git.sesse.net Git - movit/blob - test.cpp

   1 #define GL_GLEXT_PROTOTYPES 1
   2 #define NO_SDL_GLEXT 1
   3
   4 #define WIDTH 1280
   5 #define HEIGHT 720
   6 #define BUFFER_OFFSET(i) ((char *)NULL + (i))
   7
   8 #define HSV_WHEEL_SIZE 128
   9
  10 #include <math.h>
  11 #include <time.h>
  12
  13 #include <string>
  14 #include <vector>
  15
  16 #include <SDL/SDL.h>
  17 #include <SDL/SDL_opengl.h>
  18 #include <SDL/SDL_image.h>
  19
  20 #include <GL/gl.h>
  21 #include <GL/glext.h>
  22
  23 #include "util.h"
  24
  25 #ifdef NDEBUG
  26 #define check_error()
  27 #else
  28 #define check_error() { int err = glGetError(); if (err != GL_NO_ERROR) { printf("GL error 0x%x at line %d\n", err, __LINE__); exit(1); } }
  29 #endif
  30
  31 unsigned char result[WIDTH * HEIGHT * 4];
  32
  33 float lift_theta = 0.0f, lift_rad = 0.0f, lift_v = 0.0f;
  34 float gamma_theta = 0.0f, gamma_rad = 0.0f, gamma_v = 0.5f;
  35 float gain_theta = 0.0f, gain_rad = 0.0f, gain_v = 0.25f;
  36 float saturation = 1.0f;
  37
  38 float lift_r = 0.0f, lift_g = 0.0f, lift_b = 0.0f;
  39 float gamma_r = 1.0f, gamma_g = 1.0f, gamma_b = 1.0f;
  40 float gain_r = 1.0f, gain_g = 1.0f, gain_b = 1.0f;
  41
  42 struct ImageFormat {
  43         enum { FORMAT_RGB, FORMAT_RGBA } format;
  44
  45         // Note: sRGB and 709 use the same colorspace primaries.
  46         enum { COLORSPACE_sRGB, COLORSPACE_REC_601_525, COLORSPACE_REC_601_625, COLORSPACE_REC_709 } color_space;
  47
  48         // Note: Rec. 601 and 709 use the same gamma curve.
  49         enum { LINEAR_LIGHT, GAMMA_sRGB, GAMMA_REC_601, GAMMA_REC_709 } gamma_curve;
  50 };
  51
  52 enum EffectId {
  53         // Mostly for internal use.
  54         GAMMA_CONVERSION = 0,
  55         RGB_PRIMARIES_CONVERSION,
  56
  57         // Color.
  58         LIFT_GAMMA_GAIN,
  59 };
  60
  61 class Effect {
  62 public:
  63         virtual bool needs_linear_light() { return true; }
  64         virtual bool needs_srgb_primaries() { return true; }
  65         virtual bool needs_many_samples() { return false; }
  66         virtual bool needs_mipmaps() { return false; }
  67         bool set_float(const std::string& key, float value);
  68         bool set_float_array(const std::string&, const float *values, size_t num_values);
  69
  70 private:
  71         bool register_float(const std::string& key, float value);
  72         bool register_float_array(const std::string& key, float *values, size_t num_values);
  73 };
  74
  75 class EffectChain {
  76 public:
  77         void set_size(unsigned width, unsigned height);
  78         void add_input(const ImageFormat &format);
  79         Effect *add_effect(EffectId effect);
  80         void add_output(const ImageFormat &format);
  81
  82         void render(unsigned char *src, unsigned char *dst);
  83
  84 private:
  85         unsigned width, height;
  86         ImageFormat input_format, output_format;
  87         std::vector<Effect *> effects;
  88 };
  89
  90 enum textures {
  91         SOURCE_IMAGE = 1,
  92         SRGB_LUT = 2,
  93         SRGB_REVERSE_LUT = 3,
  94         HSV_WHEEL = 4,
  95 };
  96
  97 GLhandleARB read_shader(const char* filename, GLenum type)
  98 {
  99         static char buf[131072];
 100         FILE *fp = fopen(filename, "r");
 101         if (fp == NULL) {
 102                 perror(filename);
 103                 exit(1);
