nuclear@1: #include <stdio.h>
nuclear@12: #include <GL/glew.h>
nuclear@1: #include "vr.h"
nuclear@1: #include "vr_impl.h"
nuclear@15: #include "vr_sdr.h"
nuclear@12: 
nuclear@19: #ifndef WIN32
nuclear@19: #include <alloca.h>
nuclear@19: #else
nuclear@19: #include <malloc.h>
nuclear@19: #endif
nuclear@19: 
nuclear@21: #define USUB	28
nuclear@21: #define VSUB	40
nuclear@21: 
nuclear@21: /* these are just used for the shaderless precomputed distortion method */
nuclear@21: struct Mesh {
nuclear@21: 	int prim;
nuclear@21: 	int num_verts, num_faces;
nuclear@21: 	unsigned int vbo;
nuclear@21: 	unsigned int ibo;
nuclear@21: };
nuclear@21: struct Vertex {
nuclear@21: 	float x, y, z;
nuclear@21: 	float tx, ty;
nuclear@21: };
nuclear@21: 
nuclear@21: 
nuclear@18: static void init_ctx();
nuclear@1: static bool init_ovr();
nuclear@12: static bool init_sdr();
nuclear@1: 
nuclear@21: static Mesh gen_view_mesh(int usub, int vsub, float aspect, float lens_center_offset,
nuclear@21: 		float scale, const float *dist_factors, float tex_scale_x, float tex_scale_y);
nuclear@21: static void distort_texcoords(float *tc, float aspect, float lens_center_offset, float scale, const float *dist_factors);
nuclear@21: static float barrel_scale(float rad, const float *k);
nuclear@21: 
nuclear@3: VRContext vr_ctx;
nuclear@12: static unsigned int sdrprog;
nuclear@1: 
nuclear@21: static Mesh wrapmesh[2];
nuclear@21: static bool mesh_valid;
nuclear@21: 
nuclear@21: bool dbg_enable;
nuclear@21: 
nuclear@21: 
nuclear@1: extern "C" int vr_init(enum vr_init_mode mode)
nuclear@1: {
nuclear@12: 	glewInit();
nuclear@12: 
nuclear@18: 	init_ctx();
nuclear@18: 
nuclear@1: 	if(!init_ovr()) {
nuclear@1: 		return -1;
nuclear@1: 	}
nuclear@12: 
nuclear@12: 	if(!init_sdr()) {
nuclear@12: 		return -1;
nuclear@12: 	}
nuclear@12: 
nuclear@1: 	return 0;
nuclear@1: }
nuclear@1: 
nuclear@1: extern "C" void vr_shutdown(void)
nuclear@1: {
nuclear@15: 	delete [] vr_ctx.info.display;
nuclear@3: 	//System::Destroy();
nuclear@1: }
nuclear@1: 
nuclear@18: static void init_ctx()
nuclear@18: {
nuclear@18: 	vr_ctx.info.width = 1280;
nuclear@18: 	vr_ctx.info.height = 800;
nuclear@18: 	vr_ctx.info.fov = M_PI / 2.0;
nuclear@18: 	vr_ctx.info.aspect = (float)vr_ctx.info.width / (float)vr_ctx.info.height;
nuclear@18: 	vr_ctx.info.ipd = 0.035;
nuclear@18: 	vr_ctx.info.scale = 1.0;
nuclear@18: }
nuclear@18: 
nuclear@1: static bool init_ovr()
nuclear@1: {
nuclear@8: 	LogMaskConstants log_level = LogMask_All;
nuclear@1: 	// initialize Oculus SDK
nuclear@5: 	const char *logenv = getenv("VR_LOGLEVEL");
nuclear@5: 	if(logenv) {
nuclear@5: 		switch(atoi(logenv)) {
nuclear@5: 		case 0:
nuclear@5: 			log_level = LogMask_None;
nuclear@5: 			break;
nuclear@5: 		case 1:
nuclear@5: 			log_level = LogMask_Regular;
nuclear@5: 			break;
nuclear@5: 		case 2:
nuclear@5: 		default:
nuclear@5: 			log_level = LogMask_All;
nuclear@5: 			break;
nuclear@5: 		}
nuclear@5: 	}
nuclear@5: 
nuclear@5: 	System::Init(Log::ConfigureDefaultLog(log_level));
