1 /* 2 3 Copyright (c) 2002, Calum Robinson 4 All rights reserved. 5 6 Redistribution and use in source and binary forms, with or without 7 modification, 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 20 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND 21 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 22 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 23 DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR 24 ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 25 (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 26 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON 27 ANY 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 29 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 30 31 */ 32 33 34 #include "Texture.h" 35 #include "Shared.h" 36 37 38 static GLubyte smallTextureArray[32][32]; 39 static GLubyte bigTextureArray[256][256][2]; 40 GLuint theTexture = 0; 41 42 43 // simple smoothing routine 44 static void 45 SmoothTexture(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 69 static void 70 SpeckleTexture(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 93 static void 94 MakeSmallTexture(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 } 134 135 136 static void 137 CopySmallTextureToBigTexture(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 } 146 147 148 static void 149 AverageLastAndFirstTextures(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 } 158 159 160 void 161 MakeTexture() 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