added matrices

4 files changed, 137 insertions, 39 deletions

diff --git a/Makefile.am b/Makefile.am
index fae27fd..2a81b4c 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -6,6 +6,7 @@ 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/math_vector.h src/math/math_vector.cpp \
+                 src/math/mat4.h src/math/mat4.cpp \
                  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
diff --git a/src/engine.cpp b/src/engine.cpp
index eb3b156..4740046 100644
--- a/src/engine.cpp
+++ b/src/engine.cpp
@@ -22,6 +22,7 @@
 #include "o3d/vertex_data.h"
 #include "o3d/tri_vertex.h"
 #include "math/math_vector.h"
+#include "math/mat4.h"
 
 #define FPS 60
 
@@ -55,32 +56,10 @@ void scene_main(FB& fb, std::function<bool()> update_frame) {
         a.z += .0080f;
 
         float rad = 5.f;
-        MathVector3 ca{std::cos(a.x), std::cos(a.y), std::cos(a.z)};
-        MathVector3 sa{std::sin(a.x), std::sin(a.y), std::sin(a.z)};
-
-        std::array<MathVector3, 3> rot_x = {{
-            { 1.f, 0.f, 0.f },
-            { 0.f, ca.x, sa.x },
-            { 0.f, -sa.x, ca.x },
-        }};
-        std::array<MathVector3, 3> rot_y = {{
-            { ca.y, 0.f, -sa.y },
-            { 0.f, 1.f, 0.f },
-            { sa.y, 0.f, ca.y },
-        }};
-        std::array<MathVector3, 3> rot_z = {{
-            { ca.z, sa.z, 0.f },
-            { -sa.z, ca.z, 0.f },
-            { 0.f, 0.f, 1.f },
-        }};
-
-        auto [e_x, e_y, e_z] = rot_x;
-        e_x = e_x.x * rot_y[0] + e_x.y * rot_y[1] + e_x.z * rot_y[2];
-        e_y = e_y.x * rot_y[0] + e_y.y * rot_y[1] + e_y.z * rot_y[2];
-        e_z = e_z.x * rot_y[0] + e_z.y * rot_y[1] + e_z.z * rot_y[2];
-        e_x = e_x.x * rot_z[0] + e_x.y * rot_z[1] + e_x.z * rot_z[2];
-        e_y = e_y.x * rot_z[0] + e_y.y * rot_z[1] + e_y.z * rot_z[2];
-        e_z = e_z.x * rot_z[0] + e_z.y * rot_z[1] + e_z.z * rot_z[2];
+        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{{
             {
@@ -209,23 +188,19 @@ void scene_main(FB& fb, std::function<bool()> update_frame) {
         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,
+        }};
         for (auto obj : objs) {
             for (auto triangle : obj) {
                 TriangleVertex4 t{triangle};
 
-                // should be multiplied by a matrix, temporary replacement
-                t.vertex1.point.x *= fac_for_aspect_ratio;
-                t.vertex1.point.y = -t.vertex1.point.y;
-                t.vertex1.point.w = -t.vertex1.point.z;
-                t.vertex1.point.z = 2.f * (-t.vertex1.point.z - min_z) / (max_z - min_z) - 1.f;
-                t.vertex2.point.x *= fac_for_aspect_ratio;
-                t.vertex2.point.y = -t.vertex2.point.y;
-                t.vertex2.point.w = -t.vertex2.point.z;
-                t.vertex2.point.z = 2.f * (-t.vertex2.point.z - min_z) / (max_z - min_z) - 1.f;
-                t.vertex3.point.x *= fac_for_aspect_ratio;
-                t.vertex3.point.y = -t.vertex3.point.y;
-                t.vertex3.point.w = -t.vertex3.point.z;
-                t.vertex3.point.z = 2.f * (-t.vertex3.point.z - min_z) / (max_z - min_z) - 1.f;
+                t.vertex1.point = mat * t.vertex1.point;
+                t.vertex2.point = mat * t.vertex2.point;
+                t.vertex3.point = mat * t.vertex3.point;
 
