twn_draw.h: new camera api

src/rendering/twn_draw.c

@@ -1,8 +1,9 @@
 #include "twn_draw_c.h"
 #include "twn_draw.h"
 #include "twn_engine_context_c.h"
-#include "twn_camera.h"
+#include "twn_camera_c.h"
 #include "twn_types.h"
+#include "twn_vec.h"
 
 #include <SDL2/SDL.h>
 #include <stb_ds.h>
@@ -382,8 +383,39 @@ void render(void) {
 }
 
 
-void draw_camera(const Camera *const camera) {
-    /* TODO: skip recaulculating if it's the same? */
-    camera_projection_matrix = camera_perspective(camera);
-    camera_look_at_matrix    = camera_look_at(camera);
+void draw_camera(Vec3 position, float fov, Vec3 up, Vec3 direction) {
+    Camera const camera = {
+        .fov = fov,
+        .pos = position,
+        .target = direction,
+        .up = up,
+    };
+    camera_projection_matrix = camera_perspective(&camera);
+    camera_look_at_matrix    = camera_look_at(&camera);
+}
+
+
+/* TODO: https://stackoverflow.com/questions/62493770/how-to-add-roll-in-camera-class */
+DrawCameraFromPrincipalAxesResult draw_camera_from_principal_axes(Vec3 position, float fov, float roll, float pitch, float yaw) {
+    (void)roll;
+    float yawc, yaws, pitchc, pitchs;
+    sincosf(yaw, &yaws, &yawc);
+    sincosf(pitch, &pitchs, &pitchc);
+    Camera const camera = {
+        .fov = fov,
+        .pos = position,
+        .target = m_vec_norm(((Vec3){
+            yawc * pitchc,
+            pitchs,
+            yaws * pitchc,
+        })),
+        .up = (Vec3){0, 1, 0},
+    };
+    camera_projection_matrix = camera_perspective(&camera);
+    camera_look_at_matrix    = camera_look_at(&camera);
+
+    return (DrawCameraFromPrincipalAxesResult) {
+        .direction = camera.target,
+        .up = camera.up,
+    };
 }

src/twn_camera.c

@@ -1,4 +1,4 @@
-#include "twn_camera.h"
+#include "twn_camera_c.h"
 #include "twn_vec.h"
 #include "twn_engine_context_c.h"
 

src/twn_camera_c.h

@@ -0,0 +1,21 @@
+#ifndef TWN_CAMERA_H
+#define TWN_CAMERA_H
+
+#include "twn_types.h"
+
+/* TODO: make it cached? */
+/*       for example, perspective matrix only needs recaluclation on FOV change */
+
+/* first person camera class */
+typedef struct Camera {
+    Vec3 pos;        /* eye position */
+    Vec3 target;     /* normalized target vector */
+    Vec3 up;         /* normalized up vector */
+    float fov;       /* field of view, in radians */
+} Camera;
+
+Matrix4 camera_look_at(const Camera *camera);
+
+Matrix4 camera_perspective(const Camera *const camera);
+
+#endif

src/twn_textures_c.h

@@ -17,8 +17,8 @@
 
 
 typedef struct Texture {
-    Rect srcrect;            /* position in atlas */
-    SDL_Surface *data;          /* original image data */
+    Rect srcrect;                   /* position in atlas */
+    SDL_Surface *data;              /* original image data */
     int atlas_index;
     GPUTexture loner_texture;       /* stored directly for loners, == 0 means atlas_index should be used */
     GPUTexture repeating_texture;   /* separately allocated Texture, for loners == loner_texture */