src/libsdl/opengl.c

   1 /* OpenGL rendering
   2  *
   3  * (C) 2018 by Andreas Eversberg <jolly@eversberg.eu>
   4  * All Rights Reserved
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdint.h>
  22 #include <stdlib.h>
  23 #include <math.h>
  24 #include <errno.h>
  25 #include "print.h"
  26 #include "opengl.h"
  27 #include <GL/glew.h>
  28
  29 #define MAX_OSD 2
  30 static uint8_t *legacy_rgb = NULL;
  31 static uint8_t *benson_rgb = NULL;
  32 static uint8_t *osd_rgba[MAX_OSD] = { NULL, NULL };
  33 static GLuint legacy_name;
  34 static GLuint benson_name;
  35 static GLuint osd_name[MAX_OSD];
  36 static int screen_width, screen_height;
  37 static int image_width, image_height;
  38 static int osd_width[MAX_OSD], osd_height[MAX_OSD];
  39 static int texture_size;
  40 static int osd_size[MAX_OSD];
  41
  42 /* alloc and init an image texture with size that is greater than the power of two */
  43 int init_opengl(int _image_width, int _image_height)
  44 {
  45         int rc;
  46
  47         image_width = _image_width;
  48         image_height = _image_height;
  49
  50         /* generate texture */
  51         for (texture_size = 1; texture_size <= image_width || texture_size <= image_height; texture_size *= 2)
  52                 ;
  53
  54         legacy_rgb = calloc(texture_size * texture_size, 3);
  55         if (!legacy_rgb) {
  56                 print_error("Failed to allocate texture\n");
  57                 rc = -ENOMEM;
  58                 goto error;
  59         }
  60         glShadeModel(GL_FLAT);
  61         glPixelStorei(GL_UNPACK_ALIGNMENT, 1); /* bytes */
  62         glGenTextures(1, &legacy_name);
  63         glBindTexture(GL_TEXTURE_2D, legacy_name);
  64         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  65         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  66         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture_size, texture_size, 0, GL_RGB, GL_UNSIGNED_BYTE, legacy_rgb);
  67
  68         benson_rgb = calloc(texture_size * texture_size, 3);
  69         if (!benson_rgb) {
  70                 print_error("Failed to allocate texture\n");
  71                 rc = -ENOMEM;
  72                 goto error;
  73         }
  74
  75         glShadeModel(GL_FLAT);
  76         glPixelStorei(GL_UNPACK_ALIGNMENT, 1); /* bytes */
  77         glGenTextures(1, &benson_name);
  78         glBindTexture(GL_TEXTURE_2D, benson_name);
  79         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  80         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  81         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture_size, texture_size, 0, GL_RGB, GL_UNSIGNED_BYTE, benson_rgb);
  82
  83         return 0;
  84
  85 error:
  86         exit_opengl();
  87         return rc;
  88 }
  89
  90 /* alloc and init an osd texture with size that is greater than the power of two */
  91 int init_osd(int num, int _osd_width, int _osd_height)
  92 {
  93         int rc;
  94
  95         if (num < 0 || num >= MAX_OSD) {
  96                 print_error("given OSD number out of range");
  97                 rc = -ENOMEM;
  98                 goto error;
  99         }
 100
 101         osd_width[num] = _osd_width;
 102         osd_height[num] = _osd_height;
 103
 104         /* generate texture */
 105         for (osd_size[num] = 1; osd_size[num] <= osd_width[num] || osd_size[num] <= osd_height[num]; osd_size[num] *= 2)
 106                 ;
 107         osd_rgba[num] = calloc(osd_size[num] * osd_size[num], 4);
 108         if (!osd_rgba[num]) {
 109                 print_error("Failed to allocate texture\n");
 110                 rc = -ENOMEM;
 111                 goto error;
 112         }
 113         glPixelStorei(GL_UNPACK_ALIGNMENT, 1); /* bytes */
 114         glGenTextures(1, &osd_name[num]);
 115         glBindTexture(GL_TEXTURE_2D, osd_name[num]);
 116         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 117         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 118         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, osd_size[num], osd_size[num], 0, GL_RGBA, GL_UNSIGNED_BYTE, osd_rgba[num]);
 119
 120         return 0;
 121
 122 error:
 123         return rc;
 124 }
 125
 126 /* set clip planes so that the image portion of the image texture is centered and pixels are rectengular */
 127 void resize_opengl(int _screen_width, int _screen_height)
 128 {
 129         screen_width = _screen_width;
 130         screen_height = _screen_height;
 131 }
 132
 133 void opengl_clear(void)
 134 {
 135         /* clear screen */
 136         glClearColor(0.0, 0.0, 0.0, 1.0);
 137         glClear(GL_COLOR_BUFFER_BIT);
 138 }
 139
 140 /* set viewport for legacy image */
