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 <string.h>
  24 #include <math.h>
  25 #include <errno.h>
  26 #include "print.h"
  27 #include "opengl.h"
  28 #define GL3_PROTOTYPES 1
  29 #include <GL/glew.h>
  30
  31 #define MAX_OSD 2
  32 #define MONITOR_DISTANCE 35.0
  33 static uint8_t *image_rgb = NULL;
  34 static uint8_t *osd_rgba[MAX_OSD] = { NULL, NULL };
  35 static GLuint image_name;
  36 static GLuint osd_name[MAX_OSD];
  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 static int flip_y;
  42
  43 /* alloc and init an image texture with size that is greater than the power of two */
  44 int init_opengl_image(int _image_width, int _image_height)
  45 {
  46         int rc;
  47
  48         image_width = _image_width;
  49         image_height = _image_height;
  50
  51         /* generate texture */
  52         for (texture_size = 1; texture_size <= image_width || texture_size <= image_height; texture_size *= 2)
  53                 ;
  54
  55         image_rgb = calloc(texture_size * texture_size, 3);
  56         if (!image_rgb) {
  57                 print_error("Failed to allocate texture\n");
  58                 rc = -ENOMEM;
  59                 goto error;
  60         }
  61         glShadeModel(GL_FLAT);
  62         glPixelStorei(GL_UNPACK_ALIGNMENT, 1); /* bytes */
  63         glGenTextures(1, &image_name);
  64         glBindTexture(GL_TEXTURE_2D, image_name);
  65         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  66         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
  67         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, texture_size, texture_size, 0, GL_RGB, GL_UNSIGNED_BYTE, image_rgb);
  68
  69
  70         return 0;
  71
  72 error:
  73         exit_opengl();
  74         return rc;
  75 }
  76
  77 /* alloc and init an osd texture with size that is greater than the power of two */
  78 int init_opengl_osd(int num, int _osd_width, int _osd_height)
  79 {
  80         int rc;
  81
  82         if (num < 0 || num >= MAX_OSD) {
  83                 print_error("given OSD number out of range");
  84                 rc = -ENOMEM;
  85                 goto error;
  86         }
  87
  88         osd_width[num] = _osd_width;
  89         osd_height[num] = _osd_height;
  90
  91         /* generate texture */
  92         for (osd_size[num] = 1; osd_size[num] <= osd_width[num] || osd_size[num] <= osd_height[num]; osd_size[num] *= 2)
  93                 ;
  94         osd_rgba[num] = calloc(osd_size[num] * osd_size[num], 4);
  95         if (!osd_rgba[num]) {
  96                 print_error("Failed to allocate texture\n");
  97                 rc = -ENOMEM;
  98                 goto error;
  99         }
 100         glPixelStorei(GL_UNPACK_ALIGNMENT, 1); /* bytes */
 101         glGenTextures(1, &osd_name[num]);
 102         glBindTexture(GL_TEXTURE_2D, osd_name[num]);
 103         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
 104         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
 105         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, osd_size[num], osd_size[num], 0, GL_RGBA, GL_UNSIGNED_BYTE, osd_rgba[num]);
 106
 107         return 0;
 108
 109 error:
 110         exit_opengl();
 111         return rc;
 112 }
 113
 114 void opengl_clear(int _flip_y)
 115 {
 116         flip_y = _flip_y;
 117
 118         /* clear screen */
 119         glClearColor(0.0, 0.0, 0.0, 1.0);
 120         glClear(GL_COLOR_BUFFER_BIT);
 121 }
 122
 123 /* set viewport for improved rendering */
 124 void opengl_viewport(int view_width, int view_height, int split, int benson_at_line, double fov, double benson_size)
 125 {
 126         int view_x = 0, view_y = 0;
 127         int new_width, new_height;
 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         /* calculate a viewport that has apect of image_width:image_height */
 142         if (view_height * image_width > view_width * image_height) {
 143                 new_height = view_width * image_height / image_width;
 144                 view_y = view_y + view_height / 2 - new_height / 2;
 145                 view_height = new_height;
 146         } else if (view_height * image_width < view_width * image_height) {
 147                 new_width = view_height * image_width / image_height;
 148                 view_x = view_x + view_width / 2 - new_width / 2;
 149                 view_width = new_width;
 150         }
 151
 152         /* avoid views that are too small */
 153         if (view_width < 1 || view_height < 1)
 154                 return;
 155
 156         /* viewport and projection matrix */
 157         glViewport((GLsizei)view_x, (GLsizei)view_y, (GLsizei)view_width, (GLsizei)view_height);
 158         glMatrixMode(GL_PROJECTION);
 159         glLoadIdentity();
 160
 161         /* calculate field-of-view */
