progs/egl: Port ES1 gears to eglut.

As gears in the last demo under "screen" subdirectory, this also removes
the directory.

1 files changed, 383 insertions, 0 deletions

diff --git a/progs/egl/opengles1/gears.c b/progs/egl/opengles1/gears.c
new file mode 100644
index 00000000000..8462a4871a7
--- /dev/null
+++ b/progs/egl/opengles1/gears.c
@@ -0,0 +1,383 @@
+/*
+ * Copyright (C) 2009 Chia-I Wu <[email protected]>
+ *
+ * Based on eglgears by
+ * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
+ *
+ * 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 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
+ * BRIAN PAUL 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 <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <assert.h>
+
+#include <GLES/gl.h>
+#include "eglut.h"
+
+#ifndef M_PI
+#define M_PI 3.14159265
+#endif
+
+
+struct gear {
+   GLuint vbo;
+   GLfloat *vertices;
+   GLsizei stride;
+
+   GLint num_teeth;
+};
+
+static GLfloat view_rotx = 20.0, view_roty = 30.0, view_rotz = 0.0;
+static struct gear gears[3];
+static GLfloat angle = 0.0;
+
+/*
+ *  Initialize a gear wheel.
+ *
+ *  Input:  gear - gear to initialize
+ *          inner_radius - radius of hole at center
+ *          outer_radius - radius at center of teeth
+ *          width - width of gear
+ *          teeth - number of teeth
+ *          tooth_depth - depth of tooth
+ */
+static void
+init_gear(struct gear *gear, GLfloat inner_radius, GLfloat outer_radius,
+          GLfloat width, GLint teeth, GLfloat tooth_depth)
+{
+   GLfloat r0, r1, r2;
+   GLfloat a0, da;
+   GLint verts_per_tooth, total_verts, total_size;
+   GLint count, i;
+   GLfloat *verts;
+
+   r0 = inner_radius;
+   r1 = outer_radius - tooth_depth / 2.0;
+   r2 = outer_radius + tooth_depth / 2.0;
+
+   a0 = 2.0 * M_PI / teeth;
+   da = a0 / 4.0;
+
+   gear->vbo = 0;
+   gear->vertices = NULL;
+   gear->stride = sizeof(GLfloat) * 6; /* XYZ + normal */
+   gear->num_teeth = teeth;
+
+   verts_per_tooth = 10 + 4;
+   total_verts = teeth * verts_per_tooth;
+   total_size = total_verts * gear->stride;
+
+   verts = malloc(total_size);
+   if (!verts) {
+      printf("failed to allocate vertices\n");
+      return;
+   }
+
+#define GEAR_VERT(r, n, sign)                      \
+   do {                                            \
+      verts[count * 6 + 0] = (r) * vx[n];          \
+      verts[count * 6 + 1] = (r) * vy[n];          \
+      verts[count * 6 + 2] = (sign) * width * 0.5; \
+      verts[count * 6 + 3] = normal[0];            \
+      verts[count * 6 + 4] = normal[1];            \
+      verts[count * 6 + 5] = normal[2];            \
+      count++;                                     \
+   } while (0)
+
+   count = 0;
+   for (i = 0; i < teeth; i++) {
+      GLfloat normal[3];
+      GLfloat vx[5], vy[5];
+      GLfloat u, v;
+
+      normal[0] = 0.0;
+      normal[1] = 0.0;
+      normal[2] = 0.0;
+
+      vx[0] = cos(i * a0 + 0 * da);
+      vy[0] = sin(i * a0 + 0 * da);
+      vx[1] = cos(i * a0 + 1 * da);
+      vy[1] = sin(i * a0 + 1 * da);
+      vx[2] = cos(i * a0 + 2 * da);
+      vy[2] = sin(i * a0 + 2 * da);
