added renderer, improved various things

- Added renderer to unify frame buffers
- Added FrameBuffer class as a parent for frame buffers' classes
- Improved formatting in Makefile.am
- Added const modifier in Matrix4's methods

13 files changed, 276 insertions, 283 deletions

diff --git a/Makefile.am b/Makefile.am
index c0f1b53..ecfea3a 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,22 +1,23 @@
 EXTRA_DIST = m4/NOTES
 SUBDIRS =
 if ENABLE_TESTS
-  SUBDIRS += tests
+    SUBDIRS += tests
 endif
 ACLOCAL_AMFLAGS = -Im4 --install
 
 bin_PROGRAMS = engine
 
-engine_SOURCES = src/engine.cpp \
-                 src/fb/chfb.h src/fb/chfb.cpp src/fb/pixfb.h src/fb/pixfb.cpp \
-                 src/math/vector.h src/math/vector.cpp \
-                 src/math/mat4.h src/math/mat4.cpp \
-                 src/o3d/mesh.h src/o3d/mesh.cpp src/o3d/tri_vertex.h \
-                 src/o3d/obj3d.h src/o3d/obj3d.cpp src/o3d/tri_vertex.h \
-                 src/o3d/tri_vertex.cpp src/o3d/vertex.h src/o3d/vertex.cpp \
-                 src/o3d/vertex_data.h src/o3d/vertex_data.cpp \
-                 src/o3d/camera.h src/o3d/camera.cpp \
-                 src/o3d/scene.h src/o3d/scene.cpp
+engine_SOURCES = \
+    src/engine.cpp src/renderer.h src/renderer.cpp \
+    src/fb/fb.h src/fb/chfb.h src/fb/chfb.cpp src/fb/pixfb.h src/fb/pixfb.cpp \
+    src/math/vector.h src/math/vector.cpp \
+    src/math/mat4.h src/math/mat4.cpp \
+    src/o3d/mesh.h src/o3d/mesh.cpp src/o3d/tri_vertex.h \
+    src/o3d/obj3d.h src/o3d/obj3d.cpp src/o3d/tri_vertex.h \
+    src/o3d/tri_vertex.cpp src/o3d/vertex.h src/o3d/vertex.cpp \
+    src/o3d/vertex_data.h src/o3d/vertex_data.cpp \
+    src/o3d/camera.h src/o3d/camera.cpp \
+    src/o3d/scene.h src/o3d/scene.cpp
 engine_CPPFLAGS = -Wall -Wextra $(DEPS_CPPFLAGS)
 engine_LDFLAGS = -Wall -Wextra
 engine_LDADD = $(DEPS_LIBS)
diff --git a/src/engine.cpp b/src/engine.cpp
index aeae21c..91c0b80 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -10,6 +10,8 @@
 #include <functional>
 #include <utility>
 #include <iterator>
+#include <memory>
+#include <utility>
 #include <SDL.h>
 
 #ifdef ENABLE_NCURSES
@@ -27,6 +29,7 @@
 #include "o3d/camera.h"
 #include "math/vector.h"
 #include "math/mat4.h"
+#include "renderer.h"
 
 #define FPS 60
 
@@ -50,8 +53,7 @@ static void usage_error_exit() {
     std::exit(EXIT_FAILURE);
 }
 
-template <class FB>
-static void scene_main(FB& fb, std::function<bool()> update_frame) {
+static void scene_main(engine::Renderer& renderer, engine::math::Matrix4 final_transform_mat, std::function<bool()> update_frame) {
     float dist = 4.f;
     float rad = 5.f;
     bool cont = true;
@@ -76,7 +78,7 @@ static void scene_main(FB& fb, std::function<bool()> update_frame) {
         scene.camera.rot_y += .0065f;
         scene.camera.rot_z += .0080f;
 
-        fb.clear();
+        renderer.clear();
         auto transform_mat =
             engine::math::Matrix4::translate(-scene.camera.loc)
             * engine::math::Matrix4::rot_x(-scene.camera.rot_x)
@@ -86,15 +88,16 @@ static void scene_main(FB& fb, std::function<bool()> update_frame) {
             transform_mat * engine::math::Matrix4::translate(engine::math::Vector3{-.5f * rad, -.5f * rad, -.5f * rad}) * scale_mat,
             transform_mat * engine::math::Matrix4::translate(engine::math::Vector3{+.5f * rad, +.5f * rad, +.5f * rad}) * scale_mat,
         }};
-        auto projection_mat = engine::math::Matrix4::projection(static_cast<float>(fb.height()) / static_cast<float>(fb.width()), 2.f, 50.f);
+        auto pre_final_mat = final_transform_mat
+            * engine::math::Matrix4::projection(static_cast<float>(renderer.height()) / static_cast<float>(renderer.width()), 2.f, 50.f);
         for (int i = 0; i < 2; i++) {
-            auto final_mat = projection_mat * mats[i];
+            auto final_mat = pre_final_mat * mats[i];
             const auto& mesh = scene.objs[i].mesh;
             std::vector<engine::o3d::Vertex4> pts;
             for (const auto& vert : mesh.pts)
                 pts.push_back({ final_mat * engine::math::Vector4{vert.point}, vert.data });
             for (auto face : mesh.faces)
-                fb.draw_triangle({pts[face[0]], pts[face[1]], pts[face[2]]});
+                renderer.draw_triangle({pts[face[0]], pts[face[1]], pts[face[2]]});
         }
         cont = update_frame();
     }
@@ -121,10 +124,13 @@ static int main_term() {
 
     int w, h;
     getmaxyx(stdscr, h, w);
-    engine::fb::CharacterFrameBuffer cfb{static_cast<unsigned int>(w), static_cast<unsigned int>(h)};
+    engine::Renderer renderer{
+        std::make_unique<engine::fb::CharacterFrameBuffer>(static_cast<unsigned int>(w), static_cast<unsigned int>(h))};
 
