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-rw-r--r--Userland/Libraries/LibSoftGPU/Config.h1
-rw-r--r--Userland/Libraries/LibSoftGPU/Device.cpp95
-rw-r--r--Userland/Libraries/LibSoftGPU/Device.h2
-rw-r--r--Userland/Libraries/LibSoftGPU/PixelQuad.h2
-rw-r--r--Userland/Libraries/LibSoftGPU/Triangle.h4
5 files changed, 58 insertions, 46 deletions
diff --git a/Userland/Libraries/LibSoftGPU/Config.h b/Userland/Libraries/LibSoftGPU/Config.h
index 2f164a8eef..ddb9026cca 100644
--- a/Userland/Libraries/LibSoftGPU/Config.h
+++ b/Userland/Libraries/LibSoftGPU/Config.h
@@ -19,6 +19,7 @@ namespace SoftGPU {
static constexpr bool ENABLE_STATISTICS_OVERLAY = false;
static constexpr int MILLISECONDS_PER_STATISTICS_PERIOD = 500;
static constexpr int NUM_LIGHTS = 8;
+static constexpr int SUBPIXEL_BITS = 6;
// See: https://www.khronos.org/opengl/wiki/Common_Mistakes#Texture_edge_color_problem
// FIXME: make this dynamically configurable through ConfigServer
diff --git a/Userland/Libraries/LibSoftGPU/Device.cpp b/Userland/Libraries/LibSoftGPU/Device.cpp
index 8661c34b1a..aac6ea231d 100644
--- a/Userland/Libraries/LibSoftGPU/Device.cpp
+++ b/Userland/Libraries/LibSoftGPU/Device.cpp
@@ -46,14 +46,16 @@ using AK::SIMD::to_f32x4;
using AK::SIMD::to_u32x4;
using AK::SIMD::u32x4;
-// Both of these edge functions return positive values for counter-clockwise rotation of vertices.
-// Note that they return the area of a parallelogram with sides {a, b} and {b, c}, so _double_ the area of the triangle {a, b, c}.
-constexpr static float edge_function(FloatVector2 const& a, FloatVector2 const& b, FloatVector2 const& c)
+static constexpr int subpixel_factor = 1 << SUBPIXEL_BITS;
+
+// Returns positive values for counter-clockwise rotation of vertices. Note that it returns the
+// area of a parallelogram with sides {a, b} and {b, c}, so _double_ the area of the triangle {a, b, c}.
+constexpr static i32 edge_function(IntVector2 const& a, IntVector2 const& b, IntVector2 const& c)
{
return (c.y() - a.y()) * (b.x() - a.x()) - (c.x() - a.x()) * (b.y() - a.y());
}
-constexpr static f32x4 edge_function4(FloatVector2 const& a, FloatVector2 const& b, Vector2<f32x4> const& c)
+constexpr static i32x4 edge_function4(IntVector2 const& a, IntVector2 const& b, Vector2<i32x4> const& c)
{
return (c.y() - a.y()) * (b.x() - a.x()) - (c.x() - a.x()) * (b.y() - a.y());
}
@@ -187,24 +189,22 @@ void Device::rasterize_triangle(Triangle const& triangle)
if (m_options.enable_alpha_test && m_options.alpha_test_func == GPU::AlphaTestFunction::Never)
return;
- GPU::Vertex const& vertex0 = triangle.vertices[0];
- GPU::Vertex const& vertex1 = triangle.vertices[1];
- GPU::Vertex const& vertex2 = triangle.vertices[2];
+ auto const& vertex0 = triangle.vertices[0];
+ auto const& vertex1 = triangle.vertices[1];
+ auto const& vertex2 = triangle.vertices[2];
- // Determine the area of a parallelogram with sides (v0,v1) and (v1,v2) to calculate barycentrics
- FloatVector2 const v0 = vertex0.window_coordinates.xy();
- FloatVector2 const v1 = vertex1.window_coordinates.xy();
- FloatVector2 const v2 = vertex2.window_coordinates.xy();
+ auto const& v0 = triangle.subpixel_coordinates[0];
+ auto const& v1 = triangle.subpixel_coordinates[1];
+ auto const& v2 = triangle.subpixel_coordinates[2];
- auto const area = edge_function(v0, v1, v2);
- auto const one_over_area = 1.0f / area;
+ auto const one_over_area = 1.0f / triangle.area;
auto render_bounds = m_frame_buffer->rect();
if (m_options.scissor_enabled)
render_bounds.intersect(m_options.scissor_box);
// This function calculates the 3 edge values for the pixel relative to the triangle.
- auto calculate_edge_values4 = [v0, v1, v2](Vector2<f32x4> const& p) -> Vector3<f32x4> {
+ auto calculate_edge_values4 = [v0, v1, v2](Vector2<i32x4> const& p) -> Vector3<i32x4> {
return {
edge_function4(v1, v2, p),
edge_function4(v2, v0, p),
@@ -214,19 +214,16 @@ void Device::rasterize_triangle(Triangle const& triangle)
// Zero is used in testing against edge values below, applying the "top-left rule". If a pixel
// lies exactly on an edge shared by two triangles, we only render that pixel if the edge in
- // question is a "top" or "left" edge. By changing a float epsilon to 0, we effectively change
- // the comparisons against the edge values below from "> 0" into ">= 0".
