From 1a89978d8301803d4f90825c41c01876ea47e825 Mon Sep 17 00:00:00 2001
From: Brian Paul <brian.paul@tungstengraphics.com>
Date: Wed, 24 Sep 2003 20:41:53 +0000
Subject: [PATCH] GL_ARB_point_sprite demo

---
 progs/demos/Makefile.X11  |   1 +
 progs/demos/spriteblast.c | 520 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 521 insertions(+)
 create mode 100644 progs/demos/spriteblast.c

diff --git a/progs/demos/Makefile.X11 b/progs/demos/Makefile.X11
index 0fa11f4aedf..74e92fa2880 100644
--- a/progs/demos/Makefile.X11
+++ b/progs/demos/Makefile.X11
@@ -45,6 +45,7 @@ PROGS = \
 	renormal \
 	shadowtex \
 	spectex \
+	spriteblast \
 	stex3d \
 	teapot \
 	terrain \
diff --git a/progs/demos/spriteblast.c b/progs/demos/spriteblast.c
new file mode 100644
index 00000000000..c604536ab38
--- /dev/null
+++ b/progs/demos/spriteblast.c
@@ -0,0 +1,520 @@
+
+/* Copyright (c) Mark J. Kilgard, 1997.  */
+
+/* This program is freely distributable without licensing fees 
+   and is provided without guarantee or warrantee expressed or 
+   implied. This program is -not- in the public domain. */
+
+/* This example demonstrates how to render particle effects
+   with OpenGL.  A cloud of pinkish/orange particles explodes with the
+   particles bouncing off the ground.  When the EXT_point_parameters
+   is present , the particle size is attenuated based on eye distance. */
+
+
+/* Modified by Brian Paul to test GL_ARB_point_sprite */
+
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <math.h>       /* for cos(), sin(), and sqrt() */
+#ifdef _WIN32
+#include <windows.h>
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/glut.h>
+
+/* Some <math.h> files do not define M_PI... */
+#ifndef M_PI
+#define M_PI 3.14159265
+#endif
+
+#if 0  /* For debugging. */
+#undef GL_EXT_point_parameters
+#endif
+
+static GLfloat angle = -150;   /* in degrees */
+static int spin = 0;
+static int moving, begin;
+static int newModel = 1;
+static float theTime;
+static int repeat = 1;
+static int blend = 1;
+int useMipmaps = 1;
+int linearFiltering = 1;
+
+static GLfloat constant[3] = { .2,  0.0,     0.0 };
+static GLfloat linear[3]   = { .0,   .1,     0.0 };
+static GLfloat theQuad[3]  = { .005, 0.1, 1/600.0 };
+
+#define MAX_POINTS 2000
+
+static int numPoints = 200;
+
+static GLfloat pointList[MAX_POINTS][3];
+static GLfloat pointTime[MAX_POINTS];
+static GLfloat pointVelocity[MAX_POINTS][2];
+static GLfloat pointDirection[MAX_POINTS][2];
+static int colorList[MAX_POINTS];
+static int animate = 1, motion = 0;
+
+static GLfloat colorSet[][4] = {
+  /* Shades of red. */
+  { 0.7, 0.2, 0.4, 0.5 },
+  { 0.8, 0.0, 0.7, 0.5 },
+  { 1.0, 0.0, 0.0, 0.5 },
+  { 0.9, 0.3, 0.6, 0.5 },
+  { 1.0, 0.4, 0.0, 0.5 },
+  { 1.0, 0.0, 0.5, 0.5 },
+};
+
+#define NUM_COLORS (sizeof(colorSet)/sizeof(colorSet[0]))
+
+#define DEAD (NUM_COLORS+1)
+
+
+/* GL */
+static GLint spritePattern[16][16] = {
+   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+   { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 1, 1, 0, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0 },
+   { 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1, 0 },
+   { 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 0 },
+   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 },
+   { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
