1 files changed, 378 insertions, 0 deletions
diff --git a/progs/samples/overlay.c b/progs/samples/overlay.c
new file mode 100644
index 000000000..23b5a4793
--- /dev/null
+++ b/progs/samples/overlay.c
@@ -0,0 +1,378 @@
+/*
+ * Copyright (c) 1991, 1992, 1993 Silicon Graphics, Inc.
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and
+ * its documentation for any purpose is hereby granted without fee, provided
+ * that (i) the above copyright notices and this permission notice appear in
+ * all copies of the software and related documentation, and (ii) the name of
+ * Silicon Graphics may not be used in any advertising or
+ * publicity relating to the software without the specific, prior written
+ * permission of Silicon Graphics.
+ *
+ * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF
+ * ANY KIND,
+ * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
+ * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
+ *
+ * IN NO EVENT SHALL SILICON GRAPHICS BE LIABLE FOR
+ * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
+ * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
+ * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
+ * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+#include <time.h>
+#include <GL/glut.h>
+
+
+#ifndef PI
+#define PI 3.141592657
+#endif
+
+
+enum {
+    NORMAL = 0,
+    WEIRD = 1
+};
+
+enum {
+    STREAK = 0,
+    CIRCLE = 1
+};
+
+#define MAXSTARS 400
+#define MAXPOS 10000
+#define MAXWARP 10
+#define MAXANGLES 6000
+
+
+typedef struct _starRec {
+    GLint type;
+    float x[2], y[2], z[2];
+    float offsetX, offsetY, offsetR, rotation;
+} starRec;
+
+
+GLenum doubleBuffer;
+GLint windW, windH;
+
+GLenum flag = NORMAL, overlayInit = GL_FALSE;
+GLint starCount = MAXSTARS / 2;
+float speed = 1.0;
+GLint nitro = 0;
+starRec stars[MAXSTARS];
+float sinTable[MAXANGLES];
+
+
+float Sin(float angle)
+{
+
+    return (sinTable[(GLint)angle]);
+}
+
+float Cos(float angle)
+{
+
+    return (sinTable[((GLint)angle+(MAXANGLES/4))%MAXANGLES]);
+}
+
+void NewStar(GLint n, GLint d)
+{
+
+    if (rand()%4 == 0) {
+	stars[n].type = CIRCLE;
+    } else {
+	stars[n].type = STREAK;
+    }
+    stars[n].x[0] = (float)(rand() % MAXPOS - MAXPOS / 2);
+    stars[n].y[0] = (float)(rand() % MAXPOS - MAXPOS / 2);
+    stars[n].z[0] = (float)(rand() % MAXPOS + d);
+    if (rand()%4 == 0 && flag == WEIRD) {
+	stars[n].offsetX = (float)(rand() % 100 - 100 / 2);
+	stars[n].offsetY = (float)(rand() % 100 - 100 / 2);
+	stars[n].offsetR = (float)(rand() % 25 - 25 / 2);
+    } else {
+	stars[n].offsetX = 0.0;
+	stars[n].offsetY = 0.0;
+	stars[n].offsetR = 0.0;
+    }
+}
+
+void RotatePoint(float *x, float *y, float rotation)
+{
+    float tmpX, tmpY;
+
+    tmpX = *x * Cos(rotation) - *y * Sin(rotation);
+    tmpY = *y * Cos(rotation) + *x * Sin(rotation);
