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Commit 0d558ddf authored by Patrik Huber's avatar Patrik Huber
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First version of new software renderer 

It is modeled after the vertex shader / fragment shader approach of modern OpenGL.
It also includes a texture extraction fragment shader, which hopefully will replace the current affine texture extraction.

This is still very much experimental, containing lots of todo's. For example it contains lots of if-hacks to select the correct fragment shader (for rendering or texture extraction).
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CMakeLists.txt
View file @ 0d558ddf
......@@ -93,6 +93,10 @@ set(HEADERS
${CMAKE_CURRENT_SOURCE_DIR}/include/eos/render/detail/render_affine_detail.hpp
${CMAKE_CURRENT_SOURCE_DIR}/include/eos/render/texture_extraction.hpp
${CMAKE_CURRENT_SOURCE_DIR}/include/eos/render/detail/texture_extraction_detail.hpp
${CMAKE_CURRENT_SOURCE_DIR}/include/eos/render/SoftwareRenderer.hpp
${CMAKE_CURRENT_SOURCE_DIR}/include/eos/render/VertexShader.hpp
${CMAKE_CURRENT_SOURCE_DIR}/include/eos/render/FragmentShader.hpp
${CMAKE_CURRENT_SOURCE_DIR}/include/eos/render/detail/Vertex.hpp
)
add_library(eos INTERFACE)
......
include/eos/render/FragmentShader.hpp 0 → 100644
View file @ 0d558ddf
/*
* eos - A 3D Morphable Model fitting library written in modern C++11/14.
*
* File: include/eos/render/FragmentShader.hpp
*
* Copyright 2017 Patrik Huber
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#ifndef FRAGMENTSHADER_HPP_
#define FRAGMENTSHADER_HPP_
#include "eos/render/detail/Vertex.hpp"
#include "eos/render/utils.hpp"
#include "glm/vec3.hpp"
#include "glm/vec4.hpp"
#include "boost/optional.hpp"
// Fragment shaders are a more accurate name for the same functionality as Pixel shaders. They aren't pixels
// yet, since the output still has to past several tests (depth, alpha, stencil) as well as the fact that one
// may be using antialiasing, which renders one-fragment-to-one-pixel non-true.
// The "pixel" in "pixel shader" is a misnomer because the pixel shader doesn't operate on pixels directly.
// The pixel shader operates on "fragments" which may or may not end up as actual pixels, depending on several
// factors outside of the pixel shader.
// The shaders *can not* depend on any state - they have to be able to run independently and in parallel!
// But can they really? What about the z-test? It happens earlier at the moment - which is good?
namespace eos {
namespace render {
/**
* @brief A simple fragment shader that does vertex-colouring.
*
* Uses the vertex colour data to shade the given fragment / pixel location.
*/
class VertexColoringFragmentShader
{
public:
/**
* @brief Todo.
*
* X
* lambda is not perspectively corrected. Note: In our case, it is, as we do it in the raster loop at
* the moment?
* Note/TODO: We should document in what range we expect ::color to be! Eg specify that Mesh should be
* [0,255]? But don't we then lose precision sometimes (e.g. superres)? I think we can leave Mesh /
* everything in [0,1] and convert at the very end.
*
* @param[in] x X.
* @ return RGBA... in [0, 1]?
*/
template <typename T, glm::precision P = glm::defaultp>
glm::tvec4<T, P>
shade_triangle_pixel(int x, int y, const detail::v2::Vertex<T, P>& point_a,
const detail::v2::Vertex<T, P>& point_b, const detail::v2::Vertex<T, P>& point_c,
const glm::tvec3<T, P>& lambda, const boost::optional<Texture>& texture, float dudx,
float dudy, float dvdx, float dvdy)
{
// attributes interpolation
glm::tvec3<T, P> color_persp =
lambda[0] * point_a.color + lambda[1] * point_b.color + lambda[2] * point_c.color;
return glm::tvec4<T, P>(color_persp, T(1));
};
};
/**
* @brief A fragment shader that textures...
*
* X.
*/
class TexturingFragmentShader
{
public:
/**
* @brief Todo.
*
* See comments above about lambda (persp. corrected?) and the colour range.
*
* @param[in] x X.
* @ return RGBA... in [0, 1]?
*/
template <typename T, glm::precision P = glm::defaultp>
glm::tvec4<T, P>
shade_triangle_pixel(int x, int y, const detail::v2::Vertex<T, P>& point_a,
const detail::v2::Vertex<T, P>& point_b, const detail::v2::Vertex<T, P>& point_c,
const glm::tvec3<T, P>& lambda, const boost::optional<eos::render::Texture>& texture,
float dudx, float dudy, float dvdx, float dvdy)
{
glm::tvec2<T, P> texcoords_persp =
lambda[0] * point_a.texcoords + lambda[1] * point_b.texcoords + lambda[2] * point_c.texcoords;
// The Texture is in BGR, thus tex2D returns BGR
// Todo: Think about changing that.
glm::tvec3<T, P> texture_color =
detail::tex2d(texcoords_persp, texture.get(), dudx, dudy, dvdx, dvdy); // uses the current texture
glm::tvec3<T, P> pixel_color = glm::tvec3<T, P>(texture_color[2], texture_color[1], texture_color[0]);
// other: color.mul(tex2D(texture, texCoord));
return glm::tvec4<T, P>(pixel_color, T(1));
};
};
/**
* @brief X.
