Initial import

10 files changed, 1121 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..7b1eaf7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,17 @@
+Makefile
+Makefile.in
+aclocal.m4
+autom4te.cache/
+config.h
+config.h.in~
+config.log
+config.status
+configure
+depcomp
+install-sh
+missing
+.deps/
+src/bezier_surface
+stamp-h1
+*.o
+*.in
diff --git a/Makefile.am b/Makefile.am
new file mode 100644
index 0000000..e2a677f
--- /dev/null
+++ b/Makefile.am
@@ -0,0 +1,30 @@
+# Copyright © 2012 Ian D. Romanick
+# All Rights Reserved.
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# on the rights to use, copy, modify, merge, publish, distribute, sub
+# license, and/or sell copies of the Software, and to permit persons to whom
+# the Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice (including the next
+# paragraph) shall be included in all copies or substantial portions of the
+# Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
+# AUTHORS, COPYRIGHT HOLDERS, AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+# USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+AUTOMAKE_OPTIONS = foreign
+SUBDIRS = src
+
+EXTRA_DIST = \
+	data/simple.vert \
+	data/simple.frag \
+	src/shader.h \
+	src/nano_kontrol.h
diff --git a/config.h.in b/config.h.in
new file mode 100644
index 0000000..952c75a
--- /dev/null
+++ b/config.h.in
@@ -0,0 +1,61 @@
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#undef HAVE_INTTYPES_H
+
+/* Define to 1 if you have the `GL' library (-lGL). */
+#undef HAVE_LIBGL
+
+/* Define to 1 if you have the `GLEW' library (-lGLEW). */
+#undef HAVE_LIBGLEW
+
+/* Define to 1 if you have the <memory.h> header file. */
+#undef HAVE_MEMORY_H
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#undef HAVE_STDINT_H
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#undef HAVE_STDLIB_H
+
+/* Define to 1 if you have the <strings.h> header file. */
+#undef HAVE_STRINGS_H
+
+/* Define to 1 if you have the <string.h> header file. */
+#undef HAVE_STRING_H
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#undef HAVE_SYS_STAT_H
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#undef HAVE_SYS_TYPES_H
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#undef HAVE_UNISTD_H
+
+/* Name of package */
+#undef PACKAGE
+
+/* Define to the address where bug reports for this package should be sent. */
+#undef PACKAGE_BUGREPORT
+
+/* Define to the full name of this package. */
+#undef PACKAGE_NAME
+
+/* Define to the full name and version of this package. */
+#undef PACKAGE_STRING
+
+/* Define to the one symbol short name of this package. */
+#undef PACKAGE_TARNAME
+
+/* Define to the home page for this package. */
+#undef PACKAGE_URL
+
+/* Define to the version of this package. */
+#undef PACKAGE_VERSION
+
+/* Define to 1 if you have the ANSI C header files. */
+#undef STDC_HEADERS
+
+/* Version number of package */
+#undef VERSION
diff --git a/configure.ac b/configure.ac
new file mode 100644
index 0000000..c4ba3dc
--- /dev/null
+++ b/configure.ac
@@ -0,0 +1,95 @@
+#                                               -*- Autoconf -*-
+# Process this file with autoconf to produce a configure script.
+
+AC_PREREQ(2.61)
+AC_INIT(bezier_surface, 2012Q4.1, idr@freedesktop.org, bezier_surface)
+AC_CONFIG_SRCDIR([Makefile.am])
+AM_CONFIG_HEADER([config.h])
+
+AM_INIT_AUTOMAKE
+
+# Checks for programs.
+AC_PROG_CXX
+AC_PROG_CC
+AC_PROG_MAKE_SET
+AC_PROG_RANLIB
+PKG_PROG_PKG_CONFIG
+
+# Checks for libraries.
+
+# Checks for header files.
+
+# Checks for typedefs, structures, and compiler characteristics.
+
+# Checks for library functions.
+AC_HEADER_STDC
+
+
+# SDL is required for this application.  Find its header files and
+# libraries.  Make sure they exist.
+
+CPPFLAGS="$CPPFLAGS `sdl-config --cflags`"
+LIBS="$LIBS `sdl-config --libs`"
+
+AC_CHECK_HEADER(SDL.h, [], [exit 1])
+
+CPPFLAGS="$CPPFLAGS `pkg-config --cflags alsa`"
+LIBS="$LIBS `pkg-config --libs alsa`"
+
+# OpenGL is required for this application.  Find its header files and
+# libraries.  Make sure they exist.
