improved matrices, cube building and command parsing

5 files changed, 124 insertions, 163 deletions

diff --git a/src/engine.cpp b/src/engine.cpp
index 4740046..69b2f43 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -9,6 +9,7 @@
 #include <vector>
 #include <functional>
 #include <utility>
+#include <iterator>
 #include <SDL.h>
 
 #ifdef ENABLE_NCURSES
@@ -49,158 +50,30 @@ template <class FB>
 void scene_main(FB& fb, std::function<bool()> update_frame) {
     MathVector3 a{0.f, 0.f, 0.f};
     float dist = 4.f;
+    float rad = 5.f;
     bool cont = true;
+    std::array<Object3D, 2> objs{{ Object3D::cube(), Object3D::cube() }};
+    auto scale_mat = Mat4::scale(rad);
     while (cont) {
         a.x += .0050f;
         a.y += .0065f;
         a.z += .0080f;
 
-        float rad = 5.f;
-        auto [e4_x, e4_y, e4_z, e4_w] = (Mat4::rot_x(a.x) * Mat4::rot_y(a.y) * Mat4::rot_z(a.z)).to_vecs();
-        auto e_x = e4_x.xyz();
-        auto e_y = e4_y.xyz();
-        auto e_z = e4_z.xyz();
-
-        std::array<Object3D, 2> objs{{
-            {
-                {
-                    {
-                        rad * (-e_x + -e_y + -e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + -e_y + -e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (-e_x + +e_y + -e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + +e_y + -e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (-e_x + -e_y + +e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + -e_y + +e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (-e_x + +e_y + +e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + +e_y + +e_z - .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    }
-                },
-                {
-                    // face 1
-                    { 0, 2, 3 },
-                    { 0, 3, 1 },
-
-                    // face 2
-                    { 0, 4, 6 },
-                    { 0, 6, 2 },
-
-                    // face 3
-                    { 0, 1, 5 },
-                    { 0, 5, 4 },
-
-                    // face 4
-                    { 7, 6, 4 },
-                    { 7, 4, 5 },
-
-                    // face 5
-                    { 7, 3, 2 },
-                    { 7, 2, 6 },
-
-                    // face 6
-                    { 7, 5, 1 },
-                    { 7, 1, 3 },
-                }
-            },
-            {
-                {
-                    {
-                        rad * (-e_x + -e_y + -e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + -e_y + -e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (-e_x + +e_y + -e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + +e_y + -e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (-e_x + -e_y + +e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + -e_y + +e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (-e_x + +e_y + +e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    },
-                    {
-                        rad * (+e_x + +e_y + +e_z + .5f * (e_x + e_y + e_z)) - dist * rad * MathVector3{0.f, 0.f, 1.f},
-                        {}
-                    }
-                },
-                {
-                    // face 1
-                    { 0, 2, 3 },
-                    { 0, 3, 1 },
-
-                    // face 2
-                    { 0, 4, 6 },
-                    { 0, 6, 2 },
-
-                    // face 3
-                    { 0, 1, 5 },
-                    { 0, 5, 4 },
-
-                    // face 4
-                    { 7, 6, 4 },
-                    { 7, 4, 5 },
-
-                    // face 5
-                    { 7, 3, 2 },
-                    { 7, 2, 6 },
-
-                    // face 6
-                    { 7, 5, 1 },
-                    { 7, 1, 3 },
-                }
-            }
-        }};
         fb.clear();
-        float min_z = 2.f, max_z = 50.f;
-        float fac_for_aspect_ratio = static_cast<float>(fb.height()) / static_cast<float>(fb.width());
-        Mat4 mat{{
-            fac_for_aspect_ratio, 0.f, 0.f, 0.f,
-            0.f, -1.f, 0.f, 0.f,
-            0.f, 0.f, -2.f / (max_z - min_z), -(max_z + min_z) / (max_z - min_z),
-            0.f, 0.f, -1.f, 0.f,
+        auto transform_mat = Mat4::translate(MathVector3{0.f, 0.f, -rad * dist}) * Mat4::rot_z(a.z) * Mat4::rot_y(a.y) * Mat4::rot_x(a.x);
+        std::array<Mat4, 2> mats{{
+            transform_mat * Mat4::translate(MathVector3{-.5f * rad, -.5f * rad, -.5f * rad}) * scale_mat,
+            transform_mat * Mat4::translate(MathVector3{+.5f * rad, +.5f * rad, +.5f * rad}) * scale_mat,
         }};
-        for (auto obj : objs) {
-            for (auto triangle : obj) {
+        auto projection_mat = Mat4::projection(static_cast<float>(fb.height()) / static_cast<float>(fb.width()), 2.f, 50.f);
+        for (int i = 0; i < 2; i++) {
+            auto final_mat = projection_mat * mats[i];
+            for (auto triangle : objs[i]) {
                 TriangleVertex4 t{triangle};
 