nuclear@3: 	if(!(vr_ctx.ovr_devman = DeviceManager::Create())) {
nuclear@1: 		fprintf(stderr, "failed to create OVR device manager\n");
nuclear@1: 		return false;
nuclear@1: 	}
nuclear@1: 
nuclear@1: 	// create the display device
nuclear@4: 	HMDInfo info;
nuclear@3: 	if(!(vr_ctx.ovr_hmd_dev = vr_ctx.ovr_devman->EnumerateDevices<HMDDevice>().CreateDevice())) {
nuclear@1: 		fprintf(stderr, "no oculus rift devices found\n");
nuclear@4: 	} else {
nuclear@4: 		if(vr_ctx.ovr_hmd_dev->GetDeviceInfo(&info)) {
nuclear@4: 			printf("oculus device info:\n");
nuclear@4: 			printf("  name: %s\n", info.DisplayDeviceName);
nuclear@4: 			printf("  ipd: %f\n", info.InterpupillaryDistance);
nuclear@4: 			printf("  distortion: %f %f %f %f\n", info.DistortionK[0],
nuclear@4: 					info.DistortionK[1], info.DistortionK[2], info.DistortionK[3]);
nuclear@4: 		}
nuclear@1: 
nuclear@4: 		// calculate and store viewing parameters
nuclear@4: 		vr_ctx.info.width = info.HResolution;
nuclear@4: 		vr_ctx.info.height = info.VResolution;
nuclear@4: 		vr_ctx.info.aspect = (float)vr_ctx.info.width / (float)vr_ctx.info.height;
nuclear@4: 
nuclear@4: 		vr_ctx.info.ipd = info.InterpupillaryDistance;
nuclear@4: 		for(int i=0; i<4; i++) {
nuclear@4: 			vr_ctx.info.distort[i] = info.DistortionK[i];
nuclear@4: 		}
nuclear@12: 
nuclear@14: 		Util::Render::StereoConfig stereohelp;
nuclear@14: 		stereohelp.SetFullViewport(Util::Render::Viewport(0, 0, vr_ctx.info.width, vr_ctx.info.height));
nuclear@14: 		stereohelp.SetStereoMode(Util::Render::Stereo_LeftRight_Multipass);
nuclear@14: 		stereohelp.SetHMDInfo(info);
nuclear@14: 		stereohelp.SetDistortionFitPointVP(-1.0, 0.0);
nuclear@14: 
nuclear@14: 		vr_ctx.info.scale = stereohelp.GetDistortionScale();
nuclear@13: 
nuclear@13: 		float vhalfsz = vr_ctx.info.scale * info.VScreenSize * 0.5;
nuclear@13: 		vr_ctx.info.fov = 2.0 * atan(vhalfsz / info.EyeToScreenDistance);
nuclear@13: 
nuclear@13: 		vr_ctx.info.lens_center_offset = 0.5 - info.LensSeparationDistance / info.HScreenSize;
nuclear@13: 
nuclear@13: 		// calculate center of projection shift to match the lens positions
nuclear@13: 		float center_dist_meters = info.HScreenSize * 0.25;
nuclear@13: 		float proj_shift = center_dist_meters - info.LensSeparationDistance * 0.5;
nuclear@13: 		vr_ctx.info.proj_center_offset = 4.0 * proj_shift / info.HScreenSize;
nuclear@15: 
nuclear@16: 		// grab the display info
nuclear@15: 		vr_ctx.info.display = new char[strlen(info.DisplayDeviceName) + 1];
nuclear@15: 		strcpy(vr_ctx.info.display, info.DisplayDeviceName);
nuclear@16: 
nuclear@16: 		vr_ctx.info.display_xoffs = info.DesktopX;
nuclear@16: 		vr_ctx.info.display_yoffs = info.DesktopY;
nuclear@16: 
nuclear@16: 		printf("display: \"%s\" offset: %+d %+d\n", vr_ctx.info.display,
nuclear@16: 				vr_ctx.info.display_xoffs, vr_ctx.info.display_yoffs);
nuclear@1: 	}
nuclear@1: 
nuclear@1: 	// get the sensor device
nuclear@4: 	if(vr_ctx.ovr_hmd_dev) {
