tesselation as a function of distance

[ld42_outofspace] / sdr / field.tc.glsl

diff --git a/sdr/field.tc.glsl b/sdr/field.tc.glsl
index 71d6560..e742def 100644 (file)
--- a/sdr/field.tc.glsl
+++ b/sdr/field.tc.glsl
@@ -4,17 +4,23 @@ layout(vertices = 4) out;
 
 uniform int tess_level;
 
+in float dist[gl_MaxPatchVertices];
+
 void main()
 {
        gl_out[gl_InvocationID].gl_Position = gl_in[gl_InvocationID].gl_Position;
        gl_out[gl_InvocationID].gl_TexCoord[0] = gl_in[gl_InvocationID].gl_TexCoord[0];
        gl_out[gl_InvocationID].gl_TexCoord[1] = gl_in[gl_InvocationID].gl_TexCoord[1];
 
-       gl_TessLevelInner[0] = tess_level;
-       gl_TessLevelInner[1] = tess_level;
+       const float min_tess_dist = 800.0;
+       float t = clamp(1.0 - dist[0] / min_tess_dist, 0.0, 1.0);
+       int tess = int(t * float(tess_level - 1.0)) + 1;
+
+       gl_TessLevelInner[0] = tess;
+       gl_TessLevelInner[1] = tess;
 
-       gl_TessLevelOuter[0] = tess_level;
-       gl_TessLevelOuter[1] = tess_level;
-       gl_TessLevelOuter[2] = tess_level;
-       gl_TessLevelOuter[3] = tess_level;
+       gl_TessLevelOuter[0] = tess;
+       gl_TessLevelOuter[1] = tess;
+       gl_TessLevelOuter[2] = tess;
+       gl_TessLevelOuter[3] = tess;
 }