+
+AC_CHECK_HEADER(GL/gl.h, [], [exit 1])
+AC_CHECK_LIB([GL], [glVertexPointer], [], [exit 1])
+
+
+# GLEW is required for this application.  Find its header files and
+# libraries.  Make sure they exist.
+
+AC_CHECK_HEADER(GL/glew.h, [], [exit 1])
+AC_CHECK_LIB([GLEW], [glewInit], [], [exit 1], [-lGL])
+
+AC_LANG_CPLUSPLUS
+
+PKG_CHECK_MODULES([GLU3], [glu3])
+AC_SUBST(GLU3_CFLAGS)
+AC_SUBST(GLU3_LIBS)
+
+AC_ARG_ENABLE([debug],
+    [AS_HELP_STRING([--enable-debug],
+        [use debug compiler flags and macros @<:@default=disabled@:>@])],
+    [enable_debug="$enableval"],
+    [enable_debug=no]
+)
+if test "x$enable_debug" = xyes; then
+    DEFINES="$DEFINES -DDEBUG"
+    if test "x$GCC" = xyes; then
+	# Remove any -g flags from the command line
+	CFLAGS=[`echo $CFLAGS | sed 's/-g[^ \t]*[ \t]*//g'`]
+        CFLAGS="$CFLAGS -ggdb3 -fstack-protector -D_FORTIFY_SOURCE=2"
+    fi
+    if test "x$GXX" = xyes; then
+	# Remove any -g flags from the command line
+	CXXFLAGS=[`echo $CXXFLAGS | sed 's/-g[^ \t]*[ \t]*//g'`]
+        CXXFLAGS="$CXXFLAGS -ggdb3 -fstack-protector -D_FORTIFY_SOURCE=2"
+    fi
+fi
+
+
+if test "x$GCC" = xyes ; then
+	WARN="-Wall -Wextra -Wunsafe-loop-optimizations -Wstack-protector"
+else
+	WARN=""
+fi
+
+if test "x$GXX" = xyes ; then
+	WARN="-Wall -Wextra -Wunsafe-loop-optimizations -Wstack-protector"
+else
+	WARN=""
+fi
+
+CFLAGS="$CFLAGS $WARN"
+CXXFLAGS="$CXXFLAGS $WARN"
+
+AC_OUTPUT([Makefile
+	src/Makefile])
diff --git a/data/simple.frag b/data/simple.frag
new file mode 100644
index 0000000..89480f7
--- /dev/null
+++ b/data/simple.frag
@@ -0,0 +1,57 @@
+#version 130
+#extension GL_ARB_explicit_attrib_location: require
+
+#define DO_LIGHTING 0
+
+/* Debug mode.  This will cause the value supplied as 'normal_cs' to be
+ * written as the output color.  The normal will be remapped from the usual
+ * [-1,1] range to [0,1].
+ */
+#define SHOW_NORMALS 0
+
+/* Approximate (u,v) at the current fragment.  Passed from the vertex shader,
+ * this is used to determine the base color of the fragment.
+ */
+in vec2 frag_uv;
+
+// Direction of the normal in camera-space.
+in vec3 normal_cs;
+
+// Direction to the light in camera-space.
+uniform vec3 light_dir_cs = normalize(vec3(0., 1., 0.));
+
+layout(location = 0) out vec4 color;
+
+void main(void)
+{
+	/* Partition the surface into a checkerboard of 10x10 tiles that
+	 * alternate colors.
+	 */
+	ivec2 tile = ivec2(floor(frag_uv * 10.));
+
+	vec3 base_color = bool((tile.x ^ tile.y) & 1)
+		? vec3(0.00784313679, 0.470588207, 0.996078372)
+		: vec3(0.00784313679, 0.992156804, 0.00784313679);
+
+	/* Renormalize the normal to account for interpolation errors.
+	 */
+	vec3 n_cs = normalize(normal_cs);
+
+	/* If the polygon is back-facing, change the color and invert the
+	 * normal.  This causes back-facing polygons to have different colors
+	 * and be correctly lit.