+};
+
+
+
+
+#if 0  /* drand48 might be better on Unix machines */
+#define RANDOM_RANGE(lo, hi) ((lo) + (hi - lo) * drand48())
+#else
+static float float_rand(void) { return rand() / (float) RAND_MAX; }
+#define RANDOM_RANGE(lo, hi) ((lo) + (hi - lo) * float_rand())
+#endif
+
+#define MEAN_VELOCITY 3.0
+#define GRAVITY 2.0
+#define TIME_DELTA 0.025  /* The speed of time. */
+
+/* Modeling units of ground extent in each X and Z direction. */
+#define EDGE 12
+
+static void
+makePointList(void)
+{
+  float angle, velocity, direction;
+  int i;
+
+  motion = 1;
+  for (i=0; i<numPoints; i++) {
+    pointList[i][0] = 0.0;
+    pointList[i][1] = 0.0;
+    pointList[i][2] = 0.0;
+    pointTime[i] = 0.0;
+    angle = (RANDOM_RANGE(60.0, 70.0)) * M_PI/180.0;
+    direction = RANDOM_RANGE(0.0, 360.0) * M_PI/180.0;
+    pointDirection[i][0] = cos(direction);
+    pointDirection[i][1] = sin(direction);
+    velocity = MEAN_VELOCITY + RANDOM_RANGE(-0.8, 1.0);
+    pointVelocity[i][0] = velocity * cos(angle);
+    pointVelocity[i][1] = velocity * sin(angle);
+    colorList[i] = rand() % NUM_COLORS;
+  }
+  theTime = 0.0;
+}
+
+static void
+updatePointList(void)
+{
+  float distance;
+  int i;
+
+  motion = 0;
+  for (i=0; i<numPoints; i++) {
+    distance = pointVelocity[i][0] * theTime;
+
+    /* X and Z */
+    pointList[i][0] = pointDirection[i][0] * distance;
+    pointList[i][2] = pointDirection[i][1] * distance;
+
+    /* Z */
+    pointList[i][1] =
+      (pointVelocity[i][1] - 0.5 * GRAVITY * pointTime[i])*pointTime[i];
+
+    /* If we hit the ground, bounce the point upward again. */
+    if (pointList[i][1] <= 0.0) {
+      if (distance > EDGE) {
+        /* Particle has hit ground past the distance duration of
+          the particles.  Mark particle as dead. */
+       colorList[i] = NUM_COLORS;  /* Not moving. */
+       continue;
+      }
+
+      pointVelocity[i][1] *= 0.8;  /* 80% of previous up velocity. */
+      pointTime[i] = 0.0;  /* Reset the particles sense of up time. */
+    }
+    motion = 1;
+    pointTime[i] += TIME_DELTA;
+  }
+  theTime += TIME_DELTA;
+  if (!motion && !spin) {
+    if (repeat) {
+      makePointList();
+    } else {
+      glutIdleFunc(NULL);
+    }
+  }
+}
+
+static void
+idle(void)
+{
+  updatePointList();
+  if (spin) {
+    angle += 0.3;
+    newModel = 1;
+  }
+  glutPostRedisplay();
+}
+
+static void
+visible(int vis)
+{
+  if (vis == GLUT_VISIBLE) {
+    if (animate && (motion || spin)) {
+      glutIdleFunc(idle);
+    }
+  } else {
+    glutIdleFunc(NULL);
+  }
+}
+
+static void
+recalcModelView(void)
+{
+  glPopMatrix();
+  glPushMatrix();
+  glRotatef(angle, 0.0, 1.0, 0.0);
+  newModel = 0;
+}
+
+static void
+redraw(void)
+{
+  int i;
+
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+  if (newModel)
+    recalcModelView();
+
+  glDepthMask(GL_FALSE);
+
+  /* Draw the floor. */
+/*  glEnable(GL_TEXTURE_2D);*/
+  glColor3f(0.1, 0.5, 1.0);
+  glBegin(GL_QUADS);
+    glTexCoord2f(0.0, 0.0);
+    glVertex3f(-EDGE, -0.05, -EDGE);
+    glTexCoord2f(20.0, 0.0);
+    glVertex3f(EDGE, -0.05, -EDGE);
+    glTexCoord2f(20.0, 20.0);
+    glVertex3f(EDGE, -0.05, EDGE);
+    glTexCoord2f(0.0, 20.0);
+    glVertex3f(-EDGE, -0.05, EDGE);
+  glEnd();
+
+  /* Allow particles to blend with each other. */
+  glDepthMask(GL_TRUE);
+
+  if (blend)