nuclear@4: 		if(!(vr_ctx.ovr_sensor_dev = vr_ctx.ovr_hmd_dev->GetSensor())) {
nuclear@4: 			fprintf(stderr, "failed to get oculus sensor device\n");
nuclear@4: 		}
nuclear@4: 	} else {
nuclear@4: 		if(!(vr_ctx.ovr_sensor_dev = vr_ctx.ovr_devman->EnumerateDevices<SensorDevice>().CreateDevice())) {
nuclear@4: 			fprintf(stderr, "failed to get oculus sensor device\n");
nuclear@4: 		}
nuclear@1: 	}
nuclear@1: 
nuclear@4: 	if(vr_ctx.ovr_sensor_dev) {
nuclear@4: 		SensorInfo sinfo;
nuclear@4: 		if(vr_ctx.ovr_sensor_dev->GetDeviceInfo(&sinfo)) {
nuclear@4: 			printf("oculus sensor device info:\n");
nuclear@4: 			printf("  name: %s\n", sinfo.ProductName);
nuclear@4: 		}
nuclear@4: 
nuclear@4: 		vr_ctx.ovr_sfusion.AttachToSensor(vr_ctx.ovr_sensor_dev);
nuclear@1: 	}
nuclear@1: 	return true;
nuclear@1: }
nuclear@3: 
nuclear@13: #define EXTERNAL_SHADER
nuclear@13: 
nuclear@12: static bool init_sdr()
nuclear@12: {
nuclear@12: 	int status;
nuclear@12: 
nuclear@13: #ifdef EXTERNAL_SHADER
nuclear@17: 	FILE *fp = fopen("sdr/sdr.glsl", "rb");
nuclear@13: 	if(!fp) {
nuclear@13: 		perror("failed to load sdr.glsl");
nuclear@13: 		return false;
nuclear@13: 	}
nuclear@13: 	fseek(fp, 0, SEEK_END);
nuclear@13: 	long sz = ftell(fp);
nuclear@13: 	rewind(fp);
nuclear@13: 
nuclear@13: 	char *buf = (char*)alloca(sz + 1);
nuclear@13: 	fread(buf, 1, sz, fp);
nuclear@13: 	buf[sz] = 0;
nuclear@13: 	sdr_src = buf;
nuclear@13: 
nuclear@13: 	fclose(fp);
nuclear@13: #endif
nuclear@13: 
nuclear@12: 	unsigned int sdr = glCreateShader(GL_FRAGMENT_SHADER);
nuclear@12: 	glShaderSource(sdr, 1, &sdr_src, 0);
nuclear@12: 	glCompileShader(sdr);
nuclear@12: 	glGetShaderiv(sdr, GL_COMPILE_STATUS, &status);
nuclear@12: 	if(!status) {
nuclear@12: 		fprintf(stderr, "failed to compile distortion shader\n");
nuclear@14: 
nuclear@14: 		int loglen;
nuclear@14: 		glGetShaderiv(sdr, GL_INFO_LOG_LENGTH, &loglen);
nuclear@14: 
nuclear@14: 		if(loglen > 0) {
nuclear@14: 			char *log = (char*)alloca(loglen);
nuclear@14: 			glGetShaderInfoLog(sdr, loglen, &loglen, log);
nuclear@14: 			fprintf(stderr, "%s\n", log);
nuclear@14: 		}
nuclear@14: 
nuclear@12: 		return false;
nuclear@12: 	}
nuclear@12: 
nuclear@12: 	sdrprog = glCreateProgram();
nuclear@12: 	glAttachShader(sdrprog, sdr);
nuclear@12: 	glLinkProgram(sdrprog);
nuclear@12: 	if(!status) {
nuclear@12: 		fprintf(stderr, "failed to link distortion shader program\n");
nuclear@12: 		glDeleteShader(sdr);
nuclear@12: 		return false;
nuclear@12: 	}
nuclear@12: 
nuclear@12: 	int loc;
nuclear@12: 
nuclear@12: 	glUseProgram(sdrprog);
nuclear@12: 
nuclear@12: 	if((loc = glGetUniformLocation(sdrprog, "tex")) != -1) {
nuclear@12: 		glUniform1i(loc, 0);
nuclear@12: 	}
nuclear@13: 	if((loc = glGetUniformLocation(sdrprog, "lens_center_offset")) != -1) {
nuclear@13: 		glUniform1f(loc, 0);
nuclear@12: 	}
nuclear@12: 	if((loc = glGetUniformLocation(sdrprog, "scr_center")) != -1) {
nuclear@12: 		glUniform2f(loc, 0, 0);
nuclear@12: 	}