+	 */
+	if (! gl_FrontFacing) {
+		n_cs = -n_cs;
+		base_color = base_color.zxy;
+	}
+
+#if DO_LIGHTING
+	float diff = min(max(.2, dot(n_cs, light_dir_cs)), 1.);
+	color = vec4(base_color * diff, 1.);
+#elif SHOW_NORMALS
+	color = vec4(normal_cs * .5 + .5, 1.);
+#else
+	color = vec4(base_color, 1.);
+#endif
+}
diff --git a/data/simple.vert b/data/simple.vert
new file mode 100644
index 0000000..1850a67
--- /dev/null
+++ b/data/simple.vert
@@ -0,0 +1,33 @@
+#version 130
+#extension GL_ARB_explicit_attrib_location: require
+
+uniform mat4 mvp;
+uniform mat3 mv_normal;
+
+layout(location = 0) in vec2 uv;
+
+out vec4 color;
+out vec2 frag_uv;
+
+// Direction of the normal in camera-space.
+out vec3 normal_cs;
+
+void main(void)
+{
+	/* Center the region at the origin.  Assume that it's 7 units by 7
+	 * units.
+	 */
+	vec2 bias_uv = uv - 0.5;
+	vec4 position = vec4(bias_uv.x * 7.,
+			     0.0,
+			     bias_uv.y * 7.,
+			     1.0);
+	gl_Position = mvp * position;
+
+	/* Transform the normal by the inverse-transpose of the model-view
+	 * matrix.
+	 */
+	normal_cs = mv_normal * vec3(0., 1., 0.);
+
+	frag_uv = uv;
+}
diff --git a/src/Makefile.am b/src/Makefile.am
new file mode 100644
index 0000000..8d6d249
--- /dev/null
+++ b/src/Makefile.am
@@ -0,0 +1,27 @@
+# Copyright © 2012 Ian D. Romanick
+# All Rights Reserved.
+#
+# Permission is hereby granted, free of charge, to any person obtaining a
+# copy of this software and associated documentation files (the "Software"),
+# to deal in the Software without restriction, including without limitation
+# on the rights to use, copy, modify, merge, publish, distribute, sub
+# license, and/or sell copies of the Software, and to permit persons to whom
+# the Software is furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice (including the next
+# paragraph) shall be included in all copies or substantial portions of the
+# Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.  IN NO EVENT SHALL
+# AUTHORS, COPYRIGHT HOLDERS, AND/OR THEIR SUPPLIERS BE LIABLE FOR ANY CLAIM,
+# DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+# OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+# USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+bin_PROGRAMS = bezier_surface
+bezier_surface_SOURCES = main.cpp shader.cpp
+
+AM_CXXFLAGS= $(GLU3_CFLAGS)
+bezier_surface_LDADD = $(FRAMEWORK_LIBS) $(GLU3_LIBS) -lEGL
diff --git a/src/main.cpp b/src/main.cpp
new file mode 100644
index 0000000..34d4959
--- /dev/null
+++ b/src/main.cpp
@@ -0,0 +1,691 @@
+/*
+ * Copyright © 2009, 2012 Ian D. Romanick
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+#include <math.h>
+#include <GL/glew.h>
+#include <SDL.h>
+
+#include <glu3.h>
+
+#include "shader.h"
+
+#define BUFFER_OFFSET(i) ((char *)NULL + (i))
+#define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
+
+static SDL_Surface *my_surf = NULL;
+
+static bool anim = true;
+static bool done = false;
+
+static float y_angle = 0.0f;
+static float eye_distance = 15.0f;
+static float fov = 45.0f;
+
+/* Which data set is begin used for the patches?  See set_control_points.