-    scene_main(cfb, [&]() {
-        mvaddnstr(0, 0, cfb.chars(), cfb.width() * cfb.height());
+    scene_main(renderer, engine::math::Matrix4::scale(engine::math::Vector3(2.f, 1.f, 1.f)), [&]() {
+        mvaddnstr(0, 0,
+            static_cast<engine::fb::CharacterFrameBuffer*>(renderer.fb.get())->chars(),
+            renderer.width() * renderer.height());
 
         bool cont = true;
         //timeout(1000 / FPS);
@@ -156,7 +162,7 @@ static int main_term() {
         }
 
         getmaxyx(stdscr, h, w);
-        cfb.resize(static_cast<unsigned int>(w), static_cast<unsigned int>(h));
+        renderer.resize(static_cast<unsigned int>(w), static_cast<unsigned int>(h));
 
         return cont;
     });
@@ -183,17 +189,21 @@ static int main_graphical() {
     }
     window = SDL_CreateWindow("Engine", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
     if (window == NULL) {
+        SDL_Quit();
         std::cerr << "Error: SDL_CreateWindow error: " << SDL_GetError() << std::endl;
         return EXIT_FAILURE;
     }
     renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
     texture = SDL_CreateTexture(renderer, SDL_PIXELFORMAT_RGBA8888, SDL_TEXTUREACCESS_STREAMING, SCREEN_WIDTH, SCREEN_HEIGHT);
-    engine::fb::PixelFrameBuffer pfb{SCREEN_WIDTH, SCREEN_HEIGHT};
+    engine::Renderer engine_renderer{
+        std::make_unique<engine::fb::PixelFrameBuffer>(SCREEN_WIDTH, SCREEN_HEIGHT)};
 
     SDL_Event e;
 
-    scene_main(pfb, [&]() {
-        SDL_UpdateTexture(texture, NULL, pfb.pixels(), SCREEN_WIDTH * 4);
+    scene_main(engine_renderer, engine::math::Matrix4::idty(), [&]() {
+        SDL_UpdateTexture(texture, NULL,
+            static_cast<engine::fb::PixelFrameBuffer*>(engine_renderer.fb.get())->pixels(),
+            SCREEN_WIDTH * 4);
         SDL_RenderClear(renderer);
         SDL_RenderCopy(renderer, texture, NULL, NULL);
         SDL_RenderPresent(renderer);
diff --git a/src/fb/chfb.cpp b/src/fb/chfb.cpp
index c0e5cc7..b5c0ae0 100644
--- a/src/fb/chfb.cpp
+++ b/src/fb/chfb.cpp
@@ -17,7 +17,6 @@ void CharacterFrameBuffer::resize(unsigned int w, unsigned int h) {
     this->w = w;
     this->h = h;
     chars_vector.resize(w * h);
-    depth_buf.resize(w * h);
     clear();
 }
 
@@ -35,124 +34,14 @@ const char* CharacterFrameBuffer::chars() const {
 
 void CharacterFrameBuffer::clear() {
     std::fill(chars_vector.begin(), chars_vector.end(), ' ');
-    std::fill(depth_buf.begin(), depth_buf.end(), 1.f);
-    face_ind = -1;
 }
 