-                t.vertex1.point = mat * t.vertex1.point;
-                t.vertex2.point = mat * t.vertex2.point;
-                t.vertex3.point = mat * t.vertex3.point;
+                t.vertex1.point = final_mat * t.vertex1.point;
+                t.vertex2.point = final_mat * t.vertex2.point;
+                t.vertex3.point = final_mat * t.vertex3.point;
 
                 fb.draw_triangle(t);
             }
@@ -285,13 +158,14 @@ int main_graphical() {
     SDL_Renderer* renderer = NULL;
     SDL_Texture* texture = NULL;
 
+    // init
     if (SDL_Init(SDL_INIT_VIDEO) < 0) {
-        fprintf(stderr, "Error: SDL_Init error: %s\n", SDL_GetError());
+        std::cerr << "Error: SDL_Init error: " << SDL_GetError() << std::endl;
         return EXIT_FAILURE;
     }
     window = SDL_CreateWindow("Engine", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN);
     if (window == NULL) {
-        fprintf(stderr, "Error: SDL_CreateWindow error: %s\n", SDL_GetError());
+        std::cerr << "Error: SDL_CreateWindow error: " << SDL_GetError() << std::endl;
         return EXIT_FAILURE;
     }
     renderer = SDL_CreateRenderer(window, -1, SDL_RENDERER_ACCELERATED);
@@ -307,14 +181,17 @@ int main_graphical() {
         SDL_RenderPresent(renderer);
         SDL_UpdateWindowSurface(window);
         bool cont = true;
-        while (SDL_WaitEventTimeout(&e, 10)) {
-            if (e.type == SDL_QUIT) {
-                cont = false;
-            }
+        if (SDL_WaitEventTimeout(&e, 10)) {
+            do {
+                if (e.type == SDL_QUIT) {
+                    cont = false;
+                }
+            } while (SDL_PollEvent(&e));
         }
         return cont;
     });
 
+    // terminate
     SDL_DestroyTexture(texture);
     SDL_DestroyRenderer(renderer);
     SDL_DestroyWindow(window);
@@ -323,29 +200,38 @@ int main_graphical() {
     return EXIT_SUCCESS;
 }
 
