From c29e4ecb7de4cb10f48b2526bc1abae847c718e2 Mon Sep 17 00:00:00 2001
From: pacien
Date: Thu, 28 Dec 2017 01:19:45 +0100
Subject: Add new geometry common types and functions

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 include/common/geom.h     | 93 +++++++++++++++++++++++++++++++++++++++++++----
 include/common/time.h     |  4 +-
 src/common/geom.c         | 27 +++++++++++++-
 src/morpher/trianglemap.c |  2 +-
 test/common/geom.c        | 21 +++++++++++
 5 files changed, 137 insertions(+), 10 deletions(-)
 create mode 100644 test/common/geom.c

diff --git a/include/common/geom.h b/include/common/geom.h
index b3564a5..334e95c 100644
--- a/include/common/geom.h
+++ b/include/common/geom.h
@@ -14,6 +14,12 @@
  */
 typedef int32_t IntVector;
 
+/**
+ * Type: RealVector
+ * An abstract 1-D real vector.
+ */
+typedef double RealVector;
+
 /**
  * Struct: CartesianVector
  * An abstract 2-D vector in cartesian coordinates.
@@ -26,6 +32,19 @@ typedef struct {
   IntVector x, y;
 } CartesianVector;
 
+/**
+ * Struct: BarycentricVector
+ * An abstract barycentric coordinate tuple relative to a triangle.
+ * The third barycentric coordinate is deduced from the first two ones.
+ *
+ * Fields:
+ *   a - the first barycentric coordinate
+ *   b - the second barycentric coordinate
+ */
+typedef struct {
+  RealVector a, b;
+} BarycentricVector;
+
 /**
  * Struct: CartesianMapping
  * A tuple of cartesian vectors representing a mapping.
@@ -38,6 +57,16 @@ typedef struct {
   CartesianVector origin, target;
 } CartesianMapping;
 
+/**
+ * Struct: Triangle
+ * Represents a simple triangle with three vertices.
+ *
+ * Fields:
+ *   v[] - array of vertices
+ */
+typedef struct {
+  CartesianVector v[3];
+} Triangle;
 
 /**
  * Function: m
@@ -65,6 +94,19 @@ CartesianMapping m(int x, int y);
  */
 CartesianVector v(int x, int y);
 
+/**
+ * Function: b
+ * Shorthand for a barycentric vector.
+ *
+ * Parameters:
+ *   a - the a-coordinate
+ *   b - the b-coordinate
+ *
+ * Returns:
+ *   A barycentric vector
+ */
+BarycentricVector b(double a, double b);
+
 /**
  * Function: mappings_equals
  * Compares two cartesian mappings.
@@ -92,17 +134,54 @@ bool mappings_equals(CartesianMapping m1, CartesianMapping m2);
 bool vector_equals(CartesianVector v1, CartesianVector v2);
 
 /**
- * Function: triangle_area
- * Computes the area of a triangle.
+ * Function: barycentric_vector_equals
+ * Compares two barycentric vectors.
+ *
+ * Parameters:
+ *   v1 - the first vector
+ *   v2 - the second vector
+ *
+ * Returns:
+ *   T(v1 is equal to v2)
+ */
+bool barycentric_vector_equals(BarycentricVector b1, BarycentricVector b2);
+
+/**
+ * Function: square_area
+ * Computes the area of a square spawned by three positively oriented vertices.
+ *
+ * Parameters:
+ *   vi - vertices
+ *
+ * Returns:
+ *   The area of the square
+ */
+IntVector square_area(CartesianVector v1, CartesianVector v2, CartesianVector v3);
+
+/**
+ * Function: cartesian_to_barycentric
+ * Computes and returns the barycentric coordinates of a given point in the given reference triangle.
+ *
+ * Parameters:
+ *   t - reference triangle
+ *   p - the vector to convert
+ *
+ * Returns:
+ *   The barycentric coordinates vector
+ */
+BarycentricVector cartesian_to_barycentric(Triangle t, CartesianVector p);
+
+/**
+ * Function: barycentric_to_cartesian
+ * Computes and returns the cartesian coordinates of a given point in the given reference triangle.
  *
  * Parameters:
- *   v1 - first vertex
- *   v2 - second vertex
- *   v3 - third vertex
+ *   t - reference triangle
+ *   p - the vector to convert
  *
  * Returns:
- *   The area of the triangle spawned by the three supplied vertices
+ *   The cartesian coordinate vector
  */
-IntVector triangle_area(CartesianVector v1, CartesianVector v2, CartesianVector v3);
+CartesianVector barycentric_to_cartesian(Triangle t, BarycentricVector p);
 