-void CharacterFrameBuffer::_draw_cropped_triangle(engine::o3d::TriangleVertex3 triangle) {
-    std::array<engine::o3d::Vertex3*, 3> sorted_vs = { &triangle.vertex1, &triangle.vertex2, &triangle.vertex3 };
-
-#define SWAP_IF_LT(X,Y) ({\
-            if (sorted_vs[X]->point.y < sorted_vs[Y]->point.y) {\
-                engine::o3d::Vertex3* temp = sorted_vs[X];\
-                sorted_vs[X] = sorted_vs[Y];\
-                sorted_vs[Y] = temp;\
-            }\
-        })
-    SWAP_IF_LT(1, 0);
-    SWAP_IF_LT(2, 1);
-    SWAP_IF_LT(1, 0);
-#undef SWAP_IF_LT
-
-    engine::o3d::Vertex3 middle_vl = *sorted_vs[1];
-    float fac = (sorted_vs[1]->point.y - sorted_vs[0]->point.y) / (sorted_vs[2]->point.y - sorted_vs[0]->point.y);
-    engine::o3d::Vertex3 middle_vr{
-        {
-            sorted_vs[0]->point.x + fac * (sorted_vs[2]->point.x - sorted_vs[0]->point.x),
-            sorted_vs[1]->point.y,
-            sorted_vs[0]->point.z + fac * (sorted_vs[2]->point.z - sorted_vs[0]->point.z)
-        },
-        engine::o3d::VertexData::lerp(sorted_vs[0]->data, sorted_vs[2]->data, fac)
-    };
-    if (middle_vr.point.x < middle_vl.point.x) {
-        engine::o3d::Vertex3 temp = middle_vr;
-        middle_vr = middle_vl;
-        middle_vl = temp;
-    }
-
-    // top triangle
-    {
-        if (sorted_vs[0]->point.y != sorted_vs[1]->point.y) {
-            int top_y = static_cast<int>(std::floor(sorted_vs[0]->point.y + 1.f));
-            int bottom_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y - 1.f));
-            for (int y = top_y; y <= bottom_y; y++) {
-                float iy = static_cast<float>(y);
-                float s = (iy - sorted_vs[0]->point.y) / (sorted_vs[1]->point.y - sorted_vs[0]->point.y);
-                float xl = sorted_vs[0]->point.x + s * (middle_vl.point.x - sorted_vs[0]->point.x);
-                float xr = sorted_vs[0]->point.x + s * (middle_vr.point.x - sorted_vs[0]->point.x);
-                int left_x = static_cast<int>(std::ceil(xl));
-                int right_x = static_cast<int>(std::ceil(xr - 1.f));
-                for (int x = left_x; x <= right_x; x++) {
-                    float ix = static_cast<float>(x);
-                    float t = (ix - xl) / (xr - xl);
-                    // depth and vd don't take into account perspective
-                    float depth = sorted_vs[0]->point.z + s * (middle_vl.point.z - sorted_vs[0]->point.z + t * (middle_vr.point.z - middle_vl.point.z));
-                    // VertexData vd = VertexData::bilerp(sorted_vs[0]->data, middle_vl.data, middle_vr.data, s, t);
-                    if (depth < depth_buf[x + y * w]) {
-                        depth_buf[x + y * w] = depth;
-                        chars_vector[x + y * w] = face_char();
-                    }
-                }
-            }
-        }
-    }
-
-    // bottom triangle
-    {
-        if (sorted_vs[1]->point.y != sorted_vs[2]->point.y) {
-            int bottom_y = static_cast<int>(std::floor(sorted_vs[2]->point.y));
-            int top_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y));
-            for (int y = top_y; y <= bottom_y; y++) {
-                float iy = static_cast<float>(y);
-                float s = (iy - sorted_vs[2]->point.y) / (sorted_vs[1]->point.y - sorted_vs[2]->point.y);
-                float xl = sorted_vs[2]->point.x + s * (middle_vl.point.x - sorted_vs[2]->point.x);
-                float xr = sorted_vs[2]->point.x + s * (middle_vr.point.x - sorted_vs[2]->point.x);
-                int left_x = static_cast<int>(std::ceil(xl));
-                int right_x = static_cast<int>(std::ceil(xr - 1.f));
-                for (int x = left_x; x <= right_x; x++) {
-                    float ix = static_cast<float>(x);
-                    float t = (ix - xl) / (xr - xl);
-                    // depth and vd don't take into account perspective
-                    float depth = sorted_vs[2]->point.z + s * (middle_vl.point.z - sorted_vs[2]->point.z + t * (middle_vr.point.z - middle_vl.point.z));
-                    // VertexData vd = VertexData::bilerp(sorted_vs[2]->data, middle_vl.data, middle_vr.data, s, t);
-                    if (depth < depth_buf[x + y * w]) {
-                        depth_buf[x + y * w] = depth;
-                        chars_vector[x + y * w] = face_char();
-                    }
-                }
-            }
-        }
-    }
-}
-
-void CharacterFrameBuffer::draw_triangle(engine::o3d::TriangleVertex4 triangle) {
-    face_ind++;
-    for (auto t1 : triangle.crop_z_out(-1.f, 1.f)) {
-        auto t1_2 = t1.div_by_w();
-        t1_2.vertex1.point.x *= 2.f;
-        t1_2.vertex2.point.x *= 2.f;
-        t1_2.vertex3.point.x *= 2.f;
-        for (auto t2 : t1_2.crop_xy_out(-1.f, 1.f, -1.f, 1.f)) {
-            engine::math::Vector2 pp1 = t2.vertex1.point.xy(),
-                                      pp2 = t2.vertex2.point.xy(),
-                                      pp3 = t2.vertex3.point.xy();
-            if ((pp2 - pp1).det(pp3 - pp1) >= 0.f) continue;
-            t2.vertex1.point = (t2.vertex1.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
-            t2.vertex2.point = (t2.vertex2.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
-            t2.vertex3.point = (t2.vertex3.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
-            float fw = static_cast<float>(w), fh = static_cast<float>(h);
-            t2.vertex1.point.x = t2.vertex1.point.x * fw - .5f;
-            t2.vertex1.point.y = t2.vertex1.point.y * fh - .5f;
-            t2.vertex2.point.x = t2.vertex2.point.x * fw - .5f;
-            t2.vertex2.point.y = t2.vertex2.point.y * fh - .5f;
-            t2.vertex3.point.x = t2.vertex3.point.x * fw - .5f;
-            t2.vertex3.point.y = t2.vertex3.point.y * fh - .5f;
-            _draw_cropped_triangle(t2);
-        }
-    }
+void CharacterFrameBuffer::draw_point(int x, int y, engine::math::Vector3 loc, const engine::o3d::VertexData& vd) {
+    (void) vd;
+    chars_vector[x + y * w] = face_char(static_cast<int>(loc.x));
 }
 
-char CharacterFrameBuffer::face_char() const {
+char CharacterFrameBuffer::face_char(int face_ind) const {
     int n = 1 + face_ind / 2;
     return (n < 10 ? '0' : 'A' - 10) + n;
 }
diff --git a/src/fb/chfb.h b/src/fb/chfb.h
index 9e10a0d..280f6d8 100644
--- a/src/fb/chfb.h
+++ b/src/fb/chfb.h
@@ -2,12 +2,11 @@
 #define FB_CHFB_H
 