*
* X.
* Inverts the perspective texture mapping. Can be derived using some tedious algebra.
* Todo: Probably move to a texturing file, internal/detail one, where we will also put the tex2d, mipmapping
* etc stuff?
*
* @param[in] X X.
* @return X.
*/
template <typename T, glm::precision P = glm::defaultp>
glm::tvec3<T, P> compute_inverse_perspectively_correct_lambda(const glm::tvec3<T, P>& lambda_world,
const T& one_over_w0, const T& one_over_w1,
const T& one_over_w2)
{
float w0 = 1 / one_over_w0;
float w1 = 1 / one_over_w1;
float w2 = 1 / one_over_w2;
float d = w0 - (w0 - w1) * lambda_world.y - (w0 - w2) * lambda_world.z;
if (d == 0)
return lambda_world;
glm::tvec3<T, P> lambda;
lambda.z = lambda_world.z * w2 / d;
lambda.y = lambda_world.y * w1 / d;
lambda.x = 1 - lambda.y - lambda.z;
return lambda;
};
class ExtractionFragmentShader
{
public:
/**
* @brief X.
*
* X.
* Inverts the perspective texture mapping. Can be derived using some tedious algebra.
* NOTE: This one actually takes/needs the perspectively corrected lambda I think!
*
* Todo: Probably move to a texturing file, internal/detail one, where we will also put the tex2d,
* mipmapping etc stuff?
*
* @param[in] X X.
* @return X.
*/
template <typename T, glm::precision P = glm::defaultp>
glm::tvec4<T, P>
shade_triangle_pixel(int x, int y, const detail::v2::Vertex<T, P>& point_a,
const detail::v2::Vertex<T, P>& point_b, const detail::v2::Vertex<T, P>& point_c,
const glm::tvec3<T, P>& lambda, const boost::optional<Texture>& texture, float dudx,
float dudy, float dvdx, float dvdy)
{
auto corrected_lambda = compute_inverse_perspectively_correct_lambda(
lambda, point_a.position.w, point_b.position.w, point_c.position.w);
glm::tvec2<T, P> texcoords_persp = corrected_lambda[0] * point_a.texcoords +
corrected_lambda[1] * point_b.texcoords +
corrected_lambda[2] * point_c.texcoords;
// Texturing, no mipmapping:
cv::Vec2f image_tex_coords = detail::texcoord_wrap(cv::Vec2f(texcoords_persp.s, texcoords_persp.t));
image_tex_coords[0] *= texture->mipmaps[0].cols;
image_tex_coords[1] *= texture->mipmaps[0].rows;
cv::Vec3f texture_color = detail::tex2d_linear(image_tex_coords, 0, texture.get()) / 255.0;
glm::tvec3<T, P> pixel_color = glm::tvec3<T, P>(texture_color[2], texture_color[1], texture_color[0]);
return glm::tvec4<T, P>(pixel_color, T(1));
};
};
} /* namespace render */
} /* namespace eos */
#endif /* FRAGMENTSHADER_HPP_ */
include/eos/render/SoftwareRenderer.hpp 0 → 100644
View file @ 0d558ddf
/*
* eos - A 3D Morphable Model fitting library written in modern C++11/14.
*
* File: include/eos/render/SoftwareRenderer.hpp
*
* Copyright 2017 Patrik Huber
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#ifndef SOFTWARERENDERER_HPP_
#define SOFTWARERENDERER_HPP_
#include "eos/core/Mesh.hpp"
#include "eos/render/detail/Vertex.hpp"
#include "eos/render/utils.hpp" // for Texture, potentially others
#include "glm/mat4x4.hpp"
#include "glm/vec2.hpp"
#include "glm/vec4.hpp"
#include "opencv2/core/core.hpp"
#include "boost/optional.hpp"
#include <array>
#include <limits>
/**
* @file include/eos/render/SoftwareRenderer.hpp
* @brief This file implements a software renderer, in the spirit of OpenGL conventions and vertex and
* fragment shaders.
*
* Might be worth adding the comments from render.hpp, regarding the pipeline and
* OpenGL conventions etc.
*/
namespace eos {
namespace render {
// Forward declarations (these functions should probably be moved into detail/):
template <typename T, glm::precision P = glm::defaultp>
glm::tvec4<T, P> divide_by_w(const glm::tvec4<T, P>& vertex);
template <typename T, glm::precision P = glm::defaultp>
std::vector<detail::v2::Vertex<T, P>>
clip_polygon_to_plane_in_4d(const std::vector<detail::v2::Vertex<T, P>>& vertices,
const glm::tvec4<T, P>& plane_normal);
/**
* @brief X.
