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* Copyright (C) 2002 Terence M. Welsh
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* Ported to Linux by Tugrul Galatali <tugrul@galatali.com>
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* Skyrocket is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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* Skyrocket is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#include "skyrocket_flare.h"
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#define max(x, y) ((x > y) ? x : y)
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unsigned int flarelist[4];
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extern int xsize, ysize;
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extern float aspectRatio;
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// Generate textures for lens flares
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// then applies textures to geometry in display lists
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unsigned char flare[FLARESIZE][FLARESIZE][4];
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unsigned int flaretex[4];
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glGenTextures (4, flaretex);
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// First flare: basic sphere
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for (i = 0; i < FLARESIZE; i++) {
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for (j = 0; j < FLARESIZE; j++) {
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x = float (i - FLARESIZE / 2) / float (FLARESIZE / 2);
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y = float (j - FLARESIZE / 2) / float (FLARESIZE / 2);
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temp = 1.0f - ((x * x) + (y * y));
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flare[i][j][3] = char (255.0f * temp * temp);
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glBindTexture (GL_TEXTURE_2D, flaretex[0]);
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//glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexImage2D (GL_TEXTURE_2D, 0, 4, FLARESIZE, FLARESIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, flare);
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// Second flare: flattened sphere
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for (i = 0; i < FLARESIZE; i++) {
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for (j = 0; j < FLARESIZE; j++) {
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x = float (i - FLARESIZE / 2) / float (FLARESIZE / 2);
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y = float (j - FLARESIZE / 2) / float (FLARESIZE / 2);
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temp = 2.5f * (1.0f - ((x * x) + (y * y)));
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//temp = temp * temp * temp * temp;
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flare[i][j][3] = char (255.0f * temp);
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glBindTexture (GL_TEXTURE_2D, flaretex[1]);
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//glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexImage2D (GL_TEXTURE_2D, 0, 4, FLARESIZE, FLARESIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, flare);
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for (i = 0; i < FLARESIZE; i++) {
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for (j = 0; j < FLARESIZE; j++) {
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x = float (i - FLARESIZE / 2) / float (FLARESIZE / 2);
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y = float (j - FLARESIZE / 2) / float (FLARESIZE / 2);
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temp = 4.0f * ((x * x) + (y * y)) * (1.0f - ((x * x) + (y * y)));
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temp = temp * temp * temp * temp;
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flare[i][j][3] = char (255.0f * temp);
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glBindTexture (GL_TEXTURE_2D, flaretex[2]);
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//glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexImage2D (GL_TEXTURE_2D, 0, 4, FLARESIZE, FLARESIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, flare);
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// Fourth flare: kick-ass flare
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for (i = 0; i < FLARESIZE; i++) {
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for (j = 0; j < FLARESIZE; j++) {
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x = float (i - FLARESIZE / 2) / float (FLARESIZE / 2);
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y = float (j - FLARESIZE / 2) / float (FLARESIZE / 2);
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flare[i][j][0] = 255;
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flare[i][j][1] = 255;
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temp = 0.14f * (1.0f - max (x, y)) / max ((x * y), 0.05f);
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flare[i][j][2] = char (255.0f * temp);
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temp = 0.1f * (1.0f - max (x, y)) / max ((x * y), 0.1f);
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flare[i][j][3] = char (255.0f * temp);
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glBindTexture (GL_TEXTURE_2D, flaretex[3]);
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//glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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glTexImage2D (GL_TEXTURE_2D, 0, 4, FLARESIZE, FLARESIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, flare);
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// Build display lists
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flarelist[0] = glGenLists (4);
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flarelist[1] = flarelist[0] + 1;
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flarelist[2] = flarelist[0] + 2;
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flarelist[3] = flarelist[0] + 3;
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for (i = 0; i < 4; i++) {
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glNewList (flarelist[i], GL_COMPILE);
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glBindTexture (GL_TEXTURE_2D, flaretex[i]);
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glBegin (GL_TRIANGLE_STRIP);
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glTexCoord2f (0.0f, 0.0f);
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glVertex3f (-0.5f, -0.5f, 0.0f);
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glTexCoord2f (1.0f, 0.0f);
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glVertex3f (0.5f, -0.5f, 0.0f);
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glTexCoord2f (0.0f, 1.0f);
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glVertex3f (-0.5f, 0.5f, 0.0f);
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glTexCoord2f (1.0f, 1.0f);
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glVertex3f (0.5f, 0.5f, 0.0f);
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void cleanupFlares ()
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glDeleteLists (flarelist[0], 4);
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// Draw a flare at a specified (x,y) location on the screen
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// Screen corners are at (0,0) and (1,1)
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// alpha = 0.0 for lowest intensity; alpha = 1.0 for highest intensity
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void flare (float x, float y, float red, float green, float blue, float alpha)
