300 lines
10 KiB
WebGPU Shading Language
300 lines
10 KiB
WebGPU Shading Language
struct VertexInput {
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@location(0) position: vec3<f32>,
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@location(1) normal: vec3<f32>,
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@location(2) uv: vec2<f32>,
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@location(3) instance_model_0: vec4<f32>,
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@location(4) instance_model_1: vec4<f32>,
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@location(5) instance_model_2: vec4<f32>,
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@location(6) instance_model_3: vec4<f32>,
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}
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struct VertexOutput {
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@builtin(position) clip_position: vec4<f32>,
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@location(0) world_position: vec3<f32>,
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@location(1) world_normal: vec3<f32>,
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@location(2) light_space_position: vec4<f32>,
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}
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struct Uniforms {
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model: mat4x4<f32>,
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view: mat4x4<f32>,
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projection: mat4x4<f32>,
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light_view_projection: mat4x4<f32>,
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camera_position: vec3<f32>,
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height_scale: f32,
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time: f32,
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shadow_bias: f32,
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light_direction: vec3<f32>,
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}
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@group(0) @binding(0)
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var<uniform> uniforms: Uniforms;
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@group(0) @binding(1)
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var shadow_map: texture_depth_2d;
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@group(0) @binding(2)
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var shadow_sampler: sampler_comparison;
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@group(0) @binding(3)
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var dither_texture_array: texture_2d_array<f32>;
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@group(0) @binding(4)
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var dither_sampler: sampler;
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@group(0) @binding(5)
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var flowmap_texture: texture_2d<f32>;
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@group(0) @binding(6)
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var flowmap_sampler: sampler;
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const PI: f32 = 3.14159265359;
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const TERRAIN_BOUNDS: vec2<f32> = vec2<f32>(1000.0, 1000.0);
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const LINE_THICKNESS: f32 = 0.1;
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const OCTAVE_STEPS: f32 = 4.0;
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const STROKE_LENGTH: f32 = 0.8;
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fn hash2(p: vec2<f32>) -> f32 {
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let p3 = fract(vec3<f32>(p.x, p.y, p.x) * 0.13);
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let p3_dot = dot(p3, vec3<f32>(p3.y + 3.333, p3.z + 3.333, p3.x + 3.333));
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return fract((p3.x + p3.y) * p3_dot);
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}
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fn rand(p: vec2f) -> f32 {
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return fract(sin(dot(p, vec2f(12.9898, 78.233))) * 43758.5453);
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}
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struct StrokeData {
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world_pos_2d: vec2<f32>,
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tile_center: vec2<f32>,
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tile_size: f32,
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direction_to_light: vec2<f32>,
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distance_to_light: f32,
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perpendicular_to_light: vec2<f32>,
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rotation_t: f32,
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line_direction: vec2<f32>,
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perpendicular_to_line: vec2<f32>,
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octave_index: f32,
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offset: vec2<f32>,
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local_pos: vec2<f32>,
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}
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fn compute_perpendicular(dir: vec2<f32>) -> vec2<f32> {
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return normalize(vec2<f32>(-dir.y, dir.x));
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}
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fn compute_rotation_t(distance_to_light: f32) -> f32 {
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return pow(min(max(distance_to_light - 1.0 / OCTAVE_STEPS, 0.0) * OCTAVE_STEPS, 1.0), 2.0);
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}
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fn sample_shadow_map(light_space_pos: vec4<f32>) -> f32 {
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let proj_coords = light_space_pos.xyz / light_space_pos.w;
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let ndc_coords = proj_coords * vec3<f32>(0.5, -0.5, 1.0) + vec3<f32>(0.5, 0.5, 0.0);
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if ndc_coords.x < 0.0 || ndc_coords.x > 1.0 ||
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ndc_coords.y < 0.0 || ndc_coords.y > 1.0 ||
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ndc_coords.z < 0.0 || ndc_coords.z > 1.0 {
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return 1.0;
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}
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let depth = ndc_coords.z - uniforms.shadow_bias;
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let shadow = textureSampleCompare(shadow_map, shadow_sampler, ndc_coords.xy, depth);
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return shadow;
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}
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fn hatching_lighting(world_pos: vec3<f32>, tile_scale: f32, direction: vec2<f32>, distance: f32) -> f32 {