+ */
+static unsigned data_set = 0;
+
+static Uint32 t0;
+
+static GLuint bo;
+
+static GLUmat4 projection_matrix;
+
+class bezier_patch_program : public shader_program {
+public:
+	bezier_patch_program(GLuint vs, GLuint fs)
+		: shader_program(vs, fs, 0)
+	{
+		/* empty */
+	}
+
+	void set_attribute_locations()
+	{
+	}
+
+	void get_uniform_locations()
+	{
+		this->mvp_uniform =
+			glGetUniformLocation(this->program, "mvp");
+		this->mv_normal_uniform =
+			glGetUniformLocation(this->program, "mv_normal");
+		this->light_dir_cs_uniform =
+			glGetUniformLocation(this->program, "light_dir_cs");
+	}
+
+	GLint mvp_uniform;
+	GLint mv_normal_uniform;
+	GLint light_dir_cs_uniform;
+};
+
+static bezier_patch_program *patch_program = 0;
+
+static GLuint timer_queries[1] = { 0, };
+
+static inline
+float degrees_to_radians(float f)
+{
+	return (f * M_PI) / 180.0;
+}
+
+
+class simple_consumer : public GLUshapeConsumer {
+public:
+	simple_consumer(void *_data, unsigned num_verts, uintptr_t base_offset)
+	{
+		GLUvec4 *data = (GLUvec4 *) _data;
+
+		this->uv = &data[0 * num_verts];
+		this->uv_offset = (uintptr_t) ((char *) this->uv
+					       - (char *) _data)
+			+ base_offset;
+
+		this->position = NULL;
+		this->normal = NULL;
+		this->tangent = NULL;
+		this->vertex_count = num_verts;
+
+		this->elt = (GLushort *) &data[1 * num_verts];
+		this->elt_offset = (uintptr_t) ((char *) this->elt
+						- (char *) _data)
+			+ base_offset;
+	}
+
+	virtual void begin_primitive(GLenum mode, unsigned count)
+	{
+		this->mode = mode;
+		this->elt_count = count;
+	}
+
+        virtual void index_batch(const unsigned *idx, unsigned count)
+	{
+		for (unsigned i = 0; i < count; i++)
+			this->elt[i] = GLushort(idx[i]);
+
+		this->elt += count;
+	}
+
+	GLushort *elt;
+	uintptr_t elt_offset;
+	unsigned elt_count;
+
+	uintptr_t uv_offset;
+
+	GLenum mode;
+};
+
+class patch_producer : public GLUmeshProducer {
+public:
+	patch_producer(unsigned rows, unsigned columns)
+		: GLUmeshProducer(rows, columns, columns)
+	{
+		/* empty */
+	}
+
+	virtual unsigned vertex_count(void) const
+	{
+		return (this->rows + 1) * this->columns;
+	}
+
+	virtual void generate(GLUshapeConsumer *consumer) const
+	{
+		unsigned idx = 0;
+		const float u_step = 1. / (this->columns - 1);
+		const float v_step = 1. / this->rows;
+		float u;
+		float v;
+
+		v = 0;
+		for (unsigned i = 0; i < (this->rows + 1); i++ ) {
+			u = 0.;
+			for (unsigned j = 0; j < this->columns; j++) {
+				consumer->uv[idx] = GLUvec4(u, v, 0., 0.);
+				idx++;
+				u += u_step;
+			}
+
+			v += v_step;
+		}
+
+		consumer->vertex_batch(NULL,
+				       NULL,
+				       NULL,
+				       consumer->uv,
+				       idx);
+
+                GLUmeshProducer::generate(consumer);
+	}
+};
+
+static simple_consumer *mesh_sink;
+
+/**
+ * Fill a buffer object with data defining a worm.
+ */
+static simple_consumer *
+fill_in_object_data(GLuint buf)
+{
+	patch_producer mesh_source(29, 29);
+
+	const unsigned num_verts = mesh_source.vertex_count();
