + +void main() { + float out_shadow_term; + float out_weight; + vec4 out_edges; + ivec2 ssC = ivec2(gl_GlobalInvocationID.xy); + if (any(greaterThanEqual(ssC, params.screen_size))) { //too large, do nothing + return; } - float A = max(0.0, 1.0 - sum * params.intensity_div_r6 * (5.0 / float(NUM_SAMPLES))); + vec2 uv = vec2(gl_GlobalInvocationID) + vec2(0.5); +#ifdef SSAO_BASE + generate_SSAO_shadows_internal(out_shadow_term, out_edges, out_weight, uv, params.quality, true); + + imageStore(dest_image, ivec2(gl_GlobalInvocationID.xy), vec4(out_shadow_term, out_weight / (float(SSAO_ADAPTIVE_TAP_BASE_COUNT) * 4.0), 0.0, 0.0)); +#else + generate_SSAO_shadows_internal(out_shadow_term, out_edges, out_weight, uv, params.quality, false); // pass in quality levels + if (params.quality == 0) { + out_edges = vec4(1.0); + } - imageStore(dest_image, ssC, vec4(A)); + imageStore(dest_image, ivec2(gl_GlobalInvocationID.xy), vec4(out_shadow_term, pack_edges(out_edges), 0.0, 0.0)); +#endif } |