src/libopengl/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 <string.h>
  24 #include <math.h>
  25 #include <errno.h>
  26 #include "../libsdl/print.h"
  27 #include "opengl.h"
  28 #define GL3_PROTOTYPES 1
  29 #include <GL/glew.h>
  30
  31 #define MAX_OSD 2
  32 static uint8_t *image_rgb = NULL;
  33 static uint8_t *osd_rgba[MAX_OSD] = { NULL, NULL };
  34 static GLuint image_name;
  35 static GLuint osd_name[MAX_OSD];
  36 static int image_width, image_height;
  37 static int osd_width[MAX_OSD], osd_height[MAX_OSD];
  38 static int texture_size;
  39 static int osd_size[MAX_OSD];
  40 static int flip_y;
  41
  42 /* alloc and init an image texture with size that is greater than the power of two */
  43 int init_opengl_image(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         image_rgb = calloc(texture_size * texture_size, 3);
  55         if (!image_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, &image_name);
  63         glBindTexture(GL_TEXTURE_2D, image_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, image_rgb);
  67
  68
  69         return 0;
  70
  71 error:
  72         exit_opengl();
  73         return rc;
  74 }
  75
  76 /* alloc and init an osd texture with size that is greater than the power of two */
  77 int init_opengl_osd(int num, int _osd_width, int _osd_height)
  78 {
  79         int rc;
  80
  81         if (num < 0 || num >= MAX_OSD) {
  82                 print_error("given OSD number out of range");
  83                 rc = -ENOMEM;
  84                 goto error;
  85         }
  86
  87         osd_width[num] = _osd_width;
  88         osd_height[num] = _osd_height;
  89
  90         /* generate texture */
  91         for (osd_size[num] = 1; osd_size[num] <= osd_width[num] || osd_size[num] <= osd_height[num]; osd_size[num] *= 2)
  92                 ;
  93         osd_rgba[num] = calloc(osd_size[num] * osd_size[num], 4);
  94         if (!osd_rgba[num]) {
  95                 print_error("Failed to allocate texture\n");
  96                 rc = -ENOMEM;
  97                 goto error;
  98         }
  99         glPixelStorei(GL_UNPACK_ALIGNMENT, 1); /* bytes */
 100         glGenTextures(1, &osd_name[num]);
 101         glBindTexture(GL_TEXTURE_2D, osd_name[num]);
 102         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 103         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 104         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, osd_size[num], osd_size[num], 0, GL_RGBA, GL_UNSIGNED_BYTE, osd_rgba[num]);
 105
 106         return 0;
 107
 108 error:
 109         exit_opengl();
 110         return rc;
 111 }
 112
 113 void opengl_clear(int _flip_y)
 114 {
 115         flip_y = _flip_y;
 116
 117         /* clear screen */
 118         glClearColor(0.05, 0.05, 0.05, 1.0);
 119         glClear(GL_COLOR_BUFFER_BIT);
 120 }
 121
 122 /* set viewport for improved rendering */
 123 void opengl_viewport(int view_width, int view_height, int split, int benson_at_line, double fov, double benson_size)
 124 {
 125         int view_x = 0, view_y = 0;
 126         double factor_height = 1.0;
 127         double factor_width = 1.0;
 128
 129         /* center view, or put it in the top half of the window */
 130         if (split == 1) {
 131                 view_y = view_height / 2;
 132                 view_height = view_height / 2;
 133         } else if (split == 2) {
 134                 view_height = view_height / 2;
 135         }
 136
 137         /* avoid division by zero, if one dimension is too small */
 138         if (view_width < 1 || view_height < 1)
 139                 return;
 140
 141         /* expand width or height, if apect of image_width:image_height does not match the view_width:view_height */
 142         if (view_height * image_width > view_width * image_height)
 143                 factor_height = (double)(view_height * image_width) / (double)(view_width * image_height);
 144         else if (view_height * image_width < view_width * image_height)
 145                 factor_width = (double)(view_width * image_height) / (double)(view_height * image_width);
 146
