blob: 802f3980faf7415887c903824a1883006d417747 [file] [log] [blame]
/* San Angeles Observation OpenGL ES version example
* Copyright 2004-2005 Jetro Lauha
* All rights reserved.
* Web: http://iki.fi/jetro/
*
* This source is free software; you can redistribute it and/or
* modify it under the terms of EITHER:
* (1) The GNU Lesser General Public License as published by the Free
* Software Foundation; either version 2.1 of the License, or (at
* your option) any later version. The text of the GNU Lesser
* General Public License is included with this source in the
* file LICENSE-LGPL.txt.
* (2) The BSD-style license that is included with this source in
* the file LICENSE-BSD.txt.
*
* This source is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the files
* LICENSE-LGPL.txt and LICENSE-BSD.txt for more details.
*
* $Id: demo.c,v 1.10 2005/02/08 20:54:39 tonic Exp $
* $Revision: 1.10 $
*/
#include <stdlib.h>
#include <math.h>
#include <float.h>
#include <assert.h>
#include <GLES/gl.h>
#include "app.h"
#include "shapes.h"
#include "cams.h"
// Total run length is 20 * camera track base unit length (see cams.h).
#define RUN_LENGTH (20 * CAMTRACK_LEN)
#undef PI
#define PI 3.1415926535897932f
#define RANDOM_UINT_MAX 65535
static unsigned long sRandomSeed = 0;
static void seedRandom(unsigned long seed)
{
sRandomSeed = seed;
}
static unsigned long randomUInt()
{
sRandomSeed = sRandomSeed * 0x343fd + 0x269ec3;
return sRandomSeed >> 16;
}
// Capped conversion from float to fixed.
static long floatToFixed(float value)
{
if (value < -32768) value = -32768;
if (value > 32767) value = 32767;
return (long)(value * 65536);
}
#define FIXED(value) floatToFixed(value)
// Definition of one GL object in this demo.
typedef struct {
/* Vertex array and color array are enabled for all objects, so their
* pointers must always be valid and non-NULL. Normal array is not
* used by the ground plane, so when its pointer is NULL then normal
* array usage is disabled.
*
* Vertex array is supposed to use GL_FIXED datatype and stride 0
* (i.e. tightly packed array). Color array is supposed to have 4
* components per color with GL_UNSIGNED_BYTE datatype and stride 0.
* Normal array is supposed to use GL_FIXED datatype and stride 0.
*/
GLfixed *vertexArray;
GLubyte *colorArray;
GLfixed *normalArray;
GLint vertexComponents;
GLsizei count;
} GLOBJECT;
static long sStartTick = 0;
static long sTick = 0;
static int sCurrentCamTrack = 0;
static long sCurrentCamTrackStartTick = 0;
static long sNextCamTrackStartTick = 0x7fffffff;
static GLOBJECT *sSuperShapeObjects[SUPERSHAPE_COUNT] = { NULL };
static GLOBJECT *sGroundPlane = NULL;
typedef struct {
float x, y, z;
} VECTOR3;
static void freeGLObject(GLOBJECT *object)
{
if (object == NULL)
return;
free(object->normalArray);
free(object->colorArray);
free(object->vertexArray);
free(object);
}
static GLOBJECT * newGLObject(long vertices, int vertexComponents,
int useNormalArray)
{
GLOBJECT *result;
result = (GLOBJECT *)malloc(sizeof(GLOBJECT));
if (result == NULL)
return NULL;
result->count = vertices;
result->vertexComponents = vertexComponents;
result->vertexArray = (GLfixed *)malloc(vertices * vertexComponents *
sizeof(GLfixed));
result->colorArray = (GLubyte *)malloc(vertices * 4 * sizeof(GLubyte));
if (useNormalArray)
{
result->normalArray = (GLfixed *)malloc(vertices * 3 *
