move raycastign to its own file

src/map.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include <stdint.h>
+
+#define MAP_SIZE 8
+static uint8_t MAPDATA[MAP_SIZE * MAP_SIZE] = {
+    1, 1, 1, 1, 1, 1, 1, 1,
+    1, 0, 0, 0, 0, 0, 0, 1,
+    1, 0, 0, 0, 0, 3, 0, 1,
+    1, 0, 0, 0, 0, 0, 0, 1,
+    1, 0, 2, 0, 4, 4, 0, 1,
+    1, 0, 0, 0, 4, 0, 0, 1,
+    1, 0, 3, 0, 0, 0, 0, 1,
+    1, 1, 1, 1, 1, 1, 1, 1,
+};
+
+#define value(x, y) (MAPDATA[(x) + MAP_SIZE * (y)])

src/ray.c

@@ -0,0 +1,106 @@
+#include "ray.h"
+#include "map.h"
+
+#include <math.h>
+
+float v2_cross(v2 a, v2 b) {
+    return fabs(a.x * b.y - a.y * b.x);
+}
+
+float v2_len(v2 a) {
+    return sqrt(a.x * a.x + a.y * a.y);
+}
+
+float v2_square_dist(v2 a, v2 b) {
+    return pow(a.x - b.x, 2) + pow(a.y - b.y, 2);
+}
+
+#define PI		3.14159265358979323846
+#define PIH		1.57079632679489661923
+#define PI2		6.28318530718
+
+uint32_t cast_ray(v2 pos, float theta, v2* hit_pos) {
+
+    const v2i move = {
+        #define sign(a) ((a) < 0 ? -1 : 1)
+        sign(cos(theta)),
+        sign(sin(theta)),
+    };
+
+    const v2i offset = {
+        move.x == -1 ? 1 : 0,
+        move.y == -1 ? 1 : 0
+    };
+    
+    const float tanc = tan(theta);
+    const float cotc = tan(PIH - (theta));
+
+    v2i posi = {
+        (int)pos.x + offset.x,
+        (int)pos.y + offset.y
+    };
+
+    bool fx = false;
+    uint32_t vx = 0;
+    float x;
+
+    while (!fx) {
+        posi.y += move.y;
+        x = cotc * (posi.y - pos.y) + pos.x;
+        
+        if (fabs(x) - pos.x >= MAP_SIZE) break;
+
+        vx = value((int)x, posi.y - offset.y);
+        
+        if (vx != 0) {
+            fx = true;
+        }
+    }
+
+    bool fy = false;
+    uint32_t vy = 0;
+    float y;
+
+    while (!fy) {
+        posi.x += move.x;
+        y = tanc * (posi.x - pos.x) + pos.y;
+
+        if (fabs(y) - pos.y >= MAP_SIZE) break;
+
+        vy = value(posi.x - offset.x, (int)y);
+
+        if (vy != 0) {
+            fy = true;
+        }
+    }
+
+    uint32_t hit;
+    if (!fx && !fy) {
+        hit = 0;
+        hit_pos->x = pos.x + 1000 * move.x;
+        hit_pos->y = pos.y + 1000 * move.y;
+        return false;
+    } else if (fx && !fy) {
+        hit = vx;
+        hit_pos->x = x;
+        hit_pos->y = posi.y;
+    } else if (fy && !fx) {
+        hit = vy;
+        hit_pos->x = posi.x;
+        hit_pos->y = y;
+    } else {
+        const v2 posx = {x, posi.y};
+        const v2 posy = {posi.x, y};
+        if (v2_square_dist(posx, pos) < v2_square_dist(posy, pos)) {
+            hit = vx;
+            hit_pos->x = x;
+            hit_pos->y = posi.y;
+        } else {
+            hit = vy;
+            hit_pos->x = posi.x;
+            hit_pos->y= y;
+        }
+    }
+
+    return hit;
+}

src/ray.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include <stdbool.h>
+#include <stdint.h>
+
+typedef struct {
+    float x, y;
+} v2;
+
+typedef struct {
+    int x, y;
+} v2i;
+
+
+float v2_cross(v2 a, v2 b);
+float v2_len(v2 a);
+float v2_square_dist(v2 a, v2 b);
+v2 v2_add(v2 a, v2 b);
+
+uint32_t cast_ray(v2 pos, float theta, v2* hit_pos); 

src/renderer.c

@@ -1,5 +1,6 @@
 #include "renderer.h"
 #include "screen.h"
+#include "ray.h"
 
 #include <math.h>
 
@@ -13,16 +14,11 @@ void init_camera(Camera* camera) {
     camera->angle = PI / 4;
 }
 
-typedef struct {
-    float x, y;
-} v2;
-
-typedef struct {
-    int x, y;
-} v2i;
+static double fov = PI / 4;
 
 #define MOVE_SPEED      1
 #define ROTATE_SPEED    PI / 2
+#define FOV_CHANGE_SPEED 1
 void update_camera(Camera* camera, Screen* screen) {
     double rotate = 0;
 
@@ -63,22 +59,25 @@ void update_camera(Camera* camera, Screen* screen) {
         move.y -= left.y;
     }
 
+    if (key_pressed(screen, SDL_SCANCODE_EQUALS)) {
+        fov += FOV_CHANGE_SPEED * screen->delta; 
+    }
+
+    if (key_pressed(screen, SDL_SCANCODE_MINUS)) {
+        fov -= FOV_CHANGE_SPEED * screen->delta;
+    }
+
     camera->x += move.x * MOVE_SPEED * screen->delta;
     camera->y += move.y * MOVE_SPEED * screen->delta;
 }
 
