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 #ifdef NDEBUG
  24 #define check_error()
  25 #else
  26 #define check_error() { int err = glGetError(); if (err != GL_NO_ERROR) { printf("GL error 0x%x at line %d\n", err, __LINE__); exit(1); } }
  27 #endif
  28
  29 unsigned char result[WIDTH * HEIGHT * 4];
  30
  31 float lift_theta = 0.0f, lift_rad = 0.0f, lift_v = 0.0f;
  32 float gamma_theta = 0.0f, gamma_rad = 0.0f, gamma_v = 0.5f;
  33 float gain_theta = 0.0f, gain_rad = 0.0f, gain_v = 0.25f;
  34 float saturation = 1.0f;
  35
  36 float lift_r = 0.0f, lift_g = 0.0f, lift_b = 0.0f;
  37 float gamma_r = 1.0f, gamma_g = 1.0f, gamma_b = 1.0f;
  38 float gain_r = 1.0f, gain_g = 1.0f, gain_b = 1.0f;
  39
  40 struct ImageFormat {
  41         enum { FORMAT_RGB, FORMAT_RGBA } format;
  42
  43         // Note: sRGB and 709 use the same colorspace primaries.
  44         enum { COLORSPACE_sRGB, COLORSPACE_REC_601_525, COLORSPACE_REC_601_625, COLORSPACE_REC_709 } color_space;
  45
  46         // Note: Rec. 601 and 709 use the same gamma curve.
  47         enum { LINEAR_LIGHT, GAMMA_sRGB, GAMMA_REC_601, GAMMA_REC_709 } gamma_curve;
  48 };
  49
  50 enum EffectId {
  51         // Mostly for internal use.
  52         GAMMA_CONVERSION = 0,
  53         RGB_PRIMARIES_CONVERSION,
  54
  55         // Color.
  56         LIFT_GAMMA_GAIN,
  57 };
  58
  59 class Effect {
  60 public:
  61         virtual bool needs_linear_light() { return true; }
  62         virtual bool needs_srgb_primaries() { return true; }
  63         virtual bool needs_many_samples() { return false; }
  64         virtual bool needs_mipmaps() { return false; }
  65         bool set_float(const std::string& key, float value);
  66         bool set_float_array(const std::string&, const float *values, size_t num_values);
  67
  68 private:
  69         bool register_float(const std::string& key, float value);
  70         bool register_float_array(const std::string& key, float *values, size_t num_values);
  71 };
  72
  73 class EffectChain {
  74 public:
  75         void set_size(unsigned width, unsigned height);
  76         void add_input(const ImageFormat &format);
  77         Effect *add_effect(EffectId effect);
  78         void add_output(const ImageFormat &format);
  79
  80         void render(unsigned char *src, unsigned char *dst);
  81
  82 private:
  83         unsigned width, height;
  84         ImageFormat input_format, output_format;
  85         std::vector<Effect *> effects;
  86 };
  87
  88 enum textures {
  89         SOURCE_IMAGE = 1,
  90         SRGB_LUT = 2,
  91         SRGB_REVERSE_LUT = 3,
  92         HSV_WHEEL = 4,
  93 };
  94
  95 // assumes h in [0, 2pi> or [-pi, pi>
  96 void hsv2rgb(float h, float s, float v, float *r, float *g, float *b)
  97 {
  98         if (h < 0.0f) {
  99                 h += 2.0f * M_PI;
 100         }
 101         float c = v * s;
 102         float hp = (h * 180.0 / M_PI) / 60.0;
 103         float x = c * (1 - fabs(fmod(hp, 2.0f) - 1.0f));
 104
 105         if (hp >= 0 && hp < 1) {
 106                 *r = c;
 107                 *g = x;
 108                 *b = 0.0f;
 109         } else if (hp >= 1 && hp < 2) {
 110                 *r = x;
 111                 *g = c;
 112                 *b = 0.0f;
 113         } else if (hp >= 2 && hp < 3) {
 114                 *r = 0.0f;
 115                 *g = c;
 116                 *b = x;
 117         } else if (hp >= 3 && hp < 4) {
 118                 *r = 0.0f;
 119                 *g = x;
 120                 *b = c;
 121         } else if (hp >= 4 && hp < 5) {
