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citra/src/video_core/swrasterizer/lighting.cpp

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// Copyright 2017 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "common/math_util.h"
#include "video_core/swrasterizer/lighting.h"
namespace Pica {
static float LookupLightingLut(const Pica::State::Lighting& lighting, size_t lut_index, u8 index,
float delta) {
ASSERT_MSG(lut_index < lighting.luts.size(), "Out of range lut");
ASSERT_MSG(index < lighting.luts[lut_index].size(), "Out of range index");
const auto& lut = lighting.luts[lut_index][index];
float lut_value = lut.ToFloat();
float lut_diff = lut.DiffToFloat();
return lut_value + lut_diff * delta;
}
std::tuple<Math::Vec4<u8>, Math::Vec4<u8>> ComputeFragmentsColors(
const Pica::LightingRegs& lighting, const Pica::State::Lighting& lighting_state,
const Math::Quaternion<float>& normquat, const Math::Vec3<float>& view,
const Math::Vec4<u8> (&texture_color)[4]) {
Math::Vec3<float> surface_normal;
Math::Vec3<float> surface_tangent;
if (lighting.config0.bump_mode != LightingRegs::LightingBumpMode::None) {
Math::Vec3<float> perturbation =
texture_color[lighting.config0.bump_selector].xyz().Cast<float>() / 127.5f -
Math::MakeVec(1.0f, 1.0f, 1.0f);
if (lighting.config0.bump_mode == LightingRegs::LightingBumpMode::NormalMap) {
if (!lighting.config0.disable_bump_renorm) {
const float z_square = 1 - perturbation.xy().Length2();
perturbation.z = std::sqrt(std::max(z_square, 0.0f));
}
surface_normal = perturbation;
surface_tangent = Math::MakeVec(1.0f, 0.0f, 0.0f);
} else if (lighting.config0.bump_mode == LightingRegs::LightingBumpMode::TangentMap) {
surface_normal = Math::MakeVec(0.0f, 0.0f, 1.0f);
surface_tangent = perturbation;
} else {
LOG_ERROR(HW_GPU, "Unknown bump mode %u", lighting.config0.bump_mode.Value());
}
} else {
surface_normal = Math::MakeVec(0.0f, 0.0f, 1.0f);
surface_tangent = Math::MakeVec(1.0f, 0.0f, 0.0f);
}
// Use the normalized the quaternion when performing the rotation
auto normal = Math::QuaternionRotate(normquat, surface_normal);
auto tangent = Math::QuaternionRotate(normquat, surface_tangent);
Math::Vec4<float> diffuse_sum = {0.0f, 0.0f, 0.0f, 1.0f};
Math::Vec4<float> specular_sum = {0.0f, 0.0f, 0.0f, 1.0f};
for (unsigned light_index = 0; light_index <= lighting.max_light_index; ++light_index) {
unsigned num = lighting.light_enable.GetNum(light_index);
const auto& light_config = lighting.light[num];
Math::Vec3<float> refl_value = {};
Math::Vec3<float> position = {float16::FromRaw(light_config.x).ToFloat32(),
float16::FromRaw(light_config.y).ToFloat32(),
float16::FromRaw(light_config.z).ToFloat32()};
Math::Vec3<float> light_vector;
if (light_config.config.directional)
light_vector = position;
else
light_vector = position + view;
light_vector.Normalize();
Math::Vec3<float> norm_view = view.Normalized();
Math::Vec3<float> half_vector = norm_view + light_vector;
float dist_atten = 1.0f;
if (!lighting.IsDistAttenDisabled(num)) {
auto distance = (-view - position).Length();
float scale = Pica::float20::FromRaw(light_config.dist_atten_scale).ToFloat32();
float bias = Pica::float20::FromRaw(light_config.dist_atten_bias).ToFloat32();
size_t lut =
static_cast<size_t>(LightingRegs::LightingSampler::DistanceAttenuation) + num;
float sample_loc = MathUtil::Clamp(scale * distance + bias, 0.0f, 1.0f);
u8 lutindex =
static_cast<u8>(MathUtil::Clamp(std::floor(sample_loc * 256.0f), 0.0f, 255.0f));
float delta = sample_loc * 256 - lutindex;
dist_atten = LookupLightingLut(lighting_state, lut, lutindex, delta);
}
auto GetLutValue = [&](LightingRegs::LightingLutInput input, bool abs,