*
* Can this go into the SoftwareRenderer class or something? No, I think FragShader needs it? Where to put it?
*/
template <typename T, glm::precision P = glm::defaultp>
using Triangle = std::array<detail::v2::Vertex<T, P>, 3>;
/**
* @brief X.
*
* Longer.
*
* @tparam VertexShaderType vs-type.
* @tparam FragmentShaderType fs-type.
*/
template <typename VertexShaderType, typename FragmentShaderType>
class SoftwareRenderer
{
public:
SoftwareRenderer(int viewport_width, int viewport_height)
: viewport_width(viewport_width), viewport_height(viewport_height)
{
colorbuffer = cv::Mat(viewport_height, viewport_width, CV_8UC4, cv::Scalar::all(255));
depthbuffer =
std::numeric_limits<double>::max() * Mat::ones(viewport_height, viewport_width, CV_64FC1);
};
// Deleting copy constructor and assignment for now because e.g. the framebuffer member is a
// cv::Mat, so copying a renderer will not copy the framebuffer. We may want to fix that properly.
SoftwareRenderer(const SoftwareRenderer& rhs) = delete;
SoftwareRenderer& operator=(const SoftwareRenderer&) = delete;
/**
* @brief Todo.
*
* Todo.
* The returned framebuffer cv::Mat is a smart-pointer to the colorbuffer object inside SoftwareRenderer,
* and will be overwritten on the next call to render(). If you want a copy, use .clone()!
*
* @param[in] mesh The mesh to render.
* @param[in] model_view_matrix The mesh to render.
* @param[in] projection_matrix The mesh to render.
* @param[in] texture The mesh to render.
* @ return The framebuffer (colourbuffer) with the rendered object.
*/
template <typename T, glm::precision P = glm::defaultp>
cv::Mat render(const eos::core::Mesh& mesh, const glm::tmat4x4<T, P>& model_view_matrix,
const glm::tmat4x4<T, P>& projection_matrix,
const boost::optional<eos::render::Texture>& texture = boost::none)
{
assert(mesh.vertices.size() == mesh.colors.size() ||
mesh.colors.empty()); // The number of vertices has to be equal for both shape and colour, or,
// alternatively, it has to be a shape-only model.
assert(mesh.vertices.size() == mesh.texcoords.size() ||
mesh.texcoords.empty()); // same for the texcoords
// Add another assert: If cv::Mat texture != empty (and/or texturing=true?), then we need texcoords?
using cv::Mat;
using std::vector;
vector<glm::tvec4<T, P>> clipspace_vertices;
for (const auto& vertex_position : mesh.vertices)
{
clipspace_vertices.push_back(
vertex_shader(vertex_position, model_view_matrix, projection_matrix));
// Note: if mesh.colors.empty() (in case of shape-only model!), then the vertex colour is no
// longer set to gray. But we don't want that here, maybe we only want texturing, then we don't
// need vertex-colours at all! We can do it in a custom VertexShader if needed!
}
// All vertices are in clip-space now. Prepare the rasterisation stage:
vector<Triangle<T, P>> triangles_to_raster;
// This builds the (one and final) triangles to render. Meaning: The triangles formed of mesh.tvi (the
// ones that survived the clip/culling), plus possibly more that intersect one of the frustum planes
// (i.e. this can generate new triangles with new pos/vc/texcoords).
for (const auto& tri_indices : mesh.tvi)
{
unsigned char visibility_bits[3];
for (unsigned char k = 0; k < 3; k++)
{
visibility_bits[k] = 0;
const auto x_cc = clipspace_vertices[tri_indices[k]].x;
const auto y_cc = clipspace_vertices[tri_indices[k]].y;
const auto z_cc = clipspace_vertices[tri_indices[k]].z;
const auto w_cc = clipspace_vertices[tri_indices[k]].w;
if (x_cc < -w_cc) // true if outside of view frustum. False if on or inside the plane.
visibility_bits[k] |= 1; // set bit if outside of frustum
if (x_cc > w_cc)
visibility_bits[k] |= 2;
if (y_cc < -w_cc)
visibility_bits[k] |= 4;
if (y_cc > w_cc)
visibility_bits[k] |= 8;
if (enable_near_clipping && z_cc < -w_cc) // near plane frustum clipping
visibility_bits[k] |= 16;
if (enable_far_clipping && z_cc > w_cc) // far plane frustum clipping
visibility_bits[k] |= 32;
} // if all bits are 0, then it's inside the frustum
// all vertices are not visible - reject the triangle.
if ((visibility_bits[0] & visibility_bits[1] & visibility_bits[2]) > 0)
{
continue;
}
// all vertices are visible - pass the whole triangle to the rasteriser. = All bits of all 3
// triangles are 0.
if ((visibility_bits[0] | visibility_bits[1] | visibility_bits[2]) == 0)
{
// relevant part of process_prospective_tri:
std::array<glm::tvec4<T, P>, 3> prospective_tri{
divide_by_w(clipspace_vertices[tri_indices[0]]),
divide_by_w(clipspace_vertices[tri_indices[1]]),
divide_by_w(clipspace_vertices[tri_indices[2]])};
// We have a prospective tri in NDC coords now, with its vertices having coords [x_ndc, y_ndc,
// z_ndc, 1/w_clip].
