/*
* Copyright (c) 2021, Stephan Unverwerth <s.unverwerth@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/SIMDExtras.h>
#include <AK/SIMDMath.h>
#include <LibSoftGPU/Config.h>
#include <LibSoftGPU/Image.h>
#include <LibSoftGPU/SIMD.h>
#include <LibSoftGPU/Sampler.h>
#include <math.h>
namespace SoftGPU {
using AK::SIMD::f32x4;
using AK::SIMD::i32x4;
using AK::SIMD::u32x4;
using AK::SIMD::clamp;
using AK::SIMD::expand4;
using AK::SIMD::floor_int_range;
using AK::SIMD::frac_int_range;
using AK::SIMD::maskbits;
using AK::SIMD::to_f32x4;
using AK::SIMD::to_i32x4;
using AK::SIMD::to_u32x4;
static f32x4 wrap_repeat(f32x4 value)
{
return frac_int_range(value);
}
[[maybe_unused]] static f32x4 wrap_clamp(f32x4 value)
{
return clamp(value, expand4(0.0f), expand4(1.0f));
}
static f32x4 wrap_clamp_to_edge(f32x4 value, f32x4 num_texels)
{
f32x4 const clamp_limit = .5f / num_texels;
return clamp(value, clamp_limit, 1.f - clamp_limit);
}
static f32x4 wrap_mirrored_repeat(f32x4 value, f32x4 num_texels)
{
f32x4 integer = floor_int_range(value);
f32x4 frac = value - integer;
auto is_odd = to_i32x4(integer) & 1;
return wrap_clamp_to_edge(is_odd ? 1 - frac : frac, num_texels);
}
static f32x4 wrap(f32x4 value, GPU::TextureWrapMode mode, f32x4 num_texels)
{
switch (mode) {
case GPU::TextureWrapMode::Repeat:
return wrap_repeat(value);
case GPU::TextureWrapMode::MirroredRepeat:
return wrap_mirrored_repeat(value, num_texels);
case GPU::TextureWrapMode::Clamp:
if constexpr (CLAMP_DEPRECATED_BEHAVIOR) {
return wrap_clamp(value);
}
return wrap_clamp_to_edge(value, num_texels);
case GPU::TextureWrapMode::ClampToBorder:
case GPU::TextureWrapMode::ClampToEdge:
return wrap_clamp_to_edge(value, num_texels);
default:
VERIFY_NOT_REACHED();
}
}
ALWAYS_INLINE static Vector4<f32x4> texel4(Image const& image, u32x4 level, u32x4 x, u32x4 y)
{
auto const& t0 = image.texel(level[0], x[0], y[0], 0);
auto const& t1 = image.texel(level[1], x[1], y[1], 0);
auto const& t2 = image.texel(level[2], x[2], y[2], 0);
auto const& t3 = image.texel(level[3], x[3], y[3], 0);
return Vector4<f32x4> {
f32x4 { t0.x(), t1.x(), t2.x(), t3.x() },
f32x4 { t0.y(), t1.y(), t2.y(), t3.y() },
f32x4 { t0.z(), t1.z(), t2.z(), t3.z() },
f32x4 { t0.w(), t1.w(), t2.w(), t3.w() },
};
}
ALWAYS_INLINE static Vector4<f32x4> texel4border(Image const& image, u32x4 level, u32x4 x, u32x4 y, FloatVector4 const& border, u32x4 w, u32x4 h)
{
auto border_mask = maskbits(x < 0 || x >= w || y < 0 || y >= h);
auto const& t0 = (border_mask & 1) > 0 ? border : image.texel(level[0], x[0], y[0], 0);
auto const& t1 = (border_mask & 2) > 0 ? border : image.texel(level[1], x[1], y[1], 0);
auto const& t2 = (border_mask & 4) > 0 ? border : image.texel(level[2], x[2], y[2], 0);
auto const& t3 = (border_mask & 8) > 0 ? border : image.texel(level[3], x[3], y[3], 0);
return Vector4<f32x4> {
f32x4 { t0.x(), t1.x(), t2.x(), t3.x() },
f32x4 { t0.y(), t1.y(), t2.y(), t3.y() },
f32x4 { t0.z(), t1.z(), t2.z(), t3.z() },
f32x4 { t0.w(), t1.w(), t2.w(), t3.w() },
};
}
Vector4<AK::SIMD::f32x4> Sampler::sample_2d(Vector2<AK::SIMD::f32x4> const& uv) const
{
if (m_config.bound_image.is_null())
return expand4(FloatVector4 { 1, 0, 0, 1 });
auto const& image = *static_ptr_cast<Image>(m_config.bound_image);
// FIXME: Make base level configurable with glTexParameteri(GL_TEXTURE_BASE_LEVEL, base_level)
constexpr unsigned base_level = 0;
// Determine the texture scale factor. See OpenGL 1.5 spec chapter 3.8.8.
// FIXME: Static casting from u32 to float could silently truncate here.