 141 void opengl_viewport_legacy(int split)
 142 {
 143         int view_x, view_y;
 144         int view_width, view_height;
 145         int new_width, new_height;
 146
 147         if (!split) {
 148                 view_x = 0;
 149                 view_y = 0;
 150                 view_width = screen_width;
 151                 view_height = screen_height;
 152         } else {
 153                 view_x = 0;
 154                 view_y = screen_height / 2;
 155                 view_width = screen_width;
 156                 view_height = screen_height / 2;
 157         }
 158
 159         /* avoid division by zero, if one dimension is too small */
 160         if (view_width < 1 || view_height < 1)
 161                 return;
 162
 163         /* calculate a viewport that has apect of image_width:image_height */
 164         if (view_height * image_width > view_width * image_height) {
 165                 new_height = view_width * image_height / image_width;
 166                 view_y = view_y + view_height / 2 - new_height / 2;
 167                 view_height = new_height;
 168         } else if (view_height * image_width < view_width * image_height) {
 169                 new_width = view_height * image_width / image_height;
 170                 view_x = view_x + view_width / 2 - new_width / 2;
 171                 view_width = new_width;
 172         }
 173
 174         /* avoid views that are too small */
 175         if (view_width < 1 || view_height < 1)
 176                 return;
 177
 178         /* viewport and projection matrix to view rectangle */
 179         glViewport((GLsizei)view_x, (GLsizei)view_y, (GLsizei)view_width, (GLsizei)view_height);
 180         glMatrixMode(GL_PROJECTION);
 181         glLoadIdentity();
 182         glOrtho(0.0, 1.0, 1.0, 0.0, -1.0, 1.0);
 183         glMatrixMode(GL_MODELVIEW);
 184 }
 185
 186 /* render legacy image texture */
 187 void opengl_blit_legacy(uint8_t *rgb, int filter)
 188 {
 189         double width = (double)image_width / (double)texture_size;
 190         double height = (double)image_height / (double)texture_size;
 191
 192         glEnable(GL_TEXTURE_2D);
 193         glBindTexture(GL_TEXTURE_2D, legacy_name);
 194         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);  /* no modulation with color */
 195         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 196         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 197         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, image_width, image_height, GL_RGB, GL_UNSIGNED_BYTE, rgb);
 198         glBegin(GL_QUADS);
 199         glTexCoord2f(0.0, 0.0);
 200         glVertex3f(0.0, 0.0, 0.0);
 201         glTexCoord2f(width, 0.0);
 202         glVertex3f(1.0, 0.0, 0.0);
 203         glTexCoord2f(width, height);
 204         glVertex3f(1.0, 1.0, 0.0);
 205         glTexCoord2f(0.0, height);
 206         glVertex3f(0.0, 1.0, 0.0);
 207         glEnd();
 208         glDisable(GL_TEXTURE_2D);
 209 }
 210
 211 /* set viewport for improved rendering */
 212 void opengl_viewport_improved(int split, int benson_at_line, double fov, double benson_size)
 213 {
 214         int view_x, view_y;
 215         int view_width, view_height;
 216         int new_width, new_height;
 217
 218         /* center view, or put it in the top half of the window */
 219         if (!split) {
 220                 view_x = 0;
 221                 view_y = 0;
 222                 view_width = screen_width;
 223                 view_height = screen_height;
 224         } else {
 225                 view_x = 0;
 226                 view_y = 0;
 227                 view_width = screen_width;
 228                 view_height = screen_height / 2;
 229         }
 230
 231         /* avoid division by zero, if one dimension is too small */
 232         if (view_width < 1 || view_height < 1)
 233                 return;
 234
 235         /* calculate a viewport that has apect of image_width:image_height */
 236         if (view_height * image_width > view_width * image_height) {
 237                 new_height = view_width * image_height / image_width;
 238                 view_y = view_y + view_height / 2 - new_height / 2;
 239                 view_height = new_height;
 240         } else if (view_height * image_width < view_width * image_height) {
 241                 new_width = view_height * image_width / image_height;
 242                 view_x = view_x + view_width / 2 - new_width / 2;
 243                 view_width = new_width;
 244         }
 245
 246         /* avoid views that are too small */
 247         if (view_width < 1 || view_height < 1)
 248                 return;
 249
 250         /* viewport and projection matrix */
 251         glViewport((GLsizei)view_x, (GLsizei)view_y, (GLsizei)view_width, (GLsizei)view_height);
