General Purpose library for Freestanding C++ and POSIX systems
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#pragma once
#include "gp_config.hpp"
#include "gp/math.hpp"
#include "gp/function.hpp"
#include "gp/algorithm/min_of.hpp"
#include "gp/indexed_array.hpp"
#include "gp/allocator/buddy.hpp"
using vec2 = gp::vec2_g<>;
using vec3 = gp::vec3_g<>;
using vec4 = gp::vec4_g<>;
struct camera{
vec3 position;
vec3 normal;
};
using index_t = size_t;
using distance_t = gp_config::rendering::default_type;
using color_t = GP_CONFIG__RENDERING__COLOR_T;
struct render_point{
distance_t distance;
index_t material;
bool operator<(const render_point& rhs) {
return distance < rhs.distance;
}
};
using sdf_t = gp::function<render_point(vec3&), gp::buddy<>>;
using material_t = gp::function<color_t(vec3&), gp::buddy<>>;
class renderer {
using g_t = gp_config::rendering::default_type;
constexpr static auto epsilon = gp_config::rendering::epsilon;
public:
gp::indexed_array<sdf_t, 4096> scene_elements;
gp::indexed_array<material_t, 4096> materials;
gp::buddy<> allocator;
material_t sky_box;
vec2 _resolution{128,64};
camera _camera{{0, 0, -1}, {0, 0, 0}};
vec2 _fov{90, 45};
distance_t projection_start = 1;
distance_t projection_end = 50;
size_t passes = 12;
renderer(gp::buffer<char> allocation_buffer)
: allocator(allocation_buffer.begin().data, allocation_buffer.size())
, sky_box{gp::reference_wrapper<gp::buddy<>>{allocator}}
{}
render_point sdf(vec3& render_target) {
return gp::min_of(
scene_elements.begin(),
scene_elements.end(),
[&](auto& p){
return p(render_target);
}
);
}
auto& get_allocator() {
return allocator;
}
color_t render(vec2 pixel) {
g_t depth = projection_start;
vec3 target = _camera.normal;
auto half_res = _resolution/vec2{2.0, 2.0};
pixel = pixel - half_res;
pixel = pixel / half_res;
pixel = pixel * _fov;
pixel = pixel / vec2{180, 180} * vec2{gp::pi<g_t>,gp::pi<g_t>};
// Y-rot (adjusts x)
target = vec3{
target.x*gp::cos(pixel.x) + target.z*gp::sin(pixel.x),
target.y,
-target.x*gp::sin(pixel.x)+target.z*gp::cos(pixel.x)
};
// X-rot (adjusts y)
target = vec3{
target.x,
target.y*gp::cos(pixel.y) - target.z*gp::sin(pixel.y),
target.y*gp::sin(pixel.y) + target.z*gp::cos(pixel.y)
};
vec3 render_target{_camera.position};
for(int i = 1; i < passes; ++i) {
render_point distance = sdf(render_target);
if(distance.distance < epsilon) {
return materials[distance.material](render_target);
}
depth += distance.distance;
if(depth >= projection_end) {
break;
}
render_target = _camera.position+depth*target;
}
return sky_box(render_target);
}
};