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float fadewidth, temp;
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glBlendFunc (GL_SRC_ALPHA, GL_ONE);
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// Fade alpha if source is off edge of screen
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fadewidth = float (xsize) / 10.0f;
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temp = fadewidth + y;
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alpha *= temp / fadewidth;
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temp = fadewidth - y + ysize;
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alpha *= temp / fadewidth;
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temp = fadewidth + x;
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alpha *= temp / fadewidth;
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temp = fadewidth - x + xsize;
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alpha *= temp / fadewidth;
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// Find lens flare vector
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// This vector runs from the light source through the screen's center
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dx = 0.5f * aspectRatio - x;
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// Setup projection matrix
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glMatrixMode (GL_PROJECTION);
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gluOrtho2D (0, aspectRatio, 0, 1.0f);
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glMatrixMode (GL_MODELVIEW);
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glTranslatef (x + dx * 0.05f, y + dy * 0.05f, 0.0f);
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glScalef (0.065f, 0.065f, 0.065f);
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glColor4f (red, green, blue, alpha * 0.4f);
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glCallList (flarelist[2]);
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glTranslatef (x + dx * 0.15f, y + dy * 0.15f, 0.0f);
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glScalef (0.04f, 0.04f, 0.04f);
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glColor4f (red * 0.9f, green * 0.9f, blue, alpha * 0.9f);
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glCallList (flarelist[1]);
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glTranslatef (x + dx * 0.25f, y + dy * 0.25f, 0.0f);
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glScalef (0.06f, 0.06f, 0.06f);
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glColor4f (red * 0.8f, green * 0.8f, blue, alpha * 0.9f);
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glCallList (flarelist[1]);
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glTranslatef (x + dx * 0.35f, y + dy * 0.35f, 0.0f);
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glScalef (0.08f, 0.08f, 0.08f);
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glColor4f (red * 0.7f, green * 0.7f, blue, alpha * 0.9f);
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glCallList (flarelist[1]);
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glTranslatef (x + dx * 1.25f, y + dy * 1.25f, 0.0f);
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glScalef (0.05f, 0.05f, 0.05f);
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glColor4f (red, green * 0.6f, blue * 0.6f, alpha * 0.9f);
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glCallList (flarelist[1]);
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glTranslatef (x + dx * 1.65f, y + dy * 1.65f, 0.0f);
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glRotatef (x, 0, 0, 1);
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glScalef (0.3f, 0.3f, 0.3f);
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glColor4f (red, green, blue, alpha);
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glCallList (flarelist[3]);
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glTranslatef (x + dx * 1.85f, y + dy * 1.85f, 0.0f);
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glScalef (0.04f, 0.04f, 0.04f);
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glColor4f (red, green * 0.6f, blue * 0.6f, alpha * 0.9f);
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glCallList (flarelist[1]);
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glTranslatef (x + dx * 2.2f, y + dy * 2.2f, 0.0f);
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glScalef (0.3f, 0.3f, 0.3f);
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glColor4f (red, green, blue, alpha * 0.7f);
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glCallList (flarelist[1]);
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glTranslatef (x + dx * 2.5f, y + dy * 2.5f, 0.0f);
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glScalef (0.6f, 0.6f, 0.6f);
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glColor4f (red, green, blue, alpha * 0.8f);
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glCallList (flarelist[3]);
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// Unsetup projection matrix
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glMatrixMode (GL_PROJECTION);
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glMatrixMode (GL_MODELVIEW);
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// super bright elongated glow for sucker, shockwave, stretcher, and bigmama
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void superFlare (float x, float y, float red, float green, float blue, float alpha)
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float fadewidth, temp;
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glBlendFunc (GL_SRC_ALPHA, GL_ONE);
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// Fade alpha if source is off edge of screen
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fadewidth = float (xsize) / 10.0f;
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temp = fadewidth + y;
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alpha *= temp / fadewidth;
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temp = fadewidth - y + ysize;
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alpha *= temp / fadewidth;
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temp = fadewidth + x;
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alpha *= temp / fadewidth;
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temp = fadewidth - x + xsize;
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alpha *= temp / fadewidth;
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// Setup projection matrix
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glMatrixMode (GL_PROJECTION);
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gluOrtho2D (0, aspectRatio, 0, 1.0f);
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glMatrixMode (GL_MODELVIEW);
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glTranslatef (x, y, 0.0f);
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glScalef (2.0f * alpha, 0.08f, 0.0f);
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glColor4f (red, green, blue, alpha);
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glCallList (flarelist[0]);
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glTranslatef (x, y, 0.0f);
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glScalef (0.4f, 0.35f * alpha + 0.05f, 1.0f);
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glColor4f (red, green, blue, alpha * 0.4f);
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glCallList (flarelist[2]);
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// Unsetup projection matrix
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glMatrixMode (GL_PROJECTION);
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glMatrixMode (GL_MODELVIEW);