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LibSoftGPU: Implement per-vertex Lighting during T&L Stage

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We now perform per vertex lighting during the Transform and Lighting
stage of the pipeline before the triangles are sent off to be
rasterized.
This commit is contained in:
Jesse Buhagiar 2022-01-09 23:11:12 +11:00 • committed by Linus Groh
parent 5a1f559ed9
commit 9aae648482
Notes: sideshowbarker 2024-07-17 21:06:10 +09:00
1 changed files with 67 additions and 0 deletions

67
Userland/Libraries/LibSoftGPU/Device.cpp
View file

@ -6,6 +6,7 @@
*/
#include <AK/Function.h>
#include <AK/Math.h>
#include <AK/SIMDExtras.h>
#include <AK/SIMDMath.h>
#include <LibCore/ElapsedTimer.h>
@ -665,6 +666,72 @@ void Device::draw_primitives(PrimitiveType primitive_type, FloatMatrix4x4 const&
if (m_clipped_vertices.size() < 3)
continue;
if (m_options.lighting_enabled) {
auto const& front_material = m_materials.at(0);
// Walk through each vertex
for (auto& vertex : m_clipped_vertices) {
FloatVector4 result_color = front_material.emissive + (front_material.ambient * m_lighting_model.scene_ambient_color);
for (auto const& light : m_lights) {
if (!light.is_enabled)
continue;
FloatVector4 vertex_to_light;
// Light attenuation value.
float light_attenuation_factor = 1.0f;
if (light.position.w() != 0.0f) {
vertex_to_light = light.position - vertex.eye_coordinates;
auto const vertex_to_light_length = vertex_to_light.length();
auto const vertex_to_light_length_squared = vertex_to_light_length * vertex_to_light_length;
light_attenuation_factor = 1.0f / (light.constant_attenuation + (light.linear_attenuation * vertex_to_light_length) + (light.quadratic_attenuation * vertex_to_light_length_squared));
vertex_to_light = vertex_to_light / vertex_to_light_length;
} else {
vertex_to_light = light.position.normalized();
}
// Spotlight factor
float spotlight_factor = 1.0f;
if (light.spotlight_cutoff_angle != 180.0f) {
const auto spotlight_direction_normalized = light.spotlight_direction.normalized();
const auto light_to_vertex_dot_normalized_spotlight_direction = spotlight_direction_normalized.dot(FloatVector3(vertex_to_light.x(), vertex_to_light.y(), vertex_to_light.z()));
const auto cos_spotlight_cutoff = AK::cos<float>(light.spotlight_cutoff_angle);
if (light_to_vertex_dot_normalized_spotlight_direction >= cos_spotlight_cutoff)
spotlight_factor = AK::pow<float>(light_to_vertex_dot_normalized_spotlight_direction, light.spotlight_exponent);
else
spotlight_factor = 0.0f;
}
// FIXME: Specular. The math for it doesn't quite make sense...
(void)m_lighting_model.viewer_at_infinity;
// FIXME: The spec allows for splitting the colors calculated here into multiple different colors (primary/secondary color). Investigate what this means.
(void)m_lighting_model.single_color;
// FIXME: Two sided lighting should be implemented eventually (I believe this is where the normals are -ve and then lighting is calculated with the BACK material)
(void)m_lighting_model.two_sided_lighting;
// Ambient
auto const ambient_component = front_material.ambient * light.ambient_intensity;
// Diffuse
auto const normal_dot_vertex_to_light = vertex.normal.dot(FloatVector3(vertex_to_light.x(), vertex_to_light.y(), vertex_to_light.z()));
auto const diffuse_component = ((front_material.diffuse * light.diffuse_intensity) * normal_dot_vertex_to_light).clamped(0.0f, 1.0f);
FloatVector4 color = ambient_component;
color += diffuse_component;
color = color * light_attenuation_factor * spotlight_factor;
result_color += color;
}
vertex.color = result_color;
vertex.color.set_w(front_material.diffuse.w()); // OpenGL 1.5 spec, page 59: "The A produced by lighting is the alpha value associated with diffuse color material"
vertex.color.clamp(0.0f, 1.0f);
}
}
for (auto& vec : m_clipped_vertices) {
// To normalized device coordinates (NDC)
auto const one_over_w = 1 / vec.clip_coordinates.w();