GLUshape: Add GLUcube class to generate cubes

3 files changed, 190 insertions, 1 deletions

diff --git a/include/glu3.h b/include/glu3.h
index 6e809e5..f634a57 100644
--- a/include/glu3.h
+++ b/include/glu3.h
@@ -419,6 +419,28 @@ private:
 	unsigned slices;
 	unsigned stacks;
 };
+
+
+/**
+ * Shape generator that generates a cube.
+ */
+class GLUcube : public GLUshape {
+public:
+	/**
+	 * Construct a new cube shape generator
+	 *
+	 * \param radius  Distance from the center of the cube to the center
+	 *                of one of the axis-aligned faces.
+	 */
+	GLUcube(GLdouble radius);
+	virtual unsigned vertex_count(void) const;
+	virtual unsigned element_count(void) const;
+	virtual unsigned primitive_count(void) const;
+	virtual void generate(GLUshapeConsumer *consumer) const;
+
+private:
+	double radius;
+};
 #endif	
 
 #ifndef __cplusplus
diff --git a/src/Makefile.am b/src/Makefile.am
index 697a60e..624d383 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -24,7 +24,8 @@ AM_CXXFLAGS=-I../include
 AM_CFLAGS=-I../include
 
 lib_LIBRARIES = libGLU3.a
-libGLU3_a_SOURCES = matrix.c load_text.c arcball.c revolve.c mesh.c sphere.cpp
+libGLU3_a_SOURCES = matrix.c load_text.c arcball.c revolve.c mesh.c \
+	sphere.cpp cube.cpp
 
 libGLU3includedir = ${includedir}
 libGLU3include_HEADERS = ../include/glu3.h ../include/glu3_scalar.h
diff --git a/src/cube.cpp b/src/cube.cpp
new file mode 100644
index 0000000..c1f13ed
--- /dev/null
+++ b/src/cube.cpp
@@ -0,0 +1,166 @@
+/*
+ * Copyright © 2010 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 "glu3.h"
+
+GLUcube::GLUcube(double radius) :
+	radius(radius)
+{
+}
+
+unsigned
+GLUcube::vertex_count(void) const
+{
+	/* Due to differeing normals and texture coordinates, each face of the
+	 * cube has four unique vertices.  This means that each unique vertex
+	 * position will appear in the output three times.  Note: 8*3 = 6*4.
+	 */
+	return 6 * 4;
+}
+
+unsigned
+GLUcube::element_count(void) const
+{
+	/* Each face is made up of two triangles.  All data is sent in a single
+	 * triangle list.
+	 */
+	return 6 * 2 * 3;
+}
+
+unsigned
+GLUcube::primitive_count(void) const
+{
+	/* Each face is made up of two triangles.  All data is sent in a single
+	 * triangle list.
+	 */
+	return 1;
+}
+
+#define Elements(a)  (sizeof(a) / sizeof(a[0]))
+
+void
+GLUcube::generate(GLUshapeConsumer *consumer) const
+{
+	static const float p[] = {
+		+1.0,  1.0,  1.0, 1.0,
+		-1.0,  1.0,  1.0, 1.0,
+		+1.0, -1.0,  1.0, 1.0,
+		-1.0, -1.0,  1.0, 1.0,
+		+1.0,  1.0, -1.0, 1.0,
+		-1.0,  1.0, -1.0, 1.0,
+		+1.0, -1.0, -1.0, 1.0,
+		-1.0, -1.0, -1.0, 1.0,
+	};
+
+#define X 0
+#define Y 1
+#define Z 2
+#define P 0
+#define N 1
+#define V(x, y, z, n) (((((z) * 4) + (y * 2) + x) * 3) + (n))
+	
+
+	static const unsigned char elts[] = {
+		/* +X face */
+		V(P, P, P, X), V(P, N, N, X), V(P, P, N, X),
+		V(P, P, P, X), V(P, N, P, X), V(P, N, N, X),
+
+		/* +Y face */
+		V(P, P, P, Y), V(P, P, N, Y), V(N, P, N, Y),
+		V(P, P, P, Y), V(N, P, N, Y), V(N, P, P, Y),
+
+		/* +Z face */
+		V(N, P, P, Z), V(P, N, P, Z), V(P, P, P, Z),
+		V(N, P, P, Z), V(N, N, P, Z), V(P, N, P, Z),
+
+		/* -X face */
+		V(N, P, P, X), V(N, P, N, X), V(N, N, N, X),
+		V(N, P, P, X), V(N, N, N, X), V(N, N, P, X),
+
+		/* -Y face */
+		V(P, N, P, Y), V(N, N, N, Y), V(P, N, N, Y),
+		V(P, N, P, Y), V(N, N, P, Y), V(N, N, N, Y),
+
+		/* -Z face */
+		V(N, P, N, Z), V(P, P, N, Z), V(P, N, N, Z),
+		V(N, P, N, Z), V(P, N, N, Z), V(N, N, N, Z),
+	};
+
+#undef X
+#undef Y
+#undef Z
+#undef N
+#undef P
+#undef V
+
+	unsigned i;
+
+
+	for (i = 0; i < Elements(p); i += 4) {
+		GLUvec4 n;
+		GLUvec4 t;
+		GLUvec4 uv;
+
+		n = GLUvec4(p[i + 0], 0.0, 0.0, 0.0);
+		t = GLUvec4(0.0, 0.0, p[i + 0], 0.0);
+		uv = GLUvec4((p[i + 2] + 1.0) * 0.5,
+			     (p[i + 1] + 1.0) * 0.5,
+			     0.0,
+			     0.0);
+		consumer->vertex(GLUvec4(p[i + 0], p[i + 1], 
+					 p[i + 2], p[i + 3]),
+				 n,
+				 t,
+				 uv);
+
+		n = GLUvec4(0.0, p[i + 1], 0.0, 0.0);
+		t = GLUvec4(p[i + 1], 0.0, 0.0, 0.0);
+		uv = GLUvec4((p[i + 0] + 1.0) * 0.5,
+			     (p[i + 2] + 1.0) * 0.5,
+			     0.0,
+			     0.0);
+		consumer->vertex(GLUvec4(p[i + 0], p[i + 1],
+					 p[i + 2], p[i + 3]),
+				 n,
+				 t,
+				 uv);
+
+		n = GLUvec4(0.0, 0.0, p[i + 2], 0.0);
+		t = GLUvec4(p[i + 2], 0.0, 0.0, 0.0);
+		uv = GLUvec4((p[i + 0] + 1.0) * 0.5,
+			     (p[i + 1] + 1.0) * 0.5,
+			     0.0,
+			     0.0);
+		consumer->vertex(GLUvec4(p[i + 0], p[i + 1],
+					 p[i + 2], p[i + 3]),
+				 n,
+				 t,
+				 uv);
+	}
+
+	consumer->begin_primitive(GL_TRIANGLES);
+
+	for (i = 0; i < Elements(elts); i++)
+		consumer->index(elts[i]);
+	
+	consumer->end_primitive();
+}