 104         }
 105
 106         int len = fread(buf, 1, sizeof(buf), fp);
 107         fclose(fp);
 108
 109         GLhandleARB obj = glCreateShaderObjectARB(type);
 110         const GLchar* source[] = { buf };
 111         const GLint length[] = { len };
 112         glShaderSource(obj, 1, source, length);
 113         glCompileShader(obj);
 114
 115         GLchar info_log[4096];
 116         GLsizei log_length = sizeof(info_log) - 1;
 117         glGetShaderInfoLog(obj, log_length, &log_length, info_log);
 118         info_log[log_length] = 0;
 119         printf("shader compile log: %s\n", info_log);
 120
 121         GLint status;
 122         glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
 123         if (status == GL_FALSE) {
 124                 exit(1);
 125         }
 126
 127         return obj;
 128 }
 129
 130 void draw_picture_quad(GLint prog, int frame)
 131 {
 132         glUseProgramObjectARB(prog);
 133         check_error();
 134
 135         glActiveTexture(GL_TEXTURE0);
 136         glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
 137         glUniform1i(glGetUniformLocation(prog, "tex"), 0);
 138
 139         glActiveTexture(GL_TEXTURE1);
 140         glBindTexture(GL_TEXTURE_1D, SRGB_LUT);
 141         glUniform1i(glGetUniformLocation(prog, "srgb_tex"), 1);
 142
 143         glActiveTexture(GL_TEXTURE2);
 144         glBindTexture(GL_TEXTURE_1D, SRGB_REVERSE_LUT);
 145         glUniform1i(glGetUniformLocation(prog, "srgb_reverse_tex"), 2);
 146
 147         glUniform3f(glGetUniformLocation(prog, "lift"), lift_r, lift_g, lift_b);
 148         //glUniform3f(glGetUniformLocation(prog, "gamma"), gamma_r, gamma_g, gamma_b);
 149         glUniform3f(glGetUniformLocation(prog, "inv_gamma_22"),
 150                     2.2f / gamma_r,
 151                     2.2f / gamma_g,
 152                     2.2f / gamma_b);
 153         glUniform3f(glGetUniformLocation(prog, "gain_pow_inv_gamma"),
 154                     pow(gain_r, 1.0f / gamma_r),
 155                     pow(gain_g, 1.0f / gamma_g),
 156                     pow(gain_b, 1.0f / gamma_b));
 157         glUniform1f(glGetUniformLocation(prog, "saturation"), saturation);
 158
 159         glDisable(GL_BLEND);
 160         check_error();
 161         glDisable(GL_DEPTH_TEST);
 162         check_error();
 163         glDepthMask(GL_FALSE);
 164         check_error();
 165
 166         glMatrixMode(GL_PROJECTION);
 167         glLoadIdentity();
 168         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
 169
 170         glMatrixMode(GL_MODELVIEW);
 171         glLoadIdentity();
 172
 173         glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
 174 //      glClear(GL_COLOR_BUFFER_BIT);
 175         check_error();
 176
 177         glBegin(GL_QUADS);
 178
 179         glTexCoord2f(0.0f, 1.0f);
 180         glVertex2f(0.0f, 0.0f);
 181
 182         glTexCoord2f(1.0f, 1.0f);
 183         glVertex2f(1.0f, 0.0f);
 184
 185         glTexCoord2f(1.0f, 0.0f);
 186         glVertex2f(1.0f, 1.0f);
 187
 188         glTexCoord2f(0.0f, 0.0f);
 189         glVertex2f(0.0f, 1.0f);
 190
 191         glEnd();
 192         check_error();
 193 }
 194
 195 void draw_hsv_wheel(float y, float rad, float theta, float value)
 196 {
 197         glUseProgramObjectARB(0);
 198         check_error();
 199         glActiveTexture(GL_TEXTURE0);
 200         check_error();
