Tess

HydraEngine/source/ShaderFiles/landscape_shader.tesc

@@ -5,6 +5,14 @@
 // this value controls the size of the input and output arrays
 layout (vertices=4) out;
 
+layout(binding = 0) uniform uniform_per_frame
+{	
+	mat4 view;
+	mat4 proj;	
+	vec3 viewer_pos;	
+	uint light_count;
+} ubo_per_frame;
+
 layout (location=0) in VS_OUT
 {
 	vec2 vsUV;
@@ -29,6 +37,11 @@ layout (location=0) out TC_OUT
 	flat uint vsMaterialID;
 }tc_out[];
 
+float inv_lerp (float a, float b, float t)
+{
+    return (t - a) / (b - a);
+
+}
 
 void main()
 {
@@ -44,17 +57,31 @@ void main()
     tc_out[gl_InvocationID].vsChunkID = tc_in[gl_InvocationID].vsChunkID;
     tc_out[gl_InvocationID].vsMaterialID = tc_in[gl_InvocationID].vsMaterialID;
 	
+
+    vec3 centre = (gl_in[0].gl_Position.xyz + 
+                    gl_in[1].gl_Position.xyz + 
+                    gl_in[2].gl_Position.xyz + 
+                    gl_in[3].gl_Position.xyz) / 4.0;
+
+    float patch_width = abs(length(gl_in[2].gl_Position.xyz - gl_in[0].gl_Position.xyz));
+    float player_dist = abs(length(centre - ubo_per_frame.viewer_pos)) * 0.1;
+
+    float tess_factor = 1.0 - inv_lerp(0, patch_width, player_dist);
+    tess_factor = max(0.5, tess_factor);
     // ----------------------------------------------------------------------
     // invocation zero controls tessellation levels for the entire patch
     if (gl_InvocationID == 0)
     {
         
-        int divs = 63;
-        gl_TessLevelOuter[0] = divs;
-        gl_TessLevelOuter[1] = divs;
-        gl_TessLevelOuter[2] = divs;
-        gl_TessLevelOuter[3] = divs;
-        gl_TessLevelInner[0] = divs;
-        gl_TessLevelInner[1] = divs;
+        float edgedivs = 32.0;
+        float innerdivs = tess_factor * 64.0;
+        
+        gl_TessLevelOuter[0] = edgedivs;
+        gl_TessLevelOuter[1] = edgedivs;
+        gl_TessLevelOuter[2] = edgedivs;
+        gl_TessLevelOuter[3] = edgedivs;
+
+        gl_TessLevelInner[0] = innerdivs;
+        gl_TessLevelInner[1] = innerdivs;
     }
 }

HydraEngine/source/ShaderFiles/landscape_shader.tese

@@ -1,7 +1,7 @@
 // tessellation evaluation shader
 #version 450 core
 
-layout (quads, equal_spacing, ccw) in;
+layout (quads, fractional_even_spacing, ccw) in;
 
 layout(std430, binding = 1) readonly buffer positions_buffer 
 {
@@ -67,6 +67,8 @@ void main()
     vec4 p10 = gl_in[2].gl_Position;
     vec4 p11 = gl_in[3].gl_Position;
 
+
+
     // compute patch surface normal
     vec4 uVec = p01 - p00;
     vec4 vVec = p10 - p00;
@@ -90,4 +92,7 @@ void main()
 	mat4 view = ubo_per_frame.view;
 	mat4 proj = ubo_per_frame.proj;
     gl_Position = proj * view * model * p;
+
+   
+    
 }

HydraEngine/source/ShaderFiles/landscape_shader.vert

@@ -44,7 +44,7 @@ void main()
 	mat4 view = ubo_per_frame.view;
 	mat4 proj = ubo_per_frame.proj;
 	//model = mat4(1);
- 	gl_Position = proj * view * model * vec4(inPos, 1.0);
+ 	gl_Position = vec4(inPos, 1.0);// proj * view * model * vec4(inPos, 1.0);
 	vs_out.vsWorldPos =  model * vec4(inPos,1);
 
 	vs_out.vsNormal = normalize(vec3(model * vec4(normalize(inNormal),0)));