oculus2
view src/main.c @ 26:a7a3f89def42
... see previous commit
| author | John Tsiombikas <nuclear@member.fsf.org> |
|---|---|
| date | Sat, 11 Apr 2015 03:53:21 +0300 |
| parents | 0c7d02c58e4e |
| children |
line source
1 /* Very simple OculusSDK OpenGL usage example.
2 *
3 * Uses SDL2 (www.libsdl.org) for event handling and OpenGL context management.
4 * Uses GLEW (glew.sourceforge.net) for OpenGL extension wrangling.
5 *
6 * Author: John Tsiombikas <nuclear@member.fsf.org>
7 * This code is in the public domain. Do whatever you like with it.
8 */
9 #include <stdio.h>
10 #include <stdlib.h>
11 #include <assert.h>
12 #include <SDL2/SDL.h>
13 #include <GL/glew.h>
15 #ifdef WIN32
16 #define OVR_OS_WIN32
17 #elif defined(__APPLE__)
18 #define OVR_OS_MAC
19 #else
20 #define OVR_OS_LINUX
21 #include <X11/Xlib.h>
22 #include <GL/glx.h>
23 #endif
25 #include <OVR_CAPI.h>
26 #include <OVR_CAPI_GL.h>
28 int init(void);
29 void cleanup(void);
30 void toggle_hmd_fullscreen(void);
31 void display(void);
32 void draw_scene(void);
33 void draw_box(float xsz, float ysz, float zsz, float norm_sign);
34 void update_rtarg(int width, int height);
35 int handle_event(SDL_Event *ev);
36 int key_event(int key, int state);
37 void reshape(int x, int y);
38 unsigned int next_pow2(unsigned int x);
39 void quat_to_matrix(const float *quat, float *mat);
40 unsigned int gen_chess_tex(float r0, float g0, float b0, float r1, float g1, float b1);
42 static SDL_Window *win;
43 static SDL_GLContext ctx;
44 static int win_width, win_height;
46 static unsigned int fbo, fb_tex, fb_depth;
47 static int fb_width, fb_height;
48 static int fb_tex_width, fb_tex_height;
50 static ovrHmd hmd;
51 static ovrSizei eyeres[2];
52 static ovrEyeRenderDesc eye_rdesc[2];
53 static ovrGLTexture fb_ovr_tex[2];
54 static union ovrGLConfig glcfg;
55 static unsigned int distort_caps;
56 static unsigned int hmd_caps;
58 static unsigned int chess_tex;
61 int main(int argc, char **argv)
62 {
63 if(init() == -1) {
64 return 1;
65 }
67 for(;;) {
68 SDL_Event ev;
69 while(SDL_PollEvent(&ev)) {
70 if(handle_event(&ev) == -1) {
71 goto done;
72 }
73 }
74 display();
75 }
77 done:
78 cleanup();
79 return 0;
80 }
83 int init(void)
84 {
85 int i, x, y;
86 unsigned int flags;
88 /* libovr must be initialized before we create the OpenGL context */
89 ovr_Initialize(0);
91 SDL_Init(SDL_INIT_VIDEO | SDL_INIT_TIMER);
93 x = y = SDL_WINDOWPOS_UNDEFINED;
94 flags = SDL_WINDOW_OPENGL;
95 if(!(win = SDL_CreateWindow("press 'f' to move to the HMD", x, y, 1024, 640, flags))) {
96 fprintf(stderr, "failed to create window\n");
97 return -1;
98 }
99 if(!(ctx = SDL_GL_CreateContext(win))) {
100 fprintf(stderr, "failed to create OpenGL context\n");
101 return -1;
102 }
104 glewInit();
106 if(!(hmd = ovrHmd_Create(0))) {
107 fprintf(stderr, "failed to open Oculus HMD, falling back to virtual debug HMD\n");
108 if(!(hmd = ovrHmd_CreateDebug(ovrHmd_DK2))) {
109 fprintf(stderr, "failed to create virtual debug HMD\n");
110 return -1;
111 }
112 }
113 printf("initialized HMD: %s - %s\n", hmd->Manufacturer, hmd->ProductName);
115 /* resize our window to match the HMD resolution */
