From 420bbc3aa6a48ffe53f1e3b4b464d0b97a2d5b3f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miloslav=20=C4=8C=C3=AD=C5=BE?= <tastyfish@seznam.cz>
Date: Sat, 11 May 2019 21:50:03 +0200
Subject: [PATCH] Implement FOV

---
 s3l.h     | 17 +++++------------
 testSDL.c |  1 +
 2 files changed, 6 insertions(+), 12 deletions(-)

diff --git a/s3l.h b/s3l.h
index a3c883c..b42876e 100644
--- a/s3l.h
+++ b/s3l.h
@@ -1315,14 +1315,6 @@ void S3L_makeWorldMatrix(S3L_Transform3D worldTransform, S3L_Mat4 *m)
 
 void S3L_makeCameraMatrix(S3L_Transform3D cameraTransform, S3L_Mat4 *m)
 {
-/*
-  S3L_makeTranslationMat(
-    -1 * cameraTransform.translation.x,
-    -1 * cameraTransform.translation.y,
-    -1 * cameraTransform.translation.z,
-    m);
-*/
-
   S3L_makeTranslationMat(
     -1 * cameraTransform.translation.x,
     -1 * cameraTransform.translation.y,
@@ -1340,10 +1332,11 @@ void S3L_makeCameraMatrix(S3L_Transform3D cameraTransform, S3L_Mat4 *m)
   S3L_mat4Xmat4(m,&r);
 }
 
-static inline void S3L_zDivide(S3L_Vec4 *vector)
+static inline void S3L_perspectiveDivide(S3L_Vec4 *vector,
+  S3L_Unit focalLength)
 {
-  vector->x = (vector->x * S3L_FRACTIONS_PER_UNIT) / S3L_nonZero(vector->z);
-  vector->y = (vector->y * S3L_FRACTIONS_PER_UNIT) / S3L_nonZero(vector->z);
+  vector->x = (vector->x * focalLength) / vector->z;
+  vector->y = (vector->y * focalLength) / vector->z;
 }
 
 void S3L_drawModelIndexed(
@@ -1382,7 +1375,7 @@ void S3L_drawModelIndexed(
       transformed##n.x = pointModel.x;\
       transformed##n.y = pointModel.y;\
       transformed##n.z = pointModel.z;\
-      S3L_zDivide(&transformed##n);
+      S3L_perspectiveDivide(&transformed##n,camera->focalLength);
 
     project(0)
     project(1)
diff --git a/testSDL.c b/testSDL.c
index 33eaa99..60a830b 100644
--- a/testSDL.c
+++ b/testSDL.c
@@ -196,6 +196,7 @@ int main()
   SDL_Event event;
 
   S3L_initCamera(&camera);
+
   camera.transform.translation.z = -S3L_FRACTIONS_PER_UNIT * 2;
 //  camera.transform.translation.x = S3L_FRACTIONS_PER_UNIT;
 //  camera.transform.translation.y = S3L_FRACTIONS_PER_UNIT;