sizeof(GLfixed));
}
else
result->normalArray = NULL;
if (result->vertexArray == NULL ||
result->colorArray == NULL ||
(useNormalArray && result->normalArray == NULL))
{
freeGLObject(result);
return NULL;
}
return result;
}
static void drawGLObject(GLOBJECT *object)
{
assert(object != NULL);
glVertexPointer(object->vertexComponents, GL_FIXED,
0, object->vertexArray);
glColorPointer(4, GL_UNSIGNED_BYTE, 0, object->colorArray);
// Already done in initialization:
//glEnableClientState(GL_VERTEX_ARRAY);
//glEnableClientState(GL_COLOR_ARRAY);
if (object->normalArray)
{
glNormalPointer(GL_FIXED, 0, object->normalArray);
glEnableClientState(GL_NORMAL_ARRAY);
}
else
glDisableClientState(GL_NORMAL_ARRAY);
glDrawArrays(GL_TRIANGLES, 0, object->count);
}
static void vector3Sub(VECTOR3 *dest, VECTOR3 *v1, VECTOR3 *v2)
{
dest->x = v1->x - v2->x;
dest->y = v1->y - v2->y;
dest->z = v1->z - v2->z;
}
static void superShapeMap(VECTOR3 *point, float r1, float r2, float t, float p)
{
// sphere-mapping of supershape parameters
point->x = (float)(cos(t) * cos(p) / r1 / r2);
point->y = (float)(sin(t) * cos(p) / r1 / r2);
point->z = (float)(sin(p) / r2);
}
static float ssFunc(const float t, const float *p)
{
return (float)(pow(pow(fabs(cos(p[0] * t / 4)) / p[1], p[4]) +
pow(fabs(sin(p[0] * t / 4)) / p[2], p[5]), 1 / p[3]));
}
// Creates and returns a supershape object.
// Based on Paul Bourke's POV-Ray implementation.
// http://astronomy.swin.edu.au/~pbourke/povray/supershape/
static GLOBJECT * createSuperShape(const float *params)
{
const int resol1 = (int)params[SUPERSHAPE_PARAMS - 3];
const int resol2 = (int)params[SUPERSHAPE_PARAMS - 2];
// latitude 0 to pi/2 for no mirrored bottom
// (latitudeBegin==0 for -pi/2 to pi/2 originally)
const int latitudeBegin = resol2 / 4;
const int latitudeEnd = resol2 / 2; // non-inclusive
const int longitudeCount = resol1;
const int latitudeCount = latitudeEnd - latitudeBegin;
const long triangleCount = longitudeCount * latitudeCount * 2;
const long vertices = triangleCount * 3;
GLOBJECT *result;
float baseColor[3];
int a, longitude, latitude;
long currentVertex, currentQuad;
result = newGLObject(vertices, 3, 1);
if (result == NULL)
return NULL;
for (a = 0; a < 3; ++a)
baseColor[a] = ((randomUInt() % 155) + 100) / 255.f;
currentQuad = 0;
currentVertex = 0;
// longitude -pi to pi
for (longitude = 0; longitude < longitudeCount; ++longitude)
{
// latitude 0 to pi/2
for (latitude = latitudeBegin; latitude < latitudeEnd; ++latitude)
{
float t1 = -PI + longitude * 2 * PI / resol1;
float t2 = -PI + (longitude + 1) * 2 * PI / resol1;
float p1 = -PI / 2 + latitude * 2 * PI / resol2;
float p2 = -PI / 2 + (latitude + 1) * 2 * PI / resol2;
float r0, r1, r2, r3;
r0 = ssFunc(t1, params);
r1 = ssFunc(p1, &params[6]);
r2 = ssFunc(t2, params);
r3 = ssFunc(p2, &params[6]);
if (r0 != 0 && r1 != 0 && r2 != 0 && r3 != 0)
{
VECTOR3 pa, pb, pc, pd;
VECTOR3 v1, v2, n;
float ca;
int i;
//float lenSq, invLenSq;
superShapeMap(&pa, r0, r1, t1, p1);
superShapeMap(&pb, r2, r1, t2, p1);
superShapeMap(&pc, r2, r3, t2, p2);
superShapeMap(&pd, r0, r3, t1, p2);
// kludge to set lower edge of the object to fixed level
if (latitude == latitudeBegin + 1)
pa.z = pb.z = 0;
vector3Sub(&v1, &pb, &pa);
vector3Sub(&v2, &pd, &pa);
// Calculate normal with cross product.