116 SDL_SetWindowSize(win, hmd->Resolution.w, hmd->Resolution.h);
117 SDL_SetWindowPosition(win, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
118 win_width = hmd->Resolution.w;
119 win_height = hmd->Resolution.h;
121 /* enable position and rotation tracking */
122 ovrHmd_ConfigureTracking(hmd, ovrTrackingCap_Orientation | ovrTrackingCap_MagYawCorrection | ovrTrackingCap_Position, 0);
123 /* retrieve the optimal render target resolution for each eye */
124 eyeres[0] = ovrHmd_GetFovTextureSize(hmd, ovrEye_Left, hmd->DefaultEyeFov[0], 1.0);
125 eyeres[1] = ovrHmd_GetFovTextureSize(hmd, ovrEye_Right, hmd->DefaultEyeFov[1], 1.0);
127 /* and create a single render target texture to encompass both eyes */
128 fb_width = eyeres[0].w + eyeres[1].w;
129 fb_height = eyeres[0].h > eyeres[1].h ? eyeres[0].h : eyeres[1].h;
130 update_rtarg(fb_width, fb_height);
132 /* fill in the ovrGLTexture structures that describe our render target texture */
133 for(i=0; i<2; i++) {
134 fb_ovr_tex[i].OGL.Header.API = ovrRenderAPI_OpenGL;
135 fb_ovr_tex[i].OGL.Header.TextureSize.w = fb_tex_width;
136 fb_ovr_tex[i].OGL.Header.TextureSize.h = fb_tex_height;
137 /* this next field is the only one that differs between the two eyes */
138 fb_ovr_tex[i].OGL.Header.RenderViewport.Pos.x = i == 0 ? 0 : fb_width / 2.0;
139 fb_ovr_tex[i].OGL.Header.RenderViewport.Pos.y = 0;
140 fb_ovr_tex[i].OGL.Header.RenderViewport.Size.w = fb_width / 2.0;
141 fb_ovr_tex[i].OGL.Header.RenderViewport.Size.h = fb_height;
142 fb_ovr_tex[i].OGL.TexId = fb_tex; /* both eyes will use the same texture id */
143 }
145 /* fill in the ovrGLConfig structure needed by the SDK to draw our stereo pair
146 * to the actual HMD display (SDK-distortion mode)
147 */
148 memset(&glcfg, 0, sizeof glcfg);
149 glcfg.OGL.Header.API = ovrRenderAPI_OpenGL;
150 glcfg.OGL.Header.BackBufferSize.w = win_width;
151 glcfg.OGL.Header.BackBufferSize.h = win_height;
152 glcfg.OGL.Header.Multisample = 1;
154 #ifdef OVR_OS_WIN32
155 glcfg.OGL.Window = GetActiveWindow();
156 glcfg.OGL.DC = wglGetCurrentDC();
157 #elif defined(OVR_OS_LINUX)
158 glcfg.OGL.Disp = glXGetCurrentDisplay();
159 #endif
161 if(hmd->HmdCaps & ovrHmdCap_ExtendDesktop) {
162 printf("running in \"extended desktop\" mode\n");
163 } else {
164 /* to sucessfully draw to the HMD display in "direct-hmd" mode, we have to
165 * call ovrHmd_AttachToWindow
166 * XXX: this doesn't work properly yet due to bugs in the oculus 0.4.1 sdk/driver
167 */
168 #ifdef WIN32
169 ovrHmd_AttachToWindow(hmd, glcfg.OGL.Window, 0, 0);
170 #elif defined(OVR_OS_LINUX)
171 ovrHmd_AttachToWindow(hmd, (void*)glXGetCurrentDrawable(), 0, 0);
172 #endif
173 printf("running in \"direct-hmd\" mode\n");
174 }
176 /* enable low-persistence display and dynamic prediction for lattency compensation */
177 hmd_caps = ovrHmdCap_LowPersistence | ovrHmdCap_DynamicPrediction;
178 ovrHmd_SetEnabledCaps(hmd, hmd_caps);
180 /* configure SDK-rendering and enable OLED overdrive and timewrap, which
181 * shifts the image before drawing to counter any lattency between the call
182 * to ovrHmd_GetEyePose and ovrHmd_EndFrame.