 162         double slope = tan(fov / 360 * M_PI);
 163         /* make frustum to center the view in the game view above benson */
 164         double left = -slope;
 165         double right = slope;
 166         double benson_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 167         double top = slope * ((double)image_height - benson_start_at_position) / (double)image_width;
 168         double bottom = -slope * ((double)image_height * 2.0 - ((double)image_height - benson_start_at_position)) / (double)image_width;
 169         glFrustum(left, right, bottom, top, 1.0, 5000000000.0);
 170
 171         glMatrixMode(GL_MODELVIEW);
 172 }
 173
 174 /* render image or only benson */
 175 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)
 176 {
 177         double texture_left = 0;
 178         double texture_right = ((double)image_width) / (double)texture_size;
 179         double texture_top = ((double)benson_at_line) / (double)texture_size;
 180         double texture_bottom = ((double)image_height) / (double)texture_size;
 181         double image_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 182         double image_top = -((double)image_height - image_start_at_position) / (double)image_width;
 183         double image_bottom = -((double)image_height * 2.0 - ((double)image_height - image_start_at_position)) / (double)image_width;
 184
 185         /* calculate field-of-view */
 186         double slope = tan(fov / 360 * M_PI) * monitor_distance;
 187
 188         /* render image */
 189         glEnable(GL_TEXTURE_2D);
 190         glBindTexture(GL_TEXTURE_2D, image_name);
 191         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);  /* no modulation with color */
 192         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 193         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 194         if (render_benson_only) {
 195                 /* render benson only, and copy top line of benson to one line above, so the texture filter will not take false data above benson */
 196                 rgb += image_width * (benson_at_line - 1) * 3;
 197                 memcpy(rgb, rgb + image_width * 3, image_width * 3);
 198                 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, benson_at_line - 1, image_width, image_height - benson_at_line - 1, GL_RGB, GL_UNSIGNED_BYTE, rgb);
 199         } else {
 200                 image_top = -image_top;
 201                 texture_top = 0.0;
 202                 glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, image_width, image_height, GL_RGB, GL_UNSIGNED_BYTE, rgb);
 203         }
 204         glBegin(GL_QUADS);
 205         glTexCoord2f(texture_left, texture_bottom);
 206         glVertex3f(-benson_size * slope, image_bottom * slope, -monitor_distance);
 207         glTexCoord2f(texture_right, texture_bottom);
 208         glVertex3f(benson_size * slope, image_bottom * slope, -monitor_distance);
 209         glTexCoord2f(texture_right, texture_top);
 210         glVertex3f(benson_size * slope, image_top * slope, -monitor_distance);
 211         glTexCoord2f(texture_left, texture_top);
 212         glVertex3f(-benson_size * slope, image_top * slope, -monitor_distance);
 213         glEnd();
 214         glDisable(GL_TEXTURE_2D);
 215 }
 216
 217 /* render osd texture */
 218 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)
 219 {
 220         double texture_left = 0.0;
 221         double texture_right = (double)osd_width[num] / (double)osd_size[num];
 222         double texture_top = 0.0;
 223         double texture_bottom = (double)osd_height[num] / (double)osd_size[num];
 224         double benson_start_at_position;
 225         double osd_left = 0.0;
 226         double osd_right = 1.0;
 227         double osd_top = 0.0;
 228         double osd_bottom = 1.0;
 229         double slope, range, center;
 230         if (fov) {
 231                 osd_left = -1.0;
 232                 osd_right = 1.0;
 233                 benson_start_at_position = ((double)image_height - (double)benson_at_line) * benson_size;
 234                 osd_top = ((double)image_height - benson_start_at_position) / (double)image_width;
 235                 osd_bottom = -((double)image_height * 2.0 - ((double)image_height - benson_start_at_position)) / (double)image_width;
 236                 /* calculate field-of-view */
 237                 slope = tan(fov / 360 * M_PI) * monitor_distance;
 238         }
 239         range = (osd_right - osd_left) / 2.0;
 240         center = (osd_right + osd_left) / 2.0;
 241         osd_left = (osd_left - center) * scale_x + center + range * offset_x;
 242         osd_right = (osd_right - center) * scale_x + center + range * offset_x;
 243         range = (osd_bottom - osd_top) / 2.0;
 244         center = (osd_bottom + osd_top) / 2.0;