 122                 *r = x;
 123                 *g = 0.0f;
 124                 *b = c;
 125         } else {
 126                 *r = c;
 127                 *g = 0.0f;
 128                 *b = x;
 129         }
 130
 131         float m = v - c;
 132         *r += m;
 133         *g += m;
 134         *b += m;
 135 }
 136
 137 GLhandleARB read_shader(const char* filename, GLenum type)
 138 {
 139         static char buf[131072];
 140         FILE *fp = fopen(filename, "r");
 141         if (fp == NULL) {
 142                 perror(filename);
 143                 exit(1);
 144         }
 145
 146         int len = fread(buf, 1, sizeof(buf), fp);
 147         fclose(fp);
 148
 149         GLhandleARB obj = glCreateShaderObjectARB(type);
 150         const GLchar* source[] = { buf };
 151         const GLint length[] = { len };
 152         glShaderSource(obj, 1, source, length);
 153         glCompileShader(obj);
 154
 155         GLchar info_log[4096];
 156         GLsizei log_length = sizeof(info_log) - 1;
 157         glGetShaderInfoLog(obj, log_length, &log_length, info_log);
 158         info_log[log_length] = 0;
 159         printf("shader compile log: %s\n", info_log);
 160
 161         GLint status;
 162         glGetShaderiv(obj, GL_COMPILE_STATUS, &status);
 163         if (status == GL_FALSE) {
 164                 exit(1);
 165         }
 166
 167         return obj;
 168 }
 169
 170 void draw_picture_quad(GLint prog, int frame)
 171 {
 172         glUseProgramObjectARB(prog);
 173         check_error();
 174
 175         glActiveTexture(GL_TEXTURE0);
 176         glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
 177         glUniform1i(glGetUniformLocation(prog, "tex"), 0);
 178
 179         glActiveTexture(GL_TEXTURE1);
 180         glBindTexture(GL_TEXTURE_1D, SRGB_LUT);
 181         glUniform1i(glGetUniformLocation(prog, "srgb_tex"), 1);
 182
 183         glActiveTexture(GL_TEXTURE2);
 184         glBindTexture(GL_TEXTURE_1D, SRGB_REVERSE_LUT);
 185         glUniform1i(glGetUniformLocation(prog, "srgb_reverse_tex"), 2);
 186
 187         glUniform3f(glGetUniformLocation(prog, "lift"), lift_r, lift_g, lift_b);
 188         //glUniform3f(glGetUniformLocation(prog, "gamma"), gamma_r, gamma_g, gamma_b);
 189         glUniform3f(glGetUniformLocation(prog, "inv_gamma_22"),
 190                     2.2f / gamma_r,
 191                     2.2f / gamma_g,
 192                     2.2f / gamma_b);
 193         glUniform3f(glGetUniformLocation(prog, "gain_pow_inv_gamma"),
 194                     pow(gain_r, 1.0f / gamma_r),
 195                     pow(gain_g, 1.0f / gamma_g),
 196                     pow(gain_b, 1.0f / gamma_b));
 197         glUniform1f(glGetUniformLocation(prog, "saturation"), saturation);
 198
 199         glDisable(GL_BLEND);
 200         check_error();
 201         glDisable(GL_DEPTH_TEST);
 202         check_error();
 203         glDepthMask(GL_FALSE);
 204         check_error();
 205
 206         glMatrixMode(GL_PROJECTION);
 207         glLoadIdentity();
 208         glOrtho(0.0, 1.0, 0.0, 1.0, 0.0, 1.0);
 209
 210         glMatrixMode(GL_MODELVIEW);
 211         glLoadIdentity();
 212
 213         glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
 214 //      glClear(GL_COLOR_BUFFER_BIT);
 215         check_error();
 216
 217         glBegin(GL_QUADS);
 218
 219         glTexCoord2f(0.0f, 1.0f);
 220         glVertex2f(0.0f, 0.0f);
 221
 222         glTexCoord2f(1.0f, 1.0f);
 223         glVertex2f(1.0f, 0.0f);
 224
 225         glTexCoord2f(1.0f, 0.0f);
