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LibGL: SoftwareRasterizer: Use perspective correct interpolation

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Stephan Unverwerth 2021-05-11 19:25:17 +02:00 • committed by Andreas Kling
parent 4b55aea307
commit b63b15eeb5
2 changed files with 23 additions and 14 deletions
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1
Userland/Libraries/LibGL/SoftwareGLContext.cpp
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@ -238,6 +238,7 @@ void SoftwareGLContext::gl_end()
vec.set_x(vec.x() / vec.w()); vec.set_x(vec.x() / vec.w());
vec.set_y(vec.y() / vec.w()); vec.set_y(vec.y() / vec.w());
vec.set_z(vec.z() / vec.w()); vec.set_z(vec.z() / vec.w());
vec.set_w(1 / vec.w());
} }
vertex.x = vec.x(); vertex.x = vec.x();

36
Userland/Libraries/LibGL/SoftwareRasterizer.cpp
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@ -196,8 +196,26 @@ static void rasterize_triangle(const RasterizerOptions& options, Gfx::Bitmap& re
if (~pixel_mask[y] & (1 << x)) if (~pixel_mask[y] & (1 << x))
continue; continue;
// Perspective correct barycentric coordinates
auto barycentric = FloatVector3(coords.x(), coords.y(), coords.z()) * one_over_area; auto barycentric = FloatVector3(coords.x(), coords.y(), coords.z()) * one_over_area;
*pixel = to_rgba32(pixel_shader(barycentric, triangle)); float interpolated_reciprocal_w = interpolate(triangle.vertices[0].w, triangle.vertices[1].w, triangle.vertices[2].w, barycentric);
float interpolated_w = 1 / interpolated_reciprocal_w;
barycentric = barycentric * FloatVector3(triangle.vertices[0].w, triangle.vertices[1].w, triangle.vertices[2].w) * interpolated_w;
// FIXME: make this more generic. We want to interpolate more than just color and uv
auto rgba = interpolate(
FloatVector4(triangle.vertices[0].r, triangle.vertices[0].g, triangle.vertices[0].b, triangle.vertices[0].a),
FloatVector4(triangle.vertices[1].r, triangle.vertices[1].g, triangle.vertices[1].b, triangle.vertices[1].a),
FloatVector4(triangle.vertices[2].r, triangle.vertices[2].g, triangle.vertices[2].b, triangle.vertices[2].a),
barycentric);
auto uv = interpolate(
FloatVector2(triangle.vertices[0].u, triangle.vertices[0].v),
FloatVector2(triangle.vertices[1].u, triangle.vertices[1].v),
FloatVector2(triangle.vertices[2].u, triangle.vertices[2].v),
barycentric);
*pixel = to_rgba32(pixel_shader(uv, rgba));
} }
} }
} }
@ -219,19 +237,9 @@ SoftwareRasterizer::SoftwareRasterizer(const Gfx::IntSize& min_size)
void SoftwareRasterizer::submit_triangle(const GLTriangle& triangle) void SoftwareRasterizer::submit_triangle(const GLTriangle& triangle)
{ {
if (m_options.shade_smooth) { rasterize_triangle(m_options, *m_render_target, *m_depth_buffer, triangle, [](const FloatVector2&, const FloatVector4& color) -> FloatVector4 {
rasterize_triangle(m_options, *m_render_target, *m_depth_buffer, triangle, [](const FloatVector3& v, const GLTriangle& t) -> FloatVector4 { return color;
const float r = t.vertices[0].r * v.x() + t.vertices[1].r * v.y() + t.vertices[2].r * v.z(); });
const float g = t.vertices[0].g * v.x() + t.vertices[1].g * v.y() + t.vertices[2].g * v.z();
const float b = t.vertices[0].b * v.x() + t.vertices[1].b * v.y() + t.vertices[2].b * v.z();
const float a = t.vertices[0].a * v.x() + t.vertices[1].a * v.y() + t.vertices[2].a * v.z();
return { r, g, b, a };
});
} else {
rasterize_triangle(m_options, *m_render_target, *m_depth_buffer, triangle, [](const FloatVector3&, const GLTriangle& t) -> FloatVector4 {
return { t.vertices[0].r, t.vertices[0].g, t.vertices[0].b, t.vertices[0].a };
});
}
} }
void SoftwareRasterizer::resize(const Gfx::IntSize& min_size) void SoftwareRasterizer::resize(const Gfx::IntSize& min_size)