+	const unsigned num_elts = mesh_source.element_count();
+
+	const unsigned size = (4 * sizeof(float) * num_verts)
+		+ (sizeof(GLushort) * num_elts);
+
+	glBindBuffer(GL_ARRAY_BUFFER, buf);
+	glBufferData(GL_ARRAY_BUFFER, size, NULL, GL_STATIC_DRAW);
+	void *ptr = glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);
+
+	simple_consumer *cons = new simple_consumer(ptr, num_verts, 0);
+	mesh_source.generate(cons);
+
+	glUnmapBuffer(GL_ARRAY_BUFFER);
+
+	return cons;
+}
+
+static GLUvec4
+lerp(GLUvec4 const &a, GLUvec4 const &b, float t)
+{
+	return (b - a) * t + a;
+}
+
+static void
+set_control_points(float angle, GLUvec4 *p)
+{
+	static const GLUvec4 a[16] = {
+		GLUvec4( 9.0f, 0.0f,  7.0f, 1.0f),
+		GLUvec4( 4.5f, 0.0f,  7.0f, 1.0f),
+		GLUvec4(-4.5f, 0.0f,  7.0f, 1.0f),
+		GLUvec4(-9.0f, 0.0f,  7.0f, 1.0f),
+
+		GLUvec4( 9.0f, 0.0f,  3.5f, 1.0f),
+		GLUvec4( 4.5f, 0.0f,  3.5f, 1.0f),
+		GLUvec4(-4.5f, 0.0f,  3.5f, 1.0f),
+		GLUvec4(-9.0f, 0.0f,  3.5f, 1.0f),
+
+		GLUvec4( 9.0f, 0.0f, -3.5f, 1.0f),
+		GLUvec4( 4.5f, 0.0f, -3.5f, 1.0f),
+		GLUvec4(-4.5f, 0.0f, -3.5f, 1.0f),
+		GLUvec4(-9.0f, 0.0f, -3.5f, 1.0f),
+
+		GLUvec4( 9.0f, 0.0f, -7.0f, 1.0f),
+		GLUvec4( 4.5f, 0.0f, -7.0f, 1.0f),
+		GLUvec4(-4.5f, 0.0f, -7.0f, 1.0f),
+		GLUvec4(-9.0f, 0.0f, -7.0f, 1.0f),
+	};
+
+	static const GLUvec4 b[16] = {
+		GLUvec4( 2.0f, 0.0f,  1.0f, 1.0f),
+		GLUvec4( 4.5f, 4.0f,  7.0f, 1.0f),
+		GLUvec4(-4.5f, 4.0f,  7.0f, 1.0f),
+		GLUvec4(-2.0f, 0.0f,  1.0f, 1.0f),
+
+		GLUvec4( 4.0f, 2.0f,  0.5f, 1.0f),
+		GLUvec4( 4.5f, 8.0f,  0.5f, 1.0f),
+		GLUvec4(-4.5f, 8.0f,  0.5f, 1.0f),
+		GLUvec4(-4.0f, 2.0f,  0.5f, 1.0f),
+
+		GLUvec4( 4.0f, 2.0f, -0.5f, 1.0f),
+		GLUvec4( 4.5f, 8.0f, -0.5f, 1.0f),
+		GLUvec4(-4.5f, 8.0f, -0.5f, 1.0f),
+		GLUvec4(-4.0f, 2.0f, -0.5f, 1.0f),
+
+		GLUvec4( 2.0f, 0.0f, -1.0f, 1.0f),
+		GLUvec4( 4.5f, 4.0f, -7.0f, 1.0f),
+		GLUvec4(-4.5f, 4.0f, -7.0f, 1.0f),
+		GLUvec4(-2.0f, 0.0f, -1.0f, 1.0f),
+	};
+
+#define Z (0.866025404 * 10.)
+#define Y (0.5         * 10.)
+
+	static const GLUvec4 c[16] = {
+		GLUvec4( 9.0f, 0.0f,  0.0f, 1.0f),
+		GLUvec4( 4.5f, 0.0f,  0.0f, 1.0f),
+		GLUvec4(-4.5f, 0.0f,  0.0f, 1.0f),
+		GLUvec4(-9.0f, 0.0f,  0.0f, 1.0f),
+
+		GLUvec4( 9.0f, Y,  Z, 1.0f),
+		GLUvec4( 4.5f, Y,  Z, 1.0f),
+		GLUvec4(-4.5f, Y,  Z, 1.0f),
+		GLUvec4(-9.0f, Y,  Z, 1.0f),
+
+		GLUvec4( 9.0f, Y, -Z, 1.0f),
+		GLUvec4( 4.5f, Y, -Z, 1.0f),
+		GLUvec4(-4.5f, Y, -Z, 1.0f),
+		GLUvec4(-9.0f, Y, -Z, 1.0f),
+
+		GLUvec4( 9.0f, 0.0f,  0.0f, 1.0f),
+		GLUvec4( 4.5f, 0.0f,  0.0f, 1.0f),
+		GLUvec4(-4.5f, 0.0f,  0.0f, 1.0f),
+		GLUvec4(-9.0f, 0.0f,  0.0f, 1.0f),
+	};
+
+#undef Z
+#undef Y
+
+	const GLUvec4 *const target = (data_set == 0) ? b : c;
+	const float t = 1. - ((cos(angle) + 1.) / 2.);
+
+	for (unsigned i = 0; i < ARRAY_SIZE(a); i++)
+		p[i] = lerp(a[i], target[i], t);
+}
+
+static void
+Redisplay(void)
+{
+	static Uint32 last_t = ~0;
+	Uint32 t = SDL_GetTicks();
+
+
+	/* Update animation parameters based on the elaped time.
