422 lines
12 KiB
C
422 lines
12 KiB
C
/*
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* Copyright (C) 1999-2001 Brian Paul All Rights Reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a
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* copy of this software and associated documentation files (the "Software"),
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* to deal in the Software without restriction, including without limitation
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* the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included
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* in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
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* AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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/*
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* Ported to GLES2.
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* Kristian Høgsberg <krh@bitplanet.net>
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* May 3, 2010
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*/
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/*
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* Command line options:
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* -info print GL implementation information
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*
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*/
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#define GL_GLEXT_PROTOTYPES
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#define EGL_EGLEXT_PROTOTYPES
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#include <math.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <sys/time.h>
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#include <unistd.h>
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#include <GLES2/gl2.h>
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#include <EGL/egl.h>
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#include <EGL/eglext.h>
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#include "eglut.h"
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struct gear {
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GLfloat *vertices;
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GLuint vbo;
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int count;
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};
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static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
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static struct gear *gear1, *gear2, *gear3;
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static GLfloat angle = 0.0;
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static GLuint proj_location, light_location, color_location;
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static GLfloat proj[16];
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static GLfloat *
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vert(GLfloat *p, GLfloat x, GLfloat y, GLfloat z, GLfloat *n)
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{
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p[0] = x;
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p[1] = y;
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p[2] = z;
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p[3] = n[0];
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p[4] = n[1];
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p[5] = n[2];
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return p + 6;
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}
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/* Draw a gear wheel. You'll probably want to call this function when
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* building a display list since we do a lot of trig here.
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*
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* Input: inner_radius - radius of hole at center
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* outer_radius - radius at center of teeth
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* width - width of gear
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* teeth - number of teeth
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* tooth_depth - depth of tooth
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*/
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static struct gear *
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gear(GLfloat inner_radius, GLfloat outer_radius, GLfloat width,
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GLint teeth, GLfloat tooth_depth)
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{
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GLint i;
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GLfloat r0, r1, r2;
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GLfloat da;
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GLfloat *p, *v;
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struct gear *gear;
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double s[5], c[5];
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GLfloat verts[3 * 14], normal[3];
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const int tris_per_tooth = 20;
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gear = malloc(sizeof *gear);
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if (gear == NULL)
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return NULL;
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r0 = inner_radius;
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r1 = outer_radius - tooth_depth / 2.0;
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r2 = outer_radius + tooth_depth / 2.0;
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da = 2.0 * M_PI / teeth / 4.0;
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gear->vertices = calloc(teeth * tris_per_tooth * 3 * 6,
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sizeof *gear->vertices);
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s[4] = 0;
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c[4] = 1;
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v = gear->vertices;
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for (i = 0; i < teeth; i++) {
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s[0] = s[4];
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c[0] = c[4];
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sincos(i * 2.0 * M_PI / teeth + da, &s[1], &c[1]);
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sincos(i * 2.0 * M_PI / teeth + da * 2, &s[2], &c[2]);
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sincos(i * 2.0 * M_PI / teeth + da * 3, &s[3], &c[3]);
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sincos(i * 2.0 * M_PI / teeth + da * 4, &s[4], &c[4]);
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normal[0] = 0.0;
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normal[1] = 0.0;
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normal[2] = 1.0;
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v = vert(v, r2 * c[1], r2 * s[1], width * 0.5, normal);
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v = vert(v, r2 * c[1], r2 * s[1], width * 0.5, normal);
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v = vert(v, r2 * c[2], r2 * s[2], width * 0.5, normal);
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v = vert(v, r1 * c[0], r1 * s[0], width * 0.5, normal);
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v = vert(v, r1 * c[3], r1 * s[3], width * 0.5, normal);
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v = vert(v, r0 * c[0], r0 * s[0], width * 0.5, normal);
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v = vert(v, r1 * c[4], r1 * s[4], width * 0.5, normal);
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v = vert(v, r0 * c[4], r0 * s[4], width * 0.5, normal);
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v = vert(v, r0 * c[4], r0 * s[4], width * 0.5, normal);
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v = vert(v, r0 * c[0], r0 * s[0], width * 0.5, normal);
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v = vert(v, r0 * c[4], r0 * s[4], -width * 0.5, normal);
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v = vert(v, r0 * c[0], r0 * s[0], -width * 0.5, normal);
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normal[0] = 0.0;
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normal[1] = 0.0;
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normal[2] = -1.0;
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v = vert(v, r0 * c[4], r0 * s[4], -width * 0.5, normal);
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v = vert(v, r0 * c[4], r0 * s[4], -width * 0.5, normal);
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v = vert(v, r1 * c[4], r1 * s[4], -width * 0.5, normal);
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v = vert(v, r0 * c[0], r0 * s[0], -width * 0.5, normal);
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v = vert(v, r1 * c[3], r1 * s[3], -width * 0.5, normal);
