Files
OpenSpace/shaders/fieldline_gs.glsl
2014-12-01 16:27:30 +01:00

99 lines
4.1 KiB
GLSL

/*****************************************************************************************
* *
* OpenSpace *
* *
* Copyright (c) 2014 *
* *
* Permission is hereby granted, free of charge, to any person obtaining a copy of this *
* software and associated documentation files (the "Software"), to deal in the Software *
* without restriction, including without limitation the rights to use, copy, modify, *
* merge, publish, distribute, sublicense, and/or sell copies of the Software, and to *
* permit persons to whom the Software is furnished to do so, subject to the following *
* conditions: *
* *
* The above copyright