131 lines
4.0 KiB
GLSL
131 lines
4.0 KiB
GLSL
uniform int enable_normals;
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uniform int enable_tangents;
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uniform int enable_bitangents;
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uniform int enable_wireframe;
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uniform int enable_triangle_normals;
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layout(triangles) in;
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layout(line_strip, max_vertices = 24) out;
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in vec3 o_normal[];
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in vec3 o_tangent[];
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in vec3 o_bitangent[];
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flat out vec4 o_color;
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void main()
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{
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if (enable_normals == 0 && enable_tangents == 0 &&
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enable_bitangents == 0 && enable_wireframe == 0 &&
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enable_triangle_normals == 0)
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{
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return;
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}
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// colors for different type of new lines
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vec4 edge_color = vec4(0.2, 0.1, 0.1, 1.0);
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vec4 face_normal_color = vec4(0.5, 0.7, 0.2, 1.0);
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vec4 normal_color = vec4(0.0, 1.0, 0.2, 1.0);
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vec4 tangent_color = vec4(1.0, 0.3, 0.2, 1.0);
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vec4 bitangent_color = vec4(0.0, 0.1, 1.0, 1.0);
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// form two vectors from triangle
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vec3 V0 = gl_in[0].gl_Position.xyz - gl_in[1].gl_Position.xyz;
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vec3 V1 = gl_in[2].gl_Position.xyz - gl_in[1].gl_Position.xyz;
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// calculate normal as perpendicular to two vectors of the triangle
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vec3 V0_V1_crossed = cross(V1, V0);
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float normal_scale = min(length(V0_V1_crossed) * 10.0, 0.25);
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vec3 N = normalize(V0_V1_crossed);
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// normals of each vertex of the triangle
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vec3 nor[3];
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nor[0] = o_normal[0].xyz;
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nor[1] = o_normal[1].xyz;
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nor[2] = o_normal[2].xyz;
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// positions of each vertex of the triangle
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// shifted a bit along normal
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// so there won't be Z fighting when rendered over the mesh
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vec4 pos[3];
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pos[0] = u_projection_view_matrix *
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vec4(gl_in[0].gl_Position.xyz + nor[0] * 0.01, 1.0);
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pos[1] = u_projection_view_matrix *
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vec4(gl_in[1].gl_Position.xyz + nor[1] * 0.01, 1.0);
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pos[2] = u_projection_view_matrix *
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vec4(gl_in[2].gl_Position.xyz + nor[2] * 0.01, 1.0);
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// output normals, tangents and bitangents for each vertex of the triangle
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for (int i=0; i < gl_in.length(); i++)
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{
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// get position of the vertex
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vec3 P = gl_in[i].gl_Position.xyz;
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if (enable_normals > 0)
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{
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// create normal for vertex
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o_color = normal_color;
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gl_Position = pos[i];
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EmitVertex();
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gl_Position = u_projection_view_matrix * vec4(P + o_normal[i].xyz
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* normal_scale, 1.0);
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EmitVertex();
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EndPrimitive();
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}
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if (enable_tangents > 0)
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{
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// create tangent for vertex
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o_color = tangent_color;
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gl_Position = pos[i];
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EmitVertex();
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gl_Position = u_projection_view_matrix *
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vec4(P + o_tangent[i].xyz * normal_scale, 1.0);
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EmitVertex();
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EndPrimitive();
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}
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if (enable_bitangents > 0)
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{
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// create bitangent for vertex
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o_color = bitangent_color;
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gl_Position = pos[i];
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EmitVertex();
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gl_Position = u_projection_view_matrix * vec4(P +
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o_bitangent[i].xyz * normal_scale, 1.0);
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EmitVertex();
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EndPrimitive();
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}
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}
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if (enable_wireframe > 0)
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{
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// create edges for triangle
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o_color = edge_color;
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gl_Position = pos[0];
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EmitVertex();
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gl_Position = pos[1];
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EmitVertex();
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gl_Position = pos[2];
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EmitVertex();
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gl_Position = pos[0];
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EmitVertex();
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// end line strip after four added vertices, so we will get three lines
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EndPrimitive();
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}
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if (enable_triangle_normals > 0)
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{
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// create normal for triangle
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o_color = face_normal_color;
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// position as arithmetic average
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vec3 P = (gl_in[0].gl_Position.xyz + gl_in[1].gl_Position.xyz
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+ gl_in[2].gl_Position.xyz) / 3.0;
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gl_Position = u_projection_view_matrix * vec4(P, 1.0);
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EmitVertex();
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gl_Position = u_projection_view_matrix * vec4(P + N * normal_scale, 1.0);
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EmitVertex();
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EndPrimitive();
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}
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}
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