c++ - Walking an object on a terrain (made using heightmap) in OpenGL -

-

to walk object on terrain, i'm keeping camera , object fixed, , moving terrain according keyboard button pressed (using gltranslatef). i'm able move along x , z axis easily, when i'm moving along y axis, i'm having lot of trouble. here essential parts of code:

i've made class called terrain uses bmp file height @ different points. essential code is:

float terrain::getheight(int x, int z) {     return hs[z][x]; }  terrain* loadterrain(const char* filename, float height) {     image* image = loadbmp(filename);     terrain* t = new terrain(image->width, image->height);     (int y = 0; y < image->height; y++) {         (int x = 0; x < image->width; x++) {             unsigned char color = (unsigned char) image->pixels[3                     * (y * image->width + x)];             float h = height * ((color / 255.0f) - 0.5f);             t->setheight(x, y, h);          }     }      delete image;     t->computenormals();     return t; }

so i've stored them in array , can y using x , z anytime. here code drawterrain, takes 3 float values, xx,yy , zz, , use gltranslatef translate terrain in xx , zz directions (i haven't used yy yet).

void drawterrain(float xx, float yy, float zz, float aangle) {     float yyy;     glpushmatrix();     gltranslatef(0.0f, 0.0f, 0.0f);     glrotatef(-aangle, 0.0f, 1.0f, 0.0f);     gltranslatef(xx, yy, zz);      glfloat ambientcolor[] = { 0.4f, 0.4f, 0.4f, 1.0f };     gllightmodelfv(gl_light_model_ambient, ambientcolor);      glfloat lightcolor0[] = { 0.6f, 0.6f, 0.6f, 1.0f };     glfloat lightpos0[] = { -0.5f, 0.8f, 0.1f, 0.0f };     gllightfv(gl_light0, gl_diffuse, lightcolor0);     gllightfv(gl_light0, gl_position, lightpos0);     glenable(gl_texture_2d);     glbindtexture(gl_texture_2d, _textureid1);     gltexparameteri(gl_texture_2d, gl_texture_min_filter, gl_nearest);     gltexparameteri(gl_texture_2d, gl_texture_mag_filter, gl_nearest);      float scale = 50.0f / max(_terrain->width() - 1, _terrain->length() - 1);     glscalef(scale, scale, scale);     gltranslatef(-(float) (_terrain->width() - 1) / 2, 0.0f,             -(float) (_terrain->length() - 1) / 2);      glcolor3f(1.0f, 1.0f, 1.0f);     (int z = 0; z < _terrain->length() - 1; z++) {         //makes opengl draw triangle @ every 3 consecutive vertices         glbegin(gl_triangle_strip);         (int x = 0; x < _terrain->width(); x += 2) {             /*if (x == 0 && z == 0)              gltexcoord2f(0.0f, 0.0f);              if (x == _terrain->width() - 1 && z == 0)              gltexcoord2f(1.0f, 0.0f);              if (x == 0 && z == _terrain->length() - 1)              gltexcoord2f(0.0f, 1.0f);              if (x == _terrain->width() - 1 && z == _terrain->length() - 1)              gltexcoord2f(1.0f, 1.0f);*/             vec3f normal = _terrain->getnormal(x, z);             glnormal3f(normal[0], normal[1], normal[2]);             gltexcoord2f((float) x / _terrain->width(),                     (float) z / _terrain->length());             glvertex3f(x, _terrain->getheight(x, z), z);             normal = _terrain->getnormal(x, z + 1);             glnormal3f(normal[0], normal[1], normal[2]);             gltexcoord2f((float) x / _terrain->width(),                     (float) (z + 1) / _terrain->length());             glvertex3f(x, _terrain->getheight(x, z + 1), z + 1);             glnormal3f(normal[0], normal[1], normal[2]);             gltexcoord2f((float) (x + 1) / _terrain->width(),                     (float) z / _terrain->length());             glvertex3f(x + 1, _terrain->getheight(x + 1, z), z);             glnormal3f(normal[0], normal[1], normal[2]);             gltexcoord2f((float) (x + 1) / _terrain->width(),                     (float) (z + 1) / _terrain->length());             glvertex3f(x + 1, _terrain->getheight(x + 1, z + 1), z + 1);          }         //_y = (float) _terrain->getheight((int) (_x * max(_terrain->width() - 1, _terrain->length() - 1) / 50.0f), (int) (_z * max(_terrain->width() - 1, _terrain->length() - 1) / 50.0f));         glend();     }