/* i j k i j
* v1.x v1.y v1.z | v1.x v1.y
* v2.x v2.y v2.z | v2.x v2.y
*/
n.x = v1.y * v2.z - v1.z * v2.y;
n.y = v1.z * v2.x - v1.x * v2.z;
n.z = v1.x * v2.y - v1.y * v2.x;
/* Pre-normalization of the normals is disabled here because
* they will be normalized anyway later due to automatic
* normalization (GL_NORMALIZE). It is enabled because the
* objects are scaled with glScale.
*/
/*
lenSq = n.x * n.x + n.y * n.y + n.z * n.z;
invLenSq = (float)(1 / sqrt(lenSq));
n.x *= invLenSq;
n.y *= invLenSq;
n.z *= invLenSq;
*/
ca = pa.z + 0.5f;
for (i = currentVertex * 3;
i < (currentVertex + 6) * 3;
i += 3)
{
result->normalArray[i] = FIXED(n.x);
result->normalArray[i + 1] = FIXED(n.y);
result->normalArray[i + 2] = FIXED(n.z);
}
for (i = currentVertex * 4;
i < (currentVertex + 6) * 4;
i += 4)
{
int a, color[3];
for (a = 0; a < 3; ++a)
{
color[a] = (int)(ca * baseColor[a] * 255);
if (color[a] > 255) color[a] = 255;
}
result->colorArray[i] = (GLubyte)color[0];
result->colorArray[i + 1] = (GLubyte)color[1];
result->colorArray[i + 2] = (GLubyte)color[2];
result->colorArray[i + 3] = 0;
}
result->vertexArray[currentVertex * 3] = FIXED(pa.x);
result->vertexArray[currentVertex * 3 + 1] = FIXED(pa.y);
result->vertexArray[currentVertex * 3 + 2] = FIXED(pa.z);
++currentVertex;
result->vertexArray[currentVertex * 3] = FIXED(pb.x);
result->vertexArray[currentVertex * 3 + 1] = FIXED(pb.y);
result->vertexArray[currentVertex * 3 + 2] = FIXED(pb.z);
++currentVertex;
result->vertexArray[currentVertex * 3] = FIXED(pd.x);
result->vertexArray[currentVertex * 3 + 1] = FIXED(pd.y);
result->vertexArray[currentVertex * 3 + 2] = FIXED(pd.z);
++currentVertex;
result->vertexArray[currentVertex * 3] = FIXED(pb.x);
result->vertexArray[currentVertex * 3 + 1] = FIXED(pb.y);
result->vertexArray[currentVertex * 3 + 2] = FIXED(pb.z);
++currentVertex;
result->vertexArray[currentVertex * 3] = FIXED(pc.x);
result->vertexArray[currentVertex * 3 + 1] = FIXED(pc.y);
result->vertexArray[currentVertex * 3 + 2] = FIXED(pc.z);
++currentVertex;
result->vertexArray[currentVertex * 3] = FIXED(pd.x);
result->vertexArray[currentVertex * 3 + 1] = FIXED(pd.y);
result->vertexArray[currentVertex * 3 + 2] = FIXED(pd.z);
++currentVertex;
} // r0 && r1 && r2 && r3
++currentQuad;
} // latitude
} // longitude
// Set number of vertices in object to the actual amount created.