 #include <vector>
-#include "math/vector.h"
-#include "o3d/tri_vertex.h"
+#include "fb/fb.h"
 
 namespace engine::fb {
 
-class CharacterFrameBuffer {
+class CharacterFrameBuffer : public FrameBuffer {
     public:
         CharacterFrameBuffer(unsigned int w, unsigned int h);
         void resize(unsigned int w, unsigned int h);
@@ -15,16 +14,13 @@ class CharacterFrameBuffer {
         unsigned int height() const;
         const char* chars() const;
         void clear();
-        void draw_triangle(engine::o3d::TriangleVertex4 triangle);
+        void draw_point(int x, int y, engine::math::Vector3 loc, const engine::o3d::VertexData& vd);
 
     private:
         unsigned int w, h;
         std::vector<char> chars_vector;
-        std::vector<float> depth_buf;
-        int face_ind;
 
-        void _draw_cropped_triangle(engine::o3d::TriangleVertex3 triangle);
-        char face_char() const;
+        char face_char(int face_inf) const;
 };
 
 }
diff --git a/src/fb/fb.h b/src/fb/fb.h
new file mode 100644
index 0000000..04b13ee
--- /dev/null
+++ b/src/fb/fb.h
@@ -0,0 +1,20 @@
+#ifndef FB_FB_H
+#define FB_FB_H
+
+#include "math/vector.h"
+#include "o3d/vertex_data.h"
+
+namespace engine::fb {
+
+class FrameBuffer {
+    public:
+        virtual void resize(unsigned int w, unsigned int h) = 0;
+        virtual unsigned int width() const = 0;
+        virtual unsigned int height() const = 0;
+        virtual void clear() = 0;
+        virtual void draw_point(int x, int y, engine::math::Vector3 loc, const engine::o3d::VertexData& vd) = 0;
+};
+
+}
+
+#endif // FB_FB_H
diff --git a/src/fb/pixfb.cpp b/src/fb/pixfb.cpp
index af220c6..26bc8f2 100644
--- a/src/fb/pixfb.cpp
+++ b/src/fb/pixfb.cpp
@@ -3,6 +3,7 @@
 #include <cmath>
 #include <vector>
 #include <cstdint>
+#include <algorithm>
 #include "math/vector.h"
 #include "o3d/vertex.h"
 #include "o3d/tri_vertex.h"
@@ -18,7 +19,6 @@ void PixelFrameBuffer::resize(unsigned int w, unsigned int h) {
     this->w = w;
     this->h = h;
     pixels_vector.resize(w * h);
-    depth_buf.resize(w * h);
     clear();
 }
 
@@ -36,120 +36,14 @@ const uint32_t* PixelFrameBuffer::pixels() const {
 
 void PixelFrameBuffer::clear() {
     std::fill(pixels_vector.begin(), pixels_vector.end(), 0x000000FF);
-    std::fill(depth_buf.begin(), depth_buf.end(), 1.f);
-    face_ind = -1;
 }
 
