progs/egl/opengles1/tri.c

   1 /*
   2  * Copyright (C) 2008  Brian Paul   All Rights Reserved.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included
  12  * in all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  15  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
  18  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  19  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  20  */
  21
  22 /*
  23  * Draw a triangle with X/EGL and OpenGL ES 1.x
  24  * Brian Paul
  25  * 5 June 2008
  26  */
  27
  28 #define USE_FIXED_POINT 0
  29
  30
  31 #include <assert.h>
  32 #include <math.h>
  33 #include <stdio.h>
  34 #include <GLES/gl.h>  /* use OpenGL ES 1.x */
  35 #include <GLES/glext.h>
  36 #include <EGL/egl.h>
  37
  38 #include "eglut.h"
  39
  40
  41 #define FLOAT_TO_FIXED(X)   ((X) * 65535.0)
  42
  43
  44
  45 static GLfloat view_rotx = 0.0, view_roty = 0.0, view_rotz = 0.0;
  46
  47
  48 static void
  49 draw(void)
  50 {
  51 #if USE_FIXED_POINT
  52    static const GLfixed verts[3][2] = {
  53       { -65536, -65536 },
  54       {  65536, -65536 },
  55       {      0,  65536 }
  56    };
  57    static const GLfixed colors[3][4] = {
  58       { 65536,     0,     0,    65536 },
  59       {     0, 65536,     0 ,   65536},
  60       {     0,     0, 65536 ,   65536}
  61    };
  62 #else
  63    static const GLfloat verts[3][2] = {
  64       { -1, -1 },
  65       {  1, -1 },
  66       {  0,  1 }
  67    };
  68    static const GLfloat colors[3][4] = {
  69       { 1, 0, 0, 1 },
  70       { 0, 1, 0, 1 },
  71       { 0, 0, 1, 1 }
  72    };
  73 #endif
  74
  75    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  76
  77    glPushMatrix();
  78    glRotatef(view_rotx, 1, 0, 0);
  79    glRotatef(view_roty, 0, 1, 0);
  80    glRotatef(view_rotz, 0, 0, 1);
  81
  82    {
  83 #if USE_FIXED_POINT
  84       glVertexPointer(2, GL_FIXED, 0, verts);
  85       glColorPointer(4, GL_FIXED, 0, colors);
  86 #else
  87       glVertexPointer(2, GL_FLOAT, 0, verts);
  88       glColorPointer(4, GL_FLOAT, 0, colors);
  89 #endif
  90       glEnableClientState(GL_VERTEX_ARRAY);
  91       glEnableClientState(GL_COLOR_ARRAY);
  92
  93       /* draw triangle */
  94       glDrawArrays(GL_TRIANGLES, 0, 3);
  95
  96       /* draw some points */
  97       glPointSizex(FLOAT_TO_FIXED(15.5));
  98       glDrawArrays(GL_POINTS, 0, 3);
  99
 100       glDisableClientState(GL_VERTEX_ARRAY);
 101       glDisableClientState(GL_COLOR_ARRAY);
 102    }
 103
 104    if (0) {
 105       /* test code */
 106       GLfixed size;
 107       glGetFixedv(GL_POINT_SIZE, &size);
 108       printf("GL_POINT_SIZE = 0x%x %f\n", size, size / 65536.0);
 109    }
 110
 111    glPopMatrix();
 112 }
 113
 114
 115 /* new window size or exposure */
 116 static void
 117 reshape(int width, int height)
 118 {
 119    GLfloat ar = (GLfloat) width / (GLfloat) height;
 120
 121    glViewport(0, 0, (GLint) width, (GLint) height);
 122
 123    glMatrixMode(GL_PROJECTION);
 124    glLoadIdentity();
 125 #ifdef GL_VERSION_ES_CM_1_0
 126    glFrustumf(-ar, ar, -1, 1, 5.0, 60.0);
 127 #else
 128    glFrustum(-ar, ar, -1, 1, 5.0, 60.0);
 129 #endif
 130
 131    glMatrixMode(GL_MODELVIEW);
 132    glLoadIdentity();
 133    glTranslatef(0.0, 0.0, -10.0);
 134 }
 135
 136
 137 static void
 138 test_query_matrix(void)
 139 {
 140    PFNGLQUERYMATRIXXOESPROC procQueryMatrixx;
 141    typedef void (*voidproc)();
 142    GLfixed mantissa[16];
 143    GLint exponent[16];
 144    GLbitfield rv;
 145    int i;
 146
 147    procQueryMatrixx = (PFNGLQUERYMATRIXXOESPROC) eglGetProcAddress("glQueryMatrixxOES");
 148    assert(procQueryMatrixx);
 149    /* Actually try out this one */
 150    rv = (*procQueryMatrixx)(mantissa, exponent);
 151    for (i = 0; i < 16; i++) {
 152       if (rv & (1<<i)) {
 153         printf("matrix[%d] invalid\n", i);
 154       }
 155       else {
 156          printf("matrix[%d] = %f * 2^(%d)\n", i, mantissa[i]/65536.0, exponent[i]);
 157       }
 158    }
 159    assert(!eglGetProcAddress("glFoo"));
 160 }
 161
 162
 163 static void
 164 init(void)
 165 {
 166    glClearColor(0.4, 0.4, 0.4, 0.0);
 167
 168    if (0)
 169       test_query_matrix();
 170 }
 171
 172 static void
 173 special_key(int special)
 174 {
 175    switch (special) {
 176    case EGLUT_KEY_LEFT:
 177       view_roty += 5.0;
 178       break;
 179    case EGLUT_KEY_RIGHT:
 180       view_roty -= 5.0;
 181       break;
 182    case EGLUT_KEY_UP:
 183       view_rotx += 5.0;
 184       break;
 185    case EGLUT_KEY_DOWN:
 186       view_rotx -= 5.0;
 187       break;
 188    default:
 189       break;
 190    }
 191 }
 192
 193 int
 194 main(int argc, char *argv[])
 195 {
 196    eglutInitWindowSize(300, 300);
 197    eglutInitAPIMask(EGLUT_OPENGL_ES1_BIT);
 198    eglutInit(argc, argv);
 199
 200    eglutCreateWindow("tri");
 201
 202    eglutReshapeFunc(reshape);
 203    eglutDisplayFunc(draw);
 204    eglutSpecialFunc(special_key);
 205
 206    init();
 207
 208    eglutMainLoop();
 209
 210    return 0;
 211 }