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LibSoftGPU: Add mipmap selection to sampler class

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Stephan Unverwerth 2022-02-19 02:16:44 +01:00 • committed by Linus Groh
parent dd900570fd
commit 7a19d0b4f9
2 changed files with 42 additions and 3 deletions
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43
Userland/Libraries/LibSoftGPU/Sampler.cpp
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@ -111,9 +111,46 @@ Vector4<AK::SIMD::f32x4> Sampler::sample_2d(Vector2<AK::SIMD::f32x4> const& uv)
auto const& 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.level_width(base_level)));
texel_coordinates.set_y(texel_coordinates.y() * static_cast<float>(image.level_height(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.
auto filter = scale_factor[0] > 1 ? m_config.texture_mag_filter : m_config.texture_min_filter;
if (m_config.mipmap_filter == MipMapFilter::None)
return sample_2d_lod(uv, expand4(base_level), filter);
// 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(image.num_levels() - 1.0f);
auto level = min(max(log2_approximate(scale_factor) * 0.5f, min_level), max_level);
auto lower_level_texel = sample_2d_lod(uv, to_u32x4(level), filter);
if (m_config.mipmap_filter == MipMapFilter::Nearest)
return lower_level_texel;
auto higher_level_texel = sample_2d_lod(uv, to_u32x4(min(level + 1.f, max_level)), 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, TextureFilter filter) const
{
auto const& image = *m_config.bound_image;
u32x4 const layer = expand4(0u);
// FIXME: calculate actual mipmap level to use
u32x4 const level = expand4(0u);
u32x4 const width = {
image.level_width(level[0]),
@ -137,7 +174,7 @@ Vector4<AK::SIMD::f32x4> Sampler::sample_2d(Vector2<AK::SIMD::f32x4> const& uv)
f32x4 u = s * to_f32x4(width);
f32x4 v = t * to_f32x4(height);
if (m_config.texture_mag_filter == TextureFilter::Nearest) {
if (filter == TextureFilter::Nearest) {
u32x4 i = to_u32x4(u);
u32x4 j = to_u32x4(v);
u32x4 k = expand4(0u);