From 80e6f9727541cf1e63ddd1e48e24f7a5fd214b0c Mon Sep 17 00:00:00 2001
From: Eric-Paul Ickhorn <ericp.ickhorn@gmail.com>
Date: Fri, 13 Oct 2023 14:37:02 +0200
Subject: [PATCH] Added mouse-based rotation and rotation-dependant movement

---
 code/source-c/main.c | 61 ++++++++++++++++++++++++++++++++------------
 1 file changed, 45 insertions(+), 16 deletions(-)

diff --git a/code/source-c/main.c b/code/source-c/main.c
index 6d8d302..251f1e1 100644
--- a/code/source-c/main.c
+++ b/code/source-c/main.c
@@ -65,7 +65,7 @@ float triangle_vertices[108] =
 };
 
 tc_vec3_s               tc_camera_position = { 0.0f, 0.0f, 0.0f };
-tc_vec3_s               tc_camera_rotation = { 0.0f, 0.0f, 0.0f };
+// tc_vec3_s               tc_camera_rotation = { 0.0f, 0.0f, 0.0f };
 
 tc_block_s block;
 
@@ -117,10 +117,12 @@ void render()
     glViewport(0, 0, fb_width, fb_height);
     mat4x4_perspective(projection_matrix, 120, ((float) fb_width) / ((float) fb_height), 0.0001f, 1000.0f);
     
+    tc_vec3_s   camera_rotation         = tc_game_state_g.renderer.active_camera.rotation;
+    
     mat4x4_identity(view_matrix);
-    mat4x4_rotate_X(view_matrix, view_matrix, tc_camera_rotation.x);
-    mat4x4_rotate_Y(view_matrix, view_matrix, tc_camera_rotation.y);
-    mat4x4_rotate_Z(view_matrix, view_matrix, tc_camera_rotation.z);
+    mat4x4_rotate_X(view_matrix, view_matrix, camera_rotation.x);
+    mat4x4_rotate_Y(view_matrix, view_matrix, camera_rotation.y);
+    mat4x4_rotate_Z(view_matrix, view_matrix, camera_rotation.z);
     
     mat4x4_translate_in_place(view_matrix, -tc_camera_position.x, -tc_camera_position.y, tc_camera_position.z);
     
@@ -255,6 +257,20 @@ bool update()
                 }
                 
             break;
+            
+            case SDL_MOUSEMOTION:
+            {
+                if(!(event.motion.state & SDL_BUTTON_LMASK)) break;
+                tc_game_state_g.renderer.active_camera.rotation.y += event.motion.xrel / 50.0f;
+                tc_game_state_g.renderer.active_camera.rotation.x += event.motion.yrel / 50.0f;
+                
+                if(tc_game_state_g.renderer.active_camera.rotation.x > (3.1415f/2.0f)) 
+                    tc_game_state_g.renderer.active_camera.rotation.x = (3.1415f/2.0f);
+                
+                if(tc_game_state_g.renderer.active_camera.rotation.x < -(3.1415f/2.0f)) 
+                    tc_game_state_g.renderer.active_camera.rotation.x = -(3.1415f/2.0f);
+                
+            } break;
         }
     }
     
@@ -268,35 +284,48 @@ bool update()
         tc_camera_position.y += 0.25;
     }
     
+    
+    
+    tc_vec3_s       difference_in_perspective;
+    difference_in_perspective.x         = 0.0f;
+    difference_in_perspective.y         = 0.0f;
+    difference_in_perspective.z         = 0.0f;
+    
     if(go_left)
     {
-        tc_camera_position.x -= 0.25;
+        difference_in_perspective.x -= 0.45f;
     }
     
     if(go_right)
     {
-        tc_camera_position.x += 0.25;
+        difference_in_perspective.x += 0.45f;
     }
     
     if(go_forward)
     {
-        tc_camera_position.z += 0.25;
+        difference_in_perspective.z += 0.4f;
     }
     
     if(go_backwards)
     {
-        tc_camera_position.z -= 0.25;
+        difference_in_perspective.z -= 0.4f;
     }
     
-    if(rotate_left)
-    {
-        tc_camera_rotation.y -= 0.1f / (3.1415 * 2);
-    }
+    mat4x4          position_matrix;
+    mat4x4_identity(position_matrix);
     
-    if(rotate_right)
-    {
-        tc_camera_rotation.y += 0.1f / (3.1415 * 2);
-    }
+    mat4x4_translate(position_matrix, difference_in_perspective.x, 0.0f, difference_in_perspective.z);
+    
+    mat4x4_rotate_X(position_matrix, position_matrix, tc_game_state_g.renderer.active_camera.rotation.x);
+    mat4x4_rotate_Y(position_matrix, position_matrix, tc_game_state_g.renderer.active_camera.rotation.y);
+    mat4x4_rotate_Z(position_matrix, position_matrix, tc_game_state_g.renderer.active_camera.rotation.z);
+    
+    vec4            viewed_difference = { difference_in_perspective.x, 0.0f, difference_in_perspective.z };
+    vec4            raw_difference = { 0.0f, 0.0f, 0.0f };
+    mat4x4_mul_vec4(raw_difference, position_matrix, viewed_difference);
+    
+    tc_camera_position.x += raw_difference[0];
+    tc_camera_position.z += raw_difference[2];
     
     tc_game_state_g.main_world->loading_center.x        = ((int32_t) tc_camera_position.x) / 32;
     tc_game_state_g.main_world->loading_center.y        = ((int32_t) tc_camera_position.y) / 32;