 #endif
diff --git a/include/common/time.h b/include/common/time.h
index 54a7bb2..e207ad7 100644
--- a/include/common/time.h
+++ b/include/common/time.h
@@ -5,6 +5,8 @@
  * File: time.h
  */
 
+#include "geom.h"
+
 /**
  * Constants: Time vectors
  *
@@ -18,6 +20,6 @@
  * Type: TimeVector
  * An abstract time vector.
  */
-typedef float TimeVector;
+typedef RealVector TimeVector;
 
 #endif
diff --git a/src/common/geom.c b/src/common/geom.c
index 219270f..eb35727 100644
--- a/src/common/geom.c
+++ b/src/common/geom.c
@@ -1,6 +1,12 @@
 #include "common/geom.h"
+#include <math.h>
+#include <common/geom.h>
 #include "morpher/matrix.h"
 
+static inline IntVector int_round(RealVector x) {
+  return (IntVector) round(x);
+}
+
 CartesianMapping m(int x, int y) {
   return (CartesianMapping) {{x, y},
                              {x, y}};
@@ -10,6 +16,10 @@ CartesianVector v(int x, int y) {
   return (CartesianVector) {x, y};
 }
 
+BarycentricVector b(double a, double b) {
+  return (BarycentricVector) {a, b};
+}
+
 bool mappings_equals(CartesianMapping m1, CartesianMapping m2) {
   return vector_equals(m1.origin, m2.origin) && vector_equals(m1.target, m2.target);
 }
@@ -18,7 +28,22 @@ bool vector_equals(CartesianVector v1, CartesianVector v2) {
   return v1.x == v2.x && v1.y == v2.y;
 }
 
-IntVector triangle_area(CartesianVector v1, CartesianVector v2, CartesianVector v3) {
+bool barycentric_vector_equals(BarycentricVector b1, BarycentricVector b2) {
+  return b1.a == b2.a && b1.b == b2.b;
+}
+
+IntVector square_area(CartesianVector v1, CartesianVector v2, CartesianVector v3) {
   return matrix_int_det2(v1.x - v3.x, v2.x - v3.x,
                          v1.y - v3.y, v2.y - v3.y);
 }
+
+BarycentricVector cartesian_to_barycentric(Triangle t, CartesianVector p) {
+  RealVector total_area = square_area(t.v[0], t.v[1], t.v[2]);
+  return (BarycentricVector) {square_area(t.v[1], t.v[2], p) / total_area,
+                              square_area(t.v[2], t.v[0], p) / total_area};
+}
+
+CartesianVector barycentric_to_cartesian(Triangle t, BarycentricVector p) {
+  return (CartesianVector) {int_round(p.a * (t.v[0].x - t.v[2].x) + p.b * (t.v[1].x - t.v[2].x) + t.v[2].x),
+                            int_round(p.a * (t.v[0].y - t.v[2].y) + p.b * (t.v[1].y - t.v[2].y) + t.v[2].y)};
+}
diff --git a/src/morpher/trianglemap.c b/src/morpher/trianglemap.c
index e2f3eb9..ad526bc 100644
--- a/src/morpher/trianglemap.c
+++ b/src/morpher/trianglemap.c
@@ -30,7 +30,7 @@ TriangleMap *trianglemap_to(TriangleMap *t, CartesianVector v) {
   int edge;
 