nuclear@12: 	if((loc = glGetUniformLocation(sdrprog, "scale")) != -1) {
nuclear@13: 		glUniform1f(loc, vr_ctx.info.scale);
nuclear@13: 	}
nuclear@13: 	if((loc = glGetUniformLocation(sdrprog, "aspect")) != -1) {
nuclear@13: 		printf("setting aspect: %f\n", vr_ctx.info.aspect / 2.0);
nuclear@13: 		glUniform1f(loc, vr_ctx.info.aspect / 2.0);
nuclear@12: 	}
nuclear@12: 	if((loc = glGetUniformLocation(sdrprog, "scale_in")) != -1) {
nuclear@12: 		glUniform2f(loc, 1, 1);
nuclear@12: 	}
nuclear@13: 	if((loc = glGetUniformLocation(sdrprog, "dist_factors")) != -1) {
nuclear@12: 		glUniform4f(loc, vr_ctx.info.distort[0], vr_ctx.info.distort[1],
nuclear@12: 				vr_ctx.info.distort[2], vr_ctx.info.distort[3]);
nuclear@12: 	}
nuclear@12: 
nuclear@12: 	return true;
nuclear@12: }
nuclear@12: 
nuclear@16: extern "C" const char *vr_get_display_name(void)
nuclear@16: {
nuclear@16: 	return vr_ctx.info.display;
nuclear@16: }
nuclear@16: 
nuclear@16: extern "C" void vr_get_display_pos(int *xptr, int *yptr)
nuclear@16: {
nuclear@16: 	*xptr = vr_ctx.info.display_xoffs;
nuclear@16: 	*yptr = vr_ctx.info.display_yoffs;
nuclear@16: }
nuclear@16: 
nuclear@3: extern "C" int vr_get_width(void)
nuclear@3: {
nuclear@3: 	return vr_ctx.info.width;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" int vr_get_height(void)
nuclear@3: {
nuclear@3: 	return vr_ctx.info.height;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" float vr_get_fov(void)
nuclear@3: {
nuclear@3: 	return vr_ctx.info.fov;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" float vr_get_aspect(void)
nuclear@3: {
nuclear@3: 	return vr_ctx.info.aspect;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" void vr_set_eyedist(float ipd)
nuclear@3: {
nuclear@3: 	vr_ctx.info.ipd = ipd;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" float vr_get_eyedist(void)
nuclear@3: {
nuclear@3: 	return vr_ctx.info.ipd;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" void vr_set_distort(const float *coef)
nuclear@3: {
nuclear@3: 	memcpy(vr_ctx.info.distort, coef, sizeof vr_ctx.info.distort);
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" void vr_get_distort(float *coef)
nuclear@3: {
nuclear@3: 	memcpy(coef, vr_ctx.info.distort, sizeof vr_ctx.info.distort);
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" void vr_set_prediction_sec(float dt)
nuclear@3: {
nuclear@3: 	vr_ctx.ovr_sfusion.SetPrediction(dt);
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" float vr_get_prediction_sec(void)
nuclear@3: {
nuclear@3: 	return vr_ctx.ovr_sfusion.GetPredictionDelta();
nuclear@3: }
nuclear@3: 
nuclear@13: extern "C" void vr_get_view_matrix(float *res, int eye)
nuclear@13: {
nuclear@13: 	// TODO
nuclear@13: }
nuclear@13: 
nuclear@13: extern "C" void vr_get_proj_matrix(float *res, int eye)
nuclear@13: {
nuclear@13: 	static float eye_scale[] = {0.0, 1.0, -1.0};
nuclear@13: 
nuclear@13: 	Matrix4f proj = Matrix4f::PerspectiveRH(vr_ctx.info.fov, vr_ctx.info.aspect / 2.0, 0.3, 1000.0);
