power_play/res/sh/shade.hlsl
2025-07-18 12:04:06 -05:00

121 lines
3.8 KiB
HLSL

#include "sh/common.hlsl"
/* ========================== *
* Root signature
* ========================== */
#define ROOTSIG \
"RootConstants(num32BitConstants = 9, b0), " \
"DescriptorTable(SRV(t0, space = 0, numDescriptors = unbounded, flags = DESCRIPTORS_VOLATILE)), " \
"DescriptorTable(SRV(t0, space = 1, numDescriptors = unbounded, flags = DESCRIPTORS_VOLATILE)), " \
"DescriptorTable(UAV(u0, space = 2, numDescriptors = unbounded, flags = DESCRIPTORS_VOLATILE)), " \
\
\
"StaticSampler(s0, " \
"filter = FILTER_MIN_MAG_MIP_POINT, " \
"addressU = TEXTURE_ADDRESS_CLAMP, " \
"addressV = TEXTURE_ADDRESS_CLAMP, " \
"addressW = TEXTURE_ADDRESS_CLAMP, " \
"maxAnisotropy = 1)"
ConstantBuffer<struct sh_shade_constants> g_constants : register(b0);
Texture2D<float4> g_gbuff_textures[] : register(t0, space0);
Texture2D<uint2> g_emittance_flood_textures[] : register(t0, space1);
RWTexture2D<float4> g_write_textures[]: register(u0, space2);
SamplerState g_sampler : register(s0);
struct cs_input {
DECLS(uint3, SV_DispatchThreadID);
};
#define SAMPLES 4
#define MARCHES 16
/* ========================== *
* Lighting
* ========================== */
#define AMBIENT float4(1, 1, 1, 1)
INLINE float4 get_light_in_dir(uint2 ray_start, float2 ray_dir)
{
float4 result = AMBIENT;
float2 at_float = ray_start;
uint2 at_uint = ray_start;
for (uint i = 0; i < MARCHES; ++i) {
uint2 flood = g_emittance_flood_textures[g_constants.emittance_flood_tex_urid][at_uint];
float2 dist_vec = at_float - (float2)flood;
float dist = length(dist_vec);
if (dist <= 1) {
result = g_gbuff_textures[g_constants.emittance_tex_urid][flood];
break;
} else {
at_float += ray_dir * dist;
at_uint = round(at_float);
if (at_uint.x < 0 || at_uint.x >= g_constants.tex_width || at_uint.y < 0 || at_uint.y >= g_constants.tex_height) {
/* Ambient lighting (ray hit edge of screen) */
break;
}
}
}
return result;
}
float rand_float_from_float2(float2 pos) {
return frac(sin(dot(pos.xy, float2(12.9898,78.233))) * 43758.5453123);
}
INLINE float4 get_light_at_pos(uint2 pos)
{
float4 result = 0;
for (int i = 0; i < SAMPLES; ++i) {
float angle = TAU * (((float)i + rand_float_from_float2(pos + (float)i + sin(g_constants.time))) / ((float)SAMPLES - 1));
float2 dir = float2(cos(angle), sin(angle));
float4 light_in_dir = get_light_in_dir(pos, dir);
result += light_in_dir;
}
result /= SAMPLES;
return result;
}
/* ========================== *
* Tone map
* ========================== */
/* ACES approximation by Krzysztof Narkowicz
* https://knarkowicz.wordpress.com/2016/01/06/aces-filmic-tone-mapping-curve/ */
INLINE float3 tone_map(float3 v)
{
return saturate((v * (2.51f * v + 0.03f)) / (v * (2.43f * v + 0.59f) + 0.14f));
}
/* ========================== *
* Entry point
* ========================== */
[numthreads(8, 8, 1)]
SH_ENTRY(ROOTSIG) void cs(struct cs_input input)
{
uint2 id = input.SV_DispatchThreadID.xy;
if (id.x >= g_constants.tex_width || id.y >= g_constants.tex_height) {
return; /* Overflow */
}
float4 albedo = g_gbuff_textures[g_constants.albedo_tex_urid][id];
float4 lighting = get_light_at_pos(id);
float4 color = albedo * lighting;
// float4 color = albedo + lighting;
/* Tonemap */
/* TODO: Dynamic exposure based on average scene luminance */
color *= g_constants.exposure;
color.rgb = tone_map(color.rgb);
/* Gamma correct */
color = pow(abs(color), 1/g_constants.gamma);
g_write_textures[g_constants.write_tex_urid][id] = color;
}