   for (edge = 0; edge < 3; ++edge)
-    if (triangle_area(t->vertices[edge].origin, t->vertices[(edge + 1) % 3].origin, v) > 0)
+    if (square_area(t->vertices[edge].origin, t->vertices[(edge + 1) % 3].origin, v) > 0)
       return t->neighbors[edge];
 
   return t;
diff --git a/test/common/geom.c b/test/common/geom.c
new file mode 100644
index 0000000..f05e0a1
--- /dev/null
+++ b/test/common/geom.c
@@ -0,0 +1,21 @@
+#include "common/geom.h"
+#include <assert.h>
+
+static void test_square_area() {
+  assert(square_area(v(0, 0), v(10, 0), v(10, 10)) == 100);
+  assert(square_area(v(0, 0), v(0, 10), v(10, 10)) == -100);
+}
+
+static void test_cartesian_barycentric_vectors() {
+  Triangle t = {{v(0, 0), v(10, 0), v(10, 10)}};
+  CartesianVector c = v(3, 2);
+  BarycentricVector bv = cartesian_to_barycentric(t, c);
+  assert(barycentric_vector_equals(bv, b(0.7, 0.1)));
+  assert(vector_equals(barycentric_to_cartesian(t, bv), c));
+}
+
+int main(int argc, char **argv) {
+  test_square_area();
+  test_cartesian_barycentric_vectors();
+  return 0;
+}
-- 
cgit v1.2.3


From c970da3f5830fae5b4d98dcdcc8d34d678ec0434 Mon Sep 17 00:00:00 2001
From: pacien
Date: Thu, 28 Dec 2017 01:22:03 +0100
Subject: Refactor canvas

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 include/painter/canvas.h | 76 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/blender/canvas.c     | 23 ---------------
 src/painter/canvas.c     | 27 +++++++++++++++++
 3 files changed, 103 insertions(+), 23 deletions(-)
 create mode 100644 include/painter/canvas.h
 delete mode 100644 src/blender/canvas.c
 create mode 100644 src/painter/canvas.c