+      vx[3] = cos(i * a0 + 3 * da);
+      vy[3] = sin(i * a0 + 3 * da);
+      vx[4] = cos(i * a0 + 4 * da);
+      vy[4] = sin(i * a0 + 4 * da);
+
+      /* outward faces of a tooth, 10 verts */
+      normal[0] = vx[0];
+      normal[1] = vy[0];
+      GEAR_VERT(r1, 0,  1);
+      GEAR_VERT(r1, 0, -1);
+
+      u = r2 * vx[1] - r1 * vx[0];
+      v = r2 * vy[1] - r1 * vy[0];
+      normal[0] = v;
+      normal[1] = -u;
+      GEAR_VERT(r2, 1,  1);
+      GEAR_VERT(r2, 1, -1);
+
+      normal[0] = vx[0];
+      normal[1] = vy[0];
+      GEAR_VERT(r2, 2,  1);
+      GEAR_VERT(r2, 2, -1);
+
+      u = r1 * vx[3] - r2 * vx[2];
+      v = r1 * vy[3] - r2 * vy[2];
+      normal[0] = v;
+      normal[1] = -u;
+      GEAR_VERT(r1, 3,  1);
+      GEAR_VERT(r1, 3, -1);
+
+      normal[0] = vx[0];
+      normal[1] = vy[0];
+      GEAR_VERT(r1, 4,  1);
+      GEAR_VERT(r1, 4, -1);
+
+      /* inside radius cylinder, 4 verts */
+      normal[0] = -vx[4];
+      normal[1] = -vy[4];
+      GEAR_VERT(r0, 4,  1);
+      GEAR_VERT(r0, 4, -1);
+
+      normal[0] = -vx[0];
+      normal[1] = -vy[0];
+      GEAR_VERT(r0, 0,  1);
+      GEAR_VERT(r0, 0, -1);
+
+      assert(count % verts_per_tooth == 0);
+   }
+   assert(count == total_verts);
+#undef GEAR_VERT
+
+   gear->vertices = verts;
+
+   /* setup VBO */
+   glGenBuffers(1, &gear->vbo);
+   if (gear->vbo) {
+      glBindBuffer(GL_ARRAY_BUFFER, gear->vbo);
+      glBufferData(GL_ARRAY_BUFFER, total_size, verts, GL_STATIC_DRAW);
+   }
+}
+
+
+static void
+draw_gear(const struct gear *gear)
+{
+   GLint i;
+
+   if (!gear->vbo && !gear->vertices) {
+      printf("nothing to be drawn\n");
+      return;
+   }
+
+   if (gear->vbo) {
+      glBindBuffer(GL_ARRAY_BUFFER, gear->vbo);
+      glVertexPointer(3, GL_FLOAT, gear->stride, (const GLvoid *) 0);
+      glNormalPointer(GL_FLOAT, gear->stride, (const GLvoid *) (sizeof(GLfloat) * 3));
+   } else {
+      glBindBuffer(GL_ARRAY_BUFFER, 0);
+      glVertexPointer(3, GL_FLOAT, gear->stride, gear->vertices);
+      glNormalPointer(GL_FLOAT, gear->stride, gear->vertices + 3);
+   }
+
+   glEnableClientState(GL_VERTEX_ARRAY);
+
+   for (i = 0; i < gear->num_teeth; i++) {
+      const GLint base = (10 + 4) * i;
+      GLushort indices[7];
+
+      glShadeModel(GL_FLAT);
+
+      /* front face */
+      indices[0] = base + 12;
+      indices[1] = base +  0;
+      indices[2] = base +  2;
+      indices[3] = base +  4;
+      indices[4] = base +  6;
+      indices[5] = base +  8;
+      indices[6] = base + 10;
+
+      glNormal3f(0.0, 0.0, 1.0);
+      glDrawElements(GL_TRIANGLE_FAN, 7, GL_UNSIGNED_SHORT, indices);
+
+      /* back face */
+      indices[0] = base + 13;
+      indices[1] = base + 11;
+      indices[2] = base +  9;
+      indices[3] = base +  7;
+      indices[4] = base +  5;
+      indices[5] = base +  3;
+      indices[6] = base +  1;
+
+      glNormal3f(0.0, 0.0, -1.0);
+      glDrawElements(GL_TRIANGLE_FAN, 7, GL_UNSIGNED_SHORT, indices);
+
+      glEnableClientState(GL_NORMAL_ARRAY);
+
+      /* outward face of a tooth */
+      glDrawArrays(GL_TRIANGLE_STRIP, base, 10);
+