- constexpr auto epsilon = NumericLimits<float>::epsilon();
- FloatVector3 zero { epsilon, epsilon, epsilon };
- if (v2.y() < v1.y() || (v2.y() == v1.y() && v2.x() < v1.x()))
- zero.set_x(0.f);
- if (v0.y() < v2.y() || (v0.y() == v2.y() && v0.x() < v2.x()))
- zero.set_y(0.f);
- if (v1.y() < v0.y() || (v1.y() == v0.y() && v1.x() < v0.x()))
- zero.set_z(0.f);
+ // question is a "top" or "left" edge. By setting either a 1 or 0, we effectively change the
+ // comparisons against the edge values below from "> 0" into ">= 0".
+ IntVector3 const zero {
+ (v2.y() < v1.y() || (v2.y() == v1.y() && v2.x() < v1.x())) ? 0 : 1,
+ (v0.y() < v2.y() || (v0.y() == v2.y() && v0.x() < v2.x())) ? 0 : 1,
+ (v1.y() < v0.y() || (v1.y() == v0.y() && v1.x() < v0.x())) ? 0 : 1,
+ };
// This function tests whether a point as identified by its 3 edge values lies within the triangle
- auto test_point4 = [zero](Vector3<f32x4> const& edges) -> i32x4 {
+ auto test_point4 = [zero](Vector3<i32x4> const& edges) -> i32x4 {
return edges.x() >= zero.x()
&& edges.y() >= zero.y()
&& edges.z() >= zero.z();
@@ -234,10 +231,10 @@ void Device::rasterize_triangle(Triangle const& triangle)
// Calculate block-based bounds
// clang-format off
- int const bx0 = max(render_bounds.left(), min(min(v0.x(), v1.x()), v2.x())) & ~1;
- int const bx1 = (min(render_bounds.right(), max(max(v0.x(), v1.x()), v2.x())) & ~1) + 2;
- int const by0 = max(render_bounds.top(), min(min(v0.y(), v1.y()), v2.y())) & ~1;
- int const by1 = (min(render_bounds.bottom(), max(max(v0.y(), v1.y()), v2.y())) & ~1) + 2;
+ int const bx0 = max(render_bounds.left(), min(min(v0.x(), v1.x()), v2.x()) / subpixel_factor) & ~1;
+ int const bx1 = (min(render_bounds.right(), max(max(v0.x(), v1.x()), v2.x()) / subpixel_factor) & ~1) + 2;
+ int const by0 = max(render_bounds.top(), min(min(v0.y(), v1.y()), v2.y()) / subpixel_factor) & ~1;
+ int const by1 = (min(render_bounds.bottom(), max(max(v0.y(), v1.y()), v2.y()) / subpixel_factor) & ~1) + 2;
// clang-format on
// Calculate depth of fragment for fog;
@@ -252,12 +249,12 @@ void Device::rasterize_triangle(Triangle const& triangle)
};
}
- float const render_bounds_left = render_bounds.left();
- float const render_bounds_right = render_bounds.right();
- float const render_bounds_top = render_bounds.top();
- float const render_bounds_bottom = render_bounds.bottom();
+ auto const render_bounds_left = render_bounds.left();
+ auto const render_bounds_right = render_bounds.right();
+ auto const render_bounds_top = render_bounds.top();
+ auto const render_bounds_bottom = render_bounds.bottom();
- auto const half_pixel_offset = Vector2<f32x4> { expand4(.5f), expand4(.5f) };
+ auto const half_pixel_offset = Vector2<i32x4> { expand4(subpixel_factor / 2), expand4(subpixel_factor / 2) };
auto color_buffer = m_frame_buffer->color_buffer();
auto depth_buffer = m_frame_buffer->depth_buffer();
@@ -314,17 +311,15 @@ void Device::rasterize_triangle(Triangle const& triangle)
// Iterate over all blocks within the bounds of the triangle
for (int by = by0; by < by1; by += 2) {
- auto const f_by = static_cast<float>(by);
for (int bx = bx0; bx < bx1; bx += 2) {
PixelQuad quad;
- auto const f_bx = static_cast<float>(bx);
quad.screen_coordinates = {
- f32x4 { f_bx, f_bx + 1, f_bx, f_bx + 1 },
- f32x4 { f_by, f_by, f_by + 1, f_by + 1 },
+ i32x4 { bx, bx + 1, bx, bx + 1 },
+ i32x4 { by, by, by + 1, by + 1 },
};
- auto edge_values = calculate_edge_values4(quad.screen_coordinates + half_pixel_offset);
+ auto edge_values = calculate_edge_values4(quad.screen_coordinates * subpixel_factor + half_pixel_offset);
// Generate triangle coverage mask
quad.mask = test_point4(edge_values);
@@ -401,7 +396,11 @@ void Device::rasterize_triangle(Triangle const& triangle)
}