 226         glVertex2f(1.0f, 1.0f);
 227
 228         glTexCoord2f(0.0f, 0.0f);
 229         glVertex2f(0.0f, 1.0f);
 230
 231         glEnd();
 232         check_error();
 233 }
 234
 235 void draw_hsv_wheel(float y, float rad, float theta, float value)
 236 {
 237         glUseProgramObjectARB(0);
 238         check_error();
 239         glActiveTexture(GL_TEXTURE0);
 240         check_error();
 241         glEnable(GL_TEXTURE_2D);
 242         check_error();
 243         glBindTexture(GL_TEXTURE_2D, HSV_WHEEL);
 244         check_error();
 245         glActiveTexture(GL_TEXTURE1);
 246         check_error();
 247         glBindTexture(GL_TEXTURE_2D, 0);
 248         check_error();
 249         glActiveTexture(GL_TEXTURE0);
 250         glEnable(GL_BLEND);
 251         check_error();
 252         glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 253         check_error();
 254
 255         // wheel
 256         glBegin(GL_QUADS);
 257
 258         glTexCoord2f(0.0f, 1.0f);
 259         glVertex2f(0.0f, y);
 260
 261         glTexCoord2f(1.0f, 1.0f);
 262         glVertex2f(0.2f * 9.0f / 16.0f, y);
 263
 264         glTexCoord2f(1.0f, 0.0f);
 265         glVertex2f(0.2f * 9.0f / 16.0f, y + 0.2f);
 266
 267         glTexCoord2f(0.0f, 0.0f);
 268         glVertex2f(0.0f, y + 0.2f);
 269
 270         glEnd();
 271
 272         // wheel selector
 273         glDisable(GL_TEXTURE_2D);
 274         glColor3f(0.0f, 0.0f, 0.0f);
 275         glPointSize(5.0f);
 276         glBegin(GL_POINTS);
 277         glVertex2f((0.1f + rad * cos(theta) * 0.1f) * 9.0f / 16.0f, y + 0.1f - rad * sin(theta) * 0.1f);
 278         glEnd();
 279
 280         // value slider
 281         glDisable(GL_TEXTURE_2D);
 282         glBegin(GL_QUADS);
 283
 284         glColor3f(0.0f, 0.0f, 0.0f);
 285         glVertex2f(0.22f * 9.0f / 16.0f, y);
 286         glVertex2f(0.24f * 9.0f / 16.0f, y);
 287
 288         glColor3f(1.0f, 1.0f, 1.0f);
 289         glVertex2f(0.24f * 9.0f / 16.0f, y + 0.2f);
 290         glVertex2f(0.22f * 9.0f / 16.0f, y + 0.2f);
 291
 292         glEnd();
 293
 294         // value selector
 295         glColor3f(0.0f, 0.0f, 0.0f);
 296         glPointSize(5.0f);
 297         glBegin(GL_POINTS);
 298         glVertex2f(0.23f * 9.0f / 16.0f, y + value * 0.2f);
 299         glEnd();
 300
 301         glColor3f(1.0f, 1.0f, 1.0f);
 302 }
 303
 304 void draw_saturation_bar(float y)
 305 {
 306         glUseProgramObjectARB(0);
 307         check_error();
 308
 309         // value slider
 310         glDisable(GL_TEXTURE_2D);
 311         glBegin(GL_QUADS);
 312
 313         glColor3f(0.0f, 0.0f, 0.0f);
 314         glVertex2f(0.0f * 9.0f / 16.0f, y + 0.02f);
 315         glVertex2f(0.0f * 9.0f / 16.0f, y);
 316
 317         glColor3f(1.0f, 1.0f, 1.0f);
 318         glVertex2f(0.2f * 9.0f / 16.0f, y);
 319         glVertex2f(0.2f * 9.0f / 16.0f, y + 0.02f);
 320
 321         glEnd();
 322
 323         // value selector
 324         glColor3f(0.0f, 0.0f, 0.0f);
 325         glPointSize(5.0f);
 326         glBegin(GL_POINTS);
 327         glVertex2f(0.2f * (saturation / 4.0f) * 9.0f / 16.0f, y + 0.01f);
 328         glEnd();
 329
 330         glColor3f(1.0f, 1.0f, 1.0f);
 331 }
 332
 333 void make_hsv_wheel_texture()
 334 {
 335         static unsigned char hsv_pix[HSV_WHEEL_SIZE * HSV_WHEEL_SIZE * 4];
 336         for (int y = 0; y < HSV_WHEEL_SIZE; ++y) {
 337                 for (int x = 0; x < HSV_WHEEL_SIZE; ++x) {
 338                         float yf = 2.0f * y / (float)(HSV_WHEEL_SIZE) - 1.0f;