-
-#define MAP_SIZE 8
-static uint8_t MAPDATA[MAP_SIZE * MAP_SIZE] = {
-    1, 1, 1, 1, 1, 1, 1, 1,
-    1, 0, 0, 0, 0, 0, 0, 1,
-    1, 0, 0, 0, 0, 3, 0, 1,
-    1, 0, 0, 0, 0, 0, 0, 1,
-    1, 0, 2, 0, 4, 4, 0, 1,
-    1, 0, 0, 0, 4, 0, 0, 1,
-    1, 0, 3, 0, 0, 0, 0, 1,
-    1, 1, 1, 1, 1, 1, 1, 1,
+v2 get_cam_right(const Camera* camera) {
+    v2 cam_right = {
+        -sin(camera->angle),
+        cos(camera->angle)
     };
+    return cam_right;
+}
 
 static void verline(Screen* screen, int x, int y0, int y1, uint32_t color) {
     for (int y = y0; y <= y1; y++) {
@@ -86,124 +85,31 @@ static void verline(Screen* screen, int x, int y0, int y1, uint32_t color) {
     }
 }
 
-static float v2_cross(v2 a, v2 b) {
-    return fabs(a.x * b.y - a.y * b.x);
-}
-
-static float v2_len(v2 a) {
-    return sqrt(a.x * a.x + a.y * a.y);
-}
-
-static float v2_square_dist(v2 a, v2 b) {
-    return pow(a.x - b.x, 2) + pow(a.y - b.y, 2);
-}
-
 #define min(a, b) ((a) < (b) ? (a) : (b))
 #define max(a, b) ((a) > (b) ? (a) : (b))
-#define sign(a) ((a) < 0 ? -1 : 1)
-#define value(x, y) (MAPDATA[(x) + MAP_SIZE * (y)])
 
 void render(Screen* screen, const Camera* camera) {
 
-    const double fov = PI / 3;
-
-    const v2 cam_right = {
-        -sin(camera->angle),
-        cos(camera->angle)
-    };
-    
     const v2 pos = {
         camera->x,
         camera->y
     };
 
+    const v2 cam_right = get_cam_right(camera);
+
     for (int sx = 0; sx < screen->width; sx++) {
 
         const float xcam = (2 * (sx / (float) (screen->width))) - 1;
         const float change = fov * atan(xcam);
+        const float theta = camera->angle + change;
 
-        const v2i move = {
-            sign(cos(camera->angle + change)),
-            sign(sin(camera->angle + change)),
-        };
+        v2 hit_pos;
+        uint32_t hit = cast_ray(pos, theta, &hit_pos);
 
-        const v2i offset = {
-            move.x == -1 ? 1 : 0,
-            move.y == -1 ? 1 : 0
-        };
+        hit_pos.x -= pos.x;
+        hit_pos.y -= pos.y;
 
-        const float tanc = tan(camera->angle + change);
-        const float cotc = tan(PIH - (camera->angle + change));
-
-        v2i posi = {
-            (int)pos.x + offset.x,
-            (int)pos.y + offset.y
-        };
-
-        bool fx = false;
-        uint32_t vx = 0;
-        float x;
-
-        while (!fx) {
-            posi.y += move.y;
-            x = cotc * (posi.y - pos.y) + pos.x;
-            
-            if (fabs(x) - pos.x >= MAP_SIZE) break;
-
-            vx = value((int)x, posi.y - offset.y);
-            
-            if (vx != 0) {
-                fx = true;
-            }
-        }
-
-        bool fy = false;
-        uint32_t vy = 0;
-        float y;
-
-        while (!fy) {
-            posi.x += move.x;
-            y = tanc * (posi.x - pos.x) + pos.y;
-
-            if (fabs(y) - pos.y >= MAP_SIZE) break;
-
-            vy = value(posi.x - offset.x, (int)y);
-
-            if (vy != 0) {
-                fy = true;
-            }
-        }
-
-        uint32_t hit;
-        if (!fx && !fy) {
-            hit = 0;
-            x = pos.x + 1000 * move.x;
-            y = pos.y + 1000 * move.y;
-        } else if (fx && !fy) {
-            hit = vx;
-            y = posi.y;
-        } else if (fy && !fx) {
-            hit = vy;
-            x = posi.x;
-        } else {
-            const v2 posx = {x, posi.y};
-            const v2 posy = {posi.x, y};
-            if (v2_square_dist(posx, pos) < v2_square_dist(posy, pos)) {
-                hit = vx;
-                y = posi.y;
-            } else {
-                hit = vy;
-                x = posi.x;
-            }
-        }
-
-        const v2 relative = {
-            x - pos.x,
-            y - pos.y
-        };
-
-        float len = v2_cross(relative, cam_right) / v2_len(cam_right);
-        if (len < 0.00001) len = 0.00001;
+        float len = v2_cross(hit_pos, cam_right) / v2_len(cam_right);
 
         uint32_t color;
         switch (hit) {

src/renderer.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include "screen.h"
+#include "ray.h"
 
 typedef struct {
     float x, y;
@@ -9,5 +10,6 @@ typedef struct {
 
 void init_camera(Camera* camera);
 void update_camera(Camera* camera, Screen* screeen);
+v2 get_cam_right(const Camera* camera);
 
 void render(Screen* screen, const Camera* camera);