From 90564274757e489429daf8bcdb92009563fd2efd Mon Sep 17 00:00:00 2001
From: Tavian Barnes <tavianator@gmail.com>
Date: Thu, 16 Jul 2009 01:49:40 +0000
Subject: Render pigments.

---
 libdimension/color.c           |  6 ++++++
 libdimension/dimension/color.h |  3 +++
 libdimension/dimension/scene.h |  1 +
 libdimension/raytrace.c        | 46 ++++++++++++++++++++++++++++++------------
 libdimension/scene.c           |  2 +-
 5 files changed, 44 insertions(+), 14 deletions(-)

(limited to 'libdimension')

diff --git a/libdimension/color.c b/libdimension/color.c
index c9a421e..7fb73ed 100644
--- a/libdimension/color.c
+++ b/libdimension/color.c
@@ -26,6 +26,12 @@ const dmnsn_CIE_XYZ dmnsn_whitepoint = { .X = 0.9504060171449392,
                                          .Y = 0.9999085943425312,
                                          .Z = 1.089062231497274 };
 
+/* Standard colors */
+const dmnsn_color dmnsn_black = { .X = 0.0, .Y = 0.0, .Z = 0.0 };
+const dmnsn_color dmnsn_white = { .X = 0.9504060171449392,
+                                  .Y = 0.9999085943425312,
+                                  .Z = 1.089062231497274 };
+
 /* Convert a CIE XYZ color to a dmnsn_color (actually a no-op) */
 dmnsn_color
 dmnsn_color_from_XYZ(dmnsn_CIE_XYZ XYZ)
diff --git a/libdimension/dimension/color.h b/libdimension/dimension/color.h
index 8b78eea..ab2ea04 100644
--- a/libdimension/dimension/color.h
+++ b/libdimension/dimension/color.h
@@ -60,6 +60,9 @@ typedef struct {
   double R, G, B; /* sRGB R, G, and B values */
 } dmnsn_sRGB;
 
+/* Standard colors */
+extern const dmnsn_color dmnsn_black, dmnsn_white;
+
 /* Standard whitepoint, determined by the conversion of sRGB white to CIE XYZ */
 extern const dmnsn_CIE_XYZ dmnsn_whitepoint;
 
diff --git a/libdimension/dimension/scene.h b/libdimension/dimension/scene.h
index 8104917..aa216f4 100644
--- a/libdimension/dimension/scene.h
+++ b/libdimension/dimension/scene.h
@@ -28,6 +28,7 @@
 typedef enum {
   DMNSN_RENDER_NONE,
   DMNSN_RENDER_OBJECTS,
+  DMNSN_RENDER_PIGMENT,
   DMNSN_RENDER_FULL
 } dmnsn_quality;
 
diff --git a/libdimension/raytrace.c b/libdimension/raytrace.c
index 10f400d..c9217ca 100644
--- a/libdimension/raytrace.c
+++ b/libdimension/raytrace.c
@@ -185,7 +185,7 @@ dmnsn_raytrace_scene_multithread_thread(void *ptr)
 
 /* Helper for dmnsn_raytrace_scene_impl - shoot a ray */
 static dmnsn_color dmnsn_raytrace_shoot(dmnsn_scene *scene, dmnsn_color color,
-                                        unsigned int x, unsigned int y);
+                                        dmnsn_line ray);
 
 /*
  * Actually raytrace a scene
@@ -196,6 +196,7 @@ dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene,
 {
   unsigned int x, y;
   unsigned int width, height;
+  dmnsn_line ray;
   dmnsn_color color;
 
   width  = scene->canvas->x;
@@ -211,7 +212,10 @@ dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene,
       color = scene->background;
 
       if (scene->quality >= DMNSN_RENDER_OBJECTS) {
-        color = dmnsn_raytrace_shoot(scene, color, x, y);
+        /* Get the ray corresponding to the (x,y)'th pixel */
+        ray = (*scene->camera->ray_fn)(scene->camera, scene->canvas, x, y);
+        /* Shoot a ray */
+        color = dmnsn_raytrace_shoot(scene, color, ray);
       }
 
       dmnsn_set_pixel(scene->canvas, x, y, color);
@@ -225,17 +229,13 @@ dmnsn_raytrace_scene_impl(dmnsn_progress *progress, dmnsn_scene *scene,
 
 /* Shoot a ray, and calculate the color, using `color' as the background */
 static dmnsn_color
-dmnsn_raytrace_shoot(dmnsn_scene *scene, dmnsn_color color,
-                     unsigned int x, unsigned int y)
+dmnsn_raytrace_shoot(dmnsn_scene *scene, dmnsn_color color, dmnsn_line ray)
 {
-  dmnsn_line ray, ray_trans;
+  dmnsn_line ray_trans;
   dmnsn_object *object;
-  dmnsn_intersection *intersection;
+  dmnsn_intersection *intersection = NULL, *intersection_temp;
   unsigned int i;
 
-  /* Get the ray corresponding to the (x,y)'th pixel */
-  ray = (*scene->camera->ray_fn)(scene->camera, scene->canvas, x, y);
-
   for (i = 0; i < dmnsn_array_size(scene->objects); ++i) {
     dmnsn_array_get(scene->objects, i, &object);
 
@@ -243,13 +243,33 @@ dmnsn_raytrace_shoot(dmnsn_scene *scene, dmnsn_color color,
     ray_trans = dmnsn_matrix_line_mul(object->trans, ray);
 
     /* Test for intersections with objects */
-    intersection = (*object->intersection_fn)(object, ray_trans);
+    intersection_temp = (*object->intersection_fn)(object, ray_trans);
+
+    if (intersection_temp &&
+        (!intersection || intersection_temp->t < intersection->t)) {
+      dmnsn_delete_intersection(intersection);
+      intersection = intersection_temp;
+    }
+  }
 
-    if (intersection) {
-      color = dmnsn_color_from_XYZ(dmnsn_whitepoint);
+  if (intersection) {
+    if (scene->quality >= DMNSN_RENDER_PIGMENT) {
+      if (intersection->texture) {
+        if (intersection->texture->pigment) {
+          color = (*intersection->texture->pigment->pigment_fn)(
+            intersection->texture->pigment,
+            dmnsn_line_point(intersection->ray, intersection->t)
+          );
+        } else {
+          color = dmnsn_black;
+        }
+      } else {
+        color = dmnsn_black;
+      }
+    } else {
+      color = dmnsn_white;
     }
 
-    /* Delete the intersection */
     dmnsn_delete_intersection(intersection);
   }
 
diff --git a/libdimension/scene.c b/libdimension/scene.c
index 12bab73..7e24403 100644
--- a/libdimension/scene.c
+++ b/libdimension/scene.c
@@ -28,7 +28,7 @@ dmnsn_new_scene()
   dmnsn_scene *scene = malloc(sizeof(dmnsn_scene));
   if (scene) {
     scene->objects = dmnsn_new_array(sizeof(dmnsn_object*));
-    scene->quality = DMNSN_RENDER_NONE;
+    scene->quality = DMNSN_RENDER_FULL;
   }
   return scene;
 }
-- 
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