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/*
* 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"
#define Elements(a) (sizeof(a) / sizeof(a[0]))
unsigned
GLUmeshProducer::vertex_count(void) const
{
return 0;
}
unsigned
GLUmeshProducer::element_count(void) const
{
return this->rows * (2 * (this->columns + 1));
}
unsigned
GLUmeshProducer::primitive_count(void) const
{
return 1;
}
#define EMIT_ELT(e) \
do { \
elts[count] = (e) + base_vertex; \
count++; \
if (count >= Elements(elts)) { \
consumer->index_batch(elts, count); \
count = 0; \
} \
} while (0)
void
GLUmeshProducer::generate(GLUshapeConsumer *consumer,
unsigned base_vertex) const
{
unsigned elts[64];
unsigned count = 0;
unsigned i;
int j;
consumer->begin_primitive(GL_TRIANGLE_STRIP, this->element_count());
for (i = 0; i < this->rows; i++) {
if ((i & 1) == 0) {
for (j = 0; j < (int)this->columns; j++) {
const unsigned e0 = ((i + 0) * this->width) + j;
const unsigned e1 = ((i + 1) * this->width) + j;
EMIT_ELT(e0);
EMIT_ELT(e1);
}
EMIT_ELT((this->columns - 1) + ((i + 1) * this->width));
} else {
for (j = this->columns - 1; j >= 0; j--) {
const unsigned e0 = ((i + 0) * this->width) + j;
const unsigned e1 = ((i + 1) * this->width) + j;
EMIT_ELT(e0);
EMIT_ELT(e1);
}
EMIT_ELT((i + 1) * this->width);
}
}
if (count != 0)
consumer->index_batch(elts, count);
consumer->end_primitive();
}
void
GLUmeshProducer::generate(GLUshapeConsumer *consumer) const
{
this->generate(consumer, 0);
}
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