 201         glEnable(GL_TEXTURE_2D);
 202         check_error();
 203         glBindTexture(GL_TEXTURE_2D, HSV_WHEEL);
 204         check_error();
 205         glActiveTexture(GL_TEXTURE1);
 206         check_error();
 207         glBindTexture(GL_TEXTURE_2D, 0);
 208         check_error();
 209         glActiveTexture(GL_TEXTURE0);
 210         glEnable(GL_BLEND);
 211         check_error();
 212         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 213         check_error();
 214
 215         // wheel
 216         glBegin(GL_QUADS);
 217
 218         glTexCoord2f(0.0f, 1.0f);
 219         glVertex2f(0.0f, y);
 220
 221         glTexCoord2f(1.0f, 1.0f);
 222         glVertex2f(0.2f * 9.0f / 16.0f, y);
 223
 224         glTexCoord2f(1.0f, 0.0f);
 225         glVertex2f(0.2f * 9.0f / 16.0f, y + 0.2f);
 226
 227         glTexCoord2f(0.0f, 0.0f);
 228         glVertex2f(0.0f, y + 0.2f);
 229
 230         glEnd();
 231
 232         // wheel selector
 233         glDisable(GL_TEXTURE_2D);
 234         glColor3f(0.0f, 0.0f, 0.0f);
 235         glPointSize(5.0f);
 236         glBegin(GL_POINTS);
 237         glVertex2f((0.1f + rad * cos(theta) * 0.1f) * 9.0f / 16.0f, y + 0.1f - rad * sin(theta) * 0.1f);
 238         glEnd();
 239
 240         // value slider
 241         glDisable(GL_TEXTURE_2D);
 242         glBegin(GL_QUADS);
 243
 244         glColor3f(0.0f, 0.0f, 0.0f);
 245         glVertex2f(0.22f * 9.0f / 16.0f, y);
 246         glVertex2f(0.24f * 9.0f / 16.0f, y);
 247
 248         glColor3f(1.0f, 1.0f, 1.0f);
 249         glVertex2f(0.24f * 9.0f / 16.0f, y + 0.2f);
 250         glVertex2f(0.22f * 9.0f / 16.0f, y + 0.2f);
 251
 252         glEnd();
 253
 254         // value selector
 255         glColor3f(0.0f, 0.0f, 0.0f);
 256         glPointSize(5.0f);
 257         glBegin(GL_POINTS);
 258         glVertex2f(0.23f * 9.0f / 16.0f, y + value * 0.2f);
 259         glEnd();
 260
 261         glColor3f(1.0f, 1.0f, 1.0f);
 262 }
 263
 264 void draw_saturation_bar(float y)
 265 {
 266         glUseProgramObjectARB(0);
 267         check_error();
 268
 269         // value slider
 270         glDisable(GL_TEXTURE_2D);
 271         glBegin(GL_QUADS);
 272
 273         glColor3f(0.0f, 0.0f, 0.0f);
 274         glVertex2f(0.0f * 9.0f / 16.0f, y + 0.02f);
 275         glVertex2f(0.0f * 9.0f / 16.0f, y);
 276
 277         glColor3f(1.0f, 1.0f, 1.0f);
 278         glVertex2f(0.2f * 9.0f / 16.0f, y);
 279         glVertex2f(0.2f * 9.0f / 16.0f, y + 0.02f);
 280
 281         glEnd();
 282
 283         // value selector
 284         glColor3f(0.0f, 0.0f, 0.0f);
 285         glPointSize(5.0f);
 286         glBegin(GL_POINTS);
 287         glVertex2f(0.2f * (saturation / 4.0f) * 9.0f / 16.0f, y + 0.01f);
 288         glEnd();
 289
 290         glColor3f(1.0f, 1.0f, 1.0f);
 291 }
 292
 293 void make_hsv_wheel_texture()
 294 {
 295         static unsigned char hsv_pix[HSV_WHEEL_SIZE * HSV_WHEEL_SIZE * 4];
 296         for (int y = 0; y < HSV_WHEEL_SIZE; ++y) {
 297                 for (int x = 0; x < HSV_WHEEL_SIZE; ++x) {
 298                         float yf = 2.0f * y / (float)(HSV_WHEEL_SIZE) - 1.0f;
 299                         float xf = 2.0f * x / (float)(HSV_WHEEL_SIZE) - 1.0f;
 300                         float rad = hypot(xf, yf);
 301                         float theta = atan2(yf, xf);
 302
 303                         float r, g, b;
