我正在尝试使用http://meatfighter.com/fluiddynamics/GPU_Gems_Chapter_38.pdf作为资源，使用WebGL进行流体模拟。我已经实现了所有功能，但我觉得有很多东西没有正常工作。我增加了边界，但似乎它们没有效果，这使我怀疑压力和平流有多大作用。我显示了发散，我在移动物体的位置以及速度到达边缘（边界）的地方变得非常小，但是我得到的压力是完全空的。我使用扩散着色器计算压力，如链接资源中所述。
我知道我发布的代码由于它的性质而有点混乱。如果有帮助，我可以提供任何图片/链接到模拟。
- 编辑 -
经过一番调查后，我认为问题与我的平流功能有关。或者至少是一个问题。我不确定如何解决它。
我所遵循的一般流程不是发布我的所有代码，而是： 平流速度 扩散速度 加速度 计算分歧 计算压力 减去渐变
用于扩散速度和计算压力我只进行了10次迭代，因为我的所有计算机都可以处理我的实现（我会优化一旦我开始工作），但我觉得计算压力和减去梯度没有任何影响。
这是我正在使用的着色器：
//advection
uniform vec2 res;//The width and height of our screen
uniform sampler2D velocity;//input velocity
uniform sampler2D quantity;//quantity to advect
void main() {
vec2 pixel = gl_FragCoord.xy / res.xy;
float i0, j0, i1, j1;
float x, y, s0, s1, t0, t1, dxt0, dyt0;
float dt = 1.0/60.0;
float Nx = res.x -1.0;
float Ny = res.y -1.0;
float i = pixel.x;
float j = pixel.y;
dxt0 = dt ;
dyt0 = dt ;
x = gl_FragCoord.x - dxt0 * (texture2D(velocity, pixel).x );
y = gl_FragCoord.y - dyt0 * (texture2D(velocity, pixel).y );
i0=x-0.5;
i1=x+0.5;
j0=y-0.5;
j1=y+0.5;
s1 = x-i0;
s0 = 1.0-s1;
t1 = y-j0;
t0 = 1.0-t1;
float p1 = (t0 * texture2D(quantity, vec2(i0,j0)/res.xy).r);
float p2 = (t1 * texture2D(quantity, vec2(i0,j1)/res.xy).r);
float p3 = (t0 * texture2D(quantity, vec2(i1,j0)/res.xy).r);
float p4 = (t1 * texture2D(quantity, vec2(i1,j1)/res.xy).r);
float total1 = s0 * (p1 + p2);
float total2 = s1 * (p3 + p4);
gl_FragColor.r = total1 + total2;
p1 = (t0 * texture2D(quantity, vec2(i0,j0)/res.xy).g);
p2 = (t1 * texture2D(quantity, vec2(i0,j1)/res.xy).g);
p3 = (t0 * texture2D(quantity, vec2(i1,j0)/res.xy).g);
p4 = (t1 * texture2D(quantity, vec2(i1,j1)/res.xy).g);
total1 = s0 * (p1 + p2);
total2 = s1 * (p3 + p4);
gl_FragColor.g = total1 + total2;
}
//diffusion shader starts here
uniform vec2 res;//The width and height of our screen
uniform sampler2D x;//Our input texture
uniform sampler2D b;
uniform float alpha;
uniform float rBeta;
void main() {
float xPixel = 1.0/res.x;
float yPixel = 1.0/res.y;
vec2 pixel = gl_FragCoord.xy / res.xy;
gl_FragColor = texture2D( b, pixel );
vec4 leftColor = texture2D(x,vec2(pixel.x-xPixel,pixel.y));
vec4 rightColor = texture2D(x,vec2(pixel.x+xPixel,pixel.y));
vec4 upColor = texture2D(x,vec2(pixel.x,pixel.y-yPixel));
vec4 downColor = texture2D(x,vec2(pixel.x,pixel.y+yPixel));
gl_FragColor.r = (gl_FragColor.r * alpha +leftColor.r + rightColor.r + upColor.r + downColor.r) * rBeta;
gl_FragColor.g = (gl_FragColor.g * alpha +leftColor.g + rightColor.g + upColor.g + downColor.g)* rBeta;
gl_FragColor.b = (gl_FragColor.b * alpha +leftColor.b + rightColor.b + upColor.b + downColor.b)* rBeta;
}
//gradient
uniform vec2 res;//The width and height of our screen
uniform sampler2D velocity;//Our input velocity
uniform sampler2D pressure;//Our input pressure
void main() {
float xPixel = 1.0/res.x;
float yPixel = 1.0/res.y;
vec2 pixel = gl_FragCoord.xy / res.xy;
vec4 leftColor = texture2D(pressure, vec2(pixel.x-xPixel,pixel.y));
vec4 rightColor = texture2D(pressure, vec2(pixel.x+xPixel,pixel.y));
vec4 upColor = texture2D(pressure, vec2(pixel.x,pixel.y-yPixel));
vec4 downColor = texture2D(pressure, vec2(pixel.x,pixel.y+yPixel));
vec2 gradient = xPixel/2.0 * vec2((rightColor.x - leftColor.x), (upColor.y - downColor.y));
//Diffuse equation
gl_FragColor = texture2D(velocity, pixel) ;
gl_FragColor.xy -= gradient;
}
uniform vec2 res;//The width and height of our screen
uniform sampler2D velocity;//Our input texture
void main() {
float xPixel = 1.0/res.x;
float yPixel = 1.0/res.y;
vec2 pixel = gl_FragCoord.xy / res.xy;
vec4 leftColor = texture2D(velocity, vec2(pixel.x-xPixel,pixel.y));
vec4 rightColor = texture2D(velocity, vec2(pixel.x+xPixel,pixel.y));
vec4 upColor = texture2D(velocity, vec2(pixel.x,pixel.y-yPixel));
vec4 downColor = texture2D(velocity, vec2(pixel.x,pixel.y+yPixel));
float div = xPixel/2.0 * ((rightColor.x - leftColor.x) + (upColor.y - downColor.y));
//Diffuse equation
gl_FragColor = vec4(div);
}