-void PixelFrameBuffer::_draw_cropped_triangle(engine::o3d::TriangleVertex3 triangle) {
-    std::array<engine::o3d::Vertex3*, 3> sorted_vs = { &triangle.vertex1, &triangle.vertex2, &triangle.vertex3 };
-
-#define SWAP_IF_LT(X,Y) ({\
-            if (sorted_vs[X]->point.y < sorted_vs[Y]->point.y) {\
-                engine::o3d::Vertex3* temp = sorted_vs[X];\
-                sorted_vs[X] = sorted_vs[Y];\
-                sorted_vs[Y] = temp;\
-            }\
-        })
-    SWAP_IF_LT(1, 0);
-    SWAP_IF_LT(2, 1);
-    SWAP_IF_LT(1, 0);
-#undef SWAP_IF_LT
-
-    engine::o3d::Vertex3 middle_vl = *sorted_vs[1];
-    float fac = (sorted_vs[1]->point.y - sorted_vs[0]->point.y) / (sorted_vs[2]->point.y - sorted_vs[0]->point.y);
-    engine::o3d::Vertex3 middle_vr{
-        {
-            sorted_vs[0]->point.x + fac * (sorted_vs[2]->point.x - sorted_vs[0]->point.x),
-            sorted_vs[1]->point.y,
-            sorted_vs[0]->point.z + fac * (sorted_vs[2]->point.z - sorted_vs[0]->point.z)
-        },
-        engine::o3d::VertexData::lerp(sorted_vs[0]->data, sorted_vs[2]->data, fac)
-    };
-    if (middle_vr.point.x < middle_vl.point.x) {
-        engine::o3d::Vertex3 temp = middle_vr;
-        middle_vr = middle_vl;
-        middle_vl = temp;
-    }
-
-    // top triangle
-    {
-        if (sorted_vs[0]->point.y != sorted_vs[1]->point.y) {
-            int top_y = static_cast<int>(std::floor(sorted_vs[0]->point.y + 1.f));
-            int bottom_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y - 1.f));
-            for (int y = top_y; y <= bottom_y; y++) {
-                float iy = static_cast<float>(y);
-                float s = (iy - sorted_vs[0]->point.y) / (sorted_vs[1]->point.y - sorted_vs[0]->point.y);
-                float xl = sorted_vs[0]->point.x + s * (middle_vl.point.x - sorted_vs[0]->point.x);
-                float xr = sorted_vs[0]->point.x + s * (middle_vr.point.x - sorted_vs[0]->point.x);
-                int left_x = static_cast<int>(std::ceil(xl));
-                int right_x = static_cast<int>(std::ceil(xr - 1.f));
-                for (int x = left_x; x <= right_x; x++) {
-                    float ix = static_cast<float>(x);
-                    float t = (ix - xl) / (xr - xl);
-                    // depth and vd don't take into account perspective
-                    float depth = sorted_vs[0]->point.z + s * (middle_vl.point.z - sorted_vs[0]->point.z + t * (middle_vr.point.z - middle_vl.point.z));
-                    // VertexData vd = VertexData::bilerp(sorted_vs[0]->data, middle_vl.data, middle_vr.data, s, t);
-                    if (depth < depth_buf[x + y * w]) {
-                        depth_buf[x + y * w] = depth;
-                        pixels_vector[x + y * w] = face_color();
-                    }
-                }
-            }
-        }
-    }
-
-    // bottom triangle
-    {
-        if (sorted_vs[1]->point.y != sorted_vs[2]->point.y) {
-            int bottom_y = static_cast<int>(std::floor(sorted_vs[2]->point.y));
-            int top_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y));
-            for (int y = top_y; y <= bottom_y; y++) {
-                float iy = static_cast<float>(y);
-                float s = (iy - sorted_vs[2]->point.y) / (sorted_vs[1]->point.y - sorted_vs[2]->point.y);
-                float xl = sorted_vs[2]->point.x + s * (middle_vl.point.x - sorted_vs[2]->point.x);
-                float xr = sorted_vs[2]->point.x + s * (middle_vr.point.x - sorted_vs[2]->point.x);
-                int left_x = static_cast<int>(std::ceil(xl));
-                int right_x = static_cast<int>(std::ceil(xr - 1.f));
-                for (int x = left_x; x <= right_x; x++) {
-                    float ix = static_cast<float>(x);
-                    float t = (ix - xl) / (xr - xl);
-                    // depth and vd don't take into account perspective
-                    float depth = sorted_vs[2]->point.z + s * (middle_vl.point.z - sorted_vs[2]->point.z + t * (middle_vr.point.z - middle_vl.point.z));
-                    // VertexData vd = VertexData::bilerp(sorted_vs[2]->data, middle_vl.data, middle_vr.data, s, t);
-                    if (depth < depth_buf[x + y * w]) {
-                        depth_buf[x + y * w] = depth;
-                        pixels_vector[x + y * w] = face_color();
-                    }
-                }
-            }
-        }
-    }
-}
-
-void PixelFrameBuffer::draw_triangle(engine::o3d::TriangleVertex4 triangle) {
-    face_ind++;
-    for (auto t1 : triangle.crop_z_out(-1.f, 1.f)) {
-        for (auto t2 : t1.div_by_w().crop_xy_out(-1.f, 1.f, -1.f, 1.f)) {
-            engine::math::Vector2 pp1 = t2.vertex1.point.xy(),
-                                      pp2 = t2.vertex2.point.xy(),
-                                      pp3 = t2.vertex3.point.xy();
-            if ((pp2 - pp1).det(pp3 - pp1) >= 0.f) continue;
-            t2.vertex1.point = (t2.vertex1.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
-            t2.vertex2.point = (t2.vertex2.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
-            t2.vertex3.point = (t2.vertex3.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
-            float fw = static_cast<float>(w), fh = static_cast<float>(h);
-            t2.vertex1.point.x = t2.vertex1.point.x * fw - .5f;
-            t2.vertex1.point.y = t2.vertex1.point.y * fh - .5f;
-            t2.vertex2.point.x = t2.vertex2.point.x * fw - .5f;
-            t2.vertex2.point.y = t2.vertex2.point.y * fh - .5f;
-            t2.vertex3.point.x = t2.vertex3.point.x * fw - .5f;
-            t2.vertex3.point.y = t2.vertex3.point.y * fh - .5f;
-            _draw_cropped_triangle(t2);
-        }
-    }
+void PixelFrameBuffer::draw_point(int x, int y, engine::math::Vector3 loc, const engine::o3d::VertexData& vd) {
+    (void) vd;
+    pixels_vector[x + y * w] = face_color(static_cast<int>(loc.x));
 }
 
-uint32_t PixelFrameBuffer::face_color() const {
+uint32_t PixelFrameBuffer::face_color(int face_ind) const {
     int n = face_ind / 2;
     return ((n % 2 ? 0xFF000000 : 0x55000000) >> ((n % 6) / 2 * 8)) | 0xFF;
 }
diff --git a/src/fb/pixfb.h b/src/fb/pixfb.h
index cdfac18..84bce2c 100644
--- a/src/fb/pixfb.h
+++ b/src/fb/pixfb.h
@@ -3,12 +3,11 @@
 
 #include <vector>
 #include <cstdint>
-#include "math/vector.h"
-#include "o3d/tri_vertex.h"
+#include "fb/fb.h"
 
 namespace engine::fb {
 
-class PixelFrameBuffer {
+class PixelFrameBuffer : public FrameBuffer {
     public:
         PixelFrameBuffer(unsigned int w, unsigned int h);
         void resize(unsigned int w, unsigned int h);
@@ -16,16 +15,14 @@ class PixelFrameBuffer {
         unsigned int height() const;
         const uint32_t* pixels() const;
         void clear();
-        void draw_triangle(engine::o3d::TriangleVertex4 triangle);
+        void draw_point(int x, int y, engine::math::Vector3 loc, const engine::o3d::VertexData& vd);
 
     private:
         unsigned int w, h;
         std::vector<uint32_t> pixels_vector;
-        std::vector<float> depth_buf;
         int face_ind;
 