LightingRegs::LightingScale scale_enum,
LightingRegs::LightingSampler sampler) {
float result = 0.0f;
switch (input) {
case LightingRegs::LightingLutInput::NH:
result = Math::Dot(normal, half_vector.Normalized());
break;
case LightingRegs::LightingLutInput::VH:
result = Math::Dot(norm_view, half_vector.Normalized());
break;
case LightingRegs::LightingLutInput::NV:
result = Math::Dot(normal, norm_view);
break;
case LightingRegs::LightingLutInput::LN:
result = Math::Dot(light_vector, normal);
break;
case LightingRegs::LightingLutInput::SP: {
Math::Vec3<s32> spot_dir{light_config.spot_x.Value(), light_config.spot_y.Value(),
light_config.spot_z.Value()};
result = Math::Dot(light_vector, spot_dir.Cast<float>() / 2047.0f);
break;
}
case LightingRegs::LightingLutInput::CP:
if (lighting.config0.config == LightingRegs::LightingConfig::Config7) {
const Math::Vec3<float> norm_half_vector = half_vector.Normalized();
const Math::Vec3<float> half_vector_proj =
norm_half_vector - normal * Math::Dot(normal, norm_half_vector);
result = Math::Dot(half_vector_proj, tangent);
} else {
result = 0.0f;
}
break;
default:
LOG_CRITICAL(HW_GPU, "Unknown lighting LUT input %u\n", static_cast<u32>(input));
UNIMPLEMENTED();
result = 0.0f;
}
u8 index;
float delta;
if (abs) {
if (light_config.config.two_sided_diffuse)
result = std::abs(result);
else
result = std::max(result, 0.0f);
float flr = std::floor(result * 256.0f);
index = static_cast<u8>(MathUtil::Clamp(flr, 0.0f, 255.0f));
delta = result * 256 - index;
} else {
float flr = std::floor(result * 128.0f);
s8 signed_index = static_cast<s8>(MathUtil::Clamp(flr, -128.0f, 127.0f));
delta = result * 128.0f - signed_index;
index = static_cast<u8>(signed_index);
}
float scale = lighting.lut_scale.GetScale(scale_enum);
return scale *
LookupLightingLut(lighting_state, static_cast<size_t>(sampler), index, delta);
};
// If enabled, compute spot light attenuation value
float spot_atten = 1.0f;
if (!lighting.IsSpotAttenDisabled(num) &&
LightingRegs::IsLightingSamplerSupported(
lighting.config0.config, LightingRegs::LightingSampler::SpotlightAttenuation)) {
auto lut = LightingRegs::SpotlightAttenuationSampler(num);
spot_atten = GetLutValue(lighting.lut_input.sp, lighting.abs_lut_input.disable_sp == 0,
lighting.lut_scale.sp, lut);
}
// Specular 0 component
float d0_lut_value = 1.0f;
if (lighting.config1.disable_lut_d0 == 0 &&
LightingRegs::IsLightingSamplerSupported(
lighting.config0.config, LightingRegs::LightingSampler::Distribution0)) {
d0_lut_value =
GetLutValue(lighting.lut_input.d0, lighting.abs_lut_input.disable_d0 == 0,
lighting.lut_scale.d0, LightingRegs::LightingSampler::Distribution0);
}
Math::Vec3<float> specular_0 = d0_lut_value * light_config.specular_0.ToVec3f();
// If enabled, lookup ReflectRed value, otherwise, 1.0 is used
if (lighting.config1.disable_lut_rr == 0 &&
LightingRegs::IsLightingSamplerSupported(lighting.config0.config,
LightingRegs::LightingSampler::ReflectRed)) {
refl_value.x =
GetLutValue(lighting.lut_input.rr, lighting.abs_lut_input.disable_rr == 0,
lighting.lut_scale.rr, LightingRegs::LightingSampler::ReflectRed);
} else {
refl_value.x = 1.0f;
}
// If enabled, lookup ReflectGreen value, otherwise, ReflectRed value is used
if (lighting.config1.disable_lut_rg == 0 &&
LightingRegs::IsLightingSamplerSupported(lighting.config0.config,
LightingRegs::LightingSampler::ReflectGreen)) {
refl_value.y =
GetLutValue(lighting.lut_input.rg, lighting.abs_lut_input.disable_rg == 0,
lighting.lut_scale.rg, LightingRegs::LightingSampler::ReflectGreen);
} else {
refl_value.y = refl_value.x;
}