// Replaces x and y of the NDC coords with the screen coords. Keep z and w the same.
const glm::tvec2<T, P> v0_screen = clip_to_screen_space(
prospective_tri[0].x, prospective_tri[0].y, viewport_width, viewport_height);
prospective_tri[0].x = v0_screen.x;
prospective_tri[0].y = v0_screen.y;
const glm::tvec2<T, P> v1_screen = clip_to_screen_space(
prospective_tri[1].x, prospective_tri[1].y, viewport_width, viewport_height);
prospective_tri[1].x = v1_screen.x;
prospective_tri[1].y = v1_screen.y;
const glm::tvec2<T, P> v2_screen = clip_to_screen_space(
prospective_tri[2].x, prospective_tri[2].y, viewport_width, viewport_height);
prospective_tri[2].x = v2_screen.x;
prospective_tri[2].y = v2_screen.y;
// Culling (front/back/none - or what are OpenGL's modes?). Do we do any culling
// elsewhere? No?
if (enable_backface_culling)
{
if (!detail::are_vertices_ccw_in_screen_space(
glm::tvec2<T, P>(prospective_tri[0].x, prospective_tri[0].y),
glm::tvec2<T, P>(prospective_tri[1].x, prospective_tri[1].y),
glm::tvec2<T, P>(prospective_tri[2].x, prospective_tri[2].y)))
continue;
}
// Get the bounding box of the triangle:
const cv::Rect boundingBox = detail::calculate_clipped_bounding_box(
glm::tvec2<T, P>(prospective_tri[0].x, prospective_tri[0].y),
glm::tvec2<T, P>(prospective_tri[1].x, prospective_tri[1].y),
glm::tvec2<T, P>(prospective_tri[2].x, prospective_tri[2].y), viewport_width,
viewport_height);
const auto min_x = boundingBox.x;
const auto max_x = boundingBox.x + boundingBox.width;
const auto min_y = boundingBox.y;
const auto max_y = boundingBox.y + boundingBox.height;
if (max_x <= min_x || max_y <= min_y)
{ // Note: Can the width/height of the bbox be negative? Maybe we only need to check for
// equality here?
continue;
}
// If we're here, the triangle is CCW in screen space and the bbox is inside the viewport!
triangles_to_raster.push_back(
Triangle<T, P>{detail::v2::Vertex<T, P>{prospective_tri[0], mesh.colors[tri_indices[0]],
mesh.texcoords[tri_indices[0]]},
detail::v2::Vertex<T, P>{prospective_tri[1], mesh.colors[tri_indices[1]],
mesh.texcoords[tri_indices[1]]},
detail::v2::Vertex<T, P>{prospective_tri[2], mesh.colors[tri_indices[2]],
mesh.texcoords[tri_indices[2]]}});
continue; // Triangle was either added or not added. Continue with next triangle.
}
// At this point, the triangle is known to be intersecting one of the view frustum's planes
// Note: It seems that this is only w.r.t. the near-plane. If a triangle is partially outside the
// tlbr viewport, it'll get rejected.
// Well, 'z' of these triangles seems to be -1, so is that really the near plane?
std::vector<detail::v2::Vertex<T, P>> vertices;
vertices.reserve(3);
vertices.push_back(detail::v2::Vertex<T, P>{clipspace_vertices[tri_indices[0]],
mesh.colors[tri_indices[0]],
mesh.texcoords[tri_indices[0]]});
vertices.push_back(detail::v2::Vertex<T, P>{clipspace_vertices[tri_indices[1]],
mesh.colors[tri_indices[1]],
mesh.texcoords[tri_indices[1]]});
vertices.push_back(detail::v2::Vertex<T, P>{clipspace_vertices[tri_indices[2]],
mesh.colors[tri_indices[2]],
mesh.texcoords[tri_indices[2]]});
// split the triangle if it intersects the near plane:
if (enable_near_clipping)
{
vertices = clip_polygon_to_plane_in_4d(
vertices, glm::tvec4<T, P>(T(0.0), T(0.0), T(-1.0),
T(-1.0))); // "Normal" (or "4D hyperplane") of the near-plane.
// I tested it and it works like this but I'm a
// little bit unsure because Songho says the normal
// of the near-plane is (0,0,-1,1) (maybe I have to
// switch around the < 0 checks in the function?)
}
// Triangulation of the polygon formed of the 'vertices' array:
if (vertices.size() >= 3)
{
for (unsigned char k = 0; k < vertices.size() - 2; k++)
{
// Build a triangle from vertices[0], vertices[1 + k], vertices[2 + k]:
// Add to triangles_to_raster if it passed culling etc.
// TODO: This does the same as above - the code is copied 1:1. Avoid!