diff --git a/include/painter/canvas.h b/include/painter/canvas.h
new file mode 100644
index 0000000..e354938
--- /dev/null
+++ b/include/painter/canvas.h
@@ -0,0 +1,76 @@
+#ifndef UPEM_MORPHING_CANVAS
+#define UPEM_MORPHING_CANVAS
+
+/**
+ * File: canvas.h
+ * "Everyday is a good day when you paint" – Bob Ross
+ */
+
+#include <MLV/MLV_image.h>
+#include "common/geom.h"
+#include "painter/color.h"
+
+/**
+ * Type: Canvas
+ * Represents a fixed size RGBa pixel matrix.
+ */
+typedef struct {
+  MLV_Image *mlv;
+} Canvas;
+
+/**
+ * Function: canvas_create
+ * Initialises a canvas of the given size
+ *
+ * Parameters:
+ *   width  - the width in pixels
+ *   height - the height in pixels
+ */
+Canvas *canvas_create(IntVector width, IntVector height);
+
+/**
+ * Function: canvas_destroy
+ * Frees all memory allocated to a canvas.
+ *
+ * Parameters:
+ *   *c - the canvas to destroy
+ */
+void canvas_destroy(Canvas *c);
+
+/**
+ * Function: canvas_set_pixel
+ * Sets the pixel colour at the given coordinates.
+ *
+ * Parameters:
+ *   *c    - the canvas to alter
+ *   pos   - the coordinate of the pixel to set
+ *   color - the new colour to set
+ */
+void canvas_set_pixel(Canvas *c, CartesianVector pos, Color color);
+
+/**
+ * Function: canvas_get_pixel
+ * Returns the colour of the pixel at the given position.
+ *
+ * Parameters:
+ *   *c  - the base canvas
+ *   pos - the coordinate of the pixel to get
+ *
+ * Returns:
+ *   The colour of the requested pixel
+ */
+Color canvas_get_pixel(Canvas *c, CartesianVector pos);
+
+/**
+ * Function: canvas_get_dim
+ * Returns the size (in pixels) of the given canvas.
+ *
+ * Parameters:
+ *   *c - the canvas
+ *
+ * Returns:
+ *   The size of the canvas
+ */
+CartesianVector canvas_get_dim(Canvas *c);
+
+#endif
diff --git a/src/blender/canvas.c b/src/blender/canvas.c
deleted file mode 100644
index b7cd9dc..0000000
--- a/src/blender/canvas.c
+++ /dev/null
@@ -1,23 +0,0 @@
-#include "blender/canvas.h"
-
-void canvas_init(Canvas *canvas, IntVector width, IntVector height) {
-  canvas->mlv = MLV_create_image(width, height);
-}
-
-void canvas_free(Canvas *canvas) {
-  MLV_free_image(canvas->mlv);
-}
-
-void canvas_set_pixel(Canvas *canvas, CartesianVector position, Color color) {
-  MLV_set_pixel_on_image(position.x, position.y, color.mlv, canvas->mlv);
-}
-
-Color canvas_get_pixel(Canvas *canvas, CartesianVector position) {
-  int r, g, b, a;
-  MLV_get_pixel_on_image(canvas->mlv, position.x, position.y, &r, &g, &b, &a);
-  return (Color) {{r, g, b, a}};
-}
-
-CartesianVector canvas_get_dim(Canvas *canvas) {
-  return (CartesianVector) {MLV_get_image_width(canvas->mlv), MLV_get_image_height(canvas->mlv)};
-}
diff --git a/src/painter/canvas.c b/src/painter/canvas.c
new file mode 100644
index 0000000..53deeb9
--- /dev/null
+++ b/src/painter/canvas.c
@@ -0,0 +1,27 @@
+#include "painter/canvas.h"
+#include "common/mem.h"
+
+Canvas *canvas_create(IntVector width, IntVector height) {
+  Canvas *c = malloc_or_die(sizeof(Canvas));
+  c->mlv = MLV_create_image(width, height);
+  return c;
+}
+
+void canvas_destroy(Canvas *c) {
+  MLV_free_image(c->mlv);
+  free(c);
+}
+
+void canvas_set_pixel(Canvas *c, CartesianVector pos, Color color) {
+  MLV_set_pixel_on_image(pos.x, pos.y, color.mlv, c->mlv);
+}
+
+Color canvas_get_pixel(Canvas *c, CartesianVector pos) {
+  int r, g, b, a;
+  MLV_get_pixel_on_image(c->mlv, pos.x, pos.y, &r, &g, &b, &a);
+  return (Color) {{a, b, g, r}};
+}
+
+CartesianVector canvas_get_dim(Canvas *c) {
+  return (CartesianVector) {MLV_get_image_width(c->mlv), MLV_get_image_height(c->mlv)};
+}
-- 
cgit v1.2.3


From 190449ee18bec69b2e385dccd9bd42ddc83dd418 Mon Sep 17 00:00:00 2001
From: pacien
Date: Thu, 28 Dec 2017 01:22:41 +0100
Subject: Refactor and test color

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 include/painter/color.h | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
 src/blender/color.c     |  8 -------
 src/painter/color.c     | 20 ++++++++++++++++
 test/painter/color.c    | 14 ++++++++++++
 4 files changed, 95 insertions(+), 8 deletions(-)
 create mode 100644 include/painter/color.h
 delete mode 100644 src/blender/color.c
 create mode 100644 src/painter/color.c
 create mode 100644 test/painter/color.c