 147         /* avoid views that are too small */
 148         if (view_width < 1 || view_height < 1)
 149                 return;
 150
 151         /* projection matrix */
 152         glViewport((GLsizei)view_x, (GLsizei)view_y, (GLsizei)view_width, (GLsizei)view_height);
 153         glMatrixMode(GL_PROJECTION);
 154         glLoadIdentity();
 155
 156         /* calculate field-of-view */
 157         double slope = tan(fov / 360 * M_PI);
 158         /* make frustum to center the view in the game view above benson */
 159         double left = -slope;
 160         double right = slope;
 161         double benson_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 162         double top = slope * ((double)image_height - benson_start_at_position) / (double)image_width;
 163         double bottom = -slope * ((double)image_height * 2.0 - ((double)image_height - benson_start_at_position)) / (double)image_width;
 164         glFrustum(left * factor_width, right * factor_width, bottom * factor_height, top * factor_height, 1.0, 5000000000.0);
 165
 166         glMatrixMode(GL_MODELVIEW);
 167 }
 168
 169 /* render image or only benson */
 170 void opengl_blit_image(uint8_t *rgb, int filter, int benson_at_line, int render_benson_only, double fov, double monitor_distance, double benson_size, int benson_case)
 171 {
 172         double texture_left = 0;
 173         double texture_right = ((double)image_width) / (double)texture_size;
 174         double texture_top = ((double)benson_at_line) / (double)texture_size;
 175         double texture_bottom = ((double)image_height) / (double)texture_size;
 176         double image_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 177         double image_top = -((double)image_height - image_start_at_position) / (double)image_width;
 178         double image_bottom = -((double)image_height * 2.0 - ((double)image_height - image_start_at_position)) / (double)image_width;
 179
 180         /* calculate field-of-view */
 181         double slope = tan(fov / 360 * M_PI) * monitor_distance;
 182
 183         /* render image */
 184
 185         if (benson_case) {
 186                 glEnable(GL_CULL_FACE);
 187                 glFrontFace(GL_CW);
 188                 glCullFace(GL_BACK);
 189         }
 190
 191         glEnable(GL_TEXTURE_2D);
 192         glBindTexture(GL_TEXTURE_2D, image_name);
 193         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);  /* no modulation with color */
 194         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 195         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 196         if (render_benson_only) {
 197                 /* render benson only, and copy top line of benson to one line above, so the texture filter will not take false data above benson */
 198                 rgb += image_width * (benson_at_line - 1) * 3;
 199                 memcpy(rgb, rgb + image_width * 3, image_width * 3);
 200                 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, benson_at_line - 1, image_width, image_height - benson_at_line - 1, GL_RGB, GL_UNSIGNED_BYTE, rgb);
 201         } else {
 202                 image_top = -image_top;
 203                 texture_top = 0.0;
 204                 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, image_width, image_height, GL_RGB, GL_UNSIGNED_BYTE, rgb);
 205         }
 206         glBegin(GL_QUADS);
 207         glTexCoord2f(texture_left, texture_bottom);
 208         glVertex3f(-benson_size * slope, image_bottom * slope, -monitor_distance);
 209         glTexCoord2f(texture_right, texture_bottom);
 210         glVertex3f(benson_size * slope, image_bottom * slope, -monitor_distance);
 211         glTexCoord2f(texture_right, texture_top);
 212         glVertex3f(benson_size * slope, image_top * slope, -monitor_distance);
 213         glTexCoord2f(texture_left, texture_top);
 214         glVertex3f(-benson_size * slope, image_top * slope, -monitor_distance);
 215         glEnd();
 216         glDisable(GL_TEXTURE_2D);
 217         /* render benson case */
 218         if (benson_case) {
 219                 double left, right, bottom, top, near, far;