// COPY START (but init of prospective_tri is changed, as well as init of 't'.)
std::array<glm::tvec4<T, P>, 3> prospective_tri{divide_by_w(vertices[0].position),
divide_by_w(vertices[1 + k].position),
divide_by_w(vertices[2 + k].position)};
const glm::tvec2<T, P> v0_screen = clip_to_screen_space(
prospective_tri[0].x, prospective_tri[0].y, viewport_width, viewport_height);
prospective_tri[0].x = v0_screen.x;
prospective_tri[0].y = v0_screen.y;
const glm::tvec2<T, P> v1_screen = clip_to_screen_space(
prospective_tri[1].x, prospective_tri[1].y, viewport_width, viewport_height);
prospective_tri[1].x = v1_screen.x;
prospective_tri[1].y = v1_screen.y;
const glm::tvec2<T, P> v2_screen = clip_to_screen_space(
prospective_tri[2].x, prospective_tri[2].y, viewport_width, viewport_height);
prospective_tri[2].x = v2_screen.x;
prospective_tri[2].y = v2_screen.y;
if (enable_backface_culling)
{
if (!detail::are_vertices_ccw_in_screen_space(
glm::tvec2<T, P>(prospective_tri[0].x, prospective_tri[0].y),
glm::tvec2<T, P>(prospective_tri[1].x, prospective_tri[1].y),
glm::tvec2<T, P>(prospective_tri[2].x, prospective_tri[2].y)))
continue;
}
const cv::Rect boundingBox = detail::calculate_clipped_bounding_box(
glm::tvec2<T, P>(prospective_tri[0].x, prospective_tri[0].y),
glm::tvec2<T, P>(prospective_tri[1].x, prospective_tri[1].y),
glm::tvec2<T, P>(prospective_tri[2].x, prospective_tri[2].y), viewport_width,
viewport_height);
const auto min_x = boundingBox.x;
const auto max_x = boundingBox.x + boundingBox.width;
const auto min_y = boundingBox.y;
const auto max_y = boundingBox.y + boundingBox.height;
if (max_x <= min_x || max_y <= min_y)
{
continue;
}
// If we're here, the triangle is CCW in screen space and the bbox is inside the viewport!
triangles_to_raster.push_back(
Triangle<T, P>{detail::v2::Vertex<T, P>{prospective_tri[0], vertices[0].color,
vertices[0].texcoords},
detail::v2::Vertex<T, P>{prospective_tri[1], vertices[1 + k].color,
vertices[1 + k].texcoords},
detail::v2::Vertex<T, P>{prospective_tri[2], vertices[2 + k].color,
vertices[2 + k].texcoords}});
// continue; // triangle was either added or not added. Continue with next triangle.
// COPY END
}
}
} // end of loop over all triangles
// Each triangle contains [x_screen, y_screen, z_ndc, 1/w_clip].
// We may have more triangles than in the original mesh.
// Raster each triangle and apply the fragment shader on each pixel:
for (const auto& tri : triangles_to_raster)
{
raster_triangle(tri[0], tri[1], tri[2], texture);
}
return colorbuffer;
};
public: // Todo: these should go private in the final implementation
cv::Mat colorbuffer;
cv::Mat depthbuffer;
boost::optional<Texture> texture = boost::none;
bool enable_backface_culling = false;
bool enable_near_clipping = true;
bool enable_far_clipping = true;
bool enable_depth_test = true; // maybe get rid of this again, it was just as a hack.
bool extracting_tex = false;
VertexShaderType vertex_shader;
FragmentShaderType fragment_shader; // Replace with Rasterizer, move FS into Rasterizer
int viewport_width;
int viewport_height;
public:
/**
* @brief Todo.
*
* X
*
* @param[in] vertex X.
* @ return X.
*/
template <typename T, glm::precision P = glm::defaultp>
void raster_triangle(const detail::v2::Vertex<T, P>& point_a, const detail::v2::Vertex<T, P>& point_b,
const detail::v2::Vertex<T, P>& point_c, const boost::optional<Texture>& texture)
{
// We already calculated this in the culling/clipping stage. Maybe we should save/cache it after all.
cv::Rect boundingBox = detail::calculate_clipped_bounding_box(
glm::tvec2<T, P>(point_a.position.x, point_a.position.y),
glm::tvec2<T, P>(point_b.position.x, point_b.position.y),
glm::tvec2<T, P>(point_c.position.x, point_c.position.y), viewport_width, viewport_height);
const auto min_x = boundingBox.x;
const auto max_x = boundingBox.x + boundingBox.width;
const auto min_y = boundingBox.y;
const auto max_y = boundingBox.y + boundingBox.height;
// These are triangle-specific, i.e. calculate once per triangle.
// These ones are needed for perspective correct lambdas! (as well as mipmapping)
const auto& one_over_w0 = point_a.position[3];
const auto& one_over_w1 = point_b.position[3];
const auto& one_over_w2 = point_c.position[3];
// These are triangle-specific, i.e. calculate once per triangle.