-        void _draw_cropped_triangle(engine::o3d::TriangleVertex3 triangle);
-        uint32_t face_color() const;
+        uint32_t face_color(int face_ind) const;
 };
 
 }
diff --git a/src/math/mat4.cpp b/src/math/mat4.cpp
index f1f28b7..b9dff15 100644
--- a/src/math/mat4.cpp
+++ b/src/math/mat4.cpp
@@ -22,6 +22,7 @@ Matrix4 Matrix4::translate(Vector3 v) {
         0.f, 0.f, 0.f, 1.f,
     };
 }
+
 Matrix4 Matrix4::scale(float fac) {
     return {
         fac, 0.f, 0.f, 0.f,
@@ -31,6 +32,15 @@ Matrix4 Matrix4::scale(float fac) {
     };
 }
 
+Matrix4 Matrix4::scale(Vector3 facs) {
+    return {
+        facs.x,    0.f,    0.f, 0.f,
+           0.f, facs.y,    0.f, 0.f,
+           0.f,    0.f, facs.z, 0.f,
+           0.f,    0.f,    0.f, 1.f,
+    };
+}
+
 Matrix4 Matrix4::rot_x(float a) {
     float c = std::cos(a);
     float s = std::sin(a);
@@ -73,11 +83,11 @@ Matrix4 Matrix4::projection(float aspect_ratio, float min_z, float max_z) {
     }};
 }
 
-Matrix4 Matrix4::operator+() {
+Matrix4 Matrix4::operator+() const {
     return *this;
 }
 
-Matrix4 Matrix4::operator-() {
+Matrix4 Matrix4::operator-() const {
     return {
         -values[ 0], -values[ 1], -values[ 2], -values[ 3],
         -values[ 4], -values[ 5], -values[ 6], -values[ 7],
@@ -86,7 +96,7 @@ Matrix4 Matrix4::operator-() {
     };
 }
 
-Matrix4 Matrix4::operator+(Matrix4 m) {
+Matrix4 Matrix4::operator+(Matrix4 m) const {
     return {
         values[ 0] + m.values[ 0], values[ 1] + m.values[ 1], values[ 2] + m.values[ 2], values[ 3] + m.values[ 3],
         values[ 4] + m.values[ 4], values[ 5] + m.values[ 5], values[ 6] + m.values[ 6], values[ 7] + m.values[ 7],
@@ -95,11 +105,11 @@ Matrix4 Matrix4::operator+(Matrix4 m) {
     };
 }
 
-Matrix4 Matrix4::operator-(Matrix4 m) {
+Matrix4 Matrix4::operator-(Matrix4 m) const {
     return *this + (-m);
 }
 
-Matrix4 Matrix4::operator*(Matrix4 m) {
+Matrix4 Matrix4::operator*(Matrix4 m) const {
     Matrix4 ret;
     for (int i = 0; i < 4; i++) {
         for (int j = 0; j < 4; j++) {
@@ -111,7 +121,7 @@ Matrix4 Matrix4::operator*(Matrix4 m) {
     return ret;
 }
 
-Vector4 Matrix4::operator*(Vector4 v) {
+Vector4 Matrix4::operator*(Vector4 v) const {
     return {
         values[ 0] * v.x + values[ 1] * v.y + values[ 2] * v.z + values[ 3] * v.w,
         values[ 4] * v.x + values[ 5] * v.y + values[ 6] * v.z + values[ 7] * v.w,
@@ -120,7 +130,7 @@ Vector4 Matrix4::operator*(Vector4 v) {
     };
 }
 
-std::array<Vector4, 4> Matrix4::to_vecs() {
+std::array<Vector4, 4> Matrix4::to_vecs() const {
     return {{
         { values[ 0], values[ 4], values[ 8], values[12] },
         { values[ 1], values[ 5], values[ 9], values[13] },
diff --git a/src/math/mat4.h b/src/math/mat4.h
index 66d6cd2..35b1ad2 100644
--- a/src/math/mat4.h
+++ b/src/math/mat4.h
@@ -11,6 +11,7 @@ class Matrix4 {
         static Matrix4 idty();
         static Matrix4 translate(Vector3 v);
         static Matrix4 scale(float fac);
+        static Matrix4 scale(Vector3 facs);
         static Matrix4 rot_x(float a);
         static Matrix4 rot_y(float a);
         static Matrix4 rot_z(float a);
@@ -18,13 +19,13 @@ class Matrix4 {
 
         std::array<float, 16> values;
 
-        Matrix4 operator+();
-        Matrix4 operator-();
-        Matrix4 operator+(Matrix4 m);
-        Matrix4 operator-(Matrix4 m);
-        Matrix4 operator*(Matrix4 m);
-        Vector4 operator*(Vector4 v);
-        std::array<Vector4, 4> to_vecs();
+        Matrix4 operator+() const;
+        Matrix4 operator-() const;
+        Matrix4 operator+(Matrix4 m) const;
+        Matrix4 operator-(Matrix4 m) const;
+        Matrix4 operator*(Matrix4 m) const;
+        Vector4 operator*(Vector4 v) const;
+        std::array<Vector4, 4> to_vecs() const;
 };
 