 245         osd_top = (osd_top - center) * scale_y + center + range * offset_y;
 246         osd_bottom = (osd_bottom - center) * scale_y + center + range * offset_y;
 247
 248         glEnable(GL_BLEND);
 249         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 250         glEnable(GL_TEXTURE_2D);
 251         glBindTexture(GL_TEXTURE_2D, osd_name[num]);
 252         glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);  /* no modulation with color */
 253         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 254         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, (filter) ? GL_LINEAR : GL_NEAREST);
 255         glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, osd_width[num], osd_height[num], GL_RGBA, GL_UNSIGNED_BYTE, rgba);
 256         glBegin(GL_QUADS);
 257         if (fov) {
 258                 /* perspective viewport */
 259                 glTexCoord2f(texture_left, texture_bottom);
 260                 glVertex3f(osd_left * slope, osd_bottom * slope, -monitor_distance);
 261                 glTexCoord2f(texture_right, texture_bottom);
 262                 glVertex3f(osd_right * slope, osd_bottom * slope, -monitor_distance);
 263                 glTexCoord2f(texture_right, texture_top);
 264                 glVertex3f(osd_right * slope, osd_top * slope, -monitor_distance);
 265                 glTexCoord2f(texture_left, texture_top);
 266                 glVertex3f(osd_left * slope, osd_top * slope, -monitor_distance);
 267         } else {
 268                 /* orthogonal viewport */
 269                 glTexCoord2f(texture_left, texture_top);
 270                 glVertex3f(osd_left, osd_top, 0.0);
 271                 glTexCoord2f(texture_right, texture_top);
 272                 glVertex3f(osd_right, osd_top, 0.0);
 273                 glTexCoord2f(texture_right, texture_bottom);
 274                 glVertex3f(osd_right, osd_bottom, 0.0);
 275                 glTexCoord2f(texture_left, texture_bottom);
 276                 glVertex3f(osd_left, osd_bottom, 0.0);
 277         }
 278         glEnd();
 279         glDisable(GL_TEXTURE_2D);
 280         glDisable(GL_BLEND);
 281 }
 282
 283 /* set color and opacity */
 284 void opengl_render_color(double r, double g, double b, double a)
 285 {
 286         if (a < 1.0) {
 287                 glEnable(GL_BLEND);
 288                 glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 289                 glColor4d(r, g, b, a);
 290         } else {
 291                 glDisable(GL_BLEND);
 292                 glColor3d(r, g, b);
 293         }
 294 }
 295
 296 /* render polygon */
 297 void opengl_render_polygon(double *x, double *y, double *z, int count, int cull_face)
 298 {
 299         int i;
 300
 301         if (cull_face) {
 302                 glEnable(GL_CULL_FACE);
 303                 glFrontFace((flip_y) ? GL_CCW : GL_CW);
 304                 glCullFace(GL_BACK);
 305         }
 306         glBegin(GL_POLYGON);
 307         for (i = 0; i < count; i++)
 308                 glVertex3d(x[i], y[i], -z[i]);
 309         glEnd();
 310         if (cull_face)
 311                 glDisable(GL_CULL_FACE);
 312 }
 313
 314 /* render polygon, but make sure any size of it is visible */
 315 void opengl_render_polygon_and_line(double *x, double *y, double *z, int count)
 316 {
 317         int i;
 318
 319         glBegin(GL_POLYGON);
 320         for (i = 0; i < count; i++)
 321                 glVertex3d(x[i], y[i], -z[i]);
 322         glEnd();
 323         glBegin(GL_LINE_LOOP);
 324         for (i = 0; i < count; i++)
 325                 glVertex3d(x[i], y[i], -z[i]);
 326         glEnd();
 327 }
 328
 329 /* render line */
 330 void opengl_render_line(double x1, double y1, double z1, double x2, double y2, double z2, double size)
 331 {
 332         if (size == 0.0) {
 333                 glBegin(GL_LINES);
 334                 glVertex3f(x1, y1, -z1);
 335                 glVertex3f(x2, y2, -z2);
 336                 glEnd();
 337                 return;
 338         }
 339 }
 340
 341 /* render point */
 342 void opengl_render_point(double x, double y, double z, double size)
 343 {
 344         if (size == 0.0) {
 345                 glBegin(GL_POINTS);
 346                 glVertex3f(x, y, -z);
 347                 glEnd();
 348                 return;
 349         }
 350 }
 351
 352 /* free image texture */
 353 void exit_opengl(void)
 354 {
 355         int i;
 356
 357         if (image_rgb) {
 358                 free(image_rgb);
 359                 image_rgb = NULL;
 360         }
 361         for (i = 0; i < MAX_OSD; i++) {
 362                 if (osd_rgba[i]) {
 363                         free(osd_rgba[i]);
 364                         osd_rgba[i] = NULL;
 365                 }
 366         }
 367 }
 368