 339                         float xf = 2.0f * x / (float)(HSV_WHEEL_SIZE) - 1.0f;
 340                         float rad = hypot(xf, yf);
 341                         float theta = atan2(yf, xf);
 342
 343                         float r, g, b;
 344                         hsv2rgb(theta, rad, 1.0f, &r, &g, &b);
 345                         hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 0] = lrintf(r * 255.0f);
 346                         hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 1] = lrintf(g * 255.0f);
 347                         hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 2] = lrintf(b * 255.0f);
 348
 349                         if (rad > 1.0f) {
 350                                 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 0;
 351                         } else {
 352                                 hsv_pix[(y * HSV_WHEEL_SIZE + x) * 4 + 3] = 255;
 353                         }
 354                 }
 355                 printf("\n");
 356         }
 357
 358         glBindTexture(GL_TEXTURE_2D, HSV_WHEEL);
 359         check_error();
 360         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 361         check_error();
 362         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, HSV_WHEEL_SIZE, HSV_WHEEL_SIZE, 0, GL_RGBA, GL_UNSIGNED_BYTE, hsv_pix);
 363         check_error();
 364 }
 365
 366 void update_hsv()
 367 {
 368         hsv2rgb(lift_theta, lift_rad, lift_v, &lift_r, &lift_g, &lift_b);
 369         hsv2rgb(gamma_theta, gamma_rad, gamma_v * 2.0f, &gamma_r, &gamma_g, &gamma_b);
 370         hsv2rgb(gain_theta, gain_rad, gain_v * 4.0f, &gain_r, &gain_g, &gain_b);
 371
 372         if (saturation < 0.0) {
 373                 saturation = 0.0;
 374         }
 375
 376         printf("lift: %f %f %f\n", lift_r, lift_g, lift_b);
 377         printf("gamma: %f %f %f\n", gamma_r, gamma_g, gamma_b);
 378         printf("gain: %f %f %f\n", gain_r, gain_g, gain_b);
 379         printf("saturation: %f\n", saturation);
 380         printf("\n");
 381 }
 382
 383 void read_colorwheel(float xf, float yf, float *rad, float *theta, float *value)
 384 {
 385         if (xf < 0.2f && yf < 0.2f) {
 386                 float xp = 2.0f * xf / 0.2f - 1.0f;
 387                 float yp = -(2.0f * yf / 0.2f - 1.0f);
 388                 *rad = hypot(xp, yp);
 389                 *theta = atan2(yp, xp);
 390                 if (*rad > 1.0) {
 391                         *rad = 1.0;
 392                 }
 393         } else if (xf >= 0.22f && xf <= 0.24f) {
 394                 *value = yf / 0.2f;
 395         }
 396 }
 397
 398 void mouse(int x, int y)
 399 {
 400         float xf = (x / (float)WIDTH) * 16.0f / 9.0f;
 401         float yf = (HEIGHT - y) / (float)HEIGHT;
 402
 403         if (yf < 0.2f) {
 404                 read_colorwheel(xf, yf, &lift_rad, &lift_theta, &lift_v);
 405         } else if (yf >= 0.2f && yf < 0.4f) {
 406                 read_colorwheel(xf, yf - 0.2f, &gamma_rad, &gamma_theta, &gamma_v);
 407         } else if (yf >= 0.4f && yf < 0.6f) {
 408                 read_colorwheel(xf, yf - 0.4f, &gain_rad, &gain_theta, &gain_v);
 409         } else if (yf >= 0.6f && yf < 0.62f && xf < 0.2f) {
 410                 saturation = (xf / 0.2f) * 4.0f;
 411         }
 412
 413         update_hsv();
 414 }
 415
 416 void load_texture(const char *filename)
 417 {
 418         SDL_Surface *img = IMG_Load(filename);
 419         if (img == NULL) {
 420                 fprintf(stderr, "Load of '%s' failed\n", filename);
 421                 exit(1);
 422         }
 423
 424         // Convert to RGB.
