From 8a67b7edbe96cc85a27eb8482068c3f400b15e8c Mon Sep 17 00:00:00 2001
From: Orange <orange-cpp@yandex.ru>
Date: Tue, 27 Aug 2024 21:41:21 +0300
Subject: [PATCH] maybe improved matrix

---
 include/omath/projection/Camera.h |  2 +-
 source/projection/Camera.cpp      | 24 ++++++++++--------------
 tests/UnitTestProjection.cpp      |  6 +++---
 3 files changed, 14 insertions(+), 18 deletions(-)

diff --git a/include/omath/projection/Camera.h b/include/omath/projection/Camera.h
index 7b2f864..c96dd16 100644
--- a/include/omath/projection/Camera.h
+++ b/include/omath/projection/Camera.h
@@ -23,7 +23,7 @@ namespace omath::projection
         static float& GetFloat2();
 
         [[nodiscard]] Matrix GetViewMatrix() const;
-        [[nodiscard]] Matrix GetProjectionMatrix(float scaleX, float scaleY) const;
+        [[nodiscard]] Matrix GetProjectionMatrix() const;
         [[nodiscard]] Matrix GetTranslationMatrix() const;
         [[nodiscard]] Matrix GetOrientationMatrix() const;
 
diff --git a/source/projection/Camera.cpp b/source/projection/Camera.cpp
index 47540a0..fe88929 100644
--- a/source/projection/Camera.cpp
+++ b/source/projection/Camera.cpp
@@ -2,9 +2,7 @@
 // Created by Vlad on 27.08.2024.
 //
 #include "omath/projection/Camera.h"
-
 #include <complex>
-
 #include "omath/angles.h"
 
 
@@ -36,24 +34,22 @@ namespace omath::projection
         return GetTranslationMatrix() * GetOrientationMatrix();
     }
 
-    Matrix Camera::GetProjectionMatrix(const float scaleX, const float scaleY) const
+    Matrix Camera::GetProjectionMatrix() const
     {
-        const float right = std::tan(angles::DegreesToRadians(m_fieldOfView) / 2.f);
+        const float right = m_nearPlaneDistance * std::tan(angles::DegreesToRadians(m_fieldOfView) / 2.f);
         const float left  = -right;
 
-        const float verticalFov = angles::DegreesToRadians(m_fieldOfView) * (m_viewPort.y / m_viewPort.x);
-
-        const float top   = std::tan(verticalFov / 2.f);
+        const float top   = right * (m_viewPort.y / m_viewPort.x);
         const float bottom = -top;
 
-        const auto far = m_farPlaneDistance;
-        const auto near = m_nearPlaneDistance;
+        const float near = m_nearPlaneDistance;
+        const float far = m_farPlaneDistance;
 
         return Matrix({
-            {scaleX / (right - left), 0.f, 0.f, 0.f},
-            {0.f, scaleY / (top - bottom), 0.f, 0.f},
-            {0.f, 0.f, (far + near) / (far - near), 1.f},
-            {0.f, 0.f, -near * far / (far - near), 0.f},
+            {2 * near / (right - left), 0.f, (right + left) / (right - left), 0.f},
+            {0.f, 2 * near / (top - bottom), (top + bottom) / (top - bottom), 0.f},
+            {0.f, 0.f, (far + near) / (far - near), 2 * near * far / (far - near)},
+            {0.f, 0.f, -1.f, 0.f},
         });
     }
 
@@ -88,7 +84,7 @@ namespace omath::projection
     {
         const auto posVecAsMatrix = Matrix({{worldPosition.x, worldPosition.y, worldPosition.z, 1.f}});
 
-        const auto viewProjectionMatrix = GetViewMatrix() * GetProjectionMatrix(GetFloat1(), GetFloat2());
+        const auto viewProjectionMatrix = GetViewMatrix() * GetProjectionMatrix();
 
         auto projected = posVecAsMatrix * viewProjectionMatrix;
 
diff --git a/tests/UnitTestProjection.cpp b/tests/UnitTestProjection.cpp
index a989c9e..dcd5d4c 100644
--- a/tests/UnitTestProjection.cpp
+++ b/tests/UnitTestProjection.cpp
@@ -9,10 +9,10 @@
 
 TEST(UnitTestProjection, IsPointOnScreen)
 {
-    const omath::projection::Camera camera({5, 0, 0}, {0, 0.f, 0.f} , {1920.f, 1080.f, 0.f}, 110, 0.1, 500);
+    const omath::projection::Camera camera({0, 0, 0}, {0, 0.f, 0.f} , {1920.f, 1080.f, 0.f}, 110, 0.1, 500);
 
-    const auto proj = camera.WorldToScreen({10, 0, 0});
+    const auto proj = camera.WorldToScreen({100, 0, 15});
     if (proj)
-        std::print("{} {} {}", proj->x, proj->y, proj->z);
+        std::print("{} {}", proj->x, proj->y);
     EXPECT_TRUE(proj.has_value());
 }
\ No newline at end of file