From 465c338628e08195eeda2f9f35bdbf1c91acb009 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Miloslav=20=C4=8C=C3=AD=C5=BE?= <tastyfish@seznam.cz>
Date: Sun, 19 May 2019 20:14:06 +0200
Subject: [PATCH] Add extra camera control

---
 s3l.h     | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-
 testSDL.c | 32 +++++++++++++++++++--------
 2 files changed, 87 insertions(+), 10 deletions(-)

diff --git a/s3l.h b/s3l.h
index a5e7d0a..c9ebac0 100644
--- a/s3l.h
+++ b/s3l.h
@@ -238,6 +238,9 @@ typedef struct
 
 static inline void S3L_initVec4(S3L_Vec4 *v);
 
+static inline void S3L_vec3Add(S3L_Vec4 *result, S3L_Vec4 added);
+static inline void S3L_vec3Sub(S3L_Vec4 *result, S3L_Vec4 substracted);
+
 #define S3L_writeVec4(v)\
   printf("Vec4: %d %d %d %d\n",((v).x),((v).y),((v).z),((v).w))
 
@@ -253,6 +256,16 @@ typedef struct
 
 static inline void S3L_initTransoform3D(S3L_Transform3D *t);
 
+/** Converts rotation transformation to three direction vectors of given length
+  (any one can be NULL, in which case it won't be computed).
+*/
+void S3L_rotationToDirections(
+  S3L_Vec4 rotation,
+  S3L_Unit length,
+  S3L_Vec4 *forw, 
+  S3L_Vec4 *right,
+  S3L_Vec4 *up);
+
 typedef S3L_Unit S3L_Mat4[4][4]; /**< 4x4 matrix, used mostly for 3D
                                       transforms. The indexing is this:
                                       matrix[column][row]. */
@@ -495,6 +508,20 @@ void S3L_initVec4(S3L_Vec4 *v)
   v->x = 0; v->y = 0; v->z = 0; v->w = S3L_FRACTIONS_PER_UNIT;
 }
 
+void S3L_vec3Add(S3L_Vec4 *result, S3L_Vec4 added)
+{
+  result->x += added.x;
+  result->y += added.y;
+  result->z += added.z;
+}
+
+void S3L_vec3Sub(S3L_Vec4 *result, S3L_Vec4 substracted)
+{
+  result->x -= substracted.x;
+  result->y -= substracted.y;
+  result->z -= substracted.z;
+}
+
 void S3L_initMat4(S3L_Mat4 *m)
 {
   #define M(x,y) (*m)[x][y]
@@ -738,8 +765,44 @@ void S3L_initCamera(S3L_Camera *c)
   S3L_initTransoform3D(&(c->transform));
 }
 
-void S3L_initPixelInfo(S3L_PixelInfo *p)
+void S3L_rotationToDirections(
+  S3L_Vec4 rotation,
+  S3L_Unit length,
+  S3L_Vec4 *forw, 
+  S3L_Vec4 *right,
+  S3L_Vec4 *up)
 {
+  S3L_Mat4 m;
+
+  S3L_makeRotationMatrix(-1 * rotation.x,-1 * rotation.y,-1 * rotation.z,&m);
+
+  if (forw != 0)
+  {
+    forw->x = 0;
+    forw->y = 0;
+    forw->z = length;
+    S3L_vec3Xmat4(forw,*m);
+  }
+
+  if (right != 0)
+  {
+    right->x = length;
+    right->y = 0;
+    right->z = 0;
+    S3L_vec3Xmat4(right,*m);
+  }
+
+  if (up != 0)
+  {
+    up->x = 0;
+    up->y = length;
+    up->z = 0;
+    S3L_vec3Xmat4(up,*m);
+  }
+}
+
+void S3L_initPixelInfo(S3L_PixelInfo *p) // TODO: maybe non-pointer for p
+{                                        // could be faster?
   p->x = 0;
   p->y = 0;
   p->barycentric0 = S3L_FRACTIONS_PER_UNIT;
diff --git a/testSDL.c b/testSDL.c
index 8929669..a9dfcb8 100644
--- a/testSDL.c
+++ b/testSDL.c
@@ -12,7 +12,7 @@
 #define S3L_RESOLUTION_X 640
 #define S3L_RESOLUTION_Y 480
 
-#define S3L_PERSPECTIVE_CORRECTION 0
+#define S3L_PERSPECTIVE_CORRECTION 1
 
 #include "s3l.h"
 
@@ -248,25 +248,33 @@ int main()
       }
     }
 
+    S3L_Vec4 camF, camR, camU;
     int step = 10;
+ 
+    S3L_rotationToDirections(
+      camera.transform.rotation,
+      step,
+      &camF,
+      &camR,
+      &camU);
 
     if (keys['w'])
-      camera.transform.translation.z += step;
+      S3L_vec3Add(&camera.transform.translation,camF);
 
     if (keys['s'])
-      camera.transform.translation.z -= step;
-
-    if (keys['a'])
-      camera.transform.translation.x -= step;
+      S3L_vec3Sub(&camera.transform.translation,camF);
 
     if (keys['d'])
-      camera.transform.translation.x += step;
+      S3L_vec3Add(&camera.transform.translation,camR);
+
+    if (keys['a'])
+      S3L_vec3Sub(&camera.transform.translation,camR);
 
     if (keys['x'])
-      camera.transform.translation.y += step;
+      camera.transform.translation.y += 10;
 
     if (keys['c'])
-      camera.transform.translation.y -= step;
+      camera.transform.translation.y -= 10;
 
     if (keys['q'])
       camera.transform.rotation.y -= 1;
@@ -274,6 +282,12 @@ int main()
     if (keys['e'])
       camera.transform.rotation.y += 1;
 
+    if (keys['r'])
+      camera.transform.rotation.x -= 1;
+
+    if (keys['t'])
+      camera.transform.rotation.x += 1;
+
     SDL_RenderClear(renderer);
     SDL_RenderCopy(renderer,texture,NULL,NULL);
     SDL_RenderPresent(renderer);