// u16 should be plenty enough for texture dimensions and would allow textures of up to 65536x65536x65536 pixels.
auto texel_coordinates = uv;
texel_coordinates.set_x(texel_coordinates.x() * static_cast<float>(image.width_at_level(base_level)));
texel_coordinates.set_y(texel_coordinates.y() * static_cast<float>(image.height_at_level(base_level)));
auto dtdx = ddx(texel_coordinates);
auto dtdy = ddy(texel_coordinates);
auto scale_factor = max(dtdx.dot(dtdx), dtdy.dot(dtdy));
// FIXME: Here we simply determine the filter based on the single scale factor of the upper left pixel.
// Actually, we could end up with different scale factors for each pixel. This however would break our
// parallelisation as we could also end up with different filter modes per pixel.
// Note: scale_factor approximates texels per pixel. This means a scale factor less than 1 indicates texture magnification.
if (scale_factor[0] <= 1.f)
return sample_2d_lod(uv, expand4(base_level), m_config.texture_mag_filter);
if (m_config.mipmap_filter == GPU::MipMapFilter::None)
return sample_2d_lod(uv, expand4(base_level), m_config.texture_min_filter);
auto texture_lod_bias = AK::clamp(m_config.level_of_detail_bias, -MAX_TEXTURE_LOD_BIAS, MAX_TEXTURE_LOD_BIAS);
// FIXME: Instead of clamping to num_levels - 1, actually make the max mipmap level configurable with glTexParameteri(GL_TEXTURE_MAX_LEVEL, max_level)
auto min_level = expand4(static_cast<float>(base_level));
auto max_level = expand4(static_cast<float>(image.number_of_levels()) - 1.f);
auto lambda_xy = log2_approximate(scale_factor) * .5f + texture_lod_bias;
auto level = clamp(lambda_xy, min_level, max_level);
auto lower_level_texel = sample_2d_lod(uv, to_u32x4(level), m_config.texture_min_filter);
if (m_config.mipmap_filter == GPU::MipMapFilter::Nearest)
return lower_level_texel;
auto higher_level_texel = sample_2d_lod(uv, to_u32x4(min(level + 1.f, max_level)), m_config.texture_min_filter);
return mix(lower_level_texel, higher_level_texel, frac_int_range(level));
}
Vector4<AK::SIMD::f32x4> Sampler::sample_2d_lod(Vector2<AK::SIMD::f32x4> const& uv, AK::SIMD::u32x4 level, GPU::TextureFilter filter) const
{
auto const& image = *static_ptr_cast<Image>(m_config.bound_image);
u32x4 const width = {
image.width_at_level(level[0]),
image.width_at_level(level[1]),
image.width_at_level(level[2]),
image.width_at_level(level[3]),
};
u32x4 const height = {
image.height_at_level(level[0]),
image.height_at_level(level[1]),
image.height_at_level(level[2]),
image.height_at_level(level[3]),
};
auto f_width = to_f32x4(width);
auto f_height = to_f32x4(height);
u32x4 width_mask = width - 1;
u32x4 height_mask = height - 1;
f32x4 u = wrap(uv.x(), m_config.texture_wrap_u, f_width) * f_width;
f32x4 v = wrap(uv.y(), m_config.texture_wrap_v, f_height) * f_height;
if (filter == GPU::TextureFilter::Nearest) {
u32x4 i = to_u32x4(u);
u32x4 j = to_u32x4(v);
i = image.width_is_power_of_two() ? i & width_mask : i % width;
j = image.height_is_power_of_two() ? j & height_mask : j % height;
return texel4(image, level, i, j);
}
u -= 0.5f;
v -= 0.5f;
f32x4 const floored_u = floor_int_range(u);
f32x4 const floored_v = floor_int_range(v);
u32x4 i0 = to_u32x4(floored_u);
u32x4 i1 = i0 + 1;
u32x4 j0 = to_u32x4(floored_v);
u32x4 j1 = j0 + 1;
if (m_config.texture_wrap_u == GPU::TextureWrapMode::Repeat) {
if (image.width_is_power_of_two()) {
i0 = i0 & width_mask;
i1 = i1 & width_mask;
} else {
i0 = i0 % width;
i1 = i1 % width;
}
}
if (m_config.texture_wrap_v == GPU::TextureWrapMode::Repeat) {
if (image.height_is_power_of_two()) {
j0 = j0 & height_mask;
j1 = j1 & height_mask;
} else {
j0 = j0 % height;
j1 = j1 % height;
}
}
Vector4<f32x4> t0, t1, t2, t3;
if (m_config.texture_wrap_u == GPU::TextureWrapMode::Repeat && m_config.texture_wrap_v == GPU::TextureWrapMode::Repeat) {
t0 = texel4(image, level, i0, j0);
t1 = texel4(image, level, i1, j0);
t2 = texel4(image, level, i0, j1);
t3 = texel4(image, level, i1, j1);
} else {
t0 = texel4border(image, level, i0, j0, m_config.border_color, width, height);
t1 = texel4border(image, level, i1, j0, m_config.border_color, width, height);
t2 = texel4border(image, level, i0, j1, m_config.border_color, width, height);
t3 = texel4border(image, level, i1, j1, m_config.border_color, width, height);
}
f32x4 const alpha = u - floored_u;
f32x4 const beta = v - floored_v;
auto const lerp_0 = mix(t0, t1, alpha);
auto const lerp_1 = mix(t2, t3, alpha);
return mix(lerp_0, lerp_1, beta);
}
}