 Matrix4 operator*(float fac, Matrix4 m);
diff --git a/src/o3d/vertex_data.cpp b/src/o3d/vertex_data.cpp
index 4e0ab04..ea8c5fd 100644
--- a/src/o3d/vertex_data.cpp
+++ b/src/o3d/vertex_data.cpp
@@ -2,14 +2,14 @@
 
 using namespace engine::o3d;
 
-VertexData VertexData::lerp(VertexData& vd1, VertexData& vd2, float s) {
+VertexData VertexData::lerp(const VertexData& vd1, const VertexData& vd2, float s) {
     (void) vd1;
     (void) vd2;
     (void) s;
     return {};
 }
 
-VertexData VertexData::bilerp(VertexData& vd1, VertexData& vd2, VertexData& vd3, float s, float t) {
+VertexData VertexData::bilerp(const VertexData& vd1, const VertexData& vd2, const VertexData& vd3, float s, float t) {
     (void) vd1;
     (void) vd2;
     (void) vd3;
diff --git a/src/o3d/vertex_data.h b/src/o3d/vertex_data.h
index dda881b..ec5fa25 100644
--- a/src/o3d/vertex_data.h
+++ b/src/o3d/vertex_data.h
@@ -5,8 +5,8 @@ namespace engine::o3d {
 
 class VertexData {
     public:
-        static VertexData lerp(VertexData& vd1, VertexData& vd2, float s);
-        static VertexData bilerp(VertexData& vd1, VertexData& vd2, VertexData& vd3, float s, float t);
+        static VertexData lerp(const VertexData& vd1, const VertexData& vd2, float s);
+        static VertexData bilerp(const VertexData& vd1, const VertexData& vd2, const VertexData& vd3, float s, float t);
 