+    *x = tmpX;
+    *y = tmpY;
+}
+
+void MoveStars(void)
+{
+    float offset;
+    GLint n;
+
+    offset = speed * 60.0;
+
+    for (n = 0; n < starCount; n++) {
+	stars[n].x[1] = stars[n].x[0];
+	stars[n].y[1] = stars[n].y[0];
+	stars[n].z[1] = stars[n].z[0];
+	stars[n].x[0] += stars[n].offsetX;
+	stars[n].y[0] += stars[n].offsetY;
+	stars[n].z[0] -= offset;
+        stars[n].rotation += stars[n].offsetR;
+        if (stars[n].rotation > MAXANGLES) {
+            stars[n].rotation = 0.0;
+	}
+    }
+}
+
+GLenum StarPoint(GLint n)
+{
+    float x0, y0, x1, y1, width;
+    GLint i;
+
+    x0 = stars[n].x[0] * windW / stars[n].z[0];
+    y0 = stars[n].y[0] * windH / stars[n].z[0];
+    RotatePoint(&x0, &y0, stars[n].rotation);
+    x0 += windW / 2.0;
+    y0 += windH / 2.0;
+
+    if (x0 >= 0.0 && x0 < windW && y0 >= 0.0 && y0 < windH) {
+	if (stars[n].type == STREAK) {
+	    x1 = stars[n].x[1] * windW / stars[n].z[1];
+	    y1 = stars[n].y[1] * windH / stars[n].z[1];
+	    RotatePoint(&x1, &y1, stars[n].rotation);
+	    x1 += windW / 2.0;
+	    y1 += windH / 2.0;
+
+	    glLineWidth(MAXPOS/100.0/stars[n].z[0]+1.0);
+	    glColor3f(1.0, (MAXWARP-speed)/MAXWARP, (MAXWARP-speed)/MAXWARP);
+	    if (fabs(x0-x1) < 1.0 && fabs(y0-y1) < 1.0) {
+		glBegin(GL_POINTS);
+		    glVertex2f(x0, y0);
+		glEnd();
+	    } else {
+		glBegin(GL_LINES);
+		    glVertex2f(x0, y0);
+		    glVertex2f(x1, y1);
+		glEnd();
+	    }
+	} else {
+	    width = MAXPOS / 10.0 / stars[n].z[0] + 1.0;
+	    glColor3f(1.0, 0.0, 0.0);
+	    glBegin(GL_POLYGON);
+		for (i = 0; i < 8; i++) {
+		    float x = x0 + width * Cos((float)i*MAXANGLES/8.0);
+		    float y = y0 + width * Sin((float)i*MAXANGLES/8.0);
+		    glVertex2f(x, y);
+		};
+	    glEnd();
+	}
+	return GL_TRUE;
+    } else {
+	return GL_FALSE;
+    }
+}
+
+void ShowStars(void)
+{
+    GLint n;
+
+    glClear(GL_COLOR_BUFFER_BIT);
+
+    for (n = 0; n < starCount; n++) {
+	if (stars[n].z[0] > speed || (stars[n].z[0] > 0.0 && speed < MAXWARP)) {
+	    if (StarPoint(n) == GL_FALSE) {
+		NewStar(n, MAXPOS);
+	    }
+	} else {
+	    NewStar(n, MAXPOS);
+	}
+    }
+}
+
+static void Init(void)
+{
+    float angle;
+    GLint n;
+
+    srand((unsigned int)time(NULL));
+
+    for (n = 0; n < MAXSTARS; n++) {
+	NewStar(n, 100);
+    }
+
+    angle = 0.0;
+    for (n = 0; n < MAXANGLES ; n++) {
+	sinTable[n] = sin(angle);
+        angle += PI / (MAXANGLES / 2.0);
+    }
+
+    glClearColor(0.0, 0.0, 0.0, 0.0);
+
+    glDisable(GL_DITHER);
+}
+
+void Reshape(int width, int height)
+{
+
+    windW = (GLint)width;
+    windH = (GLint)height;
+
+    glutUseLayer(GLUT_OVERLAY);
+
+    glViewport(0, 0, windW, windH);
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    gluOrtho2D(-0.5, windW+0.5, -0.5, windH+0.5);
+    glMatrixMode(GL_MODELVIEW);