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let world_pos_2d = vec2<f32>(world_pos.x, world_pos.z);
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let tile_size = 1.0 / tile_scale;
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let base_tile_center = floor(world_pos_2d / tile_size) * tile_size + tile_size * 0.5;
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var min_lighting = 1.0;
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for (var tile_y: i32 = -1; tile_y <= 1; tile_y++) {
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for (var tile_x: i32 = -1; tile_x <= 1; tile_x++) {
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let tile_center = base_tile_center + vec2<f32>(f32(tile_x), f32(tile_y)) * tile_size;
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let perpendicular_to_light = compute_perpendicular(direction);
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let t = compute_rotation_t(distance);
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let parallel = mix(perpendicular_to_light, direction, t / 2.0);
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let perpendicular = compute_perpendicular(parallel);
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let octave_index = round((1.0 - pow(distance, 2.0)) * OCTAVE_STEPS);
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let spacing = LINE_THICKNESS * 1.5;
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var max_offset: i32;
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switch i32(octave_index) {
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case default {
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max_offset = 0;
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}
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case 3 {
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max_offset = 3;
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}
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case 2 {
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max_offset = 9;
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}
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case 1 {
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max_offset = 9;
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}
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}
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for (var i: i32 = -max_offset; i <= max_offset; i++) {
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let random = rand(tile_center + vec2<f32>(f32(i), f32(-i)));
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var chance: f32;
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switch i32(octave_index) {
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case 1, default: {
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chance = 1.0;
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}
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case 2: {
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chance = 0.5;
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}
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case 3: {
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chance = 0.8;
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}
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}
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if random > chance {
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continue;
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}
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let offset = perpendicular * f32(i) * tile_size / f32(max_offset);
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let local_pos = world_pos_2d - tile_center - offset;
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let stroke_data = StrokeData(
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world_pos_2d,
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tile_center,
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tile_size,
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direction,
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distance,
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perpendicular_to_light,
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t,
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parallel,
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perpendicular,
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octave_index,
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offset,
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local_pos,
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);
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let lighting = line_stroke_lighting(stroke_data);
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min_lighting = min(min_lighting, lighting);
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}
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}
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}
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return min_lighting;
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}
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fn point_lighting(world_pos: vec3<f32>, point_light: vec3<f32>, tile_scale: f32) -> f32 {
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let world_pos_2d = vec2<f32>(world_pos.x, world_pos.z);
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let light_pos_2d = vec2<f32>(point_light.x, point_light.z);
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let tile_size = 1.0 / tile_scale;
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let tile_center = floor(world_pos_2d / tile_size) * tile_size + tile_size * 0.5;
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let direction_to_point = light_pos_2d - tile_center;
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let distance_to_point = min(length(direction_to_point) / 60.0, 1.0);
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let direction_normalized = normalize(direction_to_point);
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return hatching_lighting(world_pos, tile_scale, direction_normalized, distance_to_point);
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}
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fn point_lighting_with_shadow(world_pos: vec3<f32>, normal: vec3<f32>, point_light: vec3<f32>, tile_scale: f32, shadow: f32) -> f32 {
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let world_pos_2d = vec2<f32>(world_pos.x, world_pos.z);
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let light_pos_2d = vec2<f32>(point_light.x, point_light.z);
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let tile_size = 1.0 / tile_scale;
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let tile_center = floor(world_pos_2d / tile_size) * tile_size + tile_size * 0.5;
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let direction_to_point_3d = normalize(point_light - world_pos);
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let diffuse = max(0.0, dot(normalize(normal), direction_to_point_3d));
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let direction_to_point = light_pos_2d - tile_center;