+     glEnable(GL_BLEND);
+
+  glEnable(GL_TEXTURE_2D);
+#ifdef GL_ARB_point_sprite
+  glEnable(GL_POINT_SPRITE_ARB);
+#endif
+
+  glColor3f(1,1,1);
+  glBegin(GL_POINTS);
+    for (i=0; i<numPoints; i++) {
+      /* Draw alive particles. */
+      if (colorList[i] != DEAD) {
+         /*glColor4fv(colorSet[colorList[i]]);*/
+        glVertex3fv(pointList[i]);
+      }
+    }
+  glEnd();
+
+  glDisable(GL_TEXTURE_2D);
+#ifdef GL_ARB_point_sprite
+  glDisable(GL_POINT_SPRITE_ARB);
+#endif
+  glDisable(GL_BLEND);
+
+  glutSwapBuffers();
+}
+
+/* ARGSUSED2 */
+static void
+mouse(int button, int state, int x, int y)
+{
+  /* Scene can be spun around Y axis using left
+     mouse button movement. */
+  if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
+    moving = 1;
+    begin = x;
+  }
+  if (button == GLUT_LEFT_BUTTON && state == GLUT_UP) {
+    moving = 0;
+  }
+}
+
+/* ARGSUSED1 */
+static void
+mouseMotion(int x, int y)
+{
+  if (moving) {
+    angle = angle + (x - begin);
+    begin = x;
+    newModel = 1;
+    glutPostRedisplay();
+  }
+}
+
+static void
+menu(int option)
+{
+  switch (option) {
+  case 0:
+    makePointList();
+    break;
+#if GL_ARB_point_parameters
+  case 1:
+    glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, constant);
+    break;
+  case 2:
+    glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, linear);
+    break;
+  case 3:
+    glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, theQuad);
+    break;
+#endif
+  case 4:
+    blend = 1;
+    break;
+  case 5:
+    blend = 0;
+    break;
+#if GL_ARB_point_parameters
+  case 6:
+    glPointParameterfARB(GL_POINT_FADE_THRESHOLD_SIZE_ARB, 1.0);
+    break;
+  case 7:
+    glPointParameterfARB(GL_POINT_FADE_THRESHOLD_SIZE_ARB, 10.0);
+    break;
+#endif
+  case 8:
+    glEnable(GL_POINT_SMOOTH);
+    break;
+  case 9:
+    glDisable(GL_POINT_SMOOTH);
+    break;
+  case 10:
+    glPointSize(4.0);
+    break;
+  case 11:
+    glPointSize(8.0);
+    break;
+  case 12:
+    glPointSize(16.0);
+    break;
+  case 13:
+    spin = 1 - spin;
+    if (animate && (spin || motion)) {
+      glutIdleFunc(idle);
+    } else {
+      glutIdleFunc(NULL);
+    }
+    break;
+  case 14:
+    numPoints = 200;
+    break;
+  case 15:
+    numPoints = 500;
+    break;
+  case 16:
+    numPoints = 1000;
+    break;
+  case 17:
+    numPoints = 2000;
+    break;
+  case 666:
+    exit(0);
+  }
+  glutPostRedisplay();
+}
+
+/* ARGSUSED1 */
+static void
+key(unsigned char c, int x, int y)
+{
+  switch (c) {
+  case 13:
+    animate = 1 - animate;  /* toggle. */
+    if (animate && (motion || spin)) {
+      glutIdleFunc(idle);
+    } else {
+      glutIdleFunc(NULL);
+    }
+    break;
+  case ' ':
+    animate = 1;
+    makePointList();
+    glutIdleFunc(idle);
+    break;
+  case 27:
+    exit(0);
+  }
+}
+
+
+
+static void
+makeSprite(void)
+{
+   GLubyte texture[16][16][4];
+   int i, j;
+
+   if (!glutExtensionSupported("GL_ARB_point_sprite")) {
+      printf("Sorry, this demo requires GL_ARB_point_sprite.\n");
+      exit(0);
+   }
+   if (!glutExtensionSupported("GL_ARB_point_parameters")) {
+      printf("Sorry, this demo requires GL_ARB_point_parameters.\n");
+      exit(0);
+   }
+
+   for (i = 0; i < 16; i++) {
+      for (j = 0; j < 16; j++) {
+         if (spritePattern[i][j]) {
