61 lines
1.8 KiB
GLSL
61 lines
1.8 KiB
GLSL
#version 450 core
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layout (set = 0, binding = 0) uniform Matrices {
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mat4 view;
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mat4 proj;
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float time;
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vec3 cam_pos;
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vec2 viewport;
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float tess_factor;
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float tess_edge_size;
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};
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layout(set = 0, binding = 1) uniform sampler2D heightmap;
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layout (vertices = 4) out;
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layout (location = 0) in vec3 norm[];
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layout (location = 1) in vec2 texCoord[];
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layout (location = 2) in vec3 pos[];
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layout (location = 0) out vec3 _norm[4];
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layout (location = 1) out vec2 _texCoord[4];
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layout (location = 2) out vec3 _pos[4];
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float screen_space_tess(vec4 p0, vec4 p1) {
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/* calc midpoint + distance btw the two points */
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vec4 mid = (p0+p1) * 0.5;
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float r = distance(p0, p1) / 2.0;
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vec4 v0 = view * mid;
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/* projevt into clip spaace */
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vec4 clip0 = proj * (v0 - vec4(r, 0.0, 0.0, 0.0));
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vec4 clip1 = proj * (v0 + vec4(r, 0.0, 0.0, 0.0));
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clip0 /= clip0.w;
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clip1 /= clip1.w;
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/* convert to viewport coords */
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clip0.xy * viewport;
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clip1.xy * viewport;
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return clamp(distance(clip0, clip0) / tess_edge_size * tess_factor, 1.0, 64.0);
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}
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void main() {
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if(gl_InvocationID == 0) {
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gl_TessLevelOuter[0] = screen_space_tess(gl_in[3].gl_Position, gl_in[0].gl_Position);
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gl_TessLevelOuter[1] = screen_space_tess(gl_in[0].gl_Position, gl_in[1].gl_Position);
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gl_TessLevelOuter[2] = screen_space_tess(gl_in[1].gl_Position, gl_in[2].gl_Position);
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gl_TessLevelOuter[3] = screen_space_tess(gl_in[2].gl_Position, gl_in[3].gl_Position);
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gl_TessLevelInner[0] = mix(gl_TessLevelOuter[0], gl_TessLevelOuter[3], 0.5);
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gl_TessLevelInner[1] = mix(gl_TessLevelOuter[2], gl_TessLevelOuter[1], 0.5);
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}
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gl_out[gl_InvocationID].gl_Position = gl_in[gl_InvocationID].gl_Position;
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_norm[gl_InvocationID] = norm[gl_InvocationID];
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_texCoord[gl_InvocationID] = texCoord[gl_InvocationID];
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_pos[gl_InvocationID] = pos[gl_InvocationID];
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} |