如何在片段着色器中轻松更改纹理的像素颜色？ (OpenGL)

Question

My goal is to make simple sand simulation using c++ and OpenGL. Right now my plan is to have a 2d array of pixel colors and a texture the same size. To simulate sand I will update the array accordingly to the sand coordinates and where it has to travel. I'm thinking of sending the 2d array of pixels to the fragment shader and update the texture there with colors on the array. The problem is that I can't find a way to change the pixel color on the texture.

So how do I change the color of the pixel at certain coordinates on texture? Is doing this even practical? If, no what are the other ways?

Answer 1

Did u mean for texture coordinates? You can change only fragment color output. You have also the texture color but you can use only for frgament output.

gl_FragColor = tex + vec4(0.5, 0, 0, 1)*tex.a;

for blending operation

Anyway here's more info about the frag https://www.khronos.org/opengl/wiki/Fragment_Shader#Other_outputs