 304                         hsv2rgb(theta, rad, 1.0f, &r, &g, &b);
 305                         hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 0] = lrintf(r * 255.0f);
 306                         hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 1] = lrintf(g * 255.0f);
 307                         hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 2] = lrintf(b * 255.0f);
 308
 309                         if (rad > 1.0f) {
 310                                 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 0;
 311                         } else {
 312                                 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 255;
 313                         }
 314                 }
 315                 printf("\n");
 316         }
 317
 318         glBindTexture(GL_TEXTURE_2D, HSV_WHEEL);
 319         check_error();
 320         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 321         check_error();
 322         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, HSV_WHEEL_SIZE, HSV_WHEEL_SIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, hsv_pix);
 323         check_error();
 324 }
 325
 326 void update_hsv()
 327 {
 328         hsv2rgb(lift_theta, lift_rad, lift_v, &lift_r, &lift_g, &lift_b);
 329         hsv2rgb(gamma_theta, gamma_rad, gamma_v * 2.0f, &gamma_r, &gamma_g, &gamma_b);
 330         hsv2rgb(gain_theta, gain_rad, gain_v * 4.0f, &gain_r, &gain_g, &gain_b);
 331
 332         if (saturation < 0.0) {
 333                 saturation = 0.0;
 334         }
 335
 336         printf("lift: %f %f %f\n", lift_r, lift_g, lift_b);
 337         printf("gamma: %f %f %f\n", gamma_r, gamma_g, gamma_b);
 338         printf("gain: %f %f %f\n", gain_r, gain_g, gain_b);
 339         printf("saturation: %f\n", saturation);
 340         printf("\n");
 341 }
 342
 343 void read_colorwheel(float xf, float yf, float *rad, float *theta, float *value)
 344 {
 345         if (xf < 0.2f && yf < 0.2f) {
 346                 float xp = 2.0f * xf / 0.2f - 1.0f;
 347                 float yp = -(2.0f * yf / 0.2f - 1.0f);
 348                 *rad = hypot(xp, yp);
 349                 *theta = atan2(yp, xp);
 350                 if (*rad > 1.0) {
 351                         *rad = 1.0;
 352                 }
 353         } else if (xf >= 0.22f && xf <= 0.24f) {
 354                 *value = yf / 0.2f;
 355         }
 356 }
 357
 358 void mouse(int x, int y)
 359 {
 360         float xf = (x / (float)WIDTH) * 16.0f / 9.0f;
 361         float yf = (HEIGHT - y) / (float)HEIGHT;
 362
 363         if (yf < 0.2f) {
 364                 read_colorwheel(xf, yf, &lift_rad, &lift_theta, &lift_v);
 365         } else if (yf >= 0.2f && yf < 0.4f) {
 366                 read_colorwheel(xf, yf - 0.2f, &gamma_rad, &gamma_theta, &gamma_v);
 367         } else if (yf >= 0.4f && yf < 0.6f) {
 368                 read_colorwheel(xf, yf - 0.4f, &gain_rad, &gain_theta, &gain_v);
 369         } else if (yf >= 0.6f && yf < 0.62f && xf < 0.2f) {
 370                 saturation = (xf / 0.2f) * 4.0f;
 371         }
 372
 373         update_hsv();
 374 }
 375
 376 void load_texture(const char *filename)
 377 {
 378         SDL_Surface *img = IMG_Load(filename);
 379         if (img == NULL) {
 380                 fprintf(stderr, "Load of '%s' failed\n", filename);
 381                 exit(1);
 382         }
 383
 384         // Convert to RGB.