// If enabled, lookup ReflectBlue value, otherwise, ReflectRed value is used
if (lighting.config1.disable_lut_rb == 0 &&
LightingRegs::IsLightingSamplerSupported(lighting.config0.config,
LightingRegs::LightingSampler::ReflectBlue)) {
refl_value.z =
GetLutValue(lighting.lut_input.rb, lighting.abs_lut_input.disable_rb == 0,
lighting.lut_scale.rb, LightingRegs::LightingSampler::ReflectBlue);
} else {
refl_value.z = refl_value.x;
}
// Specular 1 component
float d1_lut_value = 1.0f;
if (lighting.config1.disable_lut_d1 == 0 &&
LightingRegs::IsLightingSamplerSupported(
lighting.config0.config, LightingRegs::LightingSampler::Distribution1)) {
d1_lut_value =
GetLutValue(lighting.lut_input.d1, lighting.abs_lut_input.disable_d1 == 0,
lighting.lut_scale.d1, LightingRegs::LightingSampler::Distribution1);
}
Math::Vec3<float> specular_1 =
d1_lut_value * refl_value * light_config.specular_1.ToVec3f();
// Fresnel
// Note: only the last entry in the light slots applies the Fresnel factor
if (light_index == lighting.max_light_index && lighting.config1.disable_lut_fr == 0 &&
LightingRegs::IsLightingSamplerSupported(lighting.config0.config,
LightingRegs::LightingSampler::Fresnel)) {
float lut_value =
GetLutValue(lighting.lut_input.fr, lighting.abs_lut_input.disable_fr == 0,
lighting.lut_scale.fr, LightingRegs::LightingSampler::Fresnel);
// Enabled for diffuse lighting alpha component
if (lighting.config0.fresnel_selector ==
LightingRegs::LightingFresnelSelector::PrimaryAlpha ||
lighting.config0.fresnel_selector == LightingRegs::LightingFresnelSelector::Both) {
diffuse_sum.a() = lut_value;
}
// Enabled for the specular lighting alpha component
if (lighting.config0.fresnel_selector ==
LightingRegs::LightingFresnelSelector::SecondaryAlpha ||
lighting.config0.fresnel_selector == LightingRegs::LightingFresnelSelector::Both) {
specular_sum.a() = lut_value;
}
}
auto dot_product = Math::Dot(light_vector, normal);
// Calculate clamp highlights before applying the two-sided diffuse configuration to the dot
// product.
float clamp_highlights = 1.0f;
if (lighting.config0.clamp_highlights) {
if (dot_product <= 0.0f)
clamp_highlights = 0.0f;
else
clamp_highlights = 1.0f;
}
if (light_config.config.two_sided_diffuse)
dot_product = std::abs(dot_product);
else
dot_product = std::max(dot_product, 0.0f);
if (light_config.config.geometric_factor_0 || light_config.config.geometric_factor_1) {
float geo_factor = half_vector.Length2();
geo_factor = geo_factor == 0.0f ? 0.0f : std::min(dot_product / geo_factor, 1.0f);
if (light_config.config.geometric_factor_0) {
specular_0 *= geo_factor;
}
if (light_config.config.geometric_factor_1) {
specular_1 *= geo_factor;
}
}
auto diffuse =
light_config.diffuse.ToVec3f() * dot_product + light_config.ambient.ToVec3f();
diffuse_sum += Math::MakeVec(diffuse * dist_atten * spot_atten, 0.0f);
specular_sum += Math::MakeVec(
(specular_0 + specular_1) * clamp_highlights * dist_atten * spot_atten, 0.0f);
}
diffuse_sum += Math::MakeVec(lighting.global_ambient.ToVec3f(), 0.0f);
auto diffuse = Math::MakeVec<float>(MathUtil::Clamp(diffuse_sum.x, 0.0f, 1.0f) * 255,
MathUtil::Clamp(diffuse_sum.y, 0.0f, 1.0f) * 255,
MathUtil::Clamp(diffuse_sum.z, 0.0f, 1.0f) * 255,
MathUtil::Clamp(diffuse_sum.w, 0.0f, 1.0f) * 255)
.Cast<u8>();
auto specular = Math::MakeVec<float>(MathUtil::Clamp(specular_sum.x, 0.0f, 1.0f) * 255,
MathUtil::Clamp(specular_sum.y, 0.0f, 1.0f) * 255,
MathUtil::Clamp(specular_sum.z, 0.0f, 1.0f) * 255,
MathUtil::Clamp(specular_sum.w, 0.0f, 1.0f) * 255)
.Cast<u8>();
return std::make_tuple(diffuse, specular);
}
} // namespace Pica
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