nuclear@13: 	proj = Matrix4f::Translation(vr_ctx.info.proj_center_offset * eye_scale[eye], 0, 0) * proj;
nuclear@13: 
nuclear@13: 	memcpy(res, proj.M[0], 16 * sizeof(float));
nuclear@13: }
nuclear@13: 
nuclear@3: extern "C" void vr_get_translation(float *offs)
nuclear@3: {
nuclear@3: 	// current oculus devkit doesn't do translation
nuclear@3: 	offs[0] = offs[1] = offs[2] = 0.0f;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" void vr_get_rotation(float *quat)
nuclear@3: {
nuclear@3: 	Quatf oq = vr_ctx.ovr_sfusion.GetPredictedOrientation();
nuclear@3: 	quat[0] = oq.x;
nuclear@3: 	quat[1] = oq.y;
nuclear@3: 	quat[2] = oq.z;
nuclear@3: 	quat[3] = oq.w;
nuclear@3: }
nuclear@3: 
nuclear@3: extern "C" void vr_get_rotation_euler(float *euler)
nuclear@3: {
nuclear@3: 	Quatf oq = vr_ctx.ovr_sfusion.GetPredictedOrientation();
nuclear@3: 	oq.GetEulerAngles<Axis_Y, Axis_X, Axis_Z>(euler + 1, euler, euler + 2);
nuclear@3: }
nuclear@12: 
nuclear@18: extern "C" void vr_draw_eye(int eye, unsigned int tex, float tex_scale_x, float tex_scale_y)
nuclear@12: {
nuclear@12: 	static const float rects[3][4] = {
nuclear@12: 		{-1, -1, 1, 1},
nuclear@12: 		{-1, -1, 0, 1},
nuclear@12: 		{0, -1, 1, 1}
nuclear@12: 	};
nuclear@21: 	static const float quad_trans[3] = {0, -1, 1};
nuclear@21: 	static const float quad_scale[3] = {1, 0.5, 0.5};
nuclear@12: 	static const float offs_scale[3] = {0.0, -1.0, 1.0};
nuclear@21: 	static int prev_tex_scale_x, prev_tex_scale_y;
nuclear@12: 
nuclear@12: 	glPushAttrib(GL_ENABLE_BIT);
nuclear@12: 	glDisable(GL_DEPTH_TEST);
nuclear@12: 	glDisable(GL_LIGHTING);
nuclear@21: 	glDisable(GL_CULL_FACE);
nuclear@21: 
nuclear@21: 	glMatrixMode(GL_PROJECTION);
nuclear@21: 	glPushMatrix();
nuclear@21: 	glLoadIdentity();
nuclear@12: 
nuclear@12: 	glMatrixMode(GL_MODELVIEW);
nuclear@12: 	glPushMatrix();
nuclear@12: 	glLoadIdentity();
nuclear@12: 
nuclear@21: 	if(!dbg_enable) {
nuclear@21: 		glUseProgram(sdrprog);
nuclear@12: 
nuclear@21: 		if(sdrprog) {
nuclear@21: 			int loc;
nuclear@21: 			if((loc = glGetUniformLocation(sdrprog, "lens_center_offset")) != -1) {
nuclear@21: 				float offset = vr_ctx.info.lens_center_offset * offs_scale[eye];
nuclear@21: 				glUniform1f(loc, offset);
nuclear@21: 			}
nuclear@12: 
nuclear@21: 			if((loc = glGetUniformLocation(sdrprog, "tex_scale")) != -1) {
nuclear@21: 				glUniform2f(loc, tex_scale_x, tex_scale_y);
nuclear@21: 			}
nuclear@13: 		}
nuclear@18: 
nuclear@21: 		glBindTexture(GL_TEXTURE_2D, tex);
nuclear@21: 		glBegin(GL_QUADS);
nuclear@21: 		glColor4f(1, 1, 1, 1);
nuclear@21: 		glTexCoord2f(0, 0); glVertex2f(rects[eye][0], rects[eye][1]);
nuclear@21: 		glTexCoord2f(1, 0); glVertex2f(rects[eye][2], rects[eye][1]);
nuclear@21: 		glTexCoord2f(1, 1); glVertex2f(rects[eye][2], rects[eye][3]);
nuclear@21: 		glTexCoord2f(0, 1); glVertex2f(rects[eye][0], rects[eye][3]);
nuclear@21: 		glEnd();
nuclear@21: 
nuclear@21: 		glUseProgram(0);
nuclear@21: 
nuclear@21: 	} else {
nuclear@21: 