+	 */
+	if (last_t != (Uint32)~0) {
+		float dt = (float) (t - last_t) / 1000.0f;
+
+		if (anim) {
+			/* Rotate at 60 degrees per second respectively.  All
+			 * of the measurements want angles measured in
+			 * radians.  Do the conversion here.
+			 */
+			y_angle += degrees_to_radians(60.0 * dt);
+		}
+	}
+
+	last_t = t;
+
+
+	/* For the current time, determine the location of the control points.
+	 */
+	GLUvec4 control_points[16];
+	set_control_points(y_angle, control_points);
+
+	const GLUvec4 eye(eye_distance * cos(y_angle),
+			  5.0f,
+			  eye_distance * sin(y_angle),
+			  0.0f);
+
+	const GLUmat4 view(gluLookAt(eye,
+				     GLUvec4(0.0f, 3.0f, 0.0f, 0.0f),
+				     GLUvec4(0.0f, 1.0f, 0.0f, 0.0f)));
+
+	const GLUmat4 mv(view);
+	const GLUmat4 mvp(projection_matrix * mv);
+
+	/* Based on the current time, set the position of the light in
+	 * world-space.
+	 */
+	const GLUvec4 light_dir_ws(GLUvec4(0.,
+					   fabs(cos(y_angle)),
+					   sin(y_angle),
+					   0.));
+
+	/* Transform the light position from world-space to camera-space
+	 * because all lighting calculations in the shaders will happen in
+	 * camera-space.
+	 */
+	const GLUvec4 light_dir_cs(view * light_dir_ws);
+
+	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+
+	/* Render the worm.
+	 */
+	glUseProgram(patch_program->program);
+
+	if (timer_queries[0])
+		glBeginQuery(GL_TIME_ELAPSED, timer_queries[0]);
+
+	glUniform3fv(patch_program->light_dir_cs_uniform, 1,
+		     (float *) &light_dir_cs);
+	glUniformMatrix4fv(patch_program->mvp_uniform, 1, false,
+			   (float *) &mvp);
+
+	/* Since the model-view matrix is an orthonormal basis, we can just
+	 * use the upper 3x3 portion for transforming normals.
+	 */
+	const float mv_normal[9] = {
+		mv.col[0].values[0], mv.col[0].values[1], mv.col[0].values[2],
+		mv.col[1].values[0], mv.col[1].values[1], mv.col[1].values[2],
+		mv.col[2].values[0], mv.col[2].values[1], mv.col[2].values[2],
+	};
+	glUniformMatrix3fv(patch_program->mv_normal_uniform, 1, false,
+			   mv_normal);
+
+	glDrawElements(mesh_sink->mode,
+		       mesh_sink->elt_count,
+		       GL_UNSIGNED_SHORT,
+		       BUFFER_OFFSET(mesh_sink->elt_offset));
+
+	if (timer_queries[0])
+		glEndQuery(GL_TIME_ELAPSED);
+
+	SDL_GL_SwapBuffers();
+
+	if (timer_queries[0]) {
+		static GLuint64 totals[ARRAY_SIZE(timer_queries)] = { 0, };
+		static unsigned count = 0;
+		GLuint64 result[ARRAY_SIZE(timer_queries)] = { 0, };
+
+		for (unsigned i = 0; i < ARRAY_SIZE(timer_queries); i++) {
+			glGetQueryObjectui64vEXT(timer_queries[i],
+						 GL_QUERY_RESULT,
+						 &result[i]);
+			totals[i] += result[i];
+		}
+
+		count++;
+		if (count > 100) {
+			printf("Timings: %lu\n",
+			       totals[0] / 100);
+
+			memset(totals, 0, sizeof(totals));
+			count = 0;
+		}
+	}
+
+}
+
+static GLuint
+compile_shader_from_file(GLenum target, const char *filename)
+{
+	static const char *const paths_to_try[] = {
+		"",
+		"data/",
+		"../data/",
+		0
+	};
+
+	GLuint shader;
+	char *log = NULL;
+	const char *code;
+
+	const size_t name_len = strlen(filename);
+	for (unsigned i = 0; paths_to_try[i] != 0; i++) {
+		const size_t path_len = strlen(paths_to_try[i]);
+		char *name_with_path = new char [path_len + name_len + 1];
+
+		memcpy(name_with_path, paths_to_try[i], path_len);
+		memcpy(&name_with_path[path_len], filename, name_len);
+		name_with_path[path_len + name_len] = '\0';
+
+		code = gluLoadTextFile(name_with_path);