 425         SDL_PixelFormat *fmt = img->format;
 426         SDL_LockSurface(img);
 427         unsigned char *src_pixels = (unsigned char *)img->pixels;
 428         unsigned char *dst_pixels = (unsigned char *)malloc(img->w * img->h * 3);
 429         for (unsigned i = 0; i < img->w * img->h; ++i) {
 430                 unsigned char r, g, b;
 431                 unsigned int temp;
 432                 unsigned int pixel = *(unsigned int *)(src_pixels + i * fmt->BytesPerPixel);
 433
 434                 temp = pixel & fmt->Rmask;
 435                 temp = temp >> fmt->Rshift;
 436                 temp = temp << fmt->Rloss;
 437                 r = temp;
 438
 439                 temp = pixel & fmt->Gmask;
 440                 temp = temp >> fmt->Gshift;
 441                 temp = temp << fmt->Gloss;
 442                 g = temp;
 443
 444                 temp = pixel & fmt->Bmask;
 445                 temp = temp >> fmt->Bshift;
 446                 temp = temp << fmt->Bloss;
 447                 b = temp;
 448
 449                 dst_pixels[i * 3 + 0] = r;
 450                 dst_pixels[i * 3 + 1] = g;
 451                 dst_pixels[i * 3 + 2] = b;
 452         }
 453         SDL_UnlockSurface(img);
 454
 455 #if 1
 456         // we will convert to sRGB in the shader
 457         glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, img->w, img->h, 0, GL_RGB, GL_UNSIGNED_BYTE, dst_pixels);
 458         check_error();
 459 #else
 460         // implicit sRGB conversion in hardware
 461         glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8, img->w, img->h, 0, GL_RGB, GL_UNSIGNED_BYTE, dst_pixels);
 462         check_error();
 463 #endif
 464         free(dst_pixels);
 465         SDL_FreeSurface(img);
 466 }
 467
 468 void write_ppm(const char *filename, unsigned char *screenbuf)
 469 {
 470         FILE *fp = fopen(filename, "w");
 471         fprintf(fp, "P6\n%d %d\n255\n", WIDTH, HEIGHT);
 472         for (unsigned y = 0; y < HEIGHT; ++y) {
 473                 unsigned char *srcptr = screenbuf + ((HEIGHT - y - 1) * WIDTH) * 4;
 474                 for (unsigned x = 0; x < WIDTH; ++x) {
 475                         fputc(srcptr[x * 4 + 2], fp);
 476                         fputc(srcptr[x * 4 + 1], fp);
 477                         fputc(srcptr[x * 4 + 0], fp);
 478                 }
 479         }
 480         fclose(fp);
 481 }
 482
 483 int main(int argc, char **argv)
 484 {
 485         int quit = 0;
 486
 487         SDL_Init(SDL_INIT_EVERYTHING);
 488         SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 0);
 489         SDL_GL_SetAttribute(SDL_GL_STENCIL_SIZE, 0);
 490         SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 491         SDL_SetVideoMode(WIDTH, HEIGHT, 0, SDL_OPENGL);
 492         SDL_WM_SetCaption("OpenGL window", NULL);
 493
 494         // geez
 495         glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
 496         glPixelStorei(GL_PACK_ALIGNMENT, 1);
 497
 498         glBindTexture(GL_TEXTURE_2D, SOURCE_IMAGE);
 499         check_error();
 500         glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 501         check_error();
 502
 503         load_texture("blg_wheels_woman_1.jpg");
 504         //glGenerateMipmap(GL_TEXTURE_2D);
 505         //glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 4);
 506         //check_error();
 507
 508         //load_texture("maserati_gts_wallpaper_1280x720_01.jpg");
 509         //load_texture("90630d1295075297-console-games-wallpapers-wallpaper_need_for_speed_prostreet_09_1920x1080.jpg");
 510         //load_texture("glacier-lake-1280-720-4087.jpg");
 511
 512 #if 0
 513         // sRGB reverse LUT
 514         glBindTexture(GL_TEXTURE_1D, SRGB_REVERSE_LUT);
 515         check_error();
 516         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 517         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 518         check_error();
 519         float srgb_reverse_tex[4096];
 520         for (unsigned i = 0; i < 4096; ++i) {
 521                 float x = i / 4095.0;
 522                 if (x < 0.0031308f) {
 523                         srgb_reverse_tex[i] = 12.92f * x;
 524                 } else {
 525                         srgb_reverse_tex[i] = 1.055f * pow(x, 1.0f / 2.4f) - 0.055f;
 526                 }
 527         }
 528         glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE16F_ARB, 4096, 0, GL_LUMINANCE, GL_FLOAT, srgb_reverse_tex);
 529         check_error();
 530
 531         // sRGB LUT
 532         glBindTexture(GL_TEXTURE_1D, SRGB_LUT);
 533         check_error();
