From bbe317fb2bde1b2b88df66e5426c9ee78e40a0b6 Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Thu, 16 Jul 2009 21:31:51 +0000
Subject: Have camera callbacks take canvas coordinates as doubles.

---
 libdimension/cameras.c          | 11 +++--------
 libdimension/dimension/camera.h |  3 +--
 libdimension/raytrace.c         |  4 +++-
 3 files changed, 7 insertions(+), 11 deletions(-)

(limited to 'libdimension')

diff --git a/libdimension/cameras.c b/libdimension/cameras.c
index dfe4708..9e0642f 100644
--- a/libdimension/cameras.c
+++ b/libdimension/cameras.c
@@ -26,9 +26,7 @@
 
 /* Perspective camera ray callback */
 static dmnsn_line dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
-                                                  const dmnsn_canvas *canvas,
-                                                  unsigned int x,
-                                                  unsigned int y);
+                                                  double x, double y);
 
 /* Create a new perspective camera.  Rays are aimed from the origin to a screen
    located on the z = 1 frame, from (-0.5, -0.5) to (0.5, 0.5).  Rays are then
@@ -73,8 +71,7 @@ dmnsn_set_perspective_camera_trans(dmnsn_camera *camera, dmnsn_matrix T)
 /* Perspective camera ray callback */
 static dmnsn_line
 dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
-                                const dmnsn_canvas *canvas,
-                                unsigned int x, unsigned int y)
+                                double x, double y)
 {
   dmnsn_matrix *trans = camera->ptr;
   dmnsn_line l;
@@ -83,9 +80,7 @@ dmnsn_perspective_camera_ray_fn(const dmnsn_camera *camera,
   l.x0 = dmnsn_vector_construct(0.0, 0.0, 0.0);
 
   /* Aim at the z = 1 plane */
-  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;
+  l.n = dmnsn_vector_construct(x - 0.5, y - 0.5, 1.0);
 
   return dmnsn_matrix_line_mul(*trans, l);
 }
diff --git a/libdimension/dimension/camera.h b/libdimension/dimension/camera.h
index 3e6da4f..5e7b253 100644
--- a/libdimension/dimension/camera.h
+++ b/libdimension/dimension/camera.h
@@ -30,8 +30,7 @@ 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);
+                                       double x, double y);
 
 struct dmnsn_camera {
   /* Callback functions */
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index 470af4f..df61d6b 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -213,7 +213,9 @@ dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene,
 
       if (scene->quality >= DMNSN_RENDER_OBJECTS) {
         /* Get the ray corresponding to the (x,y)'th pixel */
-        ray = (*scene->camera->ray_fn)(scene->camera, scene->canvas, x, y);
+        ray = (*scene->camera->ray_fn)(scene->camera,
+                                       ((double)x)/(scene->canvas->x - 1),
+                                       ((double)y)/(scene->canvas->y - 1));
         /* Shoot a ray */
         color = dmnsn_raytrace_shoot(scene, color, ray);
       }
-- 
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