1 | // FrameBuffer renderer in an OpenGL texture
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2 | // Andre Souza <asouza@olinux.com.br>
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3 |
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4 | #include <GL/gl.h>
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5 | #include <SDL/SDL.h>
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6 | #include <stdlib.h>
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7 | #include <string.h>
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8 |
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9 | // FLAGS
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10 | #define FB2GL_FS 1 // FULLSCREEN
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11 | #define FB2GL_RGBA 2 // Use RGBA (else use palette)
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12 | #define FB2GL_320 4 // 320x256 texture (else use 256x256)
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13 | #define FB2GL_AUDIO 8 // Activate SDL Audio
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14 | #define FB2GL_PITCH 16 // On fb2l_update, use pitch (else bytes per pixel)
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15 | #define FB2GL_EXPAND 32 // Create a RGB fb with the color lookup table
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16 |
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17 | // This extension isn't defined in OpenGL 1.1
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18 | #ifndef GL_EXT_paletted_texture
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19 | #define GL_EXT_paletted_texture 1
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20 | #endif
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21 |
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22 | class FB2GL {
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23 | private:
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24 | // Framebuffer for 8 bpp
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25 | unsigned char ogl_fb[256][256];
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26 | unsigned char ogl_fbb[256][64];
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27 | // Framebuffer for RGBA */
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28 | unsigned char ogl_fb1[256][256][4];
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29 | unsigned char ogl_fb2[256][64][4];
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30 | // Texture(s)
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31 | GLuint texture;
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32 | GLuint textureb;
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33 | // Display list
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34 | GLuint dlist;
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35 | // Color Table (256 colors, RGB)
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36 | char ogl_ctable[256][3];
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37 | char ogl_temp_ctable[256][3]; // Support for OpenGL 1.1
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38 | char flags;
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39 | void maketex();
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40 | void makedlist(int xf, int yf);
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41 | void display();
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42 |
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43 | public:
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44 | SDL_Surface *screen;
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45 | FB2GL() {
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46 | flags=0;
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47 | screen=NULL;
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48 | }
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49 | int init(int width, int height, int xfix, int yfix, char _flags);
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50 | void update(void *fb, int width, int height, int pitch, int xskip, int yskip);
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51 | void palette(int index, int r, int g, int b);
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52 | void setPalette(int first, int ncolors);
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53 | };
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54 |
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55 | void FB2GL::maketex()
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56 | {
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57 | glGenTextures(0,&texture);
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58 | glBindTexture(GL_TEXTURE_2D,texture);
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59 |
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60 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
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61 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
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62 |
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63 | // Bilinear filtering
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64 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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65 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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66 | /*
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67 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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68 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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69 | */
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70 |
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71 | if (flags & FB2GL_RGBA) {
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72 | glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,256,256,0,GL_RGBA, GL_UNSIGNED_BYTE, ogl_fb1);
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73 | }
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74 | else {
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75 | glTexImage2D(GL_TEXTURE_2D,0,GL_COLOR_INDEX,256,256,0,GL_COLOR_INDEX, GL_UNSIGNED_BYTE, ogl_fb);
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76 | }
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77 |
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78 | if (flags & FB2GL_320) {
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79 | glGenTextures(1,&textureb);
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80 | glBindTexture(GL_TEXTURE_2D,textureb);
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81 |
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82 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
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83 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
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84 |
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85 | // Bilinear filtering
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86 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
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87 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
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88 | /*
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89 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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90 | glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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91 | */
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92 |
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93 | if (flags & FB2GL_RGBA) {
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94 | glTexImage2D(GL_TEXTURE_2D,0,GL_RGBA,64,256,0,GL_RGBA,
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95 | GL_UNSIGNED_BYTE, ogl_fb2);
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96 | }
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97 | else {
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98 | glTexImage2D(GL_TEXTURE_2D,0,GL_COLOR_INDEX,64,256,0,GL_COLOR_INDEX,
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99 | GL_UNSIGNED_BYTE, ogl_fbb);
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100 | }
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101 | }
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102 |
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103 | }
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104 |
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105 | void FB2GL::makedlist(int xf, int yf)
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106 | {
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107 | double xfix=(double)xf/128; // 128 = 256/2 (half texture => 0.0 to 1.0)
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108 | double yfix=(double)yf/128;
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109 | // End of 256x256 (from -1.0 to 1.0)
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110 | double texend = (double)96/160; // 160=320/2 (== 0.0), 256-160=96.
