various improvements

- cleaned up the computation of the camera's matrix
- changed VertexData to being a struct which transmit data between the "vertex shader" and the "fragment shader"
- started working on keyboard and mouse controls
- added fov (field of view)
- changed quaternion to euler angles conversion, from zyx to zxy
- fixed computations of z coordinates in triangle rendering
- improved naming in the triangle rasterizer

1 files changed, 16 insertions, 5 deletions

diff --git a/src/math/mat4.h b/src/math/mat4.h
index adb2059..df8f533 100644
--- a/src/math/mat4.h
+++ b/src/math/mat4.h
@@ -77,15 +77,26 @@ struct Matrix4 {
         };
     }
 
-    static constexpr Matrix4 projection(float aspect_ratio, float min_z, float max_z) {
+    static constexpr Matrix4 projection(float fov, float aspect_ratio, float min_z, float max_z) {
+        float inv_tan = 1.f / std::tan(fov / 2.f);
         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,
+            aspect_ratio * inv_tan, 0.f,      0.f,                    0.f,
+            0.f,                    -inv_tan, 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,
         }};
     }
 
+    // TODO: should be Quaternion::to_mat4
+    static constexpr Matrix4 from_quaternion(const Quaternion& q) {
+        return {
+            2.f * (q.w * q.w + q.x * q.x) - 1.f, 2.f * (q.x * q.y - q.w * q.z)      , 2.f * (q.x * q.z + q.w * q.y)      , 0.f,
+            2.f * (q.x * q.y + q.w * q.z)      , 2.f * (q.w * q.w + q.y * q.y) - 1.f, 2.f * (q.y * q.z - q.w * q.x)      , 0.f,
+            2.f * (q.x * q.z - q.w * q.y)      , 2.f * (q.y * q.z + q.w * q.x)      , 2.f * (q.w * q.w + q.z * q.z) - 1.f, 0.f,
+            0.f,                                 0.f,                                 0.f,                                 1.f,
+        };
+    }
+
     std::array<float, 4 * 4> values;
 
     constexpr Matrix4 operator+() const & {