// Calculate barycentric coordinates from previously calculated edge values
- quad.barycentrics = edge_values * one_over_area;
+ quad.barycentrics = Vector3<f32x4> {
+ to_f32x4(edge_values.x()),
+ to_f32x4(edge_values.y()),
+ to_f32x4(edge_values.z()),
+ } * one_over_area;
// Depth testing
GPU::DepthType* depth_ptrs[4] = {
@@ -926,12 +925,16 @@ void Device::draw_primitives(GPU::PrimitiveType primitive_type, FloatMatrix4x4 c
}
for (auto& triangle : m_processed_triangles) {
- auto area = edge_function(triangle.vertices[0].window_coordinates.xy(), triangle.vertices[1].window_coordinates.xy(), triangle.vertices[2].window_coordinates.xy());
- if (area == 0.f)
+ triangle.subpixel_coordinates[0] = (triangle.vertices[0].window_coordinates.xy() * subpixel_factor).to_rounded<int>();
+ triangle.subpixel_coordinates[1] = (triangle.vertices[1].window_coordinates.xy() * subpixel_factor).to_rounded<int>();
+ triangle.subpixel_coordinates[2] = (triangle.vertices[2].window_coordinates.xy() * subpixel_factor).to_rounded<int>();
+
+ auto triangle_area = edge_function(triangle.subpixel_coordinates[0], triangle.subpixel_coordinates[1], triangle.subpixel_coordinates[2]);
+ if (triangle_area == 0)
continue;
if (m_options.enable_culling) {
- bool is_front = (m_options.front_face == GPU::WindingOrder::CounterClockwise ? area > 0.f : area < 0.f);
+ bool is_front = (m_options.front_face == GPU::WindingOrder::CounterClockwise ? triangle_area > 0 : triangle_area < 0);
if (!is_front && m_options.cull_back)
continue;
@@ -941,8 +944,12 @@ void Device::draw_primitives(GPU::PrimitiveType primitive_type, FloatMatrix4x4 c
}
// Force counter-clockwise ordering of vertices
- if (area < 0.f)
+ if (triangle_area < 0) {
swap(triangle.vertices[0], triangle.vertices[1]);
+ swap(triangle.subpixel_coordinates[0], triangle.subpixel_coordinates[1]);
+ triangle_area *= -1;
+ }
+ triangle.area = triangle_area;
if (texture_coordinate_generation_enabled) {
generate_texture_coordinates(triangle.vertices[0], m_options);
diff --git a/Userland/Libraries/LibSoftGPU/Device.h b/Userland/Libraries/LibSoftGPU/Device.h
index 0ca46ef9dd..e1b438deab 100644
--- a/Userland/Libraries/LibSoftGPU/Device.h
+++ b/Userland/Libraries/LibSoftGPU/Device.h
@@ -77,7 +77,7 @@ private:
void draw_statistics_overlay(Gfx::Bitmap&);
Gfx::IntRect get_rasterization_rect_of_size(Gfx::IntSize size);
- void rasterize_triangle(Triangle const& triangle);
+ void rasterize_triangle(Triangle const&);
void setup_blend_factors();
void shade_fragments(PixelQuad&);
bool test_alpha(PixelQuad&);
diff --git a/Userland/Libraries/LibSoftGPU/PixelQuad.h b/Userland/Libraries/LibSoftGPU/PixelQuad.h
index f8a5725960..399130674b 100644
--- a/Userland/Libraries/LibSoftGPU/PixelQuad.h
+++ b/Userland/Libraries/LibSoftGPU/PixelQuad.h
@@ -15,7 +15,7 @@
namespace SoftGPU {
struct PixelQuad final {
- Vector2<AK::SIMD::f32x4> screen_coordinates;
+ Vector2<AK::SIMD::i32x4> screen_coordinates;
Vector3<AK::SIMD::f32x4> barycentrics;
AK::SIMD::f32x4 depth;
Vector4<AK::SIMD::f32x4> vertex_color;
diff --git a/Userland/Libraries/LibSoftGPU/Triangle.h b/Userland/Libraries/LibSoftGPU/Triangle.h
index 29cf3e037d..b5903ffe90 100644
--- a/Userland/Libraries/LibSoftGPU/Triangle.h
+++ b/Userland/Libraries/LibSoftGPU/Triangle.h
@@ -1,6 +1,7 @@
/*
* Copyright (c) 2021, Jesse Buhagiar <jooster669@gmail.com>
* Copyright (c) 2021, Stephan Unverwerth <s.unverwerth@serenityos.org>
+ * Copyright (c) 2022, Jelle Raaijmakers <jelle@gmta.nl>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
@@ -8,11 +9,14 @@
#pragma once
#include <LibGPU/Vertex.h>
+#include <LibGfx/Vector2.h>
namespace SoftGPU {
struct Triangle {
GPU::Vertex vertices[3];
+ IntVector2 subpixel_coordinates[3];
+ i32 area;
};
}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 14:46:13 +0000