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#include "Texture.h"
33#include "Shared.h"
34
35static GLubyte smallTextureArray[32][32];
36static GLubyte bigTextureArray[256][256][2];
37GLuint theTexture = 0;
38
39/* simple smoothing routine */
40static void SmoothTexture(void)
41{
42	GLubyte filter[32][32];
43	int i,j;
44	float t;
45	for (i=1;i<31;i++)
46	{
47		for (j=1;j<31;j++)
48		{
49			t = (float) smallTextureArray[i][j]*4;
50			t += (float) smallTextureArray[i-1][j];
51			t += (float) smallTextureArray[i+1][j];
52			t += (float) smallTextureArray[i][j-1];
53			t += (float) smallTextureArray[i][j+1];
54			t /= 8.0f;
55			filter[i][j] = (GLubyte) t;
56		}
57	}
58	for (i=1;i<31;i++)
59	{
60		for (j=1;j<31;j++)
61		{
62			smallTextureArray[i][j] = filter[i][j];
63		}
64	}
65}
66
67/* add some randomness to texture data */
68static void SpeckleTexture(void)
69{
70	int i,j;
71	int speck;
72	float t;
73	for (i=2;i<30;i++)
74	{
75		for (j=2;j<30;j++)
76		{
77			speck = 1;
78			while (speck <= 32 && random() % 2)
79			{
80				t = (float) MIN_(255,smallTextureArray[i][j]+speck);
81				smallTextureArray[i][j] = (GLubyte) t;
82				speck+=speck;
83			}
84			speck = 1;
85			while (speck <= 32 && random() % 2)
86			{
87				t = (float) MAX_(0,smallTextureArray[i][j]-speck);
88				smallTextureArray[i][j] = (GLubyte) t;
89				speck+=speck;
90			}
91		}
92	}
93}
94
95static void MakeSmallTexture(void)
96{
97	static int firstTime = 1;
98	int i,j;
99	float r,t;
100	if (firstTime)
101	{
102		firstTime = 0;
103		for (i=0;i<32;i++)
104		{
105			for (j=0;j<32;j++)
106			{
107				r = (float) sqrt((i-15.5)*(i-15.5)+(j-15.5)*(j-15.5));
108				if (r > 15.0f)
109				{
110					smallTextureArray[i][j] = 0;
111				}
112				else
113				{
114					t = 255.0f * (float) cos(r*M_PI/31.0);
115					smallTextureArray[i][j] = (GLubyte) t;
116				}
117			}
118		}
119	}
120	else
121	{
122		for (i=0;i<32;i++)
123		{
124			for (j=0;j<32;j++)
125			{
126				r = (float) sqrt((i-15.5)*(i-15.5)+(j-15.5)*(j-15.5));
127				if (r > 15.0f)
128				{
129					t = 0.0f;
130				}
131				else
132				{
133					t = 255.0f * (float) cos(r*M_PI/31.0);
134				}
135				smallTextureArray[i][j] = (GLubyte) MIN_(255,(t+smallTextureArray[i][j]+smallTextureArray[i][j])/3);
136			}
137		}
138	}
139	SpeckleTexture();
140	SmoothTexture();
141	SmoothTexture();
142}
143
144static void CopySmallTextureToBigTexture(int k, int l)
145{
146	int i,j;
147	for (i=0;i<32;i++)
148	{
149		for (j=0;j<32;j++)
150		{
151			bigTextureArray[i+k][j+l][0] = smallTextureArray[i][j];
152			bigTextureArray[i+k][j+l][1] = smallTextureArray[i][j];
153		}
154	}
155}
156
157static void AverageLastAndFirstTextures(void)
158{
159	int i,j;
160	int t;
161	for (i=0;i<32;i++)
162	{
163		for (j=0;j<32;j++)
164		{
165			t = (smallTextureArray[i][j] + bigTextureArray[i][j][0]) / 2;
166			smallTextureArray[i][j] = (GLubyte) MIN_(255,t);
167		}
168	}
169}
170
171void MakeTexture()
172{
173	int i,j;
174	for (i=0;i<8;i++)
175	{
176		for (j=0;j<8;j++)
177		{
178			if (i==7 && j==7)
179			{
180				AverageLastAndFirstTextures();
181			}
182			else
183			{
184				MakeSmallTexture();
185			}
186			CopySmallTextureToBigTexture(i*32,j*32);
187		}
188	}
189
190	glPixelStorei(GL_UNPACK_ALIGNMENT,1);
191
192	glGenTextures(1, &theTexture);
193	glBindTexture(GL_TEXTURE_2D, theTexture);
194
195	/* Set the tiling mode (this is generally always GL_REPEAT). */
196	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
197	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
198
199	/* Set the filtering. */
200	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
201	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
202
203	gluBuild2DMipmaps(GL_TEXTURE_2D, 2, 256, 256, GL_LUMINANCE_ALPHA, GL_UNSIGNED_BYTE, bigTextureArray);
204	glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
205}
206