diff --git a/include/painter/color.h b/include/painter/color.h
new file mode 100644
index 0000000..2aeee3e
--- /dev/null
+++ b/include/painter/color.h
@@ -0,0 +1,61 @@
+#ifndef UPEM_MORPHING_COLOR
+#define UPEM_MORPHING_COLOR
+
+/**
+ * File: color.h
+ *
+ * See also:
+ *   A rainbow
+ */
+
+#include <MLV/MLV_color.h>
+#include <stdbool.h>
+#include "common/time.h"
+
+/**
+ * Type: ColorComponent
+ * Represents a single colour component of 32-bits RGBa tuple.
+ */
+typedef uint8_t ColorComponent;
+
+/**
+ * Type: ColorPixel
+ * Represents a single RGBa coloured pixel.
+ * Compatible with the libMLV representation.
+ */
+typedef union {
+  struct {
+    ColorComponent a, b, g, r;
+  } rgba;
+
+  MLV_Color mlv;
+} Color;
+
+/**
+ * Function: color_equals
+ * Compares the supplied colors.
+ *
+ * Parameters:
+ *   c1 - the first color
+ *   c2 - the second color
+ *
+ * Returns:
+ *   T(c1 is the same color as c2)
+ */
+bool color_equals(Color c1, Color c2);
+
+/**
+ * Function: color_blend
+ * Blends two colors.
+ *
+ * Parameters:
+ *   origin   - the first color
+ *   target   - the second color
+ *   distance - the distance from the first color
+ *
+ * Returns:
+ *   The blended color
+ */
+Color color_blend(Color origin, Color target, TimeVector distance);
+
+#endif
diff --git a/src/blender/color.c b/src/blender/color.c
deleted file mode 100644
index f92fba9..0000000
--- a/src/blender/color.c
+++ /dev/null
@@ -1,8 +0,0 @@
-#include "blender/color.h"
-
-bool color_equals(Color c1, Color c2) {
-  return c1.rgba.r == c2.rgba.r &&
-         c1.rgba.g == c2.rgba.g &&
-         c1.rgba.b == c2.rgba.b &&
-         c1.rgba.a == c2.rgba.a;
-}
diff --git a/src/painter/color.c b/src/painter/color.c
new file mode 100644
index 0000000..65c4f20
--- /dev/null
+++ b/src/painter/color.c
@@ -0,0 +1,20 @@
+#include "painter/color.h"
+#include <math.h>
+
+static inline ColorComponent blend_component(ColorComponent origin, ColorComponent target, TimeVector frame) {
+  return (ColorComponent) round(sqrt((TIME_UNIT - frame) * pow(origin, 2) + frame * pow(target, 2)));
+}
+
+bool color_equals(Color c1, Color c2) {
+  return c1.rgba.r == c2.rgba.r &&
+         c1.rgba.g == c2.rgba.g &&
+         c1.rgba.b == c2.rgba.b &&
+         c1.rgba.a == c2.rgba.a;
+}
+
+Color color_blend(Color origin, Color target, TimeVector distance) {
+  return (Color) {{blend_component(origin.rgba.a, target.rgba.a, distance),
+                   blend_component(origin.rgba.b, target.rgba.b, distance),
+                   blend_component(origin.rgba.g, target.rgba.g, distance),
+                   blend_component(origin.rgba.r, target.rgba.r, distance)}};
+}
diff --git a/test/painter/color.c b/test/painter/color.c
new file mode 100644
index 0000000..bdfe9b3
--- /dev/null
+++ b/test/painter/color.c
@@ -0,0 +1,14 @@
+#include "painter/color.h"
+#include <assert.h>
+
+static void test_color_blend() {
+  Color a = {{1, 10, 100, 200}}, b = {{100, 1, 200, 10}};
+  assert(color_equals(color_blend(a, b, TIME_ORIGIN), a));
+  assert(color_equals(color_blend(a, b, TIME_UNIT), b));
+  assert(color_equals(color_blend(a, b, 0.25), (Color) {{50, 9, 132, 173}}));
+}
+
+int main(int argc, char **argv) {
+  test_color_blend();
+  return 0;
+}
-- 
cgit v1.2.3


From 330fd85db8c89c178621d978929d911bbe93fec7 Mon Sep 17 00:00:00 2001
From: pacien
Date: Thu, 28 Dec 2017 01:23:08 +0100
Subject: Refactor canvas blender into rasterizer