result->count = currentVertex;
return result;
}
static GLOBJECT * createGroundPlane()
{
const int scale = 4;
const int yBegin = -15, yEnd = 15; // ends are non-inclusive
const int xBegin = -15, xEnd = 15;
const long triangleCount = (yEnd - yBegin) * (xEnd - xBegin) * 2;
const long vertices = triangleCount * 3;
GLOBJECT *result;
int x, y;
long currentVertex, currentQuad;
result = newGLObject(vertices, 2, 0);
if (result == NULL)
return NULL;
currentQuad = 0;
currentVertex = 0;
for (y = yBegin; y < yEnd; ++y)
{
for (x = xBegin; x < xEnd; ++x)
{
GLubyte color;
int i, a;
color = (GLubyte)((randomUInt() & 0x5f) + 81); // 101 1111
for (i = currentVertex * 4; i < (currentVertex + 6) * 4; i += 4)
{
result->colorArray[i] = color;
result->colorArray[i + 1] = color;
result->colorArray[i + 2] = color;
result->colorArray[i + 3] = 0;
}
// Axis bits for quad triangles:
// x: 011100 (0x1c), y: 110001 (0x31) (clockwise)
// x: 001110 (0x0e), y: 100011 (0x23) (counter-clockwise)
for (a = 0; a < 6; ++a)
{
const int xm = x + ((0x1c >> a) & 1);
const int ym = y + ((0x31 >> a) & 1);
const float m = (float)(cos(xm * 2) * sin(ym * 4) * 0.75f);
result->vertexArray[currentVertex * 2] =
FIXED(xm * scale + m);
result->vertexArray[currentVertex * 2 + 1] =
FIXED(ym * scale + m);
++currentVertex;
}
++currentQuad;
}
}
return result;
}
static void drawGroundPlane()
{
glDisable(GL_CULL_FACE);
glDisable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
glBlendFunc(GL_ZERO, GL_SRC_COLOR);
glDisable(GL_LIGHTING);
drawGLObject(sGroundPlane);
glEnable(GL_LIGHTING);
glDisable(GL_BLEND);
glEnable(GL_DEPTH_TEST);
}
static void drawFadeQuad()
{
static const GLfixed quadVertices[] = {
-0x10000, -0x10000,
0x10000, -0x10000,
-0x10000, 0x10000,
0x10000, -0x10000,
0x10000, 0x10000,
-0x10000, 0x10000
};
const int beginFade = sTick - sCurrentCamTrackStartTick;
const int endFade = sNextCamTrackStartTick - sTick;
const int minFade = beginFade < endFade ? beginFade : endFade;
if (minFade < 1024)
{
const GLfixed fadeColor = minFade << 6;
glColor4x(fadeColor, fadeColor, fadeColor, 0);
glDisable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
glBlendFunc(GL_ZERO, GL_SRC_COLOR);
glDisable(GL_LIGHTING);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glDisableClientState(GL_COLOR_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
glVertexPointer(2, GL_FIXED, 0, quadVertices);
glDrawArrays(GL_TRIANGLES, 0, 6);
glEnableClientState(GL_COLOR_ARRAY);
glMatrixMode(GL_MODELVIEW);
glEnable(GL_LIGHTING);
glDisable(GL_BLEND);
glEnable(GL_DEPTH_TEST);
}
}
// Called from the app framework.
void appInit()
{
int a;
glEnable(GL_NORMALIZE);
glEnable(GL_DEPTH_TEST);
glDisable(GL_CULL_FACE);
glShadeModel(GL_FLAT);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_LIGHT1);
glEnable(GL_LIGHT2);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_COLOR_ARRAY);
seedRandom(15);
for (a = 0; a < SUPERSHAPE_COUNT; ++a)
{
sSuperShapeObjects[a] = createSuperShape(sSuperShapeParams[a]);
assert(sSuperShapeObjects[a] != NULL);
}
sGroundPlane = createGroundPlane();
assert(sGroundPlane != NULL);
}
// Called from the app framework.
void appDeinit()
{
int a;
for (a = 0; a < SUPERSHAPE_COUNT; ++a)
freeGLObject(sSuperShapeObjects[a]);
freeGLObject(sGroundPlane);
}
static void gluPerspective(GLfloat fovy, GLfloat aspect,