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let distance_to_point = min(length(direction_to_point) / 60.0, 1.0);
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let direction_normalized = normalize(direction_to_point);
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let lighting_intensity = shadow * diffuse;
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let darkness = 1.0 - lighting_intensity;
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let combined_distance = min(distance_to_point + darkness * 0.5, 1.0);
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return hatching_lighting(world_pos, tile_scale, direction_normalized, combined_distance);
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}
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fn line_stroke_lighting(data: StrokeData) -> f32 {
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let octave_normalized = data.octave_index / OCTAVE_STEPS;
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if data.octave_index > 3.0 {
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return 1.0;
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} else if data.octave_index < 1.0 {
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return 0.0;
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}
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let noise = hash2(data.tile_center + data.offset) * 2.0 - 1.0;
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var noise_at_octave = noise;
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var jitter: f32;
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switch i32(data.octave_index) {
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case default {
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noise_at_octave = noise;
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jitter = 1.0;
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}
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case 2 {
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noise_at_octave = noise / 10.0;
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jitter = 1.0;
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}
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case 3 {
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noise_at_octave = noise / 20.0;
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jitter = 0.5;
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}
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}
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let line = mix(data.perpendicular_to_light, data.direction_to_light, data.rotation_t / (2.0 + noise_at_octave));
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let perpendicular_to_line = compute_perpendicular(line);
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let parallel_coord = dot(data.local_pos, line);
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let perpendicular_coord = dot(data.local_pos, perpendicular_to_line);
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let line_half_width = LINE_THICKNESS * (1.0 - octave_normalized * 0.5);
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let straight_section_half_length = max(0.0, data.tile_size * 0.4 - line_half_width);
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let parallel_jitter = (rand(data.tile_center + data.offset * 123.456) * 2.0 - 1.0) * data.tile_size * jitter;
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let jittered_parallel_coord = parallel_coord - parallel_jitter;
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let overhang = max(0.0, abs(jittered_parallel_coord) - straight_section_half_length);
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let effective_distance = sqrt(overhang * overhang + perpendicular_coord * perpendicular_coord);
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return step(line_half_width, effective_distance);
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}
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fn flowmap_path_lighting(world_pos: vec3<f32>, tile_scale: f32) -> f32 {
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let world_pos_2d = vec2<f32>(world_pos.x, world_pos.z);
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let tile_size = 1.0 / tile_scale;
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let tile_center = floor(world_pos_2d / tile_size) * tile_size + tile_size * 0.5;
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let flowmap_uv = (tile_center + TERRAIN_BOUNDS * 0.5) / TERRAIN_BOUNDS;
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let flowmap_sample = textureSampleLevel(flowmap_texture, flowmap_sampler, flowmap_uv, 0.0);
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let x = flowmap_sample.r * 2.0 - 1.0;
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let y = flowmap_sample.g * 2.0 - 1.0;
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let direction_to_path = normalize(vec2<f32>(x, y));
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let distance_to_path = flowmap_sample.b;
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return hatching_lighting(world_pos, tile_scale, direction_to_path, distance_to_path);
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}
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fn flowmap_path_lighting_with_shadow(world_pos: vec3<f32>, normal: vec3<f32>, tile_scale: f32, shadow: f32) -> f32 {
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let world_pos_2d = vec2<f32>(world_pos.x, world_pos.z);
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let tile_size = 1.0 / tile_scale;
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let tile_center = floor(world_pos_2d / tile_size) * tile_size + tile_size * 0.5;
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let flowmap_uv = (tile_center + TERRAIN_BOUNDS * 0.5) / TERRAIN_BOUNDS;
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let flowmap_sample = textureSampleLevel(flowmap_texture, flowmap_sampler, flowmap_uv, 0.0);
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let x = flowmap_sample.r * 2.0 - 1.0;
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let y = flowmap_sample.g * 2.0 - 1.0;
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let direction_to_path = normalize(vec2<f32>(x, y));
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let distance_to_path = flowmap_sample.b;
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let light_dir_3d = normalize(vec3<f32>(-x, 100.0, -y));
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let diffuse = max(0.0, dot(normalize(normal), light_dir_3d));
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let lighting_intensity = diffuse * shadow;
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let darkness = 1.0 - lighting_intensity;
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let combined_distance = min(distance_to_path + darkness * 0.5, 1.0);
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return hatching_lighting(world_pos, tile_scale, direction_to_path, combined_distance);
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}
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