 385         SDL_PixelFormat *fmt = img->format;
 386         SDL_LockSurface(img);
 387         unsigned char *src_pixels = (unsigned char *)img->pixels;
 388         unsigned char *dst_pixels = (unsigned char *)malloc(img->w * img->h * 3);
 389         for (unsigned i = 0; i < img->w * img->h; ++i) {
 390                 unsigned char r, g, b;
 391                 unsigned int temp;
 392                 unsigned int pixel = *(unsigned int *)(src_pixels + i * fmt->BytesPerPixel);
 393
 394                 temp = pixel & fmt->Rmask;
 395                 temp = temp >> fmt->Rshift;
 396                 temp = temp << fmt->Rloss;
 397                 r = temp;
 398
 399                 temp = pixel & fmt->Gmask;
 400                 temp = temp >> fmt->Gshift;
 401                 temp = temp << fmt->Gloss;
 402                 g = temp;
 403
 404                 temp = pixel & fmt->Bmask;
 405                 temp = temp >> fmt->Bshift;
 406                 temp = temp << fmt->Bloss;
 407                 b = temp;
 408
 409                 dst_pixels[i * 3 + 0] = r;
 410                 dst_pixels[i * 3 + 1] = g;
 411                 dst_pixels[i * 3 + 2] = b;
 412         }
 413         SDL_UnlockSurface(img);
 414
 415 #if 1
 416         // we will convert to sRGB in the shader
 417         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, img->w, img->h, 0, GL_RGB, GL_UNSIGNED_BYTE, dst_pixels);
 418         check_error();
 419 #else
 420         // implicit sRGB conversion in hardware
 421         glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8, img->w, img->h, 0, GL_RGB, GL_UNSIGNED_BYTE, dst_pixels);
 422         check_error();
 423 #endif
 424         free(dst_pixels);
 425         SDL_FreeSurface(img);
 426 }
 427
 428 void write_ppm(const char *filename, unsigned char *screenbuf)
 429 {
 430         FILE *fp = fopen(filename, "w");
 431         fprintf(fp, "P6\n%d %d\n255\n", WIDTH, HEIGHT);
 432         for (unsigned y = 0; y < HEIGHT; ++y) {
 433                 unsigned char *srcptr = screenbuf + ((HEIGHT - y - 1) * WIDTH) * 4;
 434                 for (unsigned x = 0; x < WIDTH; ++x) {
 435                         fputc(srcptr[x * 4 + 2], fp);
 436                         fputc(srcptr[x * 4 + 1], fp);
 437                         fputc(srcptr[x * 4 + 0], fp);
 438                 }
 439         }
 440         fclose(fp);
 441 }
 442
 443 int main(int argc, char **argv)
 444 {
 445         int quit = 0;
 446
 447         SDL_Init(SDL_INIT_EVERYTHING);
 448         SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
 449         SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
 450         SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 451         SDL_SetVideoMode(WIDTH, HEIGHT, 0, SDL_OPENGL);
 452         SDL_WM_SetCaption("OpenGL window", NULL);
 453
 454         // geez
 455         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 456         glPixelStorei(GL_PACK_ALIGNMENT, 1);
 457
 458         glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
 459         check_error();
 460         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 461         check_error();
 462
 463         load_texture("blg_wheels_woman_1.jpg");
 464         //glGenerateMipmap(GL_TEXTURE_2D);
 465         //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 4);
 466         //check_error();
 467
 468         //load_texture("maserati_gts_wallpaper_1280x720_01.jpg");
 469         //load_texture("90630d1295075297-console-games-wallpapers-wallpaper_need_for_speed_prostreet_09_1920x1080.jpg");
 470         //load_texture("glacier-lake-1280-720-4087.jpg");
 471
 472 #if 0
 473         // sRGB reverse LUT
 474         glBindTexture(GL_TEXTURE_1D, SRGB_REVERSE_LUT);
 475         check_error();
 476         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 477         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 478         check_error();
 479         float srgb_reverse_tex[4096];
 480         for (unsigned i = 0; i < 4096; ++i) {
 481                 float x = i / 4095.0;
 482                 if (x < 0.0031308f) {
 483                         srgb_reverse_tex[i] = 12.92f * x;
 484                 } else {
 485                         srgb_reverse_tex[i] = 1.055f * pow(x, 1.0f / 2.4f) - 0.055f;
 486                 }
 487         }
 488         glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE16F_ARB, 4096, 0, GL_LUMINANCE, GL_FLOAT, srgb_reverse_tex);
 489         check_error();
 490
 491         // sRGB LUT
 492         glBindTexture(GL_TEXTURE_1D, SRGB_LUT);
 493         check_error();