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v = vert(v, r1 * c[0], r1 * s[0], -width * 0.5, normal);
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v = vert(v, r2 * c[2], r2 * s[2], -width * 0.5, normal);
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v = vert(v, r2 * c[1], r2 * s[1], -width * 0.5, normal);
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v = vert(v, r1 * c[0], r1 * s[0], width * 0.5, normal);
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v = vert(v, r1 * c[0], r1 * s[0], width * 0.5, normal);
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v = vert(v, r1 * c[0], r1 * s[0], -width * 0.5, normal);
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v = vert(v, r2 * c[1], r2 * s[1], width * 0.5, normal);
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v = vert(v, r2 * c[1], r2 * s[1], -width * 0.5, normal);
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v = vert(v, r2 * c[2], r2 * s[2], width * 0.5, normal);
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v = vert(v, r2 * c[2], r2 * s[2], -width * 0.5, normal);
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v = vert(v, r1 * c[3], r1 * s[3], width * 0.5, normal);
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v = vert(v, r1 * c[3], r1 * s[3], -width * 0.5, normal);
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v = vert(v, r1 * c[4], r1 * s[4], width * 0.5, normal);
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v = vert(v, r1 * c[4], r1 * s[4], -width * 0.5, normal);
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v = vert(v, r1 * c[4], r1 * s[4], -width * 0.5, normal);
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}
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gear->count = (v - gear->vertices) / 6;
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glGenBuffers(1, &gear->vbo);
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glBindBuffer(GL_ARRAY_BUFFER, gear->vbo);
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glBufferData(GL_ARRAY_BUFFER, gear->count * 6 * 4,
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gear->vertices, GL_STATIC_DRAW);
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return gear;
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}
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static void
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multiply(GLfloat *m, const GLfloat *n)
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{
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GLfloat tmp[16];
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const GLfloat *row, *column;
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div_t d;
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int i, j;
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for (i = 0; i < 16; i++) {
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tmp[i] = 0;
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d = div(i, 4);
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row = n + d.quot * 4;
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column = m + d.rem;
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for (j = 0; j < 4; j++)
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tmp[i] += row[j] * column[j * 4];
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}
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memcpy(m, &tmp, sizeof tmp);
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}
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static void
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rotate(GLfloat *m, GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
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{
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double s, c;
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sincos(angle, &s, &c);
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GLfloat r[16] = {
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x * x * (1 - c) + c, y * x * (1 - c) + z * s, x * z * (1 - c) - y * s, 0,
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x * y * (1 - c) - z * s, y * y * (1 - c) + c, y * z * (1 - c) + x * s, 0,
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x * z * (1 - c) + y * s, y * z * (1 - c) - x * s, z * z * (1 - c) + c, 0,
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0, 0, 0, 1
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};
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multiply(m, r);
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}
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static void
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translate(GLfloat *m, GLfloat x, GLfloat y, GLfloat z)
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{
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GLfloat t[16] = { 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, x, y, z, 1 };
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multiply(m, t);
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}
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static const GLfloat light[3] = { 1.0, 1.0, -1.0 };
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static void
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draw_gear(struct gear *gear, GLfloat *m,
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GLfloat x, GLfloat y, GLfloat angle, const GLfloat *color)
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{
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GLfloat tmp[16];
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memcpy(tmp, m, sizeof tmp);
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translate(tmp, x, y, 0);
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rotate(tmp, 2 * M_PI * angle / 360.0, 0, 0, 1);
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glUniformMatrix4fv(proj_location, 1, GL_FALSE, tmp);
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glUniform3fv(light_location, 1, light);
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glUniform4fv(color_location, 1, color);
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glBindBuffer(GL_ARRAY_BUFFER, gear->vbo);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE,
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6 * sizeof(GLfloat), NULL);
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glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE,
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6 * sizeof(GLfloat), (GLfloat *) 0 + 3);
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glEnableVertexAttribArray(0);
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glEnableVertexAttribArray(1);
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glDrawArrays(GL_TRIANGLE_STRIP, 0, gear->count);
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}
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static void
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gears_draw(void)
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{
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const static GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
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const static GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
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const static GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };
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GLfloat m[16];
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glClearColor(0.0, 0.0, 0.0, 0.0);
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glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
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memcpy(m, proj, sizeof m);
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rotate(m, 2 * M_PI * view_rotx / 360.0, 1, 0, 0);
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rotate(m, 2 * M_PI * view_roty / 360.0, 0, 1, 0);
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rotate(m, 2 * M_PI * view_rotz / 360.0, 0, 0, 1);
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draw_gear(gear1, m, -3.0, -2.0, angle, red);
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draw_gear(gear2, m, 3.1, -2.0, -2 * angle - 9.0, green);
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draw_gear(gear3, m, -3.1, 4.2, -2 * angle - 25.0, blue);
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}
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/* new window size or exposure */
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static void
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gears_reshape(int width, int height)
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{
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GLfloat ar, m[16] = {
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1.0, 0.0, 0.0, 0.0,
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0.0, 1.0, 0.0, 0.0,
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0.0, 0.0, 0.1, 0.0,
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0.0, 0.0, 0.0, 1.0,
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};
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if (width < height)
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ar = width;