so translate in y direction, i've tried use following code:

float xxx,yyy,zzz; xxx = (float) (_terrain->width() - 1) / (2 * scale); xxx -= xx / scale; zzz = (float) (_terrain->length() - 1) / (2 * scale); zzz -= zz / scale; yyy = scale * _terrain->getheight(xxx,zzz); gltranslatef(0.0f,yyy,0.0f);

but translate still not working according height, , y translate not looks continuous (since i'm converting integer , float values). can fix code, or suggest other method can walk object on terrain properly? thanks.


Comments

Post a Comment

Popular posts from this blog

css - Which browser returns the correct result for getBoundingClientRect of an SVG element? -

-
this svg contains rect overflows svg element: <svg id='svg' width='10' height='10'> <rect x='-10' y='-10' width='30' height='30'/> </svg> chrome 28 , opera 12 return getboundingclientrect() svg element width , height of 10. firefox 23 reports width , height of 30. correct? jsfiddle the relevant spec cssom , delegates svg spec if svg element not "have associated css layout box". haven't found definition of "having associated css layout box", correct result seem hinge on definition, getbbox returns 30x30 rect in browsers. this firefox bug fixed now, fix in firefox nightlies , should make through firefox 33 released on 14 october 2014. see bug 530985 details.
Read more

gcc - Calling fftR4() in c from assembly -

-
i trying asm fft implementation www.embeddedsignals.com work. running make gives error: undefined reference fftr4(short*, short*, int) at top of asm have .syntax unified .thumb .global fftr4 .type fftr4, %function and there #define's associate c functions arguments registers followed macros fftr4 function uses. after that, fftr4 called .thumb_func fftr4: stmfd sp!, {r4-r11, lr} mov tmp0, #0 // bit reversed counter mov tmp1, #0 .word 0xf3a2fa92 //rbit r3,r2 //rbit r,n lsl r,#3 and c code follows: void fftr4(short *y, short *x, int n); short x[512]; short y[512]; int i; void loop() { (i=0;i<512;i++) x[i]=0; (i=0;i<512;i=i+8) { x[i+0]=16384; x[i+2]=16384; x[i+4]=-16384; x[i+6]=-16384;} fftr4(y, x, 256); serialusb.println(y[128]); serialusb.println(y[129]); serialusb.println(y[384]); serialusb.println(y[385]); // expected results: //y[128]is 8191; y[129] -8190 y[...
Read more

.htaccess - Matching full URL in RewriteCond -

-
i'm trying block post access site (and return 403), except 2 ip's , 1 url ( http://mydomain.com/about-us/contact-us/ ). here's have: rewritecond %{request_method} post rewritecond %{remote_addr} !=1.2.3.4 rewritecond %{remote_addr} !=4.3.2.1 rewritecond %{request_uri} !^http://mydomain.com/about-us/contact-us/$ rewriterule ^ / [f] these rules allowing access ip properly, contact page still not accessible. i'm not sure i'm using request_uri correctly? i've tried variations relative urls rewritecond %{request_uri} !^/about-us/contact-us$ , rewritecond %{request_uri} !^/about-us/contact-us/$ without luck. what doing wrong please? it looks me rule on file name specific. if relax bit, should work. made few other esthetic tweaks. give try: rewritecond %{request_method} post rewritecond %{remote_addr} !^1.2.3.4 rewritecond %{remote_addr} !^4.3.2.1 rewritecond %{request_uri} !about-us/contact-us rewriterule ^ - [f]
Read more