183 */
184 distort_caps = ovrDistortionCap_TimeWarp | ovrDistortionCap_Overdrive;
185 if(!ovrHmd_ConfigureRendering(hmd, &glcfg.Config, distort_caps, hmd->DefaultEyeFov, eye_rdesc)) {
186 fprintf(stderr, "failed to configure distortion renderer\n");
187 }
189 glEnable(GL_DEPTH_TEST);
190 glEnable(GL_CULL_FACE);
191 glEnable(GL_LIGHTING);
192 glEnable(GL_LIGHT0);
193 glEnable(GL_LIGHT1);
194 glEnable(GL_NORMALIZE);
196 glClearColor(0.1, 0.1, 0.1, 1);
198 chess_tex = gen_chess_tex(1.0, 0.7, 0.4, 0.4, 0.7, 1.0);
199 return 0;
200 }
202 void cleanup(void)
203 {
204 if(hmd) {
205 ovrHmd_Destroy(hmd);
206 }
207 ovr_Shutdown();
209 SDL_Quit();
210 }
212 void toggle_hmd_fullscreen(void)
213 {
214 static int fullscr, prev_x, prev_y;
215 fullscr = !fullscr;
217 if(fullscr) {
218 /* going fullscreen on the rift. save current window position, and move it
219 * to the rift's part of the desktop before going fullscreen
220 */
221 SDL_GetWindowPosition(win, &prev_x, &prev_y);
222 SDL_SetWindowPosition(win, hmd->WindowsPos.x, hmd->WindowsPos.y);
223 SDL_SetWindowFullscreen(win, SDL_WINDOW_FULLSCREEN_DESKTOP);
225 #ifdef OVR_OS_LINUX
226 /* on linux for now we have to deal with screen rotation during rendering. The docs are promoting
227 * not rotating the DK2 screen globally
228 */
229 glcfg.OGL.Header.BackBufferSize.w = hmd->Resolution.h;
230 glcfg.OGL.Header.BackBufferSize.h = hmd->Resolution.w;
232 distort_caps |= ovrDistortionCap_LinuxDevFullscreen;
233 ovrHmd_ConfigureRendering(hmd, &glcfg.Config, distort_caps, hmd->DefaultEyeFov, eye_rdesc);
234 #endif
235 } else {
236 /* return to windowed mode and move the window back to its original position */
237 SDL_SetWindowFullscreen(win, 0);
238 SDL_SetWindowPosition(win, prev_x, prev_y);
240 #ifdef OVR_OS_LINUX
241 glcfg.OGL.Header.BackBufferSize = hmd->Resolution;
243 distort_caps &= ~ovrDistortionCap_LinuxDevFullscreen;
244 ovrHmd_ConfigureRendering(hmd, &glcfg.Config, distort_caps, hmd->DefaultEyeFov, eye_rdesc);
245 #endif
246 }
247 }
249 void display(void)
250 {
251 int i;
252 ovrMatrix4f proj;
253 ovrPosef pose[2];
254 float rot_mat[16];
256 /* the drawing starts with a call to ovrHmd_BeginFrame */
257 ovrHmd_BeginFrame(hmd, 0);
259 /* start drawing onto our texture render target */
260 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
261 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
263 /* for each eye ... */
264 for(i=0; i<2; i++) {
265 ovrEyeType eye = hmd->EyeRenderOrder[i];
267 /* -- viewport transformation --
268 * setup the viewport to draw in the left half of the framebuffer when we're
269 * rendering the left eye's view (0, 0, width/2, height), and in the right half
270 * of the framebuffer for the right eye's view (width/2, 0, width/2, height)
271 */
272 glViewport(eye == ovrEye_Left ? 0 : fb_width / 2, 0, fb_width / 2, fb_height);
274 /* -- projection transformation --
275 * we'll just have to use the projection matrix supplied by the oculus SDK for this eye
276 * note that libovr matrices are the transpose of what OpenGL expects, so we have to
277 * use glLoadTransposeMatrixf instead of glLoadMatrixf to load it.