+		delete [] name_with_path;
+
+		if (code != NULL)
+			break;
+	}
+
+	if (code == NULL) {
+		fprintf(stderr, "Unable to load shader code for %s.\n",
+			filename);
+		exit(1);
+	}
+
+	shader = gluCompileShader(target, code, &log);
+	if (log != NULL) {
+		printf("Shader compile log for %s:\n%s\n", filename, log);
+		gluReleaseInfoLog(log);
+		log = NULL;
+	}
+
+	if (shader == 0) {
+		fprintf(stderr, "Failed to compile %s.\n", filename);
+		exit(1);
+	}
+
+	gluUnloadTextFile(code);
+
+	return shader;
+}
+
+static bezier_patch_program *
+create_program(GLuint vs, GLuint fs, const char *name)
+{
+	bezier_patch_program *p = new bezier_patch_program(vs, fs);
+
+	p->set_attribute_locations();
+
+	const bool linked = p->link();
+	if (p->log != NULL)
+		printf("%s link log:\n%s\n", name, p->log);
+
+	if (!linked) {
+		fprintf(stderr, "Failed to link %s.\n", name);
+		exit(1);
+	}
+
+	p->get_uniform_locations();
+	return p;
+}
+
+/* Load, compile, link, etc. the vertex and fragment programs.
+ */
+static void
+build_all_shaders(void)
+{
+	gluInitializeCompiler();
+
+	/* If there are dangling instances of these program hanging around,
+	 * clean them up.
+	 */
+	if (patch_program)
+		delete patch_program;
+
+	/* Compile all of the shaders
+	 */
+	GLuint vs = compile_shader_from_file(GL_VERTEX_SHADER,
+					     "simple.vert");
+	GLuint fs = compile_shader_from_file(GL_FRAGMENT_SHADER,
+					     "simple.frag");
+
+	patch_program = create_program(vs, fs, "simple");
+
+	/* The individual shaders have been attached to the programs, so they
+	 * can safely be deleted.
+	 */
+	glDeleteShader(vs);
+	glDeleteShader(fs);
+}
+
+
+static void
+Init(void)
+{
+	glewInit();
+
+	if (!GLEW_VERSION_3_0) {
+		printf ("Sorry, this demo requires OpenGL 3.0 or later.\n");
+		exit(1);
+	}
+
+	if (!GLEW_ARB_explicit_attrib_location) {
+		printf ("Sorry, this demo requires "
+			"GL_ARB_explicit_attrib_location.\n");
+		exit(1);
+	}
+
+	if (GLEW_EXT_timer_query || GLEW_ARB_timer_query)
+		glGenQueries(ARRAY_SIZE(timer_queries), timer_queries);
+
+	build_all_shaders();
+
+	glClearColor(.1f, .1f, .1f, 0.f);
+	glEnable(GL_DEPTH_TEST);
+
+	glGenBuffers(1, & bo);
+	mesh_sink = fill_in_object_data(bo);
+
+	glBindBuffer(GL_ARRAY_BUFFER, bo);
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, bo);
+
+	glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0,
+			      BUFFER_OFFSET(mesh_sink->uv_offset));
+	glEnableVertexAttribArray(0);
+
+
+	printf("GL_RENDERER = %s\n", (const char *) glGetString(GL_RENDERER));
+	printf("Keyboard input:\n"
+	       "    f: Toggle fullscreen.\n"
+	       "    a: Toggle animation of object.\n"
+	       "    c: Re-load and compile shader program code.\n"
+	       "  ESC: Exit program.\n");
+}
+
+
+static void
+Reshape(int width, int height)
+{
+	my_surf = SDL_SetVideoMode(width, height, 0,
+				   SDL_OPENGL | SDL_RESIZABLE);
+	if (my_surf == NULL) {
+		exit(1);
+	}
+
+	Init();
+
+	const float aspect = float(width) / float(height);
+	gluPerspective4f(& projection_matrix, degrees_to_radians(fov),
+			 aspect, 2.0f, 100.0f);
+	glViewport(0, 0, width, height);
+}
+
+
+static void
+Key(SDLKey sym, bool key_down)
+{
+	if (!key_down)
+		return;
+
+	switch (sym) {
+	case SDLK_ESCAPE:
+		done = true;
+		break;
+
+	case 'f':
+		SDL_WM_ToggleFullScreen(my_surf);
+		break;
+
+	case ' ':
+	case 'a':
+		anim = !anim;
+		break;
+
+	case 'd':
+		/* Toggle between the two data sets.