+    overlayInit = GL_FALSE;
+
+    glutUseLayer(GLUT_NORMAL);
+
+    glViewport(0, 0, windW, windH);
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+    gluOrtho2D(-0.5, windW+0.5, -0.5, windH+0.5);
+    glMatrixMode(GL_MODELVIEW);
+}
+
+static void Key(unsigned char key, int x, int y)
+{
+
+    switch (key) {
+      case 27:
+	exit(1);
+      case 32:
+	flag = (flag == NORMAL) ? WEIRD : NORMAL;
+	break;
+      case 't':
+	nitro = 1;
+	break;
+      default:
+	return;
+    }
+}
+
+void Idle(void)
+{
+
+    if (overlayInit == GL_FALSE) {
+	glutUseLayer(GLUT_OVERLAY);
+	glClear(GL_COLOR_BUFFER_BIT);
+/*	    glColor3f(1.0, 0.0, 0.0);*/
+
+	glIndexf( 2.0 );
+	glBegin(GL_POLYGON);
+	    glVertex2i(windW/4-10, windH/4-10);
+	    glVertex2i(windW/2-10, windH/4-10);
+	    glVertex2i(windW/2-10, windH/2-10);
+	    glVertex2i(windW/4-10, windH/2-10);
+	glEnd();
+
+        glIndexf( 0.0 );
+	glBegin(GL_POLYGON);
+	    glVertex2i(windW/4, windH/4);
+	    glVertex2i(windW/2, windH/4);
+	    glVertex2i(windW/2, windH/2);
+	    glVertex2i(windW/4, windH/2);
+	glEnd();
+
+        glIndexf( 1.0 );
+	glBegin(GL_POLYGON);
+	    glVertex2i(windW/4+10, windH/4+10);
+	    glVertex2i(windW/2+10, windH/4+10);
+	    glVertex2i(windW/2+10, windH/2+10);
+	    glVertex2i(windW/4+10, windH/2+10);
+	glEnd();
+
+	glutUseLayer(GLUT_NORMAL);
+	overlayInit = GL_TRUE;
+    }
+
+    MoveStars();
+    ShowStars();
+    if (nitro > 0) {
+	speed = (float)(nitro / 10) + 1.0;
+	if (speed > MAXWARP) {
+	    speed = MAXWARP;
+	}
+	if (++nitro > MAXWARP*10) {
+	    nitro = -nitro;
+	}
+    } else if (nitro < 0) {
+	nitro++;
+	speed = (float)(-nitro / 10) + 1.0;
+	if (speed > MAXWARP) {
+	    speed = MAXWARP;
+	}
+    }
+
+    glFlush();
+    if (doubleBuffer) {
+	glutSwapBuffers();
+    }
+}
+
+static GLenum Args(int argc, char **argv)
+{
+    GLint i;
+
+    doubleBuffer = GL_TRUE;
+
+    for (i = 1; i < argc; i++) {
+	if (strcmp(argv[i], "-sb") == 0) {
+	    doubleBuffer = GL_FALSE;
+	} else if (strcmp(argv[i], "-db") == 0) {
+	    doubleBuffer = GL_TRUE;
+	}
+    }
+    return GL_TRUE;
+}
+
+int main(int argc, char **argv)
+{
+    GLenum type;
+
+    glutInit(&argc, argv);
+
+    if (!glutLayerGet(GLUT_OVERLAY_POSSIBLE))
+    {
+	fprintf(stderr, "Overlay not available\n");
+	return(1);
+    }
+
+    if (Args(argc, argv) == GL_FALSE) {
+	return(1);
+    }
+
+    windW = 300;
+    windH = 300;
+    glutInitWindowPosition(0, 0); glutInitWindowSize( 300, 300);
+
+    type = GLUT_RGB;
+    type |= (doubleBuffer) ? GLUT_DOUBLE : GLUT_SINGLE;
+    glutInitDisplayMode(type);
+
+    if (glutCreateWindow("Overlay Test") == GL_FALSE) {
+	return(1);
+    }
+
+    glutEstablishOverlay();
+
+    Init();
+
+    glutReshapeFunc(Reshape);
+    glutKeyboardFunc(Key);
+    glutIdleFunc(Idle);
+    glutMainLoop();
+	return 0;
+}