1/*
2
3Copyright (c) 2002, Calum Robinson
4All rights reserved.
5
6Redistribution and use in source and binary forms, with or without
7modification, are permitted provided that the following conditions are met:
8
9* Redistributions of source code must retain the above copyright notice, this
10  list of conditions and the following disclaimer.
11
12* Redistributions in binary form must reproduce the above copyright notice,
13  this list of conditions and the following disclaimer in the documentation
14  and/or other materials provided with the distribution.
15
16* Neither the name of the author nor the names of its contributors may be used
17  to endorse or promote products derived from this software without specific
18  prior written permission.
19
20THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
21ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
22WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
23DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
24ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
25(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
27ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
29SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30
31*/
32
33
34#include "Texture.h"
35#include "Shared.h"
36
37
38static GLubyte smallTextureArray[32][32];
39static GLubyte bigTextureArray[256][256][2];
40GLuint theTexture = 0;
41
42
43// simple smoothing routine
44static void
45SmoothTexture(void)
46{
47	GLubyte filter[32][32];
48	float t;
49	for (int i = 1; i < 31; i++) {
50		for (int j = 1; j < 31; j++) {
51			t  = (float)smallTextureArray[i][j] * 4;
52			t += (float)smallTextureArray[i - 1][j];
53			t += (float)smallTextureArray[i + 1][j];
54			t += (float)smallTextureArray[i][j - 1];
55			t += (float)smallTextureArray[i][j + 1];
56			t /= 8.0f;
57			filter[i][j] = (GLubyte) t;
58		}
59	}
60
61	for (int i = 1; i < 31; i++){
62		for (int j = 1; j < 31; j++)
63			smallTextureArray[i][j] = filter[i][j];
64	}
65}
66
67
68// add some randomness to texture data
69static void
70SpeckleTexture(void)
71{
72	int speck;
73	float t;
74	for (int i = 2; i < 30; i++) {
75		for (int j = 2; j < 30; j++) {
76			speck = 1;
77			while (speck <= 32 && random() % 2) {
78				t = (float) MIN_(255, smallTextureArray[i][j] + speck);
79				smallTextureArray[i][j] = (GLubyte)t;
80				speck += speck;
81			}
82			speck = 1;
83			while (speck <= 32 && random() % 2) {
84				t = (float)MAX_(0, smallTextureArray[i][j] - speck);
85				smallTextureArray[i][j] = (GLubyte)t;
86				speck += speck;
87			}
88		}
89	}
90}
91
92
93static void
94MakeSmallTexture(void)
95{
96	static int firstTime = 1;
97
98	if (firstTime) {
99		firstTime = 0;
100		for (int i = 0; i < 32; i++) {
101			for (int j = 0; j < 32; j++) {
102				float r = (float)sqrt((i - 15.5) * (i - 15.5) + (j - 15.5)
103					* (j - 15.5));
104				if (r > 15.0f)
105					smallTextureArray[i][j] = 0;
106				else {
107					float t = 255.0f * (float) cos(r * M_PI / 31.0);
108					smallTextureArray[i][j] = (GLubyte)t;
109				}
110			}
111		}
112	} else {
113		for (int i = 0; i < 32; i++) {
114			for (int j = 0; j < 32; j++) {
115				float t;
116				float r = (float)sqrt((i - 15.5) * (i - 15.5) + (j - 15.5)
117					* (j - 15.5));
118				if (r > 15.0f)
119					t = 0.0f;
120				else
121					t = 255.0f * (float) cos(r*M_PI/31.0);
122
123				smallTextureArray[i][j]
124					= (GLubyte)MIN_(255, (t + smallTextureArray[i][j]
125						+ smallTextureArray[i][j]) / 3);
126			}
127		}
128	}
129
130	SpeckleTexture();
131	SmoothTexture();
132	SmoothTexture();
133}
134
135
136static void
137CopySmallTextureToBigTexture(int k, int l)
138{
139	for (int i = 0; i < 32; i++) {
140		for (int j = 0; j < 32; j++) {
141			bigTextureArray[i + k][j + l][0] = smallTextureArray[i][j];
142			bigTextureArray[i + k][j + l][1] = smallTextureArray[i][j];
143		}
144	}
145}
146
147
148static void
149AverageLastAndFirstTextures(void)
150{
151	for (int i = 0; i < 32; i++) {
152		for (int j = 0; j < 32; j++) {
153			int t = (smallTextureArray[i][j] + bigTextureArray[i][j][0]) / 2;
154			smallTextureArray[i][j] = (GLubyte)MIN_(255, t);
155		}
156	}
157}
158
159
160void
161MakeTexture()
162{
163	for (int i = 0; i < 8; i++) {
164		for (int j = 0; j < 8; j++) {
165			if (i == 7 && j == 7)
166				AverageLastAndFirstTextures();
167			else
168				MakeSmallTexture();
169
170			CopySmallTextureToBigTexture(i * 32, j * 32);
171		}
172	}
173
174	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
175
176	glGenTextures(1, &theTexture);
177	glBindTexture(GL_TEXTURE_2D, theTexture);
178
179	// Set the tiling mode (this is generally always GL_REPEAT).
180	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
181	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
182
183	// Set the filtering.
184	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
185	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,
186		GL_LINEAR_MIPMAP_NEAREST);
187
188	gluBuild2DMipmaps(GL_TEXTURE_2D, 2, 256, 256, GL_LUMINANCE_ALPHA,
189		GL_UNSIGNED_BYTE, bigTextureArray);
190	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
191}
192