test: add simplex noise test program.

.gitignore

@@ -82,6 +82,7 @@ demos/test/sandbox/sample
 demos/test/math/pi
 demos/test/math/poly
 demos/test/nacl_phystest
+demos/test/simplex
 demos/tutorial/01_triangle
 demos/tutorial/02_cube
 demos/tutorial/03_noise

demos/test/Makefile.am

@@ -6,7 +6,8 @@ SUBDIRS = math sandbox
 bench: benchsuite$(EXEEXT)
 	./benchsuite$(EXEEXT)
 
-noinst_PROGRAMS = benchsuite btphystest nacl_phystest meshviewer
+noinst_PROGRAMS = benchsuite btphystest nacl_phystest meshviewer \
+    simplex
 
 benchsuite_SOURCES = benchsuite.cpp \
     benchmark/vector.cpp benchmark/half.cpp benchmark/trig.cpp \
@@ -53,3 +54,7 @@ if USE_EMSCRIPTEN
 meshviewer_LDFLAGS += -s EXPORTED_FUNCTIONS="['_main', '_C_Send']"
 endif
 
+simplex_SOURCES = simplex.cpp
+simplex_CPPFLAGS = $(AM_CPPFLAGS)
+simplex_DEPENDENCIES = @LOL_DEPS@
+

demos/test/simplex.cpp

@@ -0,0 +1,73 @@
+//
+//  Simplex Noise Test Program
+//
+//  Copyright (c) 2010-2014 Sam Hocevar <sam@hocevar.net>
+//            (c) 2013-2014 Guillaume Bittoun <guillaume.bittoun@gmail.com>
+//   This program is free software; you can redistribute it and/or
+//   modify it under the terms of the Do What The Fuck You Want To
+//   Public License, Version 2, as published by Sam Hocevar. See
+//   http://www.wtfpl.net/ for more details.
+//
+
+#if HAVE_CONFIG_H
+#   include "config.h"
+#endif
+
+#include <lol/engine.h>
+
+using namespace lol;
+
+int main(int argc, char **argv)
+{
+    UNUSED(argc, argv);
+
+    int const period = 2;
+    float const zoom = 0.03f;
+
+    /* Create some gradients */
+    array2d<vec2> gradients(vec_t<ptrdiff_t, 2>({period, period}));
+    for (int i = 0 ; i < period ; ++i)
+        for (int j = 0 ; j < period ; ++j)
+            gradients[i][j] = normalize(vec2(rand(-1.f, 1.f), rand(-1.f, 1.f)));
+    simplex_interpolator<2> s;
+    s.SetGradients(gradients);
+
+    /* Create an image */
+    ivec2 const size(800, 600);
+    Image img(size);
+    array2d<vec4> &data = img.Lock2D<PixelFormat::RGBA_F32>();
+
+    /* Fill image with simplex noise */
+    for (int j = 0; j < size.y; ++j)
+    for (int i = 0; i < size.x; ++i)
+    {
+        float p = 0.5f + 0.5f * s.Interp(zoom * vec2(i, j));
+#if 0
+        for (int k = 2; k < 32; k *= 2)
+            p += 0.5f / k * s.Interp(zoom * k * vec2(i, j));
+#endif
+        data[i][j] = vec4(saturate(p), 0.f, 0.f, 1.f);
+    }
+
+    /* Mark simplex vertices */
+    vec2 dx(1.f, 0.f);
+    vec2 dy = mat2::rotate(60.f) * dx;
+    for (int j = -100; j < 100; ++j)
+    for (int i = -100; i < 100; ++i)
+    {
+        ivec2 coord = ivec2(i / zoom * dx + j / zoom * dy);
+        if (coord.x >= 0 && coord.x < size.x - 1
+             && coord.y >= 0 && coord.y < size.y - 1)
+        {
+            data[coord.x][coord.y] = vec4(1.f, 0.f, 1.f, 1.f);
+            data[coord.x + 1][coord.y] = vec4(1.f, 0.f, 1.f, 1.f);
+            data[coord.x][coord.y + 1] = vec4(1.f, 0.f, 1.f, 1.f);
+            data[coord.x + 1][coord.y + 1] = vec4(1.f, 0.f, 1.f, 1.f);
+        }
+    }
+
+    /* Save image */
+    img.Unlock2D(data);
+    img.Save("simplex.png");
+}
+