// For partial derivatives computation (for mipmapping, texturing) (they work on screen-space coords):
using eos::render::detail::plane;
const auto alpha_plane = plane(
glm::tvec3<T, P>(point_a.position[0], point_a.position[1], point_a.texcoords[0] * one_over_w0),
glm::tvec3<T, P>(point_b.position[0], point_b.position[1], point_b.texcoords[0] * one_over_w1),
glm::tvec3<T, P>(point_c.position[0], point_c.position[1], point_c.texcoords[0] * one_over_w2));
const auto beta_plane = plane(
glm::tvec3<T, P>(point_a.position[0], point_a.position[1], point_a.texcoords[1] * one_over_w0),
glm::tvec3<T, P>(point_b.position[0], point_b.position[1], point_b.texcoords[1] * one_over_w1),
glm::tvec3<T, P>(point_c.position[0], point_c.position[1], point_c.texcoords[1] * one_over_w2));
const auto gamma_plane =
plane(glm::tvec3<T, P>(point_a.position[0], point_a.position[1], one_over_w0),
glm::tvec3<T, P>(point_b.position[0], point_b.position[1], one_over_w1),
glm::tvec3<T, P>(point_c.position[0], point_c.position[1], one_over_w2));
const auto one_over_alpha_c = 1.0f / alpha_plane.c;
const auto one_over_beta_c = 1.0f / beta_plane.c;
const auto one_over_gamma_c = 1.0f / gamma_plane.c;
const auto alpha_ffx = -alpha_plane.a * one_over_alpha_c;
const auto beta_ffx = -beta_plane.a * one_over_beta_c;
const auto gamma_ffx = -gamma_plane.a * one_over_gamma_c;
const auto alpha_ffy = -alpha_plane.b * one_over_alpha_c;
const auto beta_ffy = -beta_plane.b * one_over_beta_c;
const auto gamma_ffy = -gamma_plane.b * one_over_gamma_c;
for (int yi = min_y; yi <= max_y; ++yi)
{
for (int xi = min_x; xi <= max_x; ++xi)
{
// we want centers of pixels to be used in computations. Todo: Do we? Do we pass it with or
// without +0.5 to the FragShader?
const float x = static_cast<float>(xi) + 0.5f; // double? T?
const float y = static_cast<float>(yi) + 0.5f;
// These will be used for barycentric weights computation
using detail::implicit_line;
const double one_over_v0ToLine12 =
1.0 / implicit_line(point_a.position[0], point_a.position[1], point_b.position,
point_c.position);
const double one_over_v1ToLine20 =
1.0 / implicit_line(point_b.position[0], point_b.position[1], point_c.position,
point_a.position);
const double one_over_v2ToLine01 =
1.0 / implicit_line(point_c.position[0], point_c.position[1], point_a.position,
point_b.position);
// Affine barycentric weights:
double alpha = implicit_line(x, y, point_b.position, point_c.position) * one_over_v0ToLine12;
double beta = implicit_line(x, y, point_c.position, point_a.position) * one_over_v1ToLine20;
double gamma = implicit_line(x, y, point_a.position, point_b.position) * one_over_v2ToLine01;
// if pixel (x, y) is inside the triangle or on one of its edges
if (alpha >= 0 && beta >= 0 && gamma >= 0)
{
const int pixel_index_row = yi;
const int pixel_index_col = xi;
// TODO: Check this one. What about perspective?
const double z_affine = alpha * static_cast<double>(point_a.position[2]) +
beta * static_cast<double>(point_b.position[2]) +
gamma * static_cast<double>(point_c.position[2]);
bool draw = true;
if (enable_far_clipping)
{
if (z_affine > 1.0)
{
draw = false;
}
}
bool passes_depth_test = false;
if (enable_depth_test)
{
// If enable_depth_test=false, avoid accessing the depthbuffer at all - it might be
// empty or have other dimensions.
passes_depth_test =
(z_affine < depthbuffer.at<double>(pixel_index_row, pixel_index_col));
}
// The '<= 1.0' clips against the far-plane in NDC. We clip against the near-plane
// earlier.
// if (z_affine < depthbuffer.at<double>(pixelIndexRow, pixelIndexCol)/* && z_affine <=
// 1.0*/) // what to do in ortho case without n/f "squashing"? should we always squash? or
// a flag?
if ((passes_depth_test && draw) || enable_depth_test == false)
{
// perspective-correct barycentric weights
// Todo: Check this in the original/older implementation, i.e. if all is still
// perspective-correct. I think so. Also compare 1:1 with OpenGL.
double d = alpha * one_over_w0 + beta * one_over_w1 + gamma * one_over_w2;
d = 1.0 / d;
if (!extracting_tex) // Pass the uncorrected lambda if we're extracting tex... hack...
// do properly!
{
alpha *= d * one_over_w0; // In case of affine cam matrix, everything is 1 and
// a/b/g don't get changed.
beta *= d * one_over_w1;
gamma *= d * one_over_w2;
}
glm::tvec3<T, P> lambda(alpha, beta, gamma);
glm::tvec4<T, P> pixel_color;
if (texture)
{
// check if texture != NULL?