-int main(int argc, char *argv[]) {
-    int mode = MODE_GRAPHICAL;
-    for (int i = 1; i < argc; i++) {
-        if (argv[i][0] == '-') {
-            if (argv[i][1] == '-') {
-                if (strcmp(&argv[i][2], "help") == 0) {
+std::vector<std::string_view> convert_args(int argc, char *argv[]) {
+    std::vector<std::string_view> args(argc);
+    for (int i = 0; i < argc; i++)
+        args[i] = argv[i];
+    return args;
+}
+
+void parse_args(const std::vector<std::string_view>& args, int& mode) {
+    for (auto args_iter = std::next(args.begin()); args_iter != args.end(); args_iter++) {
+        const auto& arg = *args_iter;
+        if (arg.size() >= 1 && arg[0] == '-') {
+            if (arg.size() >= 2 && arg[1] == '-') {
+                auto long_opt = arg.substr(2);
+                if (long_opt == "help") {
                     mode = MODE_HELP;
-                } else if (strcmp(&argv[i][2], "term") == 0) {
+                } else if (long_opt == "term") {
                     mode = MODE_TERM;
-                } else if (strcmp(&argv[i][2], "graphical") == 0) {
+                } else if (long_opt == "graphical") {
                     mode = MODE_GRAPHICAL;
                 } else {
-                    std::cerr << "Error: Unexpected option `--" << &argv[i][2] << "'." << std::endl;
+                    std::cerr << "Error: Unexpected option `--" << long_opt << "'." << std::endl;
                     usage_error_exit();
                 }
             } else {
-                if (!argv[i][1]) {
+                std::size_t arg_len = arg.size();
+                if (arg_len == 1) {
                     std::cerr << "Error: Unexpected argument `-'." << std::endl;
                     usage_error_exit();
                 }
-                std::size_t arg_len = strlen(&argv[i][1]);
-                for (int j = 0; j < arg_len; j++) {
-                    switch (argv[i][1 + j]) {
+                for (auto arg_iter = std::next(arg.begin()); arg_iter != arg.end(); arg_iter++) {
+                    const auto& opt = *arg_iter;
+                    switch (opt) {
                     case 'h':
                         mode = MODE_HELP;
                         break;
@@ -356,16 +242,21 @@ int main(int argc, char *argv[]) {
                         mode = MODE_GRAPHICAL;
                         break;
                     default:
-                        std::cerr << "Error: Unexpected option `-" << argv[i][1] << "'." << std::endl;
+                        std::cerr << "Error: Unexpected option `-" << opt << "'." << std::endl;
                         usage_error_exit();
                     }
                 }
             }
         } else {
-            std::cerr << "Error: Unexpected argument `" << argv[i] << "'." << std::endl;
+            std::cerr << "Error: Unexpected argument `" << arg << "'." << std::endl;
             usage_error_exit();
         }
     }
+}
+
+int main(int argc, char *argv[]) {
+    int mode = MODE_GRAPHICAL;
+    parse_args(convert_args(argc, argv), mode);
     switch (mode) {
     case MODE_HELP:
         print_usage(std::cout);
diff --git a/src/math/mat4.cpp b/src/math/mat4.cpp
index 0342fdf..ece42d8 100644
--- a/src/math/mat4.cpp
+++ b/src/math/mat4.cpp
@@ -12,6 +12,23 @@ Mat4 Mat4::idty() {
     };
 }
 
+Mat4 Mat4::translate(MathVector3 v) {
+    return {
+        1.f, 0.f, 0.f, v.x,
+        0.f, 1.f, 0.f, v.y,
+        0.f, 0.f, 1.f, v.z,
+        0.f, 0.f, 0.f, 1.f,
+    };
+}
+Mat4 Mat4::scale(float fac) {
+    return {
+        fac, 0.f, 0.f, 0.f,
+        0.f, fac, 0.f, 0.f,
+        0.f, 0.f, fac, 0.f,
+        0.f, 0.f, 0.f, 1.f,
+    };
+}
+
 Mat4 Mat4::rot_x(float a) {
     float c = std::cos(a);
     float s = std::sin(a);
@@ -45,6 +62,19 @@ Mat4 Mat4::rot_z(float a) {
     };
 }
 
