1 /*
2 * Copyright (C) 2002 Terence M. Welsh
3 * Ported to Linux by Tugrul Galatali <tugrul@galatali.com>
4 *
5 * Skyrocket is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * Skyrocket is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
19 #include <math.h>
20 #include <GL/gl.h>
21
22 #include "skyrocket_shockwave.h"
23 #include "skyrocket_world.h"
24
25 extern unsigned int cloudtex;
26
27 float shockwavegeom[7][WAVESTEPS + 1][3];
28
initShockwave()29 void initShockwave ()
30 {
31 int i, j;
32 float ch, sh;
33
34 shockwavegeom[0][0][0] = 1.0f;
35 shockwavegeom[0][0][1] = 0.0f;
36 shockwavegeom[0][0][2] = 0.0f;
37 shockwavegeom[1][0][0] = 0.985f;
38 shockwavegeom[1][0][1] = 0.035f;
39 shockwavegeom[1][0][2] = 0.0f;
40 shockwavegeom[2][0][0] = 0.95f;
41 shockwavegeom[2][0][1] = 0.05f;
42 shockwavegeom[2][0][2] = 0.0f;
43 shockwavegeom[3][0][0] = 0.85f;
44 shockwavegeom[3][0][1] = 0.05f;
45 shockwavegeom[3][0][2] = 0.0f;
46 shockwavegeom[4][0][0] = 0.75f;
47 shockwavegeom[4][0][1] = 0.035f;
48 shockwavegeom[4][0][2] = 0.0f;
49 shockwavegeom[5][0][0] = 0.65f;
50 shockwavegeom[5][0][1] = 0.01f;
51 shockwavegeom[5][0][2] = 0.0f;
52 shockwavegeom[6][0][0] = 0.5f;
53 shockwavegeom[6][0][1] = 0.0f;
54 shockwavegeom[6][0][2] = 0.0f;
55
56 for (i = 1; i <= WAVESTEPS; i++) {
57 ch = cos (6.28318530718f * (float (i) / float (WAVESTEPS)));
58 sh = sin (6.28318530718f * (float (i) / float (WAVESTEPS)));
59 for (j = 0; j <= 6; j++) {
60 shockwavegeom[j][i][0] = ch * shockwavegeom[j][0][0];
61 shockwavegeom[j][i][1] = shockwavegeom[j][0][1];
62 shockwavegeom[j][i][2] = sh * shockwavegeom[j][0][0];
63 }
64 }
65 }
66
67 // temp influences color intensity (0.0 - 1.0)
68 // texmove is amount to advance the texture coordinates
drawShockwave(float temperature,float texmove)69 void drawShockwave (float temperature, float texmove)
70 {
71 static int i, j;
72 float colors[7][4];
73 static float u, v1, v2;
74 float temp;
75
76 // setup diminishing alpha values in color array
77 if (temperature > 0.5f) {
78 temp = 1.0f;
79 colors[0][3] = 1.0f;
80 colors[1][3] = 0.9f;
81 colors[2][3] = 0.8f;
82 colors[3][3] = 0.7f;
83 colors[4][3] = 0.5f;
84 colors[5][3] = 0.3f;
85 colors[6][3] = 0.0f;
86 } else {
87 temp = temperature * 2.0f;
88 colors[0][3] = temp;
89 colors[1][3] = temp * 0.9f;
90 colors[2][3] = temp * 0.8f;
91 colors[3][3] = temp * 0.7f;
92 colors[4][3] = temp * 0.5f;
93 colors[5][3] = temp * 0.3f;
94 colors[6][3] = 0.0f;
95 }
96 // setup rgb values in color array
97 for (i = 0; i <= 5; i++) {
98 colors[i][0] = 1.0f;
99 //colors[i][1] = temp + (((1.0f - temp) * 0.5f) - (1.0f - temp) * float(i) * 0.1f);
100 colors[i][1] = temp;
101 colors[i][2] = temperature;
102 }
103
104 glDisable (GL_CULL_FACE);
105 glBlendFunc (GL_SRC_ALPHA, GL_ONE);
106 glEnable (GL_BLEND);
107 glEnable (GL_TEXTURE_2D);
108 glBindTexture (GL_TEXTURE_2D, cloudtex);
109
110 // draw bottom of shockwave
111 for (i = 0; i < 6; i++) {
112 v1 = float (i + 1) * 0.07f - texmove;
113 v2 = float (i) * 0.07f - texmove;
114
115 glBegin (GL_TRIANGLE_STRIP);
116 for (j = 0; j <= WAVESTEPS; j++) {
117 u = (float (j) / float (WAVESTEPS))*10.0f;
118 glColor4fv (colors[i + 1]);
119 glTexCoord2f (u, v1);
120 glVertex3f (shockwavegeom[i + 1][j][0], -shockwavegeom[i + 1][j][1], shockwavegeom[i + 1][j][2]);
121 glColor4fv (colors[i]);
122 glTexCoord2f (u, v2);
123 glVertex3f (shockwavegeom[i][j][0], -shockwavegeom[i][j][1], shockwavegeom[i][j][2]);
124 }
125 glEnd ();
126 }
127
128 // keep colors a little warmer on top (more green)
129 if (temperature < 0.5f)
130 for (i = 1; i <= 5; i++)
131 colors[i][1] = temperature + 0.5f;
132
133 // draw top of shockwave
134 for (i = 0; i < 6; i++) {
135 v1 = float (i) * 0.07f - texmove;
136 v2 = float (i + 1) * 0.07f - texmove;
137
138 glBegin (GL_TRIANGLE_STRIP);
139 for (j = 0; j <= WAVESTEPS; j++) {
140 u = (float (j) / float (WAVESTEPS))*10.0f;
141 glColor4fv (colors[i]);
142 glTexCoord2f (u, v1);
143 glVertex3f (shockwavegeom[i][j][0], shockwavegeom[i][j][1], shockwavegeom[i][j][2]);
144 glColor4fv (colors[i + 1]);
145 glTexCoord2f (u, v2);
146 glVertex3f (shockwavegeom[i + 1][j][0], shockwavegeom[i + 1][j][1], shockwavegeom[i + 1][j][2]);
147 }
148 glEnd ();
149 }
150
151 glEnable (GL_CULL_FACE);
152 }
153