62 lines
1.7 KiB
Text
62 lines
1.7 KiB
Text
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#version 150 compatibility
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#extension GL_EXT_geometry_shader4 : enable
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layout(points) in;
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layout(triangle_strip, max_vertices = 24) out;
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in mat3 NM[];
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in mat4 PM[];
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in vec4 color_gs[];
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out vec3 normal;
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out vec4 color;
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out vec3 position;
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flat out int side;
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int surface_side_handling(in vec3 position, inout vec3 normal, inout vec4 color);
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void emit_face(in vec3 normal_in, in vec4 c0, in vec4 c1, in vec4 c2, in vec4 c3)
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{
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color = color_gs[0];
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// compute eye space normal and first corner position
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normal = normal_in;
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position = c0.xyz;
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// determine side in eye space
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side = surface_side_handling(position, normal, color);
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if (side == -1)
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return;
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// emit face
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gl_Position = gl_ProjectionMatrix * c0;
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EmitVertex();
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position = c1.xyz;
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gl_Position = gl_ProjectionMatrix * c1;
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EmitVertex();
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position = c2.xyz;
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gl_Position = gl_ProjectionMatrix * c2;
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EmitVertex();
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position = c3.xyz;
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gl_Position = gl_ProjectionMatrix * c3;
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EmitVertex();
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EndPrimitive();
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}
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void main()
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{
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vec4 C0 = PM[0] * vec4(-0.5, -0.5, -0.5, 1.0);
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vec4 C1 = PM[0] * vec4(0.5, -0.5, -0.5, 1.0);
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vec4 C2 = PM[0] * vec4(-0.5, 0.5, -0.5, 1.0);
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vec4 C3 = PM[0] * vec4(0.5, 0.5, -0.5, 1.0);
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vec4 C4 = PM[0] * vec4(-0.5, -0.5, 0.5, 1.0);
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vec4 C5 = PM[0] * vec4(0.5, -0.5, 0.5, 1.0);
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vec4 C6 = PM[0] * vec4(-0.5, 0.5, 0.5, 1.0);
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vec4 C7 = PM[0] * vec4(0.5, 0.5, 0.5, 1.0);
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emit_face(NM[0] * vec3(-1.0, 0.0, 0.0), C0, C4, C2, C6);
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emit_face(NM[0] * vec3(1.0, 0.0, 0.0), C5, C1, C7, C3);
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emit_face(NM[0] * vec3(0.0, -1.0, 0.0), C0, C1, C4, C5);
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emit_face(NM[0] * vec3(0.0, 1.0, 0.0), C3, C2, C7, C6);
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emit_face(NM[0] * vec3(0.0, 0.0, -1.0), C0, C2, C1, C3);
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emit_face(NM[0] * vec3(0.0, 0.0, 1.0), C6, C4, C7, C5);
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}
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