+		 */
+		data_set ^= 1;
+		break;
+
+	case 'c':
+		printf("Reloading and compiling program code...\n");
+		build_all_shaders();
+		break;
+
+	default:
+		break;
+	}
+}
+
+
+/**
+ * Push an event each time the timer callback fires.
+ */
+Uint32
+timer_callback(Uint32 interval, void *not_used)
+{
+	SDL_Event e;
+
+	(void) not_used;
+
+	e.type = SDL_USEREVENT;
+	e.user.code = 0;
+	e.user.data1 = NULL;
+	e.user.data2 = NULL;
+	SDL_PushEvent(& e);
+
+	return interval;
+}
+
+
+int
+main(int argc, char **argv)
+{
+	(void) argc;
+	(void) argv;
+
+	if (SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER) < 0) {
+		exit(1);
+	}
+
+	atexit(SDL_Quit);
+
+	Reshape(800, 600);
+
+	SDL_TimerID timer_id = SDL_AddTimer(10, timer_callback, NULL);
+	t0 = SDL_GetTicks();
+
+	while (!done) {
+		bool draw = false;
+		SDL_Event event;
+
+		SDL_WaitEvent(&event);
+		do {
+			switch (event.type) {
+			case SDL_VIDEORESIZE:
+				Reshape(event.resize.w, event.resize.h);
+				break;
+
+			case SDL_QUIT:
+				done = true;
+				break;
+
+			case SDL_KEYDOWN:
+				Key(event.key.keysym.sym, true);
+				break;
+
+			case SDL_KEYUP:
+				Key(event.key.keysym.sym, false);
+				break;
+
+			case SDL_USEREVENT:
+				draw = true;
+				break;
+
+			default:
+				break;
+			}
+		} while (SDL_PollEvent(&event));
+
+
+		if (draw) {
+			Redisplay();
+		}
+	}
+
+	SDL_RemoveTimer(timer_id);
+
+	SDL_Quit();
+	return 0;
+}
diff --git a/src/shader.cpp b/src/shader.cpp
new file mode 100644
index 0000000..8456362
--- /dev/null
+++ b/src/shader.cpp
@@ -0,0 +1,69 @@
+/*
+ * Copyright © 2012 Ian D. Romanick
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+#include <stdarg.h>
+#include <GL/glew.h>
+#include <glu3.h>
+#include "shader.h"
+
+void shader_program::init()
+{
+	this->program = glCreateProgram();
+	this->log = 0;
+}
+
+shader_program::shader_program()
+{
+	init();
+}
+
+shader_program::shader_program(GLint shader, ...)
+{
+	va_list ap;
+	GLint sh;
+
+	init();
+
+	glAttachShader(this->program, shader);
+
+	va_start(ap, shader);
+	while ((sh = va_arg(ap, GLint)) != 0) {
+		glAttachShader(this->program, sh);
+	}
+	va_end(ap);
+}
+
+shader_program::~shader_program()
+{
+	glDeleteProgram(this->program);
+	this->program = 0;
+
+	if (this->log) {
+		gluReleaseInfoLog(this->log);
+		this->log = 0;
+	}
+}
+
+bool shader_program::link()
+{
+	return gluLinkProgram(this->program, &this->log);
+}
diff --git a/src/shader.h b/src/shader.h
new file mode 100644
index 0000000..5e49dc3
--- /dev/null
+++ b/src/shader.h
@@ -0,0 +1,41 @@
+/*
+ * Copyright © 2012 Ian D. Romanick
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+#ifndef SHADER_PROGRAM_H
+#define SHADER_PROGRAM_H
+
+class shader_program {
+public:
+	shader_program();
+	shader_program(GLint shader, ...);
+	~shader_program();
+
+	bool link();
+
+	GLint program;
+	char *log;
+
+private:
+	void init();
+};
+
+#endif /* SHADER_PROGRAM_H */