RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 15:48:12 +00:00
Code Issues Activity Actions

LibGL+LibSoftGPU: Implement texture coordinate generation

Browse source 
Texture coordinate generation is the concept of automatically
generating vertex texture coordinates instead of using the provided
coordinates (i.e. `glTexCoord`).

This commit implements support for:

* The `GL_TEXTURE_GEN_Q/R/S/T` capabilities
* The `GL_OBJECT_LINEAR`, `GL_EYE_LINEAR`, `GL_SPHERE_MAP`,
  `GL_REFLECTION_MAP` and `GL_NORMAL_MAP` modes
* Object and eye plane coefficients (write-only at the moment)

This changeset allows Tux Racer to render its terrain :^)
This commit is contained in:
Jelle Raaijmakers 2021-12-30 00:56:41 +01:00 • committed by Andreas Kling
parent 69da279073
commit c19632128c
5 changed files with 236 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

73
Userland/Libraries/LibSoftGPU/Device.cpp
View file

@ -533,6 +533,72 @@ DeviceInfo Device::info() const
};
}
static void generate_texture_coordinates(Vertex& vertex, RasterizerOptions const& options)
{
auto generate_coordinate = [&](size_t config_index) -> float {
auto mode = options.texcoord_generation_config[config_index].mode;
switch (mode) {
case TexCoordGenerationMode::ObjectLinear: {
auto coefficients = options.texcoord_generation_config[config_index].coefficients;
return coefficients.dot(vertex.position);
}
case TexCoordGenerationMode::EyeLinear: {
auto coefficients = options.texcoord_generation_config[config_index].coefficients;
return coefficients.dot(vertex.eye_coordinates);
}
case TexCoordGenerationMode::SphereMap: {
auto const eye_unit = vertex.eye_coordinates.normalized();
FloatVector3 const eye_unit_xyz = { eye_unit.x(), eye_unit.y(), eye_unit.z() };
auto const normal = vertex.normal;
auto reflection = eye_unit_xyz - normal * 2 * normal.dot(eye_unit_xyz);
reflection.set_z(reflection.z() + 1);
auto const reflection_value = (config_index == 0) ? reflection.x() : reflection.y();
return reflection_value / (2 * reflection.length()) + 0.5f;
}
case TexCoordGenerationMode::ReflectionMap: {
auto const eye_unit = vertex.eye_coordinates.normalized();
FloatVector3 const eye_unit_xyz = { eye_unit.x(), eye_unit.y(), eye_unit.z() };
auto const normal = vertex.normal;
auto reflection = eye_unit_xyz - normal * 2 * normal.dot(eye_unit_xyz);
switch (config_index) {
case 0:
return reflection.x();
case 1:
return reflection.y();
case 2:
return reflection.z();
default:
VERIFY_NOT_REACHED();
}
}
case TexCoordGenerationMode::NormalMap: {
auto const normal = vertex.normal;
switch (config_index) {
case 0:
return normal.x();
case 1:
return normal.y();
case 2:
return normal.z();
default:
VERIFY_NOT_REACHED();
}
}
default:
VERIFY_NOT_REACHED();
}
};
auto const enabled_coords = options.texcoord_generation_enabled_coordinates;
vertex.tex_coord = {
((enabled_coords & TexCoordGenerationCoordinate::S) > 0) ? generate_coordinate(0) : vertex.tex_coord.x(),
((enabled_coords & TexCoordGenerationCoordinate::T) > 0) ? generate_coordinate(1) : vertex.tex_coord.y(),
((enabled_coords & TexCoordGenerationCoordinate::R) > 0) ? generate_coordinate(2) : vertex.tex_coord.z(),
((enabled_coords & TexCoordGenerationCoordinate::Q) > 0) ? generate_coordinate(3) : vertex.tex_coord.w(),
};
}
void Device::draw_primitives(PrimitiveType primitive_type, FloatMatrix4x4 const& model_view_transform, FloatMatrix3x3 const& normal_transform,
FloatMatrix4x4 const& projection_transform, FloatMatrix4x4 const& texture_transform, Vector<Vertex> const& vertices,
Vector<size_t> const& enabled_texture_units)
@ -703,6 +769,13 @@ void Device::draw_primitives(PrimitiveType primitive_type, FloatMatrix4x4 const&
triangle.vertices[2].normal.normalize();
}
// Generate texture coordinates if at least one coordinate is enabled
if (m_options.texcoord_generation_enabled_coordinates != TexCoordGenerationCoordinate::None) {
generate_texture_coordinates(triangle.vertices[0], m_options);
generate_texture_coordinates(triangle.vertices[1], m_options);
generate_texture_coordinates(triangle.vertices[2], m_options);
}
// Apply texture transformation
// FIXME: implement multi-texturing: texcoords should be stored per texture unit
triangle.vertices[0].tex_coord = texture_transform * triangle.vertices[0].tex_coord;