                 fb.draw_triangle(t);
             }
diff --git a/src/math/mat4.cpp b/src/math/mat4.cpp
new file mode 100644
index 0000000..0342fdf
--- /dev/null
+++ b/src/math/mat4.cpp
@@ -0,0 +1,98 @@
+#include "math/mat4.h"
+#include <array>
+#include <cmath>
+#include "math/math_vector.h"
+
+Mat4 Mat4::idty() {
+    return {
+        1.f, 0.f, 0.f, 0.f,
+        0.f, 1.f, 0.f, 0.f,
+        0.f, 0.f, 1.f, 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);
+    return {
+        1.f, 0.f, 0.f, 0.f,
+        0.f,   c,  -s, 0.f,
+        0.f,   s,   c, 0.f,
+        0.f, 0.f, 0.f, 1.f,
+    };
+}
+
+Mat4 Mat4::rot_y(float a) {
+    float c = std::cos(a);
+    float s = std::sin(a);
+    return {
+          c, 0.f,   s, 0.f,
+        0.f, 1.f, 0.f, 0.f,
+         -s, 0.f,   c, 0.f,
+        0.f, 0.f, 0.f, 1.f,
+    };
+}
+
+Mat4 Mat4::rot_z(float a) {
+    float c = std::cos(a);
+    float s = std::sin(a);
+    return {
+          c,  -s, 0.f, 0.f,
+          s,   c, 0.f, 0.f,
+        0.f, 0.f, 1.f, 0.f,
+        0.f, 0.f, 0.f, 1.f,
+    };
+}
+
+Mat4 Mat4::operator-() {
+    return {
+        -values[ 0], -values[ 1], -values[ 2], -values[ 3],
+        -values[ 4], -values[ 5], -values[ 6], -values[ 7],
+        -values[ 8], -values[ 9], -values[10], -values[11],
+        -values[12], -values[13], -values[14], -values[15],
+    };
+}
+
+Mat4 Mat4::operator+(Mat4 m) {
+    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],
+        values[ 8] + m.values[ 8], values[ 9] + m.values[ 9], values[10] + m.values[10], values[11] + m.values[11],
+        values[12] + m.values[12], values[13] + m.values[13], values[14] + m.values[14], values[15] + m.values[15],
+    };
+}
+
+Mat4 Mat4::operator-(Mat4 m) {
+    return *this + (-m);
+}
+
+Mat4 Mat4::operator*(Mat4 m) {
+    Mat4 ret;
+    for (int i = 0; i < 4; i++) {
+        for (int j = 0; j < 4; j++) {
+            ret.values[i * 4 + j] = 0.f;
+            for (int k = 0; k < 4; k++)
+                ret.values[i * 4 + j] += values[i * 4 + k] * m.values[k * 4 + j];
+        }
+    }
+    return ret;
+}
+
+MathVector4 Mat4::operator*(MathVector4 v) {
+    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,
+        values[ 8] * v.x + values[ 9] * v.y + values[10] * v.z + values[11] * v.w,
+        values[12] * v.x + values[13] * v.y + values[14] * v.z + values[15] * v.w,
+    };
+}
+
+std::array<MathVector4, 4> Mat4::to_vecs() {
+    return {{
+        { values[ 0], values[ 4], values[ 8], values[12] },
+        { values[ 1], values[ 5], values[ 9], values[13] },
+        { values[ 2], values[ 6], values[10], values[14] },
+        { values[ 3], values[ 7], values[11], values[15] },
+    }};
+}
diff --git a/src/math/mat4.h b/src/math/mat4.h
new file mode 100644
index 0000000..d81da63
--- /dev/null
+++ b/src/math/mat4.h
@@ -0,0 +1,24 @@
+#ifndef MATH_MAT4_H
+#define MATH_MAT4_H
+
+#include <array>
+#include "math/math_vector.h"
+
+class Mat4 {
+    public:
+        static Mat4 idty();
+        static Mat4 rot_x(float a);
+        static Mat4 rot_y(float a);
+        static Mat4 rot_z(float a);
+
+        std::array<float, 16> values;
+
+        Mat4 operator-();
+        Mat4 operator+(Mat4 m);
+        Mat4 operator-(Mat4 m);
+        Mat4 operator*(Mat4 m);
+        MathVector4 operator*(MathVector4 v);
+        std::array<MathVector4, 4> to_vecs();
+};
+
+#endif // MATH_MAT4_H