GLfloat zNear, GLfloat zFar)
{
GLfloat xmin, xmax, ymin, ymax;
ymax = zNear * (GLfloat)tan(fovy * PI / 360);
ymin = -ymax;
xmin = ymin * aspect;
xmax = ymax * aspect;
glFrustumx((GLfixed)(xmin * 65536), (GLfixed)(xmax * 65536),
(GLfixed)(ymin * 65536), (GLfixed)(ymax * 65536),
(GLfixed)(zNear * 65536), (GLfixed)(zFar * 65536));
}
static void prepareFrame(int width, int height)
{
glViewport(0, 0, width, height);
glClearColorx((GLfixed)(0.1f * 65536),
(GLfixed)(0.2f * 65536),
(GLfixed)(0.3f * 65536), 0x10000);
glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(45, (float)width / height, 0.5f, 150);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
static void configureLightAndMaterial()
{
static GLfixed light0Position[] = { -0x40000, 0x10000, 0x10000, 0 };
static GLfixed light0Diffuse[] = { 0x10000, 0x6666, 0, 0x10000 };
static GLfixed light1Position[] = { 0x10000, -0x20000, -0x10000, 0 };
static GLfixed light1Diffuse[] = { 0x11eb, 0x23d7, 0x5999, 0x10000 };
static GLfixed light2Position[] = { -0x10000, 0, -0x40000, 0 };
static GLfixed light2Diffuse[] = { 0x11eb, 0x2b85, 0x23d7, 0x10000 };
static GLfixed materialSpecular[] = { 0x10000, 0x10000, 0x10000, 0x10000 };
glLightxv(GL_LIGHT0, GL_POSITION, light0Position);
glLightxv(GL_LIGHT0, GL_DIFFUSE, light0Diffuse);
glLightxv(GL_LIGHT1, GL_POSITION, light1Position);
glLightxv(GL_LIGHT1, GL_DIFFUSE, light1Diffuse);
glLightxv(GL_LIGHT2, GL_POSITION, light2Position);
glLightxv(GL_LIGHT2, GL_DIFFUSE, light2Diffuse);
glMaterialxv(GL_FRONT_AND_BACK, GL_SPECULAR, materialSpecular);
glMaterialx(GL_FRONT_AND_BACK, GL_SHININESS, 60 << 16);
glEnable(GL_COLOR_MATERIAL);
}
static void drawModels(float zScale)
{
const int translationScale = 9;
int x, y;
seedRandom(9);
glScalex(1 << 16, 1 << 16, (GLfixed)(zScale * 65536));
for (y = -5; y <= 5; ++y)
{
for (x = -5; x <= 5; ++x)
{
float buildingScale;
GLfixed fixedScale;
int curShape = randomUInt() % SUPERSHAPE_COUNT;
buildingScale = sSuperShapeParams[curShape][SUPERSHAPE_PARAMS - 1];
fixedScale = (GLfixed)(buildingScale * 65536);
glPushMatrix();
glTranslatex((x * translationScale) * 65536,
(y * translationScale) * 65536,
0);
glRotatex((GLfixed)((randomUInt() % 360) << 16), 0, 0, 1 << 16);
glScalex(fixedScale, fixedScale, fixedScale);
drawGLObject(sSuperShapeObjects[curShape]);
glPopMatrix();
}
}
for (x = -2; x <= 2; ++x)
{
const int shipScale100 = translationScale * 500;
const int offs100 = x * shipScale100 + (sTick % shipScale100);
float offs = offs100 * 0.01f;
GLfixed fixedOffs = (GLfixed)(offs * 65536);
glPushMatrix();
glTranslatex(fixedOffs, -4 * 65536, 2 << 16);
drawGLObject(sSuperShapeObjects[SUPERSHAPE_COUNT - 1]);
glPopMatrix();
glPushMatrix();
glTranslatex(-4 * 65536, fixedOffs, 4 << 16);
glRotatex(90 << 16, 0, 0, 1 << 16);
drawGLObject(sSuperShapeObjects[SUPERSHAPE_COUNT - 1]);
glPopMatrix();
}
}
/* Following gluLookAt implementation is adapted from the
* Mesa 3D Graphics library. http://www.mesa3d.org
*/
static void gluLookAt(GLfloat eyex, GLfloat eyey, GLfloat eyez,
GLfloat centerx, GLfloat centery, GLfloat centerz,
GLfloat upx, GLfloat upy, GLfloat upz)
{
GLfloat m[16];
GLfloat x[3], y[3], z[3];
GLfloat mag;
/* Make rotation matrix */
/* Z vector */
z[0] = eyex - centerx;
z[1] = eyey - centery;