 494         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 495         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 496         check_error();
 497         float srgb_tex[256];
 498         for (unsigned i = 0; i < 256; ++i) {
 499                 float x = i / 255.0;
 500                 if (x < 0.04045f) {
 501                         srgb_tex[i] = x * (1.0f / 12.92f);
 502                 } else {
 503                         srgb_tex[i] = pow((x + 0.055) * (1.0 / 1.055f), 2.4);
 504                 }
 505         }
 506         glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE16F_ARB, 256, 0, GL_LUMINANCE, GL_FLOAT, srgb_tex);
 507         check_error();
 508 #endif
 509
 510         // generate a PDO to hold the data we read back with glReadPixels()
 511         // (Intel/DRI goes into a slow path if we don't read to PDO)
 512         glBindBuffer(GL_PIXEL_PACK_BUFFER_ARB, 1);
 513         glBufferData(GL_PIXEL_PACK_BUFFER_ARB, WIDTH * HEIGHT * 4, NULL, GL_STREAM_READ);
 514
 515         make_hsv_wheel_texture();
 516         update_hsv();
 517
 518         int prog = glCreateProgram();
 519         GLhandleARB vs_obj = read_shader("vs.glsl", GL_VERTEX_SHADER);
 520         GLhandleARB fs_obj = read_shader("fs.glsl", GL_FRAGMENT_SHADER);
 521         glAttachObjectARB(prog, vs_obj);
 522         check_error();
 523         glAttachObjectARB(prog, fs_obj);
 524         check_error();
 525         glLinkProgram(prog);
 526         check_error();
 527
 528         GLchar info_log[4096];
 529         GLsizei log_length = sizeof(info_log) - 1;
 530         log_length = sizeof(info_log) - 1;
 531         glGetProgramInfoLog(prog, log_length, &log_length, info_log);
 532         info_log[log_length] = 0;
 533         printf("link: %s\n", info_log);
 534
 535         struct timespec start, now;
 536         int frame = 0, screenshot = 0;
 537         clock_gettime(CLOCK_MONOTONIC, &start);
 538
 539         while (!quit) {
 540                 SDL_Event event;
 541                 while (SDL_PollEvent(&event)) {
 542                         if (event.type == SDL_QUIT) {
 543                                 quit = 1;
 544                         } else if (event.type == SDL_KEYDOWN && event.key.keysym.sym == SDLK_ESCAPE) {
 545                                 quit = 1;
 546                         } else if (event.type == SDL_KEYDOWN && event.key.keysym.sym == SDLK_F1) {
 547                                 screenshot = 1;
 548                         } else if (event.type == SDL_MOUSEBUTTONDOWN && event.button.button == SDL_BUTTON_LEFT) {
 549                                 mouse(event.button.x, event.button.y);
 550                         } else if (event.type == SDL_MOUSEMOTION && (event.motion.state & SDL_BUTTON(1))) {
 551                                 mouse(event.motion.x, event.motion.y);
 552                         }
 553                 }
 554
 555                 ++frame;
 556
 557                 draw_picture_quad(prog, frame);
 558
 559                 glReadPixels(0, 0, WIDTH, HEIGHT, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, BUFFER_OFFSET(0));
 560                 check_error();
 561
 562                 draw_hsv_wheel(0.0f, lift_rad, lift_theta, lift_v);
 563                 draw_hsv_wheel(0.2f, gamma_rad, gamma_theta, gamma_v);
 564                 draw_hsv_wheel(0.4f, gain_rad, gain_theta, gain_v);
 565                 draw_saturation_bar(0.6f);
 566
 567                 SDL_GL_SwapBuffers();
 568                 check_error();
 569
 570                 unsigned char *screenbuf = (unsigned char *)glMapBuffer(GL_PIXEL_PACK_BUFFER_ARB, GL_READ_ONLY);
 571                 check_error();
 572                 if (screenshot) {
 573                         char filename[256];
 574                         sprintf(filename, "frame%05d.ppm", frame);
 575                         write_ppm(filename, screenbuf);
 576                         printf("Screenshot: %s\n", filename);
 577                         screenshot = 0;
 578                 }
 579                 glUnmapBuffer(GL_PIXEL_PACK_BUFFER_ARB);
 580                 check_error();
 581
 582 #if 1
 583                 clock_gettime(CLOCK_MONOTONIC, &now);
 584                 double elapsed = now.tv_sec - start.tv_sec +
 585                         1e-9 * (now.tv_nsec - start.tv_nsec);
 586                 printf("%d frames in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
 587                         frame, elapsed, frame / elapsed,
 588                         1e3 * elapsed / frame);
 589 #endif
 590         }
 591         return 0;
 592 }