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111 |
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112 | dlist=glGenLists(1);
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113 | glNewList(dlist,GL_COMPILE);
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114 |
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115 | glEnable(GL_TEXTURE_2D);
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116 |
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117 | glBindTexture(GL_TEXTURE_2D, texture);
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118 |
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119 | if (!(flags & FB2GL_320)) { // Normal 256x256
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120 | glBegin(GL_QUADS);
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121 | glTexCoord2f(0.0,1.0); glVertex2f(-1.0,-1.0-yfix); // upper left
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122 | glTexCoord2f(0.0,0.0); glVertex2f(-1.0,1.0); // lower left
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123 | glTexCoord2f(1.0,0.0); glVertex2f(1.0+xfix,1.0); // lower right
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124 | glTexCoord2f(1.0,1.0); glVertex2f(1.0+xfix,-1.0-yfix); // upper right
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125 | glEnd();
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126 | }
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127 | else { // 320x256
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128 |
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129 | // First, the 256x256 texture
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130 | glBegin(GL_QUADS);
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131 | glTexCoord2f(0.0,1.0); glVertex2f(-1.0,-1.0-yfix); // upper left
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132 | glTexCoord2f(0.0,0.0); glVertex2f(-1.0,1.0); // lower left
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133 | glTexCoord2f(1.0,0.0); glVertex2f(texend+xfix,1.0); // lower right
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134 | glTexCoord2f(1.0,1.0); glVertex2f(texend+xfix,-1.0-yfix); // upper right
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135 | glEnd();
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136 |
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137 | // 64x256
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138 | glBindTexture(GL_TEXTURE_2D, textureb);
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139 |
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140 | glBegin(GL_QUADS);
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141 | glTexCoord2f(0.0,1.0); glVertex2f(texend+xfix,-1.0-yfix); // upper left
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142 | glTexCoord2f(0.0,0.0); glVertex2f(texend+xfix,1.0); // lower left
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143 | glTexCoord2f(1.0,0.0); glVertex2f(1.0+xfix,1.0); // lower right
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144 | glTexCoord2f(1.0,1.0); glVertex2f(1.0+xfix,-1.0-yfix); // upper right
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145 | glEnd();
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146 | }
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147 |
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148 | glDisable(GL_TEXTURE_2D);
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149 |
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150 | glEndList();
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151 | }
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152 |
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153 | int FB2GL::init(int width, int height, int xfix, int yfix, char _flags)
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154 | {
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155 | char gl_ext[4096];
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156 | gl_ext[0]='\0';
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157 |
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158 | flags = _flags;
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159 |
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160 | // Fullscreen?
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161 | if ((flags & FB2GL_FS) && !screen) {
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162 | screen = SDL_SetVideoMode(width, height, 0, SDL_HWSURFACE | SDL_OPENGL | SDL_GL_DOUBLEBUFFER | SDL_FULLSCREEN);
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163 | }
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164 | else if (!screen) {
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165 | screen = SDL_SetVideoMode(width, height, 0, SDL_HWPALETTE | SDL_HWSURFACE | SDL_OPENGL | SDL_GL_DOUBLEBUFFER);
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166 | }
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167 |
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168 | if (!screen) {
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169 | fprintf(stderr, "Couldn't start video res %dx%d\n", width, height);
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170 | return 0;
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171 | }
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172 |
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173 |
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174 | if (!(flags & FB2GL_RGBA)) { // Check for Paletted Texture Extension
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175 |
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176 | strcpy(gl_ext, (char *)glGetString(GL_EXTENSIONS));
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177 | fprintf(stderr,"gl_ext= %s\n",gl_ext);
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178 |
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179 | if ( strstr( gl_ext , "GL_EXT_paletted_texture") )
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180 | glEnable(GL_EXT_paletted_texture);
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181 | else {
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182 | fprintf(stderr,"Your OpenGL version doesn't support paletted texture\n");
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183 | return 0;
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184 | }
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185 | }
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186 |
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187 | maketex();
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188 | makedlist(xfix, yfix);
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189 |
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190 | return 1;
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191 | }
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192 |
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193 | void FB2GL::display()
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194 | {
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195 | glCallList(dlist);
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196 | SDL_GL_SwapBuffers();
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197 | }
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198 |
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199 | void FB2GL::update(void *fb, int w, int h, int pitch, int xskip, int yskip) {
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200 | unsigned char *fb1=(unsigned char *)fb;
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201 | int x,y,scr_pitch,byte=0;
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202 |
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203 | if (flags & FB2GL_PITCH) scr_pitch=pitch;
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204 | else {
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205 | scr_pitch=w*pitch;
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206 | byte = pitch; // Bytes perl pixel (for RGBA mode)
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207 | }
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208 |
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209 | if (flags & FB2GL_RGBA) {
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210 |
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211 | if (flags & FB2GL_EXPAND) { // Expand the 8 bit fb into a RGB fb
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212 |
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213 | for (y=yskip; y<h; y++) {
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214 | for (x=xskip; x<w; x++) {
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215 | if (x<256) {
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216 | ogl_fb1[y][x][0] = ogl_ctable[*(fb1+x)][0];
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217 | ogl_fb1[y][x][1] = ogl_ctable[*(fb1+x)][1];
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218 | ogl_fb1[y][x][2] = ogl_ctable[*(fb1+x)][2];
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219 | }
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220 | else {
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221 | ogl_fb2[y][x-256][0] = ogl_ctable[*(fb1+x)][0];