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 include/blender/blender.h    | 26 --------------
 include/painter/rasterizer.h | 41 +++++++++++++++++++++
 src/blender/blender.c        | 39 --------------------
 src/painter/rasterizer.c     | 86 ++++++++++++++++++++++++++++++++++++++++++++
 test/blender/blender.c       | 29 ---------------
 test/painter/rasterizer.c    | 27 ++++++++++++++
 6 files changed, 154 insertions(+), 94 deletions(-)
 delete mode 100644 include/blender/blender.h
 create mode 100644 include/painter/rasterizer.h
 delete mode 100644 src/blender/blender.c
 create mode 100644 src/painter/rasterizer.c
 delete mode 100644 test/blender/blender.c
 create mode 100644 test/painter/rasterizer.c

diff --git a/include/blender/blender.h b/include/blender/blender.h
deleted file mode 100644
index 26ff802..0000000
--- a/include/blender/blender.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#ifndef UPEM_MORPHING_BLENDER
-#define UPEM_MORPHING_BLENDER
-
-/**
- * File: blender.h
- * Will it blend? That is the question.
- */
-
-#include "common/time.h"
-#include "blender/canvas.h"
-#include "morpher/morphing.h"
-
-/**
- * Function: blender_blend_canvas
- * Blends two canvas by applying the given morphing at the requested time frame.
- *
- * Parameters:
- *   *canvas   - pointer to the canvas to paint
- *   *source   - source image
- *   *target   - target image
- *   *morphing - morphing transform to apply
- *   frame     - the interpolation distance from the origin canvas [0;1]
- */
-void blender_blend_canvas(Canvas *canvas, Canvas *source, Canvas *target, Morphing *morphing, TimeVector frame);
-
-#endif
diff --git a/include/painter/rasterizer.h b/include/painter/rasterizer.h
new file mode 100644
index 0000000..204d616
--- /dev/null
+++ b/include/painter/rasterizer.h
@@ -0,0 +1,41 @@
+#ifndef UPEM_MORPHING_RASTERIZER
+#define UPEM_MORPHING_RASTERIZER
+
+/**
+ * File: rasterizer.h
+ */
+
+#include "painter/canvas.h"
+#include "morpher/morphing.h"
+
+/**
+ * Struct: RasterizationContext
+ */
+typedef struct {
+  Canvas *result, *source, *target;
+  TimeVector frame;
+} RasterizationContext;
+
+/**
+ * Struct: TriangleContext
+ */
+typedef struct {
+  Triangle current, source, target;
+} TriangleContext;
+
+/**
+ * Function: rasterize
+ * Rasterises a morphing from a source and a target image at the given time frame.
+ *
+ * Parameters:
+ *   *source - source image canvas
+ *   *target - target image canvas
+ *   *m      - reference morphing
+ *   frame   - time frame
+ *
+ * Returns:
+ *   The drawn canvas, dynamically allocated
+ */
+Canvas *rasterize(Canvas *source, Canvas *target, Morphing *m, TimeVector frame);
+
+#endif
diff --git a/src/blender/blender.c b/src/blender/blender.c
deleted file mode 100644
index 08cafa4..0000000
--- a/src/blender/blender.c
+++ /dev/null
@@ -1,39 +0,0 @@
-#include "blender/blender.h"
-#include <assert.h>
-#include <math.h>
-
-static inline ColorComponent blend_components(ColorComponent origin, ColorComponent target, TimeVector frame) {
-  // https://www.youtube.com/watch?v=LKnqECcg6Gw
-  return (ColorComponent) sqrt((TIME_UNIT - frame) * pow(origin, 2) + frame * pow(target, 2));
-}
-
-static inline Color blend_colors(Color origin, Color target, TimeVector frame) {
-  return (Color) {{blend_components(origin.rgba.r, target.rgba.r, frame),
-                   blend_components(origin.rgba.g, target.rgba.g, frame),