+      /* inside radius cylinder */
+      glShadeModel(GL_SMOOTH);
+      glDrawArrays(GL_TRIANGLE_STRIP, base + 10, 4);
+
+      glDisableClientState(GL_NORMAL_ARRAY);
+   }
+
+   glDisableClientState(GL_VERTEX_ARRAY);
+}
+
+
+static void
+gears_draw(void)
+{
+   static const GLfloat red[4] = { 0.8, 0.1, 0.0, 1.0 };
+   static const GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
+   static const GLfloat blue[4] = { 0.2, 0.2, 1.0, 1.0 };
+
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   glPushMatrix();
+   glRotatef(view_rotx, 1.0, 0.0, 0.0);
+   glRotatef(view_roty, 0.0, 1.0, 0.0);
+   glRotatef(view_rotz, 0.0, 0.0, 1.0);
+
+   glPushMatrix();
+   glTranslatef(-3.0, -2.0, 0.0);
+   glRotatef(angle, 0.0, 0.0, 1.0);
+
+   glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, red);
+   draw_gear(&gears[0]);
+
+   glPopMatrix();
+
+   glPushMatrix();
+   glTranslatef(3.1, -2.0, 0.0);
+   glRotatef(-2.0 * angle - 9.0, 0.0, 0.0, 1.0);
+
+   glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, green);
+   draw_gear(&gears[1]);
+
+   glPopMatrix();
+
+   glPushMatrix();
+   glTranslatef(-3.1, 4.2, 0.0);
+   glRotatef(-2.0 * angle - 25.0, 0.0, 0.0, 1.0);
+
+   glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, blue);
+   draw_gear(&gears[2]);
+
+   glPopMatrix();
+
+   glPopMatrix();
+}
+
+
+static void gears_fini(void)
+{
+   GLint i;
+   for (i = 0; i < 3; i++) {
+      struct gear *gear = &gears[i];
+      if (gear->vbo) {
+         glDeleteBuffers(1, &gear->vbo);
+         gear->vbo = 0;
+      }
+      if (gear->vertices) {
+         free(gear->vertices);
+         gear->vertices = NULL;
+      }
+   }
+}
+
+
+static void gears_init(void)
+{
+   static const GLfloat pos[4] = { 5.0, 5.0, 10.0, 0.0 };
+
+   glLightfv(GL_LIGHT0, GL_POSITION, pos);
+   glEnable(GL_CULL_FACE);
+   glEnable(GL_LIGHTING);
+   glEnable(GL_LIGHT0);
+   glEnable(GL_DEPTH_TEST);
+   glEnable(GL_NORMALIZE);
+
+   init_gear(&gears[0], 1.0, 4.0, 1.0, 20, 0.7);
+   init_gear(&gears[1], 0.5, 2.0, 2.0, 10, 0.7);
+   init_gear(&gears[2], 1.3, 2.0, 0.5, 10, 0.7);
+}
+
+
+/* new window size or exposure */
+static void
+gears_reshape(int width, int height)
+{
+   GLfloat h = (GLfloat) height / (GLfloat) width;
+
+   glViewport(0, 0, (GLint) width, (GLint) height);
+
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustumf(-1.0, 1.0, -h, h, 5.0, 60.0);
+
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0, 0.0, -40.0);
+}
+
+
+static void
+gears_idle(void)
+{
+  static double t0 = -1.;
+  double dt, t = eglutGet(EGLUT_ELAPSED_TIME) / 1000.0;
+  if (t0 < 0.0)
+    t0 = t;
+  dt = t - t0;
+  t0 = t;
+
+  angle += 70.0 * dt;  /* 70 degrees per second */
+  angle = fmod(angle, 360.0); /* prevents eventual overflow */
+
+  eglutPostRedisplay();
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   eglutInitWindowSize(300, 300);
+   eglutInitAPIMask(EGLUT_OPENGL_ES1_BIT);
+   eglutInit(argc, argv);
+
+   eglutCreateWindow("gears");
+
+   eglutIdleFunc(gears_idle);
+   eglutReshapeFunc(gears_reshape);
+   eglutDisplayFunc(gears_draw);
+
+   gears_init();
+
+   eglutMainLoop();
+
+   gears_fini();
+
+   return 0;
+}