nuclear@21: 		if(!mesh_valid || tex_scale_x != prev_tex_scale_x || tex_scale_y != prev_tex_scale_y) {
nuclear@21: 			for(int i=0; i<2; i++) {
nuclear@21: 				int eye = i + VR_EYE_LEFT;
nuclear@21: 
nuclear@21: 				if(wrapmesh[i].vbo) {
nuclear@21: 					glDeleteBuffers(1, &wrapmesh[i].vbo);
nuclear@21: 				}
nuclear@21: 				if(wrapmesh[i].ibo) {
nuclear@21: 					glDeleteBuffers(1, &wrapmesh[i].ibo);
nuclear@21: 				}
nuclear@21: 
nuclear@21: 				float aspect = vr_ctx.info.aspect / 2.0;
nuclear@21: 				float offset = vr_ctx.info.lens_center_offset * offs_scale[eye];
nuclear@21: 				wrapmesh[i] = gen_view_mesh(USUB, VSUB, aspect, offset, vr_ctx.info.scale, vr_ctx.info.distort,
nuclear@21: 					tex_scale_x, tex_scale_y);
nuclear@21: 			}
nuclear@21: 			mesh_valid = true;
nuclear@21: 			prev_tex_scale_x = tex_scale_x;
nuclear@21: 			prev_tex_scale_y = tex_scale_y;
nuclear@18: 		}
nuclear@21: 
nuclear@21: 		glScalef(quad_scale[eye], 1.0, 1.0);
nuclear@21: 		glTranslatef(quad_trans[eye], 0, 0);
nuclear@21: 
nuclear@21: 		glUseProgram(0);
nuclear@21: 		glBindTexture(GL_TEXTURE_2D, tex);
nuclear@21: 		glEnable(GL_TEXTURE_2D);
nuclear@21: 
nuclear@21: 		glColor3f(1, 1, 1);
nuclear@21: 
nuclear@21: 		glEnableClientState(GL_VERTEX_ARRAY);
nuclear@21: 		glEnableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@21: 
nuclear@21: 		int meshidx = eye - VR_EYE_LEFT;
nuclear@21: 		glBindBuffer(GL_ARRAY_BUFFER, wrapmesh[meshidx].vbo);
nuclear@21: 		glVertexPointer(3, GL_FLOAT, sizeof(Vertex), 0);
nuclear@21: 		glTexCoordPointer(2, GL_FLOAT, sizeof(Vertex), (void*)offsetof(Vertex, tx));
nuclear@21: 
nuclear@21: 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, wrapmesh[meshidx].ibo);
nuclear@21: 		glDrawElements(GL_TRIANGLES, wrapmesh[meshidx].num_faces * 3, GL_UNSIGNED_INT, 0);
nuclear@21: 
nuclear@21: 		glBindBuffer(GL_ARRAY_BUFFER, 0);
nuclear@21: 		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
nuclear@21: 
nuclear@21: 		glDisableClientState(GL_VERTEX_ARRAY);
nuclear@21: 		glDisableClientState(GL_TEXTURE_COORD_ARRAY);
nuclear@12: 	}
nuclear@12: 
nuclear@21: 	glMatrixMode(GL_PROJECTION);
nuclear@12: 	glPopMatrix();
nuclear@12: 	glMatrixMode(GL_MODELVIEW);
nuclear@12: 	glPopMatrix();
nuclear@12: 
nuclear@12: 	glPopAttrib();
nuclear@12: }
nuclear@21: 
nuclear@21: static Mesh gen_view_mesh(int usub, int vsub, float aspect, float lens_center_offset,
nuclear@21: 		float scale, const float *dist_factors, float tex_scale_x, float tex_scale_y)
nuclear@21: {
nuclear@21: 	int uverts = usub + 1;
nuclear@21: 	int vverts = vsub + 1;
nuclear@21: 
nuclear@21: 	int num_verts = uverts * vverts;
nuclear@21: 	int num_quads = usub * vsub;
nuclear@21: 	int num_tris = num_quads * 2;
nuclear@21: 
nuclear@21: 	Vertex *varr = new Vertex[num_verts];
nuclear@21: 	unsigned int *iarr = new unsigned int[num_tris * 3];
nuclear@21: 
nuclear@21: 	float du = 1.0 / (float)usub;
nuclear@21: 	float dv = 1.0 / (float)vsub;
nuclear@21: 
nuclear@21: 	Vertex *vptr = varr;
nuclear@21: 	for(int i=0; i<vverts; i++) {