-                   blend_components(origin.rgba.b, target.rgba.b, frame),
-                   blend_components(origin.rgba.a, target.rgba.a, frame)}};
-}
-
-void blender_blend_canvas(Canvas *canvas, Canvas *source, Canvas *target, Morphing *morphing, TimeVector frame) {
-  IntVector flat_dim;
-  CartesianVector dim, point;
-  CartesianMapping mapping;
-  Color pixel;
-
-  dim = morphing->dim;
-
-  assert(dim.x > 0 && dim.y > 0);
-  assert(vector_equals(dim, canvas_get_dim(canvas)));
-  assert(vector_equals(dim, canvas_get_dim(source)));
-  assert(vector_equals(dim, canvas_get_dim(target)));
-  assert(frame >= TIME_ORIGIN && frame <= TIME_UNIT);
-
-  for (flat_dim = (dim.x - 1) * (dim.y - 1); flat_dim >= 0; --flat_dim) {
-    point.x = flat_dim % dim.y;
-    point.y = flat_dim / dim.y;
-
-    mapping = (CartesianMapping) {point, point};
-    pixel = blend_colors(canvas_get_pixel(source, mapping.origin), canvas_get_pixel(target, mapping.target), frame);
-    canvas_set_pixel(canvas, point, pixel);
-  }
-}
diff --git a/src/painter/rasterizer.c b/src/painter/rasterizer.c
new file mode 100644
index 0000000..881920a
--- /dev/null
+++ b/src/painter/rasterizer.c
@@ -0,0 +1,86 @@
+#include "painter/rasterizer.h"
+#include <math.h>
+#include <assert.h>
+
+static inline IntVector i(double (*f)(double, double), RealVector a, RealVector b) {
+  return (IntVector) floor(f(a, b));
+}
+
+static inline CartesianVector vertex_at_frame(CartesianMapping m, TimeVector t) {
+  return (CartesianVector) {(IntVector) round((TIME_UNIT - t) * m.origin.x + t * m.target.x),
+                            (IntVector) round((TIME_UNIT - t) * m.origin.y + t * m.target.y)};
+}
+
+static inline RealVector slope(CartesianVector a, CartesianVector b) {
+  return (((RealVector) b.x) - ((RealVector) a.x)) / (((RealVector) b.y) - ((RealVector) a.y));
+}
+
+static inline int positive_y_vertex_comparator(const void *l, const void *r) {
+  return ((CartesianVector *) l)->y - ((CartesianVector *) r)->y;
+}
+
+static inline Color color_at(Canvas *c, Triangle ref, BarycentricVector b) {
+  CartesianVector v = barycentric_to_cartesian(ref, b);
+  return canvas_get_pixel(c, v);
+}
+
+static inline TriangleContext build_triangle_context(Triangle current, TriangleMap *map) {
+  TriangleContext c;
+  int cursor;
+
+  for (cursor = 0; cursor < 3; ++cursor) {
+    c.current.v[cursor] = current.v[cursor];
+    c.source.v[cursor] = map->vertices[cursor].origin;
+    c.target.v[cursor] = map->vertices[cursor].target;
+  }
+
+  return c;
+}
+
+static inline void draw_pixel(CartesianVector pos, TriangleContext *tctx, RasterizationContext *rctx) {
+  BarycentricVector b = cartesian_to_barycentric(tctx->current, pos);
+  Color c = color_blend(color_at(rctx->source, tctx->source, b), color_at(rctx->target, tctx->target, b), rctx->frame);
+  canvas_set_pixel(rctx->result, pos, c);
+}
+
+static inline void draw_flat_triangle(IntVector top, IntVector bottom,
+                                      RealVector dx1, RealVector dx2, RealVector *x1, RealVector *x2,
+                                      TriangleContext *tctx, RasterizationContext *rctx) {
+
+  IntVector y, l, r;
+  for (y = top; y <= bottom; ++y, *x1 += dx1, *x2 += dx2)
+    for (l = i(fmin, *x1, *x2), r = i(fmax, *x1, *x2); l <= r; ++l)
+      draw_pixel(v(l, y), tctx, rctx);
+}
+
