opengl es - How to store and access per fragment attributes in WebGL -


i doing particle system in webgl using three.js, , want computation of particles in shaders. achieve that, positions (for example) of particles stored in texture sampled vertex shader of each particle (point primitive).

the position texture in fact 2 render targets swapped each frame after being updated off screen. each pixel of texture represent particle. update position, read 1 of render targets (texture2d), computation, , write on other render target (fragment output).

to perform "do computation" step, need per particle attributes, velocity (and lot of others). since step done in fragment shader, can't use vertex attributes buffers, have store these properties in separate textures , sample each of them in fragment shader.

it works, sampling textures slow far know, , wonder if there better ways this, having 1 vertex per particle, each rendering single fragment of position texture. know opengl 4 alternative ways deal this, ubo or ssbo, i'm not sure webgl.


Comments

Post a Comment

Popular posts from this blog

c++ - Difference between pre and post decrement in recursive function argument -

i have following sample code used pre-decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(--c); cout << c << endl; return; } } this function give output input 4 : dp3 dp2 dp1 dp0 0 1 2 3 but when use post decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(c--); cout << c << endl; return; } } output goes in infinite loop dp4 can explain me in detail why happens ? this happens because function(c--) called same value of c , when finishes c decremented. recursively called, hence called same value no chance of return , hit stack overflow error. assume this, int x = 1, y = 0; y = x++ result y == 1 , x == 2. if y = ++x , bot x , y 2.
Read more

javascript - How to insert selected radio button value into table cell -

i have 5 radio buttons <input type="radio" id="rating">1 <input type="radio" id="rating2">2 <input type="radio" id="rating3">3 <input type="radio" id="rating4">4 <input type="radio" id="rating5">5 i have 1 table <table id="mytabledata" border="1" style="width:100%"> <tr id="templaterow"> <th>ratings</th> </tr> </table> one add button <input type="button" id="add" value="add" onclick="addradiovalue()"> i've written code dynamically add rows table, when select radio button , click on add button, value of selected radio button should inserted new cell within table ratings. i able thing text box, i'm not able radio button. can me? your problems didn't have name set on radios , tryi
Read more

css - Transitioning Transforms in Safari look terrible/shaky/stuttering -

i have few functions based on scrolling user moves elements , down along page (imitating scroll effect.) in order make little smoother using transition: transform 0.7s cubic-bezier(0.49, 0.47, 0.63, 0.85); (with proper vender prefixing). the problem works great except in safari. there -webkit-transition: -webkit-transform 0.7s cubic-bezier(0.49, 0.47, 0.63, 0.85); causes animation jerk around , gives vibrating effect. have been reading on ages , have tried setting perspective property , backface properties no luck. is there way fix this/has seen this? , safari not allow transitioning transforms? any in understanding problem amazing. i found fiddle http://jsfiddle.net/3yfspjlt/ shows problem. if doesn't blink @ first keep scrolling , down. for curious code, more curious why bug happens in safari specific use case. (although of course trying find answer). js file getelementpositions: function(){ var de = document.documentelement; var windowhight = wind
Read more