 534         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 535         glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
 536         check_error();
 537         float srgb_tex[256];
 538         for (unsigned i = 0; i < 256; ++i) {
 539                 float x = i / 255.0;
 540                 if (x < 0.04045f) {
 541                         srgb_tex[i] = x * (1.0f / 12.92f);
 542                 } else {
 543                         srgb_tex[i] = pow((x + 0.055) * (1.0 / 1.055f), 2.4);
 544                 }
 545         }
 546         glTexImage1D(GL_TEXTURE_1D, 0, GL_LUMINANCE16F_ARB, 256, 0, GL_LUMINANCE, GL_FLOAT, srgb_tex);
 547         check_error();
 548 #endif
 549
 550         // generate a PDO to hold the data we read back with glReadPixels()
 551         // (Intel/DRI goes into a slow path if we don't read to PDO)
 552         glBindBuffer(GL_PIXEL_PACK_BUFFER_ARB, 1);
 553         glBufferData(GL_PIXEL_PACK_BUFFER_ARB, WIDTH * HEIGHT * 4, NULL, GL_STREAM_READ);
 554
 555         make_hsv_wheel_texture();
 556         update_hsv();
 557
 558         int prog = glCreateProgram();
 559         GLhandleARB vs_obj = read_shader("vs.glsl", GL_VERTEX_SHADER);
 560         GLhandleARB fs_obj = read_shader("fs.glsl", GL_FRAGMENT_SHADER);
 561         glAttachObjectARB(prog, vs_obj);
 562         check_error();
 563         glAttachObjectARB(prog, fs_obj);
 564         check_error();
 565         glLinkProgram(prog);
 566         check_error();
 567
 568         GLchar info_log[4096];
 569         GLsizei log_length = sizeof(info_log) - 1;
 570         log_length = sizeof(info_log) - 1;
 571         glGetProgramInfoLog(prog, log_length, &log_length, info_log);
 572         info_log[log_length] = 0;
 573         printf("link: %s\n", info_log);
 574
 575         struct timespec start, now;
 576         int frame = 0, screenshot = 0;
 577         clock_gettime(CLOCK_MONOTONIC, &start);
 578
 579         while (!quit) {
 580                 SDL_Event event;
 581                 while (SDL_PollEvent(&event)) {
 582                         if (event.type == SDL_QUIT) {
 583                                 quit = 1;
 584                         } else if (event.type == SDL_KEYDOWN && event.key.keysym.sym == SDLK_ESCAPE) {
 585                                 quit = 1;
 586                         } else if (event.type == SDL_KEYDOWN && event.key.keysym.sym == SDLK_F1) {
 587                                 screenshot = 1;
 588                         } else if (event.type == SDL_MOUSEBUTTONDOWN && event.button.button == SDL_BUTTON_LEFT) {
 589                                 mouse(event.button.x, event.button.y);
 590                         } else if (event.type == SDL_MOUSEMOTION && (event.motion.state & SDL_BUTTON(1))) {
 591                                 mouse(event.motion.x, event.motion.y);
 592                         }
 593                 }
 594
 595                 ++frame;
 596
 597                 draw_picture_quad(prog, frame);
 598
 599                 glReadPixels(0, 0, WIDTH, HEIGHT, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, BUFFER_OFFSET(0));
 600                 check_error();
 601
 602                 draw_hsv_wheel(0.0f, lift_rad, lift_theta, lift_v);
 603                 draw_hsv_wheel(0.2f, gamma_rad, gamma_theta, gamma_v);
 604                 draw_hsv_wheel(0.4f, gain_rad, gain_theta, gain_v);
 605                 draw_saturation_bar(0.6f);
 606
 607                 SDL_GL_SwapBuffers();
 608                 check_error();
 609
 610                 unsigned char *screenbuf = (unsigned char *)glMapBuffer(GL_PIXEL_PACK_BUFFER_ARB, GL_READ_ONLY);
 611                 check_error();
 612                 if (screenshot) {
 613                         char filename[256];
 614                         sprintf(filename, "frame%05d.ppm", frame);
 615                         write_ppm(filename, screenbuf);
 616                         printf("Screenshot: %s\n", filename);
 617                         screenshot = 0;
 618                 }
 619                 glUnmapBuffer(GL_PIXEL_PACK_BUFFER_ARB);
 620                 check_error();
 621
 622 #if 1
 623                 clock_gettime(CLOCK_MONOTONIC, &now);
 624                 double elapsed = now.tv_sec - start.tv_sec +
 625                         1e-9 * (now.tv_nsec - start.tv_nsec);
 626                 printf("%d frames in %.3f seconds = %.1f fps (%.1f ms/frame)\n",
 627                         frame, elapsed, frame / elapsed,
 628                         1e3 * elapsed / frame);
 629 #endif
 630         }
 631         return 0;
 632 }