Shader fixes in the forest pond demo

[libs/gl.git] / demos / forestpond / data / fluidsim_integrate.glsl

diff --git a/demos/forestpond/data/fluidsim_integrate.glsl b/demos/forestpond/data/fluidsim_integrate.glsl
index f3805e8a8e6d2ea809659b4ecc82ed78e61843c2..70ac923fd94ed9dfe6efb47ce7304640f53a1207 100644 (file)
--- a/demos/forestpond/data/fluidsim_integrate.glsl
+++ b/demos/forestpond/data/fluidsim_integrate.glsl
@@ -1,6 +1,12 @@
 import fluidsim;
 
 #pragma MSP stage(compute)
+float get_clamping(float depth, float v_right, float v_up, float v_left, float v_down)
+{
+       float total_out = max(v_right, 0.0)+max(v_up, 0.0)-min(v_left, 0.0)-min(v_down, 0.0);
+       return min(max_flow_fraction/max(total_out*delta_time, max_flow_fraction), depth/residual_depth);
+}
+
 void main()
 {
        ivec2 size = imageSize(surface_out);
@@ -8,28 +14,30 @@ void main()
        if(coord.x>=size.x-1 || coord.y>=size.y-1)
                return;
 
-       float surface = texelFetch(surface_in, coord, 0).x;
-       float bottom = texelFetch(bottom_in, coord, 0).x;
-       float depth = surface-bottom;
-       vec2 velocity = texelFetch(velocity_in, coord, 0).xy;
-       float clamping = texelFetch(clamping_in, coord, 0).x;
-       float left_depth = get_depth(coord-ivec2(1, 0));
-       float left_clamping = texelFetch(clamping_in, coord-ivec2(1, 0), 0).x;
-       float left_vx = texelFetch(velocity_in, coord-ivec2(1, 0), 0).x;
-       float right_depth = get_depth(coord+ivec2(1, 0));
-       float right_clamping = texelFetch(clamping_in, coord+ivec2(1, 0), 0).x;
-       float down_depth = get_depth(coord-ivec2(0, 1));
-       float down_clamping = texelFetch(clamping_in, coord-ivec2(0, 1), 0).x;
-       float down_vy = texelFetch(velocity_in, coord-ivec2(0, 1), 0).y;
-       float up_depth = get_depth(coord+ivec2(0, 1));
-       float up_clamping = texelFetch(clamping_in, coord+ivec2(0, 1), 0).x;
+       vec4 data = get_data(coord);
+       vec4 right_data = get_data(coord+ivec2(1, 0));
+       vec4 up_data = get_data(coord+ivec2(0, 1));
+       vec4 left_data = get_data(coord-ivec2(1, 0));
+       vec4 down_data = get_data(coord-ivec2(0, 1));
+
+       float ul_vx = texelFetch(velocity_in, coord+ivec2(-1, 1), 0).x;
+       float left2_vx = texelFetch(velocity_in, coord-ivec2(2, 0), 0).x;
+       vec2 dl_velocity = texelFetch(velocity_in, coord-ivec2(1, 1), 0).xy;
+       float down2_vy = texelFetch(velocity_in, coord-ivec2(0, 2), 0).y;
+       float dr_vy = texelFetch(velocity_in, coord+ivec2(1, -1), 0).y;
+
+       float clamping = get_clamping(data.w, data.x, data.y, left_data.x, down_data.y);
+       float right_cl = get_clamping(right_data.w, right_data.x, right_data.y, data.x, dr_vy);
+       float up_cl = get_clamping(up_data.w, up_data.x, up_data.y, ul_vx, data.y);
+       float left_cl = get_clamping(left_data.w, left_data.x, left_data.y, left2_vx, dl_velocity.y);
+       float down_cl = get_clamping(down_data.w, down_data.x, down_data.y, dl_velocity.x, down2_vy);
 
        // Integration step: change surface level based on velocities
-       float total_flow = left_vx*mix(left_depth*left_clamping, depth*clamping, left_vx<0)-
-               velocity.x*mix(depth*clamping, right_depth*right_clamping, velocity.x<0)+
-               down_vy*mix(down_depth*down_clamping, depth*clamping, down_vy<0)-
-               velocity.y*mix(depth*clamping, up_depth*up_clamping, velocity.y<0);
-       float new_surface = surface+total_flow*delta_time;
+       float total_flow_out = data.x*mix(data.w*clamping, right_data.w*right_cl, data.x<0)+
+               data.y*mix(data.w*clamping, up_data.w*up_cl, data.y<0)-
+               left_data.x*mix(data.w*clamping, left_data.w*left_cl, left_data.x>0)-
+               down_data.y*mix(data.w*clamping, down_data.w*down_cl, down_data.y>0);
+       float new_surface = data.z-total_flow_out*delta_time;
 
        imageStore(surface_out, coord, vec4(new_surface, 0.0, 0.0, 0.0));
 }