+static inline void draw_triangle(TriangleMap *t, RasterizationContext *rctx) {
+  Triangle triangle = {{vertex_at_frame(t->vertices[0], rctx->frame),
+                        vertex_at_frame(t->vertices[1], rctx->frame),
+                        vertex_at_frame(t->vertices[2], rctx->frame)}};
+
+  TriangleContext tctx = build_triangle_context(triangle, t);
+  CartesianVector *v = triangle.v;
+  qsort(v, 3, sizeof(CartesianVector), positive_y_vertex_comparator);
+
+  {
+    RealVector dx1 = slope(v[0], v[1]), dx2 = slope(v[0], v[2]), dx3 = slope(v[1], v[2]);
+    RealVector x1 = v[0].x, x2 = v[0].x, x3 = v[1].x;
+
+    draw_flat_triangle(v[0].y, v[1].y - 1, dx1, dx2, &x1, &x2, &tctx, rctx);
+    draw_flat_triangle(v[1].y, v[2].y, dx2, dx3, &x2, &x3, &tctx, rctx);
+  }
+}
+
+Canvas *rasterize(Canvas *source, Canvas *target, Morphing *m, TimeVector frame) {
+  RasterizationContext rctx;
+  TriangleMap *t;
+
+  assert(source != NULL && target != NULL && m != NULL);
+  assert(vector_equals(canvas_get_dim(source), m->dim) && vector_equals(canvas_get_dim(target), m->dim));
+  assert(frame >= TIME_ORIGIN && frame <= TIME_UNIT);
+
+  rctx = (RasterizationContext) {canvas_create(m->dim.y, m->dim.x), source, target, frame};
+  for (t = m->first; t != NULL; t = t->next) draw_triangle(t, &rctx);
+
+  return rctx.result;
+}
diff --git a/test/blender/blender.c b/test/blender/blender.c
deleted file mode 100644
index f42322f..0000000
--- a/test/blender/blender.c
+++ /dev/null
@@ -1,29 +0,0 @@
-#include "blender/blender.h"
-#include <assert.h>
-
-static void test_canvas_blending() {
-  Morphing *morphing;
-  Canvas origin, target, result;
-  CartesianVector sample_point = {13, 17};
-
-  morphing = morphing_create(64, 64);
-  canvas_init(&origin, 64, 64);
-  canvas_init(&target, 64, 64);
-  canvas_init(&result, 64, 64);
-
-  canvas_set_pixel(&origin, sample_point, (Color) {{0xFF, 0xED, 0x00, 0x00}});
-  canvas_set_pixel(&target, sample_point, (Color) {{0x00, 0x47, 0xAB, 0x00}});
-
-  blender_blend_canvas(&result, &origin, &target, morphing, 0.125);
-  assert(color_equals(canvas_get_pixel(&result, sample_point), (Color) {{0xEE, 0xDF, 0x3C, 0x00}}));
-
-  canvas_free(&result);
-  canvas_free(&target);
-  canvas_free(&origin);
-  morphing_destroy(morphing);
-}
-
-int main(int argc, char **argv) {
-  test_canvas_blending();
-  return 0;
-}
diff --git a/test/painter/rasterizer.c b/test/painter/rasterizer.c
new file mode 100644
index 0000000..99a70b4
--- /dev/null
+++ b/test/painter/rasterizer.c
@@ -0,0 +1,27 @@
+#include "painter/rasterizer.h"
+#include <assert.h>
+
+static void test_rasterize() {
+  Morphing *morphing;
+  Canvas *origin, *target, *result;
+  CartesianVector sample_point = {13, 17};
+
+  morphing = morphing_create(100, 100);
+  origin = canvas_create(100, 100);
+  target = canvas_create(100, 100);
+  canvas_set_pixel(origin, sample_point, (Color) {{0xFF, 0x00, 0xED, 0xFF}});
+  canvas_set_pixel(target, sample_point, (Color) {{0xFF, 0xAB, 0x47, 0x00}});
+
+  result = rasterize(origin, target, morphing, 0.125);
+  assert(color_equals(canvas_get_pixel(result, sample_point), (Color) {{0xFF, 0x3C, 0xDF, 0xEF}}));
+
+  canvas_destroy(result);
+  canvas_destroy(target);
+  canvas_destroy(origin);
+  morphing_destroy(morphing);
+}
+
+int main(int argc, char **argv) {
+  test_rasterize();
+  return 0;
+}
-- 
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