+            texture[i][j][0] = 255;
+            texture[i][j][1] = 255;
+            texture[i][j][2] = 255;
+            texture[i][j][3] = 255;
+         }
+         else {
+            texture[i][j][0] = 255;
+            texture[i][j][1] = 0;
+            texture[i][j][2] = 0;
+            texture[i][j][3] = 0;
+         }
+      }
+   }
+
+   glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE,
+                texture);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+#ifdef GL_ARB_point_sprite
+   glTexEnvi(GL_POINT_SPRITE_ARB, GL_COORD_REPLACE_ARB, GL_TRUE);
+#endif
+}
+
+
+static void
+reshape(int width, int height)
+{
+  GLfloat h = (GLfloat) height / (GLfloat) width;
+
+  glViewport(0, 0, (GLint) width, (GLint) height);
+  glMatrixMode(GL_PROJECTION);
+  glLoadIdentity();
+  glFrustum(-1.0, 1.0, -h, h, 2.0, 20.0);
+  glMatrixMode(GL_MODELVIEW);
+  glLoadIdentity();
+  glTranslatef(0.0, 0.0, -60.0);
+}
+
+int
+main(int argc, char **argv)
+{
+  int i;
+  glutInit(&argc, argv);
+  glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_MULTISAMPLE);
+
+  for (i=1; i<argc; i++) {
+    if(!strcmp("-noms", argv[i])) {
+      glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+      printf("forcing no multisampling\n");
+    } else if(!strcmp("-nomipmaps", argv[i])) {
+      useMipmaps = 0;
+    } else if(!strcmp("-nearest", argv[i])) {
+      linearFiltering = 0;
+    }
+  }
+  glutInitWindowSize(600,300);
+  glutCreateWindow("sprite blast");
+  glutReshapeFunc(reshape);
+  glutDisplayFunc(redraw);
+  glutMouseFunc(mouse);
+  glutMotionFunc(mouseMotion);
+  glutVisibilityFunc(visible);
+  glutKeyboardFunc(key);
+  glutCreateMenu(menu);
+  glutAddMenuEntry("Reset time", 0);
+  glutAddMenuEntry("Constant", 1);
+  glutAddMenuEntry("Linear", 2);
+  glutAddMenuEntry("Quadratic", 3);
+  glutAddMenuEntry("Blend on", 4);
+  glutAddMenuEntry("Blend off", 5);
+  glutAddMenuEntry("Threshold 1", 6);
+  glutAddMenuEntry("Threshold 10", 7);
+  glutAddMenuEntry("Point smooth on", 8);
+  glutAddMenuEntry("Point smooth off", 9);
+  glutAddMenuEntry("Point size 4", 10);
+  glutAddMenuEntry("Point size 8", 11);
+  glutAddMenuEntry("Point size 16", 12);
+  glutAddMenuEntry("Toggle spin", 13);
+  glutAddMenuEntry("200 points ", 14);
+  glutAddMenuEntry("500 points ", 15);
+  glutAddMenuEntry("1000 points ", 16);
+  glutAddMenuEntry("2000 points ", 17);
+  glutAddMenuEntry("Quit", 666);
+  glutAttachMenu(GLUT_RIGHT_BUTTON);
+
+  glShadeModel(GL_FLAT);
+  glEnable(GL_DEPTH_TEST);
+  glEnable(GL_POINT_SMOOTH);
+  glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+  glPointSize(16.0);
+#if GL_ARB_point_parameters
+  glPointParameterfvARB(GL_POINT_DISTANCE_ATTENUATION_ARB, theQuad);
+#endif
+  glMatrixMode(GL_PROJECTION);
+  gluPerspective( /* field of view in degree */ 40.0,
+  /* aspect ratio */ 1.0,
+    /* Z near */ 0.5, /* Z far */ 40.0);
+  glMatrixMode(GL_MODELVIEW);
+  gluLookAt(0.0, 1.0, 8.0, /* eye location */
+    0.0, 1.0, 0.0,      /* center is at (0,0,0) */
+    0.0, 1.0, 0.);      /* up is in postivie Y direction */
+  glPushMatrix();       /* dummy push so we can pop on model
+                           recalc */
+
+  makePointList();
+  makeSprite();
+
+  glutMainLoop();
+  return 0;             /* ANSI C requires main to return int. */
+}
-- 
2.30.2