From 836d8f7138633517c6e503520f7be354ac32d836 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Sat, 13 Jun 2009 22:55:48 +0000
Subject: Properly forward-declare dmnsn_object and dmnsn_camera, and take a
 transformation matrix in dmnsn_new_perspective_camera().

---
 libdimension/camera.c           | 29 +++++++++++++++++++++++------
 libdimension/dimension/camera.h | 16 +++++++++++-----
 libdimension/dimension/object.h |  8 ++++++--
 libdimension/scene.c            |  4 ++--
 libdimension/sphere.c           |  4 ++--
 5 files changed, 44 insertions(+), 17 deletions(-)

(limited to 'libdimension')

diff --git a/libdimension/camera.c b/libdimension/camera.c
index 2052785..282daaf 100644
--- a/libdimension/camera.c
+++ b/libdimension/camera.c
@@ -35,32 +35,49 @@ dmnsn_delete_camera(dmnsn_camera *camera)
 
 /* Perspective camera */
 
-static dmnsn_line dmnsn_perspective_camera_ray_fn(const dmnsn_canvas *canvas,
+static dmnsn_line dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
+                                                  const dmnsn_canvas *canvas,
                                                   unsigned int x,
                                                   unsigned int y);
 
 dmnsn_camera *
-dmnsn_new_perspective_camera()
+dmnsn_new_perspective_camera(dmnsn_matrix trans)
 {
   dmnsn_camera *camera = dmnsn_new_camera();
-  camera->ray_fn = &dmnsn_perspective_camera_ray_fn;
+  if (camera) {
+    camera->ray_fn = &dmnsn_perspective_camera_ray_fn;
+
+    camera->ptr = malloc(sizeof(dmnsn_matrix));
+    if (!camera->ptr) {
+      dmnsn_delete_camera(camera);
+      return NULL;
+    }
+    *((dmnsn_matrix*)camera->ptr) = trans;
+  }
   return camera;
 }
 
 void
 dmnsn_delete_perspective_camera(dmnsn_camera *camera)
 {
-  dmnsn_delete_camera(camera);
+  if (camera) {
+    free(camera->ptr);
+    dmnsn_delete_camera(camera);
+  }
 }
 
 static dmnsn_line
-dmnsn_perspective_camera_ray_fn(const dmnsn_canvas *canvas,
+dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
+                                const dmnsn_canvas *canvas,
                                 unsigned int x, unsigned int y)
 {
+  dmnsn_matrix *trans = (dmnsn_matrix *)camera->ptr;
   dmnsn_line l;
+
   l.x0 = dmnsn_vector_construct(0.0, 0.0, 0.0);
   l.n.x = ((double)x)/(canvas->x - 1) - 0.5;
   l.n.y = ((double)y)/(canvas->y - 1) - 0.5;
   l.n.z = 1.0;
-  return l;
+
+  return dmnsn_matrix_line_mul(*trans, l);
 }
diff --git a/libdimension/dimension/camera.h b/libdimension/dimension/camera.h
index b1c4ebe..4ea1cbe 100644
--- a/libdimension/dimension/camera.h
+++ b/libdimension/dimension/camera.h
@@ -25,23 +25,29 @@
  * A camera.
  */
 
-typedef dmnsn_line dmnsn_camera_ray_fn(const dmnsn_canvas *canvas,
+/* Forward-declare dmnsn_camera */
+typedef struct dmnsn_camera dmnsn_camera;
+
+/* Camera callback types */
+typedef dmnsn_line dmnsn_camera_ray_fn(const dmnsn_camera *camera,
+                                       const dmnsn_canvas *canvas,
                                        unsigned int x, unsigned int y);
 
-typedef struct {
+struct dmnsn_camera {
   /* Generic pointer for camera info */
   void *ptr;
 
   /* Callback function */
   dmnsn_camera_ray_fn *ray_fn;
-} dmnsn_camera;
+};
 
 dmnsn_camera *dmnsn_new_camera();
 void dmnsn_delete_camera(dmnsn_camera *camera);
 
-/* A perspective camera, at the origin, looking at (0, 0, 1) */
+/* A perspective camera, at the origin, looking at (0, 0, 1).  Rays are
+   transformed by the transformation matrix `trans'. */
 
-dmnsn_camera *dmnsn_new_perspective_camera();
+dmnsn_camera *dmnsn_new_perspective_camera(dmnsn_matrix trans);
 void dmnsn_delete_perspective_camera(dmnsn_camera *camera);
 
 #endif /* DIMENSION_CAMERA_H */
diff --git a/libdimension/dimension/object.h b/libdimension/dimension/object.h
index b9702f4..bd660a0 100644
--- a/libdimension/dimension/object.h
+++ b/libdimension/dimension/object.h
@@ -25,19 +25,23 @@
  * Objects.
  */
 
+/* Forward-declare dmnsn_object */
+typedef struct dmnsn_object dmnsn_object;
+
+/* Object callback types */
 typedef dmnsn_array *dmnsn_object_intersections_fn(const dmnsn_object *object,
                                                    dmnsn_line line);
 typedef int dmnsn_object_inside_fn(const dmnsn_object *object,
                                    dmnsn_vector point);
 
-typedef struct {
+struct dmnsn_object {
   /* Generic pointer for object info */
   void *ptr;
 
   /* Callback functions */
   dmnsn_object_intersections_fn *intersections_fn;
   dmnsn_object_inside_fn        *inside_fn;
-} dmnsn_object;
+};
 
 dmnsn_object *dmnsn_new_object();
 void dmnsn_delete_object(dmnsn_object *object);
diff --git a/libdimension/scene.c b/libdimension/scene.c
index 780f8c6..4a84823 100644
--- a/libdimension/scene.c
+++ b/libdimension/scene.c
@@ -50,8 +50,8 @@ dmnsn_raytrace_scene(dmnsn_scene *scene)
 
   for (i = 0; i < scene->canvas->x; ++i) {
     for (j = 0; j < scene->canvas->y; ++j) {
-      ray = (*scene->camera->ray_fn)(scene->canvas, i, j);
-      if ((*object->intersections_fn)(ray)->length > 0) {
+      ray = (*scene->camera->ray_fn)(scene->camera, scene->canvas, i, j);
+      if ((*object->intersections_fn)(object, ray)->length > 0) {
         dmnsn_set_pixel(scene->canvas, i, j,
                         dmnsn_color_from_XYZ(dmnsn_whitepoint));
       } else {
diff --git a/libdimension/sphere.c b/libdimension/sphere.c
index 74f414d..2829720 100644
--- a/libdimension/sphere.c
+++ b/libdimension/sphere.c
@@ -22,9 +22,9 @@
 #include <stdlib.h> /* For malloc */
 #include <math.h>   /* For sqrt   */
 
-static dmnsn_array *dmnsn_sphere_intersections_fn(const dmnsn_sphere *sphere,
+static dmnsn_array *dmnsn_sphere_intersections_fn(const dmnsn_object *sphere,
                                                   dmnsn_line line);
-static int dmnsn_sphere_inside_fn(const dmnsn_sphere *sphere,
+static int dmnsn_sphere_inside_fn(const dmnsn_object *sphere,
                                   dmnsn_vector point);
 
 dmnsn_object *
-- 
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