 220                 left = -benson_size * slope;
 221                 right = benson_size * slope;
 222                 bottom = image_bottom * slope;
 223                 top = image_top * slope;
 224                 near = -monitor_distance;
 225                 far = near - benson_size * slope / 3.0;
 226                 glBegin(GL_QUADS);
 227                 /* back */
 228                 glColor4f(0.3, 0.3, 0.3, 1.0);
 229                 glVertex3f(left, top, far);
 230                 glVertex3f(right, top, far);
 231                 glVertex3f(right, bottom, far);
 232                 glVertex3f(left, bottom, far);
 233                 /* top */
 234                 glColor4f(0.2, 0.2, 0.2, 1.0);
 235                 glVertex3f(left, top, near);
 236                 glVertex3f(right, top, near);
 237                 glVertex3f(right, top, far);
 238                 glVertex3f(left, top, far);
 239                 /* bottom */
 240                 glColor4f(0.05, 0.05, 0.05, 1.0);
 241                 glVertex3f(left, bottom, far);
 242                 glVertex3f(right, bottom, far);
 243                 glVertex3f(right, bottom, near);
 244                 glVertex3f(left, bottom, near);
 245                 /* left */
 246                 glColor4f(0.1, 0.1, 0.1, 1.0);
 247                 glVertex3f(left, bottom, far);
 248                 glVertex3f(left, bottom, near);
 249                 glVertex3f(left, top, near);
 250                 glVertex3f(left, top, far);
 251                 /* right */
 252                 glVertex3f(right, top, far);
 253                 glVertex3f(right, top, near);
 254                 glVertex3f(right, bottom, near);
 255                 glVertex3f(right, bottom, far);
 256                 glEnd();
 257         }
 258
 259         if (benson_case) {
 260                 glDisable(GL_CULL_FACE);
 261         }
 262 }
 263
 264 /* render osd texture */
 265 void opengl_blit_osd(int num, uint8_t *rgba, int filter, int benson_at_line, double fov, double monitor_distance, double benson_size, double scale_x, double scale_y, double offset_x, double offset_y)
 266 {
 267         double texture_left = 0.0;
 268         double texture_right = (double)osd_width[num] / (double)osd_size[num];
 269         double texture_top = 0.0;
 270         double texture_bottom = (double)osd_height[num] / (double)osd_size[num];
 271         double benson_start_at_position;
 272         double osd_left = 0.0;
 273         double osd_right = 1.0;
 274         double osd_top = 0.0;
 275         double osd_bottom = 1.0;
 276         double slope, range, center;
 277         if (fov) {
 278                 osd_left = -1.0;
 279                 osd_right = 1.0;
 280                 benson_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 281                 osd_top = ((double)image_height - benson_start_at_position) / (double)image_width;
 282                 osd_bottom = -((double)image_height * 2.0 - ((double)image_height - benson_start_at_position)) / (double)image_width;
 283                 /* calculate field-of-view */
 284                 slope = tan(fov / 360 * M_PI) * monitor_distance;
 285         }
 286         range = (osd_right - osd_left) / 2.0;
 287         center = (osd_right + osd_left) / 2.0;
 288         osd_left = (osd_left - center) * scale_x + center + range * offset_x;
 289         osd_right = (osd_right - center) * scale_x + center + range * offset_x;
 290         range = (osd_bottom - osd_top) / 2.0;
 291         center = (osd_bottom + osd_top) / 2.0;
 292         osd_top = (osd_top - center) * scale_y + center + range * offset_y;
 293         osd_bottom = (osd_bottom - center) * scale_y + center + range * offset_y;
 294
 295         glEnable(GL_BLEND);
 296         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 297         glEnable(GL_TEXTURE_2D);
 298         glBindTexture(GL_TEXTURE_2D, osd_name[num]);
 299         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);  /* no modulation with color */
 300         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 301         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 302         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, osd_width[num], osd_height[num], GL_RGBA, GL_UNSIGNED_BYTE, rgba);