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else
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ar = height;
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m[0] = 0.1 * ar / width;
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m[5] = 0.1 * ar / height;
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memcpy(proj, m, sizeof proj);
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glViewport(0, 0, (GLint) width, (GLint) height);
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}
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static void
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gears_special(int special)
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{
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switch (special) {
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case EGLUT_KEY_LEFT:
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view_roty += 5.0;
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break;
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case EGLUT_KEY_RIGHT:
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view_roty -= 5.0;
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break;
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case EGLUT_KEY_UP:
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view_rotx += 5.0;
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break;
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case EGLUT_KEY_DOWN:
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view_rotx -= 5.0;
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break;
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}
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}
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static void
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gears_idle(void)
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{
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static double tRot0 = -1.0;
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double dt, t = eglutGet(EGLUT_ELAPSED_TIME) / 1000.0;
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if (tRot0 < 0.0)
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tRot0 = t;
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dt = t - tRot0;
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tRot0 = t;
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/* advance rotation for next frame */
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angle += 70.0 * dt; /* 70 degrees per second */
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if (angle > 3600.0)
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angle -= 3600.0;
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eglutPostRedisplay();
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}
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static const char vertex_shader[] =
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"uniform mat4 proj;\n"
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"attribute vec4 position;\n"
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"attribute vec4 normal;\n"
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"varying vec3 rotated_normal;\n"
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"varying vec3 rotated_position;\n"
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"vec4 tmp;\n"
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"void main()\n"
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"{\n"
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" gl_Position = proj * position;\n"
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" rotated_position = gl_Position.xyz;\n"
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" tmp = proj * normal;\n"
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" rotated_normal = tmp.xyz;\n"
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"}\n";
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static const char fragment_shader[] =
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//"precision mediump float;\n"
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"uniform vec4 color;\n"
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"uniform vec3 light;\n"
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"varying vec3 rotated_normal;\n"
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"varying vec3 rotated_position;\n"
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"vec3 light_direction;\n"
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"vec4 white = vec4(1.0, 1.0, 1.0, 1.0);\n"
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"void main()\n"
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"{\n"
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" light_direction = normalize(light - rotated_position);\n"
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" gl_FragColor = color + white * dot(light_direction, rotated_normal);\n"
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"}\n";
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static void
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gears_init(void)
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{
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GLuint v, f, program;
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const char *p;
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char msg[512];
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glEnable(GL_CULL_FACE);
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glEnable(GL_DEPTH_TEST);
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p = vertex_shader;
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v = glCreateShader(GL_VERTEX_SHADER);
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glShaderSource(v, 1, &p, NULL);
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glCompileShader(v);
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glGetShaderInfoLog(v, sizeof msg, NULL, msg);
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printf("vertex shader info: %s\n", msg);
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p = fragment_shader;
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f = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(f, 1, &p, NULL);
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glCompileShader(f);
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glGetShaderInfoLog(f, sizeof msg, NULL, msg);
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printf("fragment shader info: %s\n", msg);
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program = glCreateProgram();
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glAttachShader(program, v);
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glAttachShader(program, f);
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glBindAttribLocation(program, 0, "position");
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glBindAttribLocation(program, 1, "normal");
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glLinkProgram(program);
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glGetProgramInfoLog(program, sizeof msg, NULL, msg);
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printf("info: %s\n", msg);
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glUseProgram(program);
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proj_location = glGetUniformLocation(program, "proj");
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light_location = glGetUniformLocation(program, "light");
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color_location = glGetUniformLocation(program, "color");
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/* make the gears */
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gear1 = gear(1.0, 4.0, 1.0, 20, 0.7);
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gear2 = gear(0.5, 2.0, 2.0, 10, 0.7);
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gear3 = gear(1.3, 2.0, 0.5, 10, 0.7);
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}
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int
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main(int argc, char *argv[])
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{
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eglutInitWindowSize(300, 300);
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eglutInitAPIMask(EGLUT_OPENGL_ES2_BIT);
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eglutInit(argc, argv);
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eglutCreateWindow("es2gears");
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eglutIdleFunc(gears_idle);
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eglutReshapeFunc(gears_reshape);
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eglutDisplayFunc(gears_draw);
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eglutSpecialFunc(gears_special);
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gears_init();
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eglutMainLoop();
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return 0;
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}
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