 252         glMatrixMode(GL_PROJECTION);
 253         glLoadIdentity();
 254
 255         /* calculate field-of-view */
 256         double slope = tan(fov / 360 * M_PI);
 257         /* make frustum to center the view in the game view above benson */
 258         double left = -slope;
 259         double right = slope;
 260         double benson_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 261         double top = slope * ((double)image_height - benson_start_at_position) / (double)image_width;
 262         double bottom = -slope * ((double)image_height * 2.0 - ((double)image_height - benson_start_at_position)) / (double)image_width;
 263         glFrustum(left, right, bottom, top, 1.0, 5000000000.0);
 264         glMatrixMode(GL_MODELVIEW);
 265 }
 266
 267 /* render only benson */
 268 void opengl_blit_benson(uint8_t *rgb, int filter, int benson_at_line, double fov, double benson_size, int pixel_size)
 269 {
 270         double border = (benson_size != 1.0) ? (double)pixel_size : 0.0;
 271         double texture_left = border / (double)texture_size;
 272         double texture_right = ((double)image_width - border) / (double)texture_size;
 273         double texture_top = ((double)benson_at_line + border) / (double)texture_size;
 274         double texture_bottom = ((double)image_height -border) / (double)texture_size;
 275         double benson_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 276         double benson_top = -((double)image_height - benson_start_at_position) / (double)image_width;
 277         double benson_bottom = -((double)image_height * 2.0 - ((double)image_height - benson_start_at_position)) / (double)image_width;
 278
 279         /* calculate field-of-view */
 280         double slope = tan(fov / 360 * M_PI);
 281
 282         /* render benson */
 283         rgb += image_width * benson_at_line * 3;
 284         glEnable(GL_TEXTURE_2D);
 285         glBindTexture(GL_TEXTURE_2D, benson_name);
 286         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);  /* no modulation with color */
 287         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 288         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 289         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, benson_at_line, image_width, image_height - benson_at_line, GL_RGB, GL_UNSIGNED_BYTE, rgb);
 290         glBegin(GL_QUADS);
 291         glTexCoord2f(texture_left, texture_bottom);
 292         glVertex3f(-100.0 * benson_size, 100.0 * benson_bottom, -100.0 / slope);
 293         glTexCoord2f(texture_right, texture_bottom);
 294         glVertex3f(100.0 * benson_size, 100.0 * benson_bottom, -100.0 / slope);
 295         glTexCoord2f(texture_right, texture_top);
 296         glVertex3f(100.0 * benson_size, 100.0 * benson_top, -100.0 / slope);
 297         glTexCoord2f(texture_left, texture_top);
 298         glVertex3f(-100.0 * benson_size, 100.0 * benson_top, -100.0 / slope);
 299         glEnd();
 300         glDisable(GL_TEXTURE_2D);
 301 }
 302
 303 /* render osd texture */
 304 void opengl_blit_osd(int num, uint8_t *rgba, int filter, int benson_at_line, double fov, double benson_size, double scale_x, double scale_y, double offset_x, double offset_y)
 305 {
 306         double texture_left = 0.0;
 307         double texture_right = (double)osd_width[num] / (double)osd_size[num];
 308         double texture_top = 0.0;
 309         double texture_bottom = (double)osd_height[num] / (double)osd_size[num];
 310         double benson_start_at_position;
 311         double osd_left = 0.0;
 312         double osd_right = 1.0;
 313         double osd_top = 0.0;
 314         double osd_bottom = 1.0;
 315         double slope, range, center;
 316         if (fov) {
 317                 osd_left = -1.0;
 318                 osd_right = 1.0;
 319                 benson_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 320                 osd_top = ((double)image_height - benson_start_at_position) / (double)image_width;
 321                 osd_bottom = -((double)image_height * 2.0 - ((double)image_height - benson_start_at_position)) / (double)image_width;
 322                 /* calculate field-of-view */
 323                 slope = tan(fov / 360 * M_PI);
 324         }
 325         range = (osd_right - osd_left) / 2.0;
 326         center = (osd_right + osd_left) / 2.0;
 327         osd_left = (osd_left - center) * scale_x + center + range * offset_x;
 328         osd_right = (osd_right - center) * scale_x + center + range * offset_x;
 329         range = (osd_bottom - osd_top) / 2.0;
 330         center = (osd_bottom + osd_top) / 2.0;
 331         osd_top = (osd_top - center) * scale_y + center + range * offset_y;
