Add generic routines to generate triangle strip elements for rectangular meshes

3 files changed, 128 insertions, 1 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index b84e560..736ee5c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -24,7 +24,7 @@ AM_CXXFLAGS=-I../include
 AM_CFLAGS=-I../include
 
 lib_LIBRARIES = libGLU3.a
-libGLU3_a_SOURCES = matrix.c load_text.c arcball.c revolve.c
+libGLU3_a_SOURCES = matrix.c load_text.c arcball.c revolve.c mesh.c
 
 libGLU3includedir = ${includedir}
 libGLU3include_HEADERS = ../include/glu3.h ../include/glu3_scalar.h
diff --git a/src/mesh.c b/src/mesh.c
new file mode 100644
index 0000000..603570b
--- /dev/null
+++ b/src/mesh.c
@@ -0,0 +1,49 @@
+/*
+ * 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 "mesh.h"
+
+void
+generate_triangle_mesh(unsigned rows, unsigned cols, unsigned width, 
+		       mesh_begin_cb *begin_cb, 
+		       mesh_index_cb *index_cb, 
+		       mesh_end_cb *end_cb, 
+		       void *data)
+{
+	unsigned i;
+	unsigned j;
+
+	for (i = 0; i < rows; i++) {
+		(*begin_cb)(data, GL_TRIANGLE_STRIP);
+
+		for (j = 0; j < cols; j++) {
+			const unsigned e0 = ((i + 0) * width) + j;
+			const unsigned e1 = ((i + 1) * width) + j;
+
+			(*index_cb)(data, e0);
+			(*index_cb)(data, e1);
+		}
+
+		(*end_cb)(data);
+	}
+}
diff --git a/src/mesh.h b/src/mesh.h
new file mode 100644
index 0000000..41cbbba
--- /dev/null
+++ b/src/mesh.h
@@ -0,0 +1,78 @@
+/*
+ * 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"
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+typedef void (mesh_begin_cb)(void *data, GLenum mode);
+typedef void (mesh_index_cb)(void *data, unsigned index);
+typedef void (mesh_end_cb)(void *data);
+
+/**
+ * Generate indexed drawing primitives for a rectangular mesh.
+ *
+ * Generates a sequence of \c GL_TRANGLE_STRIP primitives to draw a rectangular
+ * mesh with the specified parameters.  Each triangle strip generated will be
+ * of the form:
+ *
+ * (i*width)+0, ((i+1) *width)+0, (i*width)+1, ((i+1) *width)+1, ...
+ * (i*width)+(cols-1), ((i+1) *width)+(cols-1)
+ *
+ * where \c i is the index of the row being generated, starting from 0.
+ *
+ * The triangle strips are generated in row-major order.
+ *
+ * \param rows      Number of rows of primitives in the mesh.  This value must
+ *                  be at least 1.  Note that if there are \c rows of
+ *                  primitives, there must be at least \c rows + 1 of vertices.
+ * \param cols      Number of columns of primitives in the mesh.  This value
+ *                  must be at least 1.  Note that if there are \c cols of
+ *                  primitives, there must be at least \c cols + 1 of vertices.
+ * \param width     Width, in vertices, of the underlying mesh data.  If
+ *                  \c width is greater than \c cols, data for a submesh within
+ *                  a larger primitive can be generated.  If \c width is less
+ *                  than \c cols, the results are undefined (and probably
+ *                  wrong).
+ * \param begin_cb  Call-back used to begin a new primitive.
+ * \param index_cb  Call-back used for each index within a primitive.  This
+ *                  will be called 2 * \c cols times between each call to
+ *                  \c begin_cb and \c end_cb.
+ * \param end_cb    Call-back used to end a primitive.
+ * \param data      User-supplied data pointer passed to the various call-back
+ *                  functions.
+ *
+ * \sa glDrawMeshArraysSUN
+ */
+extern void
+generate_triangle_mesh(unsigned rows, unsigned cols, unsigned width, 
+		       mesh_begin_cb *begin_cb, 
+		       mesh_index_cb *index_cb, 
+		       mesh_end_cb *end_cb, 
+		       void *data);
+
+#ifdef __cplusplus
+};
+#endif