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222 | ogl_fb2[y][x-256][1] = ogl_ctable[*(fb1+x)][1];
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223 | ogl_fb2[y][x-256][2] = ogl_ctable[*(fb1+x)][2];
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224 | }
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225 | }
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226 | fb1 += scr_pitch;
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227 | }
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228 | }
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229 | else { // No expansion
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230 | for (y=yskip; y<h; y++) {
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231 | for (x=xskip; x<w; x++) {
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232 | if (x<256) {
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233 | ogl_fb1[y-yskip][x-xskip][0] = *(fb1+(x*byte));
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234 | ogl_fb1[y-yskip][x-xskip][1] = *(fb1+(x*byte)+1);
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235 | ogl_fb1[y-yskip][x-xskip][2] = *(fb1+(x*byte)+2);
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236 | }
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237 | else {
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238 | ogl_fb2[y-yskip][x-256][0] = *(fb1+(x*byte));
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239 | ogl_fb2[y-yskip][x-256][1] = *(fb1+(x*byte)+1);
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240 | ogl_fb2[y-yskip][x-256][2] = *(fb1+(x*byte)+2);
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241 | }
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242 | }
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243 | fb1 += scr_pitch;
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244 | }
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245 | }
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246 |
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247 | // Update 256x256 texture
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248 | glBindTexture(GL_TEXTURE_2D,texture);
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249 | glFlush();
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250 | glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,256-xskip,256-yskip,GL_RGBA,
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251 | GL_UNSIGNED_BYTE,ogl_fb1);
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252 |
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253 | if (flags & FB2GL_320) {
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254 | // Update 64x256 texture
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255 | glBindTexture(GL_TEXTURE_2D,textureb);
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256 | glFlush();
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257 | glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,64-xskip,256-yskip,GL_RGBA,
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258 | GL_UNSIGNED_BYTE,ogl_fb2);
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259 | }
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260 |
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261 | }
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262 | else { // non RGBA (paletted)
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263 |
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264 | for (y=0; y<h; y++)
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265 | for (x=0; x<w; x++) {
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266 | if (x<256) {
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267 | ogl_fb[ y ][ x ] = *(fb1 + (y)*scr_pitch + x);
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268 | }
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269 | else {
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270 | ogl_fbb[ y ][ x - 256 ] = *(fb1 + y*scr_pitch + x);
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271 | }
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272 | }
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273 |
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274 | // Update 256x256 texture
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275 | glBindTexture(GL_TEXTURE_2D,texture);
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276 | glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,256-xskip,256-yskip,
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277 | GL_COLOR_INDEX, GL_UNSIGNED_BYTE,ogl_fb);
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278 |
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279 | if (flags & FB2GL_320) {
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280 | // Update 64x256 texture
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281 | glBindTexture(GL_TEXTURE_2D,textureb);
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282 | glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,64-xskip,256-yskip,
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283 | GL_COLOR_INDEX, GL_UNSIGNED_BYTE,ogl_fbb);
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284 | }
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285 |
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286 | }
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287 |
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288 | display();
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289 |
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290 | }
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291 |
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292 | void FB2GL::palette(int i, int r, int g, int b) {
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293 | if (flags & FB2GL_EXPAND) {
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294 | ogl_temp_ctable[i][0]=r;
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295 | ogl_temp_ctable[i][1]=g;
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296 | ogl_temp_ctable[i][2]=b;
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297 | }
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298 | else { // Paletted texture
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299 | ogl_ctable[i][0]=r;
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300 | ogl_ctable[i][1]=g;
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301 | ogl_ctable[i][2]=b;
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302 | }
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303 | }
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304 |
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305 | void FB2GL::setPalette(int f, int n) {
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306 | char temp[256][3];
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307 | int i;
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308 |
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309 | if (flags & FB2GL_EXPAND) {
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310 | for (i=f; i<n; i++) {
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311 | ogl_ctable[i][0] = ogl_temp_ctable[i][0];
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312 | ogl_ctable[i][1] = ogl_temp_ctable[i][1];
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313 | ogl_ctable[i][2] = ogl_temp_ctable[i][2];
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314 | }
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315 | }
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316 | else { // Paletted texture
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317 | glBindTexture(GL_TEXTURE_2D,texture);
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318 | glGetColorTable(GL_TEXTURE_2D,GL_RGB,GL_UNSIGNED_BYTE,&temp);
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319 |
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320 | for (i=f; i<n; i++) {
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321 | temp[i][0] = ogl_ctable[i][0];
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322 | temp[i][1] = ogl_ctable[i][1];
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323 | temp[i][2] = ogl_ctable[i][2];
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324 | }
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325 |
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326 | glColorTable(GL_TEXTURE_2D,GL_RGB,256,GL_RGB,GL_UNSIGNED_BYTE,&temp);
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327 |
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328 | if (flags & FB2GL_320) {
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329 | glBindTexture(GL_TEXTURE_2D,textureb);
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330 | glColorTable(GL_TEXTURE_2D,GL_RGB,256,GL_RGB,GL_UNSIGNED_BYTE,&temp);
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331 | }
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332 |
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333 | }
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334 |
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335 | }
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