+Mat4 Mat4::projection(float aspect_ratio, float min_z, float max_z) {
+    return {{
+        aspect_ratio, 0.f, 0.f, 0.f,
+        0.f, -1.f, 0.f, 0.f,
+        0.f, 0.f, -2.f / (max_z - min_z), -(max_z + min_z) / (max_z - min_z),
+        0.f, 0.f, -1.f, 0.f,
+    }};
+}
+
+Mat4 Mat4::operator+() {
+    return *this;
+}
+
 Mat4 Mat4::operator-() {
     return {
         -values[ 0], -values[ 1], -values[ 2], -values[ 3],
@@ -96,3 +126,12 @@ std::array<MathVector4, 4> Mat4::to_vecs() {
         { values[ 3], values[ 7], values[11], values[15] },
     }};
 }
+
+Mat4 operator*(float fac, Mat4 m) {
+    return {
+        fac * m.values[ 0], fac * m.values[ 1], fac * m.values[ 2], fac * m.values[ 3],
+        fac * m.values[ 4], fac * m.values[ 5], fac * m.values[ 6], fac * m.values[ 7],
+        fac * m.values[ 8], fac * m.values[ 9], fac * m.values[10], fac * m.values[11],
+        fac * m.values[12], fac * m.values[13], fac * m.values[14], fac * m.values[15],
+    };
+}
diff --git a/src/math/mat4.h b/src/math/mat4.h
index d81da63..6df9d49 100644
--- a/src/math/mat4.h
+++ b/src/math/mat4.h
@@ -7,12 +7,16 @@
 class Mat4 {
     public:
         static Mat4 idty();
+        static Mat4 translate(MathVector3 v);
+        static Mat4 scale(float fac);
         static Mat4 rot_x(float a);
         static Mat4 rot_y(float a);
         static Mat4 rot_z(float a);
+        static Mat4 projection(float aspect_ratio, float min_z, float max_z);
 
         std::array<float, 16> values;
 
+        Mat4 operator+();
         Mat4 operator-();
         Mat4 operator+(Mat4 m);
         Mat4 operator-(Mat4 m);
@@ -21,4 +25,6 @@ class Mat4 {
         std::array<MathVector4, 4> to_vecs();
 };
 
+Mat4 operator*(float fac, Mat4 m);
+
 #endif // MATH_MAT4_H
diff --git a/src/o3d/obj3d.cpp b/src/o3d/obj3d.cpp
index 46f4db6..584e304 100644
--- a/src/o3d/obj3d.cpp
+++ b/src/o3d/obj3d.cpp
@@ -34,6 +34,29 @@ Object3D::TriangleVertex3Iterator::reference Object3D::TriangleVertex3Iterator::
     };
 }
 
+Object3D Object3D::cube() {
+    return {
+        {
+            { MathVector3(-1.f, -1.f, -1.f), {} },
+            { MathVector3(+1.f, -1.f, -1.f), {} },
+            { MathVector3(-1.f, +1.f, -1.f), {} },
+            { MathVector3(+1.f, +1.f, -1.f), {} },
+            { MathVector3(-1.f, -1.f, +1.f), {} },
+            { MathVector3(+1.f, -1.f, +1.f), {} },
+            { MathVector3(-1.f, +1.f, +1.f), {} },
+            { MathVector3(+1.f, +1.f, +1.f), {} },
+        },
+        {
+            { 0, 2, 3 }, { 0, 3, 1 }, // face 1
+            { 0, 4, 6 }, { 0, 6, 2 }, // face 2
+            { 0, 1, 5 }, { 0, 5, 4 }, // face 3
+            { 7, 6, 4 }, { 7, 4, 5 }, // face 4
+            { 7, 3, 2 }, { 7, 2, 6 }, // face 5
+            { 7, 5, 1 }, { 7, 1, 3 }, // face 6
+        }
+    };
+}
+
 Object3D::Object3D(std::vector<Vertex3> pts, std::vector<std::array<int, 3>> faces) : pts{pts}, faces{faces} {
 }
 
diff --git a/src/o3d/obj3d.h b/src/o3d/obj3d.h
index 559ed63..c65a06b 100644
--- a/src/o3d/obj3d.h
+++ b/src/o3d/obj3d.h
@@ -30,6 +30,8 @@ class Object3D {
 
         };
 
+        static Object3D cube(); // this function should not be in this file
+
         Object3D(std::vector<Vertex3> pts, std::vector<std::array<int, 3>> faces);
         TriangleVertex3Iterator begin();
         TriangleVertex3Iterator end();