 332         osd_bottom = (osd_bottom - center) * scale_y + center + range * offset_y;
 333
 334         glEnable(GL_BLEND);
 335         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 336         glEnable(GL_TEXTURE_2D);
 337         glBindTexture(GL_TEXTURE_2D, osd_name[num]);
 338         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);  /* no modulation with color */
 339         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 340         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 341         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, osd_width[num], osd_height[num], GL_RGBA, GL_UNSIGNED_BYTE, rgba);
 342         glBegin(GL_QUADS);
 343         if (fov) {
 344                 /* perspective viewport */
 345                 glTexCoord2f(texture_left, texture_bottom);
 346                 glVertex3f(100.0 * osd_left, 100.0 * osd_bottom, -100.0 / slope);
 347                 glTexCoord2f(texture_right, texture_bottom);
 348                 glVertex3f(100.0 * osd_right, 100.0 * osd_bottom, -100.0 / slope);
 349                 glTexCoord2f(texture_right, texture_top);
 350                 glVertex3f(100.0 * osd_right, 100.0 * osd_top, -100.0 / slope);
 351                 glTexCoord2f(texture_left, texture_top);
 352                 glVertex3f(100.0 * osd_left, 100.0 * osd_top, -100.0 / slope);
 353         } else {
 354                 /* orthogonal viewport */
 355                 glTexCoord2f(texture_left, texture_top);
 356                 glVertex3f(osd_left, osd_top, 0.0);
 357                 glTexCoord2f(texture_right, texture_top);
 358                 glVertex3f(osd_right, osd_top, 0.0);
 359                 glTexCoord2f(texture_right, texture_bottom);
 360                 glVertex3f(osd_right, osd_bottom, 0.0);
 361                 glTexCoord2f(texture_left, texture_bottom);
 362                 glVertex3f(osd_left, osd_bottom, 0.0);
 363         }
 364         glEnd();
 365         glDisable(GL_TEXTURE_2D);
 366         glDisable(GL_BLEND);
 367 }
 368
 369 /* set color and opacity */
 370 void opengl_render_color(double r, double g, double b, double a)
 371 {
 372         if (a < 1.0) {
 373                 glEnable(GL_BLEND);
 374                 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 375                 glColor4d(r, g, b, a);
 376         } else {
 377                 glDisable(GL_BLEND);
 378                 glColor3d(r, g, b);
 379         }
 380 }
 381
 382 /* render polygon */
 383 void opengl_render_polygon(double *x, double *y, double *z, int count, int cull_face)
 384 {
 385         int i;
 386
 387         if (cull_face) {
 388                 glEnable(GL_CULL_FACE);
 389                 glFrontFace(GL_CW);
 390                 glCullFace(GL_BACK);
 391         }
 392         glBegin(GL_POLYGON);
 393         for (i = 0; i < count; i++)
 394                 glVertex3d(x[i], y[i], -z[i]);
 395         glEnd();
 396         if (cull_face)
 397                 glDisable(GL_CULL_FACE);
 398 }
 399
 400 /* render polygon, but make sure any size of it is visible */
 401 void opengl_render_polygon_and_line(double *x, double *y, double *z, int count)
 402 {
 403         int i;
 404
 405         glBegin(GL_POLYGON);
 406         for (i = 0; i < count; i++)
 407                 glVertex3d(x[i], y[i], -z[i]);
 408         glEnd();
 409         glBegin(GL_LINE_LOOP);
 410         for (i = 0; i < count; i++)
 411                 glVertex3d(x[i], y[i], -z[i]);
 412         glEnd();
 413 }
 414
 415 /* render line */
 416 void opengl_render_line(double x1, double y1, double z1, double x2, double y2, double z2, double size)
 417 {
 418         if (size == 0.0) {
 419                 glBegin(GL_LINES);
 420                 glVertex3f(x1, y1, -z1);
 421                 glVertex3f(x2, y2, -z2);
 422                 glEnd();
 423                 return;
 424         }
 425 }
 426
 427 /* render point */
 428 void opengl_render_point(double x, double y, double z, double size)
 429 {
 430         if (size == 0.0) {
 431                 glBegin(GL_POINTS);
 432                 glVertex3f(x, y, -z);
 433                 glEnd();
 434                 return;
 435         }
 436 }
 437
 438 /* free image texture */
 439 void exit_opengl(void)
 440 {
 441         int i;
 442
 443         if (legacy_rgb) {
 444                 free(legacy_rgb);
 445                 legacy_rgb = NULL;
 446         }
 447         if (benson_rgb) {
 448                 free(benson_rgb);
 449                 benson_rgb = NULL;
 450         }
 451         for (i = 0; i < MAX_OSD; i++) {
 452                 if (osd_rgba[i]) {
 453                         free(osd_rgba[i]);
 454                         osd_rgba[i] = NULL;
 455                 }
 456         }
 457 }
 458