z[2] = eyez - centerz;
mag = (float)sqrt(z[0] * z[0] + z[1] * z[1] + z[2] * z[2]);
if (mag) { /* mpichler, 19950515 */
z[0] /= mag;
z[1] /= mag;
z[2] /= mag;
}
/* Y vector */
y[0] = upx;
y[1] = upy;
y[2] = upz;
/* X vector = Y cross Z */
x[0] = y[1] * z[2] - y[2] * z[1];
x[1] = -y[0] * z[2] + y[2] * z[0];
x[2] = y[0] * z[1] - y[1] * z[0];
/* Recompute Y = Z cross X */
y[0] = z[1] * x[2] - z[2] * x[1];
y[1] = -z[0] * x[2] + z[2] * x[0];
y[2] = z[0] * x[1] - z[1] * x[0];
/* mpichler, 19950515 */
/* cross product gives area of parallelogram, which is < 1.0 for
* non-perpendicular unit-length vectors; so normalize x, y here
*/
mag = (float)sqrt(x[0] * x[0] + x[1] * x[1] + x[2] * x[2]);
if (mag) {
x[0] /= mag;
x[1] /= mag;
x[2] /= mag;
}
mag = (float)sqrt(y[0] * y[0] + y[1] * y[1] + y[2] * y[2]);
if (mag) {
y[0] /= mag;
y[1] /= mag;
y[2] /= mag;
}
#define M(row,col) m[col*4+row]
M(0, 0) = x[0];
M(0, 1) = x[1];
M(0, 2) = x[2];
M(0, 3) = 0.0;
M(1, 0) = y[0];
M(1, 1) = y[1];
M(1, 2) = y[2];
M(1, 3) = 0.0;
M(2, 0) = z[0];
M(2, 1) = z[1];
M(2, 2) = z[2];
M(2, 3) = 0.0;
M(3, 0) = 0.0;
M(3, 1) = 0.0;
M(3, 2) = 0.0;
M(3, 3) = 1.0;
#undef M
{
int a;
GLfixed fixedM[16];
for (a = 0; a < 16; ++a)
fixedM[a] = (GLfixed)(m[a] * 65536);
glMultMatrixx(fixedM);
}
/* Translate Eye to Origin */
glTranslatex((GLfixed)(-eyex * 65536),
(GLfixed)(-eyey * 65536),
(GLfixed)(-eyez * 65536));
}
static void camTrack()
{
float lerp[5];
float eX, eY, eZ, cX, cY, cZ;
float trackPos;
CAMTRACK *cam;
long currentCamTick;
int a;
if (sNextCamTrackStartTick <= sTick)
{
++sCurrentCamTrack;
sCurrentCamTrackStartTick = sNextCamTrackStartTick;
}
sNextCamTrackStartTick = sCurrentCamTrackStartTick +
sCamTracks[sCurrentCamTrack].len * CAMTRACK_LEN;
cam = &sCamTracks[sCurrentCamTrack];
currentCamTick = sTick - sCurrentCamTrackStartTick;
trackPos = (float)currentCamTick / (CAMTRACK_LEN * cam->len);
for (a = 0; a < 5; ++a)
lerp[a] = (cam->src[a] + cam->dest[a] * trackPos) * 0.01f;
if (cam->dist)
{
float dist = cam->dist * 0.1f;
cX = lerp[0];
cY = lerp[1];
cZ = lerp[2];
eX = cX - (float)cos(lerp[3]) * dist;
eY = cY - (float)sin(lerp[3]) * dist;
eZ = cZ - lerp[4];
}
else
{
eX = lerp[0];
eY = lerp[1];
eZ = lerp[2];
cX = eX + (float)cos(lerp[3]);
cY = eY + (float)sin(lerp[3]);
cZ = eZ + lerp[4];
}
gluLookAt(eX, eY, eZ, cX, cY, cZ, 0, 0, 1);
}
// Called from the app framework.
/* The tick is current time in milliseconds, width and height
* are the image dimensions to be rendered.
*/
void appRender(long tick, int width, int height)
{
if (sStartTick == 0)
sStartTick = tick;
if (!gAppAlive)
return;
// Actual tick value is "blurred" a little bit.
sTick = (sTick + tick - sStartTick) >> 1;
// Terminate application after running through the demonstration once.
if (sTick >= RUN_LENGTH)
{
gAppAlive = 0;
return;
}
// Prepare OpenGL ES for rendering of the frame.
prepareFrame(width, height);
// Update the camera position and set the lookat.
camTrack();
// Configure environment.
configureLightAndMaterial();
// Draw the reflection by drawing models with negated Z-axis.
glPushMatrix();
drawModels(-1);
glPopMatrix();
// Blend the ground plane to the window.
drawGroundPlane();
// Draw all the models normally.
drawModels(1);
// Draw fade quad over whole window (when changing cameras).
drawFadeQuad();
}