 303         glBegin(GL_QUADS);
 304         if (fov) {
 305                 /* perspective viewport */
 306                 glTexCoord2f(texture_left, texture_bottom);
 307                 glVertex3f(osd_left * slope, osd_bottom * slope, -monitor_distance);
 308                 glTexCoord2f(texture_right, texture_bottom);
 309                 glVertex3f(osd_right * slope, osd_bottom * slope, -monitor_distance);
 310                 glTexCoord2f(texture_right, texture_top);
 311                 glVertex3f(osd_right * slope, osd_top * slope, -monitor_distance);
 312                 glTexCoord2f(texture_left, texture_top);
 313                 glVertex3f(osd_left * slope, osd_top * slope, -monitor_distance);
 314         } else {
 315                 /* orthogonal viewport */
 316                 glTexCoord2f(texture_left, texture_top);
 317                 glVertex3f(osd_left, osd_top, 0.0);
 318                 glTexCoord2f(texture_right, texture_top);
 319                 glVertex3f(osd_right, osd_top, 0.0);
 320                 glTexCoord2f(texture_right, texture_bottom);
 321                 glVertex3f(osd_right, osd_bottom, 0.0);
 322                 glTexCoord2f(texture_left, texture_bottom);
 323                 glVertex3f(osd_left, osd_bottom, 0.0);
 324         }
 325         glEnd();
 326         glDisable(GL_TEXTURE_2D);
 327         glDisable(GL_BLEND);
 328 }
 329
 330 /* set color and opacity */
 331 void opengl_render_color(double r, double g, double b, double a)
 332 {
 333         if (a < 1.0) {
 334                 glEnable(GL_BLEND);
 335                 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 336                 glColor4d(r, g, b, a);
 337         } else {
 338                 glDisable(GL_BLEND);
 339                 glColor3d(r, g, b);
 340         }
 341 }
 342
 343 /* render polygon */
 344 void opengl_render_polygon(double *x, double *y, double *z, int count, int cull_face)
 345 {
 346         int i;
 347
 348         if (cull_face) {
 349                 glEnable(GL_CULL_FACE);
 350                 glFrontFace((flip_y) ? GL_CCW : GL_CW);
 351                 glCullFace(GL_BACK);
 352         }
 353         glBegin(GL_POLYGON);
 354         for (i = 0; i < count; i++)
 355                 glVertex3d(x[i], y[i], -z[i]);
 356         glEnd();
 357         if (cull_face)
 358                 glDisable(GL_CULL_FACE);
 359 }
 360
 361 /* render polygon, but make sure any size of it is visible */
 362 void opengl_render_polygon_and_line(double *x, double *y, double *z, int count)
 363 {
 364         int i;
 365
 366         glBegin(GL_POLYGON);
 367         for (i = 0; i < count; i++)
 368                 glVertex3d(x[i], y[i], -z[i]);
 369         glEnd();
 370         glBegin(GL_LINE_LOOP);
 371         for (i = 0; i < count; i++)
 372                 glVertex3d(x[i], y[i], -z[i]);
 373         glEnd();
 374 }
 375
 376 /* render line */
 377 void opengl_render_line(double x1, double y1, double z1, double x2, double y2, double z2, double size)
 378 {
 379         if (size == 0.0) {
 380                 glBegin(GL_LINES);
 381                 glVertex3f(x1, y1, -z1);
 382                 glVertex3f(x2, y2, -z2);
 383                 glEnd();
 384                 return;
 385         }
 386 }
 387
 388 /* render point */
 389 void opengl_render_point(double x, double y, double z, double size)
 390 {
 391         if (size == 0.0) {
 392                 glBegin(GL_POINTS);
 393                 glVertex3f(x, y, -z);
 394                 glEnd();
 395                 return;
 396         }
 397 }
 398
 399 /* free image texture */
 400 void exit_opengl(void)
 401 {
 402         int i;
 403
 404         if (image_rgb) {
 405                 free(image_rgb);
 406                 image_rgb = NULL;
 407         }
 408         for (i = 0; i < MAX_OSD; i++) {
 409                 if (osd_rgba[i]) {
 410                         free(osd_rgba[i]);
 411                         osd_rgba[i] = NULL;
 412                 }
 413         }
 414 }
 415