         VertexData();
 };
diff --git a/src/renderer.cpp b/src/renderer.cpp
new file mode 100644
index 0000000..a946ce3
--- /dev/null
+++ b/src/renderer.cpp
@@ -0,0 +1,145 @@
+#include "renderer.h"
+#include <array>
+#include <cmath>
+#include <algorithm>
+#include <memory>
+#include "math/vector.h"
+#include "o3d/vertex.h"
+#include "o3d/tri_vertex.h"
+#include "o3d/vertex_data.h"
+
+using namespace engine;
+
+Renderer::Renderer(std::unique_ptr<engine::fb::FrameBuffer> fb) : fb{std::move(fb)} {
+    depth_buf.resize(this->fb->width() * this->fb->height());
+}
+
+void Renderer::resize(unsigned int w, unsigned int h) {
+    fb->resize(w, h);
+    depth_buf.resize(fb->width() * fb->height());
+}
+
+unsigned int Renderer::width() const {
+    return fb->width();
+}
+
+unsigned int Renderer::height() const {
+    return fb->height();
+}
+
+void Renderer::clear() {
+    std::fill(depth_buf.begin(), depth_buf.end(), 1.f);
+    face_ind = -1;
+    fb->clear();
+}
+
+void Renderer::_draw_cropped_triangle(engine::o3d::TriangleVertex3 triangle) {
+    std::array<engine::o3d::Vertex3*, 3> sorted_vs = { &triangle.vertex1, &triangle.vertex2, &triangle.vertex3 };
+
+#define SWAP_IF_LT(X,Y) ({\
+            if (sorted_vs[X]->point.y < sorted_vs[Y]->point.y) {\
+                engine::o3d::Vertex3* temp = sorted_vs[X];\
+                sorted_vs[X] = sorted_vs[Y];\
+                sorted_vs[Y] = temp;\
+            }\
+        })
+    SWAP_IF_LT(1, 0);
+    SWAP_IF_LT(2, 1);
+    SWAP_IF_LT(1, 0);
+#undef SWAP_IF_LT
+
+    engine::o3d::Vertex3 middle_vl = *sorted_vs[1];
+    float fac = (sorted_vs[1]->point.y - sorted_vs[0]->point.y) / (sorted_vs[2]->point.y - sorted_vs[0]->point.y);
+    engine::o3d::Vertex3 middle_vr{
+        {
+            sorted_vs[0]->point.x + fac * (sorted_vs[2]->point.x - sorted_vs[0]->point.x),
+            sorted_vs[1]->point.y,
+            sorted_vs[0]->point.z + fac * (sorted_vs[2]->point.z - sorted_vs[0]->point.z)
+        },
+        engine::o3d::VertexData::lerp(sorted_vs[0]->data, sorted_vs[2]->data, fac)
+    };
+    if (middle_vr.point.x < middle_vl.point.x) {
+        engine::o3d::Vertex3 temp = middle_vr;
+        middle_vr = middle_vl;
+        middle_vl = temp;
+    }
+
+    // top triangle
+    {
+        if (sorted_vs[0]->point.y != sorted_vs[1]->point.y) {
+            int top_y = static_cast<int>(std::floor(sorted_vs[0]->point.y + 1.f));
+            int bottom_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y - 1.f));
+            for (int y = top_y; y <= bottom_y; y++) {
+                float iy = static_cast<float>(y);
+                float s = (iy - sorted_vs[0]->point.y) / (sorted_vs[1]->point.y - sorted_vs[0]->point.y);
+                float xl = sorted_vs[0]->point.x + s * (middle_vl.point.x - sorted_vs[0]->point.x);
+                float xr = sorted_vs[0]->point.x + s * (middle_vr.point.x - sorted_vs[0]->point.x);
+                int left_x = static_cast<int>(std::ceil(xl));
+                int right_x = static_cast<int>(std::ceil(xr - 1.f));
+                for (int x = left_x; x <= right_x; x++) {
+                    float ix = static_cast<float>(x);
+                    float t = (ix - xl) / (xr - xl);
+                    // depth and vd don't take into account perspective
+                    float u = s, v = t;
+                    float depth = sorted_vs[0]->point.z + u * (middle_vl.point.z - sorted_vs[0]->point.z + v * (middle_vr.point.z - middle_vl.point.z));
+                    if (depth < depth_buf[x + y * fb->width()]) {
+                        depth_buf[x + y * fb->width()] = depth;
+                        fb->draw_point(x, y, engine::math::Vector3{static_cast<float>(face_ind) + .5f, 0.f, 0.f},
+                            engine::o3d::VertexData::bilerp(sorted_vs[0]->data, middle_vl.data, middle_vr.data, u, v));
+                    }
+                }
+            }
+        }
+    }
+
+    // bottom triangle
+    {
+        if (sorted_vs[1]->point.y != sorted_vs[2]->point.y) {
+            int bottom_y = static_cast<int>(std::floor(sorted_vs[2]->point.y));
+            int top_y = static_cast<int>(std::ceil(sorted_vs[1]->point.y));
+            for (int y = top_y; y <= bottom_y; y++) {
+                float iy = static_cast<float>(y);
+                float s = (iy - sorted_vs[2]->point.y) / (sorted_vs[1]->point.y - sorted_vs[2]->point.y);
+                float xl = sorted_vs[2]->point.x + s * (middle_vl.point.x - sorted_vs[2]->point.x);
+                float xr = sorted_vs[2]->point.x + s * (middle_vr.point.x - sorted_vs[2]->point.x);
+                int left_x = static_cast<int>(std::ceil(xl));
+                int right_x = static_cast<int>(std::ceil(xr - 1.f));
+                for (int x = left_x; x <= right_x; x++) {
+                    float ix = static_cast<float>(x);
+                    float t = (ix - xl) / (xr - xl);
+                    // depth and vd don't take into account perspective
+                    float u = s, v = t;
+                    float depth = sorted_vs[2]->point.z + u * (middle_vl.point.z - sorted_vs[2]->point.z + v * (middle_vr.point.z - middle_vl.point.z));
+                    if (depth < depth_buf[x + y * fb->width()]) {
+                        depth_buf[x + y * fb->width()] = depth;
+                        fb->draw_point(x, y, engine::math::Vector3{static_cast<float>(face_ind) + .5f, 0.f, 0.f},
+                            engine::o3d::VertexData::bilerp(sorted_vs[2]->data, middle_vl.data, middle_vr.data, u, v));
+                    }
+                }
+            }
+        }
+    }
+}
+
+void Renderer::draw_triangle(engine::o3d::TriangleVertex4 triangle) {
+    face_ind++;
+    for (auto t1 : triangle.crop_z_out(-1.f, 1.f)) {
+        for (auto t2 : t1.div_by_w().crop_xy_out(-1.f, 1.f, -1.f, 1.f)) {
+            engine::math::Vector2 pp1 = t2.vertex1.point.xy(),
+                                      pp2 = t2.vertex2.point.xy(),
+                                      pp3 = t2.vertex3.point.xy();
+            if ((pp2 - pp1).det(pp3 - pp1) >= 0.f) continue;
+            t2.vertex1.point = (t2.vertex1.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
+            t2.vertex2.point = (t2.vertex2.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
+            t2.vertex3.point = (t2.vertex3.point + engine::math::Vector3{1.f, 1.f, 0.f}) / 2.f;
+            float fw = static_cast<float>(fb->width()), fh = static_cast<float>(fb->height());
+            t2.vertex1.point.x = t2.vertex1.point.x * fw - .5f;
+            t2.vertex1.point.y = t2.vertex1.point.y * fh - .5f;
+            t2.vertex2.point.x = t2.vertex2.point.x * fw - .5f;
+            t2.vertex2.point.y = t2.vertex2.point.y * fh - .5f;
+            t2.vertex3.point.x = t2.vertex3.point.x * fw - .5f;
+            t2.vertex3.point.y = t2.vertex3.point.y * fh - .5f;
+            _draw_cropped_triangle(t2);
+        }
+    }
+}
diff --git a/src/renderer.h b/src/renderer.h
new file mode 100644
index 0000000..211a6fc
--- /dev/null
+++ b/src/renderer.h
@@ -0,0 +1,30 @@
+#ifndef RENDERER_H
+#define RENDERER_H
+
+#include <memory>
+#include "fb/fb.h"
+#include "o3d/tri_vertex.h"
+
+namespace engine {
+
+class Renderer {
+    public:
+        std::unique_ptr<engine::fb::FrameBuffer> fb;
+
+        Renderer(std::unique_ptr<engine::fb::FrameBuffer> fb);
+        void resize(unsigned int w, unsigned int h);
+        unsigned int width() const;
+        unsigned int height() const;
+        void clear();
+        void draw_triangle(engine::o3d::TriangleVertex4 triangle);
+
+    private:
+        std::vector<float> depth_buf;
+        int face_ind;
+
+        void _draw_cropped_triangle(engine::o3d::TriangleVertex3 triangle);
+};
+
+}
+
+#endif // RENDERER_H