278 */
279 proj = ovrMatrix4f_Projection(hmd->DefaultEyeFov[eye], 0.5, 500.0, 1);
280 glMatrixMode(GL_PROJECTION);
281 glLoadTransposeMatrixf(proj.M[0]);
283 /* -- view/camera transformation --
284 * we need to construct a view matrix by combining all the information provided by the oculus
285 * SDK, about the position and orientation of the user's head in the world.
286 */
287 /* TODO: use ovrHmd_GetEyePoses out of the loop instead */
288 pose[eye] = ovrHmd_GetHmdPosePerEye(hmd, eye);
289 glMatrixMode(GL_MODELVIEW);
290 glLoadIdentity();
291 glTranslatef(eye_rdesc[eye].HmdToEyeViewOffset.x,
292 eye_rdesc[eye].HmdToEyeViewOffset.y,
293 eye_rdesc[eye].HmdToEyeViewOffset.z);
294 /* retrieve the orientation quaternion and convert it to a rotation matrix */
295 quat_to_matrix(&pose[eye].Orientation.x, rot_mat);
296 glMultMatrixf(rot_mat);
297 /* translate the view matrix with the positional tracking */
298 glTranslatef(-pose[eye].Position.x, -pose[eye].Position.y, -pose[eye].Position.z);
299 /* move the camera to the eye level of the user */
300 glTranslatef(0, -ovrHmd_GetFloat(hmd, OVR_KEY_EYE_HEIGHT, 1.65), 0);
302 /* finally draw the scene for this eye */
303 draw_scene();
304 }
306 /* after drawing both eyes into the texture render target, revert to drawing directly to the
307 * display, and we call ovrHmd_EndFrame, to let the Oculus SDK draw both images properly
308 * compensated for lens distortion and chromatic abberation onto the HMD screen.
309 */
310 glBindFramebuffer(GL_FRAMEBUFFER, 0);
312 ovrHmd_EndFrame(hmd, pose, &fb_ovr_tex[0].Texture);
314 /* workaround for the oculus sdk distortion renderer bug, which uses a shader
315 * program, and doesn't restore the original binding when it's done.
316 */
317 glUseProgram(0);
319 assert(glGetError() == GL_NO_ERROR);
320 }
322 void reshape(int x, int y)
323 {
324 win_width = x;
325 win_height = y;
326 }
328 void draw_scene(void)
329 {
330 int i;
331 float grey[] = {0.8, 0.8, 0.8, 1};
332 float col[] = {0, 0, 0, 1};
333 float lpos[][4] = {
334 {-8, 2, 10, 1},
335 {0, 15, 0, 1}
336 };
337 float lcol[][4] = {
338 {0.8, 0.8, 0.8, 1},
339 {0.4, 0.3, 0.3, 1}
340 };
342 for(i=0; i<2; i++) {
343 glLightfv(GL_LIGHT0 + i, GL_POSITION, lpos[i]);
344 glLightfv(GL_LIGHT0 + i, GL_DIFFUSE, lcol[i]);
345 }
347 glMatrixMode(GL_MODELVIEW);
349 glPushMatrix();
350 glTranslatef(0, 10, 0);
351 glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, grey);
352 glBindTexture(GL_TEXTURE_2D, chess_tex);
353 glEnable(GL_TEXTURE_2D);
354 draw_box(30, 20, 30, -1.0);
355 glDisable(GL_TEXTURE_2D);
356 glPopMatrix();
358 for(i=0; i<4; i++) {
359 glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, grey);
360 glPushMatrix();
361 glTranslatef(i & 1 ? 5 : -5, 1, i & 2 ? -5 : 5);
362 draw_box(0.5, 2, 0.5, 1.0);
363 glPopMatrix();
365 col[0] = i & 1 ? 1.0 : 0.3;
366 col[1] = i == 0 ? 1.0 : 0.3;
367 col[2] = i & 2 ? 1.0 : 0.3;
368 glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, col);
370 glPushMatrix();
371 if(i & 1) {
372 glTranslatef(0, 0.25, i & 2 ? 2 : -2);
373 } else {
374 glTranslatef(i & 2 ? 2 : -2, 0.25, 0);
375 }
376 draw_box(0.5, 0.5, 0.5, 1.0);
377 glPopMatrix();
378 }
380 col[0] = 1;
381 col[1] = 1;
382 col[2] = 0.4;
383 glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, col);
384 draw_box(0.05, 1.2, 6, 1.0);
385 draw_box(6, 1.2, 0.05, 1.0);
386 }
388 void draw_box(float xsz, float ysz, float zsz, float norm_sign)
389 {
390 glMatrixMode(GL_MODELVIEW);
391 glPushMatrix();
392 glScalef(xsz * 0.5, ysz * 0.5, zsz * 0.5);
394 if(norm_sign < 0.0) {
395 glFrontFace(GL_CW);
396 }
398 glBegin(GL_QUADS);
399 glNormal3f(0, 0, 1 * norm_sign);
400 glTexCoord2f(0, 0); glVertex3f(-1, -1, 1);
401 glTexCoord2f(1, 0); glVertex3f(1, -1, 1);
402 glTexCoord2f(1, 1); glVertex3f(1, 1, 1);
403 glTexCoord2f(0, 1); glVertex3f(-1, 1, 1);
404 glNormal3f(1 * norm_sign, 0, 0);
405 glTexCoord2f(0, 0); glVertex3f(1, -1, 1);
406 glTexCoord2f(1, 0); glVertex3f(1, -1, -1);
407 glTexCoord2f(1, 1); glVertex3f(1, 1, -1);
408 glTexCoord2f(0, 1); glVertex3f(1, 1, 1);
409 glNormal3f(0, 0, -1 * norm_sign);
410 glTexCoord2f(0, 0); glVertex3f(1, -1, -1);
411 glTexCoord2f(1, 0); glVertex3f(-1, -1, -1);
412 glTexCoord2f(1, 1); glVertex3f(-1, 1, -1);
413 glTexCoord2f(0, 1); glVertex3f(1, 1, -1);
414 glNormal3f(-1 * norm_sign, 0, 0);
415 glTexCoord2f(0, 0); glVertex3f(-1, -1, -1);
416 glTexCoord2f(1, 0); glVertex3f(-1, -1, 1);
417 glTexCoord2f(1, 1); glVertex3f(-1, 1, 1);
418 glTexCoord2f(0, 1); glVertex3f(-1, 1, -1);
419 glEnd();
420 glBegin(GL_TRIANGLE_FAN);
421 glNormal3f(0, 1 * norm_sign, 0);
422 glTexCoord2f(0.5, 0.5); glVertex3f(0, 1, 0);
423 glTexCoord2f(0, 0); glVertex3f(-1, 1, 1);
424 glTexCoord2f(1, 0); glVertex3f(1, 1, 1);
425 glTexCoord2f(1, 1); glVertex3f(1, 1, -1);
426 glTexCoord2f(0, 1); glVertex3f(-1, 1, -1);
427 glTexCoord2f(0, 0); glVertex3f(-1, 1, 1);
428 glEnd();
429 glBegin(GL_TRIANGLE_FAN);
430 glNormal3f(0, -1 * norm_sign, 0);
431 glTexCoord2f(0.5, 0.5); glVertex3f(0, -1, 0);
432 glTexCoord2f(0, 0); glVertex3f(-1, -1, -1);
433 glTexCoord2f(1, 0); glVertex3f(1, -1, -1);
434 glTexCoord2f(1, 1); glVertex3f(1, -1, 1);
435 glTexCoord2f(0, 1); glVertex3f(-1, -1, 1);
436 glTexCoord2f(0, 0); glVertex3f(-1, -1, -1);
437 glEnd();
439 glFrontFace(GL_CCW);
440 glPopMatrix();
441 }
443 /* update_rtarg creates (and/or resizes) the render target used to draw the two stero views */
444 void update_rtarg(int width, int height)
445 {
446 if(!fbo) {
447 /* if fbo does not exist, then nothing does... create every opengl object */
448 glGenFramebuffers(1, &fbo);
449 glGenTextures(1, &fb_tex);
450 glGenRenderbuffers(1, &fb_depth);
452 glBindTexture(GL_TEXTURE_2D, fb_tex);
453 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
454 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
455 }
457 glBindFramebuffer(GL_FRAMEBUFFER, fbo);
459 /* calculate the next power of two in both dimensions and use that as a texture size */
460 fb_tex_width = next_pow2(width);
461 fb_tex_height = next_pow2(height);
463 /* create and attach the texture that will be used as a color buffer */
464 glBindTexture(GL_TEXTURE_2D, fb_tex);
465 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, fb_tex_width, fb_tex_height, 0,
466 GL_RGBA, GL_UNSIGNED_BYTE, 0);
467 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, fb_tex, 0);
469 /* create and attach the renderbuffer that will serve as our z-buffer */
470 glBindRenderbuffer(GL_RENDERBUFFER, fb_depth);
471 glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, fb_tex_width, fb_tex_height);
472 glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, fb_depth);
474 if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
475 fprintf(stderr, "incomplete framebuffer!\n");
476 }
478 glBindFramebuffer(GL_FRAMEBUFFER, 0);
479 printf("created render target: %dx%d (texture size: %dx%d)\n", width, height, fb_tex_width, fb_tex_height);
480 }
482 int handle_event(SDL_Event *ev)
483 {
484 switch(ev->type) {
485 case SDL_QUIT:
486 return -1;
488 case SDL_KEYDOWN:
489 case SDL_KEYUP:
490 if(key_event(ev->key.keysym.sym, ev->key.state == SDL_PRESSED) == -1) {
491 return -1;
492 }
493 break;
495 case SDL_WINDOWEVENT:
496 if(ev->window.event == SDL_WINDOWEVENT_RESIZED) {
497 reshape(ev->window.data1, ev->window.data2);
498 }
499 break;
501 default:
502 break;
503 }
505 return 0;
506 }
508 int key_event(int key, int state)
509 {
510 if(state) {
511 ovrHSWDisplayState hsw;
512 ovrHmd_GetHSWDisplayState(hmd, &hsw);
513 if(hsw.Displayed) {
514 ovrHmd_DismissHSWDisplay(hmd);
515 }
517 switch(key) {
518 case 27:
519 return -1;
521 case ' ':
522 case 'r':
523 /* allow the user to recenter by pressing space */
524 ovrHmd_RecenterPose(hmd);
525 break;
527 case 'f':
528 /* press f to move the window to the HMD */
529 toggle_hmd_fullscreen();
530 break;
532 case 'v':
533 distort_caps ^= ovrDistortionCap_Vignette;
534 printf("Vignette: %s\n", distort_caps & ovrDistortionCap_Vignette ? "on" : "off");
535 ovrHmd_ConfigureRendering(hmd, &glcfg.Config, distort_caps, hmd->DefaultEyeFov, eye_rdesc);
536 break;
538 case 't':
539 distort_caps ^= ovrDistortionCap_TimeWarp;
540 printf("Time-warp: %s\n", distort_caps & ovrDistortionCap_TimeWarp ? "on" : "off");
541 ovrHmd_ConfigureRendering(hmd, &glcfg.Config, distort_caps, hmd->DefaultEyeFov, eye_rdesc);
542 break;
544 case 'o':
545 distort_caps ^= ovrDistortionCap_Overdrive;
546 printf("OLED over-drive: %s\n", distort_caps & ovrDistortionCap_Overdrive ? "on" : "off");
547 ovrHmd_ConfigureRendering(hmd, &glcfg.Config, distort_caps, hmd->DefaultEyeFov, eye_rdesc);
548 break;
550 case 'l':
551 hmd_caps ^= ovrHmdCap_LowPersistence;
552 printf("Low-persistence display: %s\n", hmd_caps & ovrHmdCap_LowPersistence ? "on" : "off");
553 ovrHmd_SetEnabledCaps(hmd, hmd_caps);
554 break;
556 default:
557 break;
558 }
559 }
560 return 0;
561 }
563 unsigned int next_pow2(unsigned int x)
564 {
565 x -= 1;
566 x |= x >> 1;
567 x |= x >> 2;
568 x |= x >> 4;
569 x |= x >> 8;
570 x |= x >> 16;
571 return x + 1;
572 }
574 /* convert a quaternion to a rotation matrix */
575 void quat_to_matrix(const float *quat, float *mat)
576 {
577 mat[0] = 1.0 - 2.0 * quat[1] * quat[1] - 2.0 * quat[2] * quat[2];
578 mat[4] = 2.0 * quat[0] * quat[1] + 2.0 * quat[3] * quat[2];
579 mat[8] = 2.0 * quat[2] * quat[0] - 2.0 * quat[3] * quat[1];
580 mat[12] = 0.0f;
582 mat[1] = 2.0 * quat[0] * quat[1] - 2.0 * quat[3] * quat[2];
583 mat[5] = 1.0 - 2.0 * quat[0]*quat[0] - 2.0 * quat[2]*quat[2];
584 mat[9] = 2.0 * quat[1] * quat[2] + 2.0 * quat[3] * quat[0];
585 mat[13] = 0.0f;
587 mat[2] = 2.0 * quat[2] * quat[0] + 2.0 * quat[3] * quat[1];
588 mat[6] = 2.0 * quat[1] * quat[2] - 2.0 * quat[3] * quat[0];
589 mat[10] = 1.0 - 2.0 * quat[0]*quat[0] - 2.0 * quat[1]*quat[1];
590 mat[14] = 0.0f;
592 mat[3] = mat[7] = mat[11] = 0.0f;
593 mat[15] = 1.0f;
594 }
596 /* generate a chessboard texture with tiles colored (r0, g0, b0) and (r1, g1, b1) */
597 unsigned int gen_chess_tex(float r0, float g0, float b0, float r1, float g1, float b1)
598 {
599 int i, j;
600 unsigned int tex;
601 unsigned char img[8 * 8 * 3];
602 unsigned char *pix = img;
604 for(i=0; i<8; i++) {
605 for(j=0; j<8; j++) {
606 int black = (i & 1) == (j & 1);
607 pix[0] = (black ? r0 : r1) * 255;
608 pix[1] = (black ? g0 : g1) * 255;
609 pix[2] = (black ? b0 : b1) * 255;
610 pix += 3;
611 }
612 }
614 glGenTextures(1, &tex);
615 glBindTexture(GL_TEXTURE_2D, tex);
616 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
617 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
618 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 8, 8, 0, GL_RGB, GL_UNSIGNED_BYTE, img);
620 return tex;
621 }