nuclear@21: 		float v = (float)i * dv;
nuclear@21: 		float y = 2.0 * v - 1.0;
nuclear@21: 
nuclear@21: 		for(int j=0; j<uverts; j++) {
nuclear@21: 			float u = (float)j * du;
nuclear@21: 			float x = 2.0 * u - 1.0;
nuclear@21: 			float tc[2] = {u, v};
nuclear@21: 
nuclear@21: 			distort_texcoords(tc, aspect, lens_center_offset, scale, dist_factors);
nuclear@21: 
nuclear@21: 			vptr->x = x;
nuclear@21: 			vptr->y = y;
nuclear@21: 			vptr->z = 0;
nuclear@21: 			vptr->tx = tc[0] * tex_scale_x;
nuclear@21: 			vptr->ty = tc[1] * tex_scale_y;
nuclear@21: 			vptr++;
nuclear@21: 		}
nuclear@21: 	}
nuclear@21: 
nuclear@21: 	unsigned int *iptr = iarr;
nuclear@21: 	for(int i=0; i<vsub; i++) {
nuclear@21: 		for(int j=0; j<usub; j++) {
nuclear@21: 			*iptr++ = i * uverts + j;
nuclear@21: 			*iptr++ = (i + 1) * uverts + j;
nuclear@21: 			*iptr++ = (i + 1) * uverts + (j + 1);
nuclear@21: 
nuclear@21: 			*iptr++ = i * uverts + j;
nuclear@21: 			*iptr++ = (i + 1) * uverts + (j + 1);
nuclear@21: 			*iptr++ = i * uverts + (j + 1);
nuclear@21: 		}
nuclear@21: 	}
nuclear@21: 
nuclear@21: 	unsigned int buf[2];
nuclear@21: 	glGenBuffers(2, buf);
nuclear@21: 	glBindBuffer(GL_ARRAY_BUFFER, buf[0]);
nuclear@21: 	glBufferData(GL_ARRAY_BUFFER, num_verts * sizeof *varr, varr, GL_STATIC_DRAW);
nuclear@21: 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buf[1]);
nuclear@21: 	glBufferData(GL_ELEMENT_ARRAY_BUFFER, num_tris * 3 * sizeof *iarr, iarr, GL_STATIC_DRAW); 
nuclear@21: 
nuclear@21: 	delete [] varr;
nuclear@21: 	delete [] iarr;
nuclear@21: 
nuclear@21: 	Mesh mesh;
nuclear@21: 	mesh.prim = GL_TRIANGLES;
nuclear@21: 	mesh.num_verts = num_verts;
nuclear@21: 	mesh.num_faces = num_tris;
nuclear@21: 	mesh.vbo = buf[0];
nuclear@21: 	mesh.ibo = buf[1];
nuclear@21: 	return mesh;
nuclear@21: }
nuclear@21: 
nuclear@21: static void distort_texcoords(float *tc, float aspect, float lens_center_offset, float scale, const float *dist_factors)
nuclear@21: {
nuclear@21: 	// map tc [0, 1] -> [-1, 1]
nuclear@21: 	float ptx = tc[0] * 2.0 - 1.0;
nuclear@21: 	float pty = tc[1] * 2.0 - 1.0;
nuclear@21: 
nuclear@21: 	ptx += lens_center_offset * 2.0;
nuclear@21: 	pty /= aspect;	// correct for aspect ratio
nuclear@21: 
nuclear@21: 	float rad = barrel_scale(ptx * ptx + pty * pty, dist_factors);
nuclear@21: 	ptx *= rad;	// scale the point by the computer distortion radius
nuclear@21: 	pty *= rad;
nuclear@21: 
nuclear@21: 	ptx /= scale;
nuclear@21: 	pty /= scale;
nuclear@21: 
nuclear@21: 	pty *= aspect;
nuclear@21: 	ptx -= lens_center_offset * 2.0;
nuclear@21: 
nuclear@21: 	// map back to range [0, 1]
nuclear@21: 	tc[0] = ptx * 0.5 + 0.5;
nuclear@21: 	tc[1] = pty * 0.5 + 0.5;
nuclear@21: }
nuclear@21: 
nuclear@21: static float barrel_scale(float rad, const float *k)
nuclear@21: {
nuclear@21: 	float radsq = rad * rad;
nuclear@21: 	float radquad = radsq * radsq;
nuclear@21: 	return k[0] + k[1] * radsq + k[2] * radquad + k[3] * radquad * radsq;
nuclear@21: }