.

src/camera.c

@@ -0,0 +1,93 @@
+#include "colla/colla.h"
+
+#include "libs/handmademath.h"
+#include "libs/sokol_gfx.h"
+
+#include "utils.h"
+
+#define WORLD_UP HMM_V3(0, 1, 0)
+#define NEAR_Z (0.1f)
+#define FAR_Z (1000.f)
+
+typedef struct camera_t camera_t;
+struct camera_t {
+    HMM_Vec3 pos;
+    HMM_Vec3 fwd;
+    HMM_Vec3 up;
+
+    float yaw, pitch;
+
+    HMM_Mat4 lookat;
+    float speed, mov_speed, look_speed;
+
+    float fov;
+};
+
+camera_t cam_init(void) {
+    camera_t cam = {
+        .fwd = { 0, 0, -1 },
+        .up  = { 0, 1, 0 },
+        .pos = { 0, 0, 0 },
+        .look_speed = 0.3f,
+        .mov_speed = 15.f,
+        .fov = HMM_DegToRad * 60.f,
+    };
+    return cam;
+}
+
+void cam_update(camera_t *cam, float dt) {
+    float strafe  = (float)((int)is_key_down(SAPP_KEYCODE_D) - (int)is_key_down(SAPP_KEYCODE_A));
+    float forward = (float)((int)is_key_down(SAPP_KEYCODE_W) - (int)is_key_down(SAPP_KEYCODE_S));
+    float movup   = (float)((int)is_key_down(SAPP_KEYCODE_Q) - (int)is_key_down(SAPP_KEYCODE_E));
+
+    float move_speed = cam->mov_speed * dt;
+    float look_speed = cam->look_speed * dt;
+
+    HMM_Vec2 delta = mouse_delta();
+    cam->yaw   += delta.X * look_speed;
+    cam->pitch -= delta.Y * look_speed;
+    float max_angle = HMM_DegToRad * 89.f;
+    cam->pitch = HMM_Clamp(-max_angle, cam->pitch, max_angle);
+
+    float yc = cosf(cam->yaw);
+    float ys = sinf(cam->yaw);
+    float pc = cosf(cam->pitch);
+    float ps = sinf(cam->pitch);
+
+    cam->fwd = HMM_Norm(HMM_V3(
+        pc * ys,
+        ps,
+        -pc * yc
+    ));
+
+    HMM_Vec3 right = HMM_Norm(HMM_Cross(cam->fwd, WORLD_UP));
+    cam->up        = HMM_Cross(right, cam->fwd);
+
+    cam->pos = HMM_Add(
+        cam->pos,
+        HMM_Mul(
+            HMM_Add(
+                HMM_Add(
+                    HMM_Mul(cam->fwd, forward), 
+                    HMM_Mul(right, strafe)
+                ),
+                HMM_Mul(cam->up, movup)
+            ), 
+            move_speed
+        )
+    );
+    
+}
+
+HMM_Mat4 cam_view(camera_t *cam) {
+    HMM_Mat4 view = HMM_LookAt_RH(cam->pos, HMM_Add(cam->pos, cam->fwd), cam->up);
+    
+    return view;
+}
+
+HMM_Mat4 cam_proj(camera_t *cam) {
+    float aspect = sapp_widthf() / sapp_heightf();
+    HMM_Mat4 proj = HMM_Perspective_RH_ZO(cam->fov, aspect, NEAR_Z, FAR_Z);
+    return proj;
+}
+