// partial derivatives (for mip-mapping, not needed for texturing otherwise!)
const float u_over_z =
-(alpha_plane.a * x + alpha_plane.b * y + alpha_plane.d) * one_over_alpha_c;
const float v_over_z =
-(beta_plane.a * x + beta_plane.b * y + beta_plane.d) * one_over_beta_c;
const float one_over_z =
-(gamma_plane.a * x + gamma_plane.b * y + gamma_plane.d) * one_over_gamma_c;
const float one_over_squared_one_over_z = 1.0f / std::pow(one_over_z, 2);
// partial derivatives of U/V coordinates with respect to X/Y pixel's screen
// coordinates
// These are exclusively used for the mipmap level computation (i.e. which mipmap
// levels to use).
// They're not needed for texturing otherwise at all!
float dudx =
one_over_squared_one_over_z * (alpha_ffx * one_over_z - u_over_z * gamma_ffx);
float dudy =
one_over_squared_one_over_z * (beta_ffx * one_over_z - v_over_z * gamma_ffx);
float dvdx =
one_over_squared_one_over_z * (alpha_ffy * one_over_z - u_over_z * gamma_ffy);
float dvdy =
one_over_squared_one_over_z * (beta_ffy * one_over_z - v_over_z * gamma_ffy);
dudx *= texture.get().mipmaps[0].cols;
dudy *= texture.get().mipmaps[0].cols;
dvdx *= texture.get().mipmaps[0].rows;
dvdy *= texture.get().mipmaps[0].rows;
// Why does it need x and y? Maybe some shaders (eg TexExtr?) need it?
pixel_color = fragment_shader.shade_triangle_pixel(
x, y, point_a, point_b, point_c, lambda, texture, dudx, dudy, dvdx, dvdy);
} else
{ // We use vertex-coloring
// Why does it need x and y?
pixel_color = fragment_shader.shade_triangle_pixel(
x, y, point_a, point_b, point_c, lambda, texture, 0, 0, 0, 0);
}
// clamp bytes to 255
// Todo: Proper casting (rounding?)? And we don't clamp/max against 255? Use
// glm::clamp?
const unsigned char red =
static_cast<unsigned char>(255.0f * std::min(pixel_color[0], T(1)));
const unsigned char green =
static_cast<unsigned char>(255.0f * std::min(pixel_color[1], T(1)));
const unsigned char blue =
static_cast<unsigned char>(255.0f * std::min(pixel_color[2], T(1)));
const unsigned char alpha =
static_cast<unsigned char>(255.0f * std::min(pixel_color[3], T(1)));
// update buffers
colorbuffer.at<cv::Vec4b>(pixel_index_row, pixel_index_col)[0] = blue;
colorbuffer.at<cv::Vec4b>(pixel_index_row, pixel_index_col)[1] = green;
colorbuffer.at<cv::Vec4b>(pixel_index_row, pixel_index_col)[2] = red;
colorbuffer.at<cv::Vec4b>(pixel_index_row, pixel_index_col)[3] = alpha;
if (enable_depth_test) // TODO: A better name for this might be enable_zbuffer? or
// enable_zbuffer_test?
{
depthbuffer.at<double>(pixel_index_row, pixel_index_col) = z_affine;
}
}
}
}
}
};
};
/**
* @brief Todo.
*
* Takes in clip coords? and outputs NDC.
* divides by w and outputs [x_ndc, y_ndc, z_ndc, 1/w_clip].
* The w-component is set to 1/w_clip (which is what OpenGL passes to the FragmentShader).
*
* @param[in] vertex X.
* @ return X.
*/
template <typename T, glm::precision P = glm::defaultp>
glm::tvec4<T, P> divide_by_w(const glm::tvec4<T, P>& vertex)
{
auto one_over_w = 1.0 / vertex.w;
// divide by w: (if ortho, w will just be 1)
glm::tvec4<T, P> v_ndc(vertex / vertex.w);
// Set the w coord to 1/w (i.e. 1/w_clip). This is what OpenGL passes to the FragmentShader.
v_ndc.w = one_over_w;
return v_ndc;
};
/**
* @brief Todo.
*
* This function copied from render_detail.hpp and adjusted for v2:: stuff.
* I think it should go back to render_details eventually.
*
* @param[in] vertices X.
* @param[in] plane_normal X.
* @ return X.
*/
template <typename T, glm::precision P = glm::defaultp>
std::vector<detail::v2::Vertex<T, P>>
clip_polygon_to_plane_in_4d(const std::vector<detail::v2::Vertex<T, P>>& vertices,
const glm::tvec4<T, P>& plane_normal)
{
std::vector<detail::v2::Vertex<T, P>> clipped_vertices;
// We can have 2 cases:
// * 1 vertex visible: we make 1 new triangle out of the visible vertex plus the 2 intersection points
// with the near-plane
// * 2 vertices visible: we have a quad, so we have to make 2 new triangles out of it.
// See here for more info?
// http://math.stackexchange.com/questions/400268/equation-for-a-line-through-a-plane-in-homogeneous-coordinates
for (unsigned int i = 0; i < vertices.size(); i++)
{
int a = i; // the current vertex
int b = (i + 1) % vertices.size(); // the following vertex (wraps around 0)
using glm::dot;
const T fa = dot(vertices[a].position, plane_normal); // Note: Shouldn't they be unit length?
const T fb = dot(vertices[b].position,
plane_normal); // < 0 means on visible side, > 0 means on invisible side?
if ((fa < 0 && fb > 0) || (fa > 0 && fb < 0)) // one vertex is on the visible side of the plane, one
// on the invisible? so we need to split?
{
const glm::tvec4<T, P> direction = vertices[b].position - vertices[a].position;
const T t = -(dot(plane_normal, vertices[a].position)) /
(dot(plane_normal, direction)); // the parametric value on the line, where the line to
// draw intersects the plane?
// generate a new vertex at the line-plane intersection point
const glm::tvec4<T, P> position = vertices[a].position + t * direction;
const glm::tvec3<T, P> color = vertices[a].color + t * (vertices[b].color - vertices[a].color);
const glm::tvec2<T, P> texcoords =
vertices[a].texcoords +
t * (vertices[b].texcoords -
vertices[a].texcoords); // We could omit that if we don't render with texture.
if (fa < 0) // we keep the original vertex plus the new one
{
clipped_vertices.push_back(vertices[a]);
clipped_vertices.push_back(detail::v2::Vertex<T, P>{position, color, texcoords});
} else if (fb < 0) // we use only the new vertex
{
clipped_vertices.push_back(detail::v2::Vertex<T, P>{position, color, texcoords});
}
} else if (fa < 0 && fb < 0) // both are visible (on the "good" side of the plane), no splitting
// required, use the current vertex
{
clipped_vertices.push_back(vertices[a]);
}
// else, both vertices are not visible, nothing to add and draw
}
return clipped_vertices;
};
} /* namespace render */
} /* namespace eos */
#endif /* SOFTWARERENDERER_HPP_ */
include/eos/render/VertexShader.hpp 0 → 100644
View file @ 0d558ddf
/*
* eos - A 3D Morphable Model fitting library written in modern C++11/14.
*
* File: include/eos/render/VertexShader.hpp
*
* Copyright 2017 Patrik Huber
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#ifndef VERTEXSHADER_HPP_
#define VERTEXSHADER_HPP_
#include "glm/mat4x4.hpp"
#include "glm/vec4.hpp"
namespace eos {
namespace render {
/**
* @brief A simple vertex shader that projects the vertex and returns the vertex in clip-space coordinates.
*/
class VertexShader
{
public:
/**
* @brief Projects the given vertex into clip-space and returns it.
*
* @param[in] vertex The vertex to project.
* @param[in] model_view_matrix The model-view matrix.
* @param[in] projection_matrix The projection matrix.
* @tparam VT Vertex type.
* @tparam VP Vertex precision.
* @tparam MT Matrix type.
* @tparam MP Matrix precision.
* @return Vertex projected to clip space.
*/
template <typename VT, glm::precision VP, typename MT, glm::precision MP = glm::defaultp>
glm::tvec4<MT, MP> operator()(const glm::tvec4<VT, VP>& vertex,
const glm::tmat4x4<MT, MP>& model_view_matrix,
const glm::tmat4x4<MT, MP>& projection_matrix)
{
return projection_matrix * model_view_matrix * vertex;
};
};
} /* namespace render */
} /* namespace eos */
#endif /* VERTEXSHADER_HPP_ */
include/eos/render/detail/Vertex.hpp 0 → 100644
View file @ 0d558ddf
/*
* eos - A 3D Morphable Model fitting library written in modern C++11/14.
*
* File: include/eos/render/detail/Vertex.hpp
*
* Copyright 2017 Patrik Huber
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#ifndef VERTEX_HPP_
#define VERTEX_HPP_
#include "glm/vec2.hpp"
#include "glm/vec3.hpp"
#include "glm/vec4.hpp"
/**
* The detail namespace contains implementations of internal functions, not part of the API we expose and not
* meant to be used by a user.
*/
namespace eos {
namespace render {
namespace detail {
// In a v2 namespace for now to disambiguate between this and the "older" Vertex class:
namespace v2 {
/**
* @brief A representation for a vertex during rendering, used internally.
*
* It's used to build the vertices that will be rendered, and new vertices that are generated by the renderer
* (during clipping).
* I should check at some point that no unnecessary copies of the vertex data is created in some places, but I
* think it's pretty much fine.
*
* FragmentShader and SoftwareRenderer use this.
*
* This is the same as the one in the current render_detail.hpp, except that this is fully templated.
*
*/
template <typename T, glm::precision P = glm::defaultp>
struct Vertex
{
glm::tvec4<T, P> position; // XYZW
glm::tvec3<T, P> color; // RGB order
glm::tvec2<T, P> texcoords; // UV
};
} /* namespace v2 */
} /* namespace detail */
} /* namespace render */
} /* namespace eos */
#endif /* VERTEX_HPP_ */
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