pyramid.c

   1 /**
   2  * @file pyramid.c
   3  * @brief The pyramid module.
   4  *
   5  * Copyright 2001, 2008 David Ashley  <dashxdr@gmail.com>
   6  * Copyright 2008 Stephen M. Webb  <stephen.webb@bregmasoft.ca>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of Version 2 of the GNU General Public License as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21 #include "pyramid.h"
  22
  23 #if defined(_WIN32) && !defined(__CYGWIN__)
  24 # define WIN32_LEAN_AND_MEAN 1
  25 # include <windows.h>
  26 #endif
  27
  28 #include <GL/gl.h>
  29 #include "vbo.h"
  30
  31 static const int row_width = (3*2);
  32 static const int bottom_vertex_count = 4;
  33 static const int side_vertex_count = 6;
  34 #define stride (row_width * sizeof(GLfloat))
  35
  36 static GLuint vbo;
  37
  38
  39 static void create(float size)
  40 {
  41         GLfloat pyramid[] = {
  42                  /* bottom */
  43                  0.0f, -1.0f,  0.0f,  size, -size,  size,
  44                  0.0f, -1.0f,  0.0f,  size, -size, -size,
  45                  0.0f, -1.0f,  0.0f, -size, -size, -size,
  46                  0.0f, -1.0f,  0.0f, -size, -size,  size,
  47                  /* sides */
  48                  0.0f,  1.0f,  0.0f,  0.0f,  size,  0.0f,
  49                  1.0f, -1.0f,  1.0f,  size, -size,  size,
  50                  1.0f, -1.0f, -1.0f,  size, -size, -size,
  51                 -1.0f, -1.0f, -1.0f, -size, -size, -size,
  52                 -1.0f, -1.0f,  1.0f, -size, -size,  size,
  53                  1.0f, -1.0f,  1.0f,  size, -size,  size
  54         };
  55         glGenBuffers(1, &vbo);
  56         glBindBuffer(GL_ARRAY_BUFFER, vbo);
  57         glBufferData(GL_ARRAY_BUFFER, sizeof(pyramid), pyramid, GL_STATIC_DRAW);
  58         glBindBuffer(GL_ARRAY_BUFFER, 0);
  59 }
  60
  61
  62 static void draw(void)
  63 {
  64         GLfloat *pyramid_normals = 0;
  65         GLfloat *pyramid_verteces = pyramid_normals + 3;
  66         glEnable(GL_NORMALIZE);
  67         glEnableClientState(GL_VERTEX_ARRAY);
  68         glEnableClientState(GL_NORMAL_ARRAY);
  69         glBindBuffer(GL_ARRAY_BUFFER, vbo);
  70         glNormalPointer(GL_FLOAT, stride, pyramid_normals);
  71         glVertexPointer(3, GL_FLOAT, stride, pyramid_verteces);
  72         glDrawArrays(GL_TRIANGLE_FAN, 0, bottom_vertex_count);
  73         glDrawArrays(GL_TRIANGLE_FAN, bottom_vertex_count, side_vertex_count);
  74         glBindBuffer(GL_ARRAY_BUFFER, 0);
  75         glDisableClientState(GL_NORMAL_ARRAY);
  76         glDisableClientState(GL_VERTEX_ARRAY);
  77         glDisable(GL_NORMALIZE);
  78 }
  79
  80
  81 static char* name(void)
  82 {
  83         return "pyramid";
  84 }
  85
  86
  87 void create_pyramid(shape* shape)
  88 {
  89         shape->create = create;
  90         shape->draw = draw;
  91         shape->name = name;
  92 }
  93
  94
  95 void makepyramid(float size)
  96 {
  97         GLfloat pyramid[] = {
  98                  /* bottom */
  99                  0.0f, -1.0f,  0.0f,  size, -size,  size,
 100                  0.0f, -1.0f,  0.0f,  size, -size, -size,
 101                  0.0f, -1.0f,  0.0f, -size, -size, -size,
 102                  0.0f, -1.0f,  0.0f, -size, -size,  size,
 103                  /* sides */
 104                  0.0f,  1.0f,  0.0f,  0.0f,  size,  0.0f,
 105                  1.0f, -1.0f,  1.0f,  size, -size,  size,
 106                  1.0f, -1.0f, -1.0f,  size, -size, -size,
 107                 -1.0f, -1.0f, -1.0f, -size, -size, -size,
 108                 -1.0f, -1.0f,  1.0f, -size, -size,  size,
 109                  1.0f, -1.0f,  1.0f,  size, -size,  size
 110         };
 111
 112         const GLfloat *pyramid_normals = pyramid;
 113         const GLfloat *pyramid_verteces = pyramid_normals + 3;
 114
 115         glEnable(GL_NORMALIZE);
 116         glEnableClientState(GL_VERTEX_ARRAY);
 117         glEnableClientState(GL_NORMAL_ARRAY);
 118
 119         glNormalPointer(GL_FLOAT, stride, pyramid_normals);
 120         glVertexPointer(3, GL_FLOAT, stride, pyramid_verteces);
 121         glDrawArrays(GL_TRIANGLE_FAN, 0, bottom_vertex_count);
 122         glDrawArrays(GL_TRIANGLE_FAN, bottom_vertex_count, side_vertex_count);
 123         glDisableClientState(GL_NORMAL_ARRAY);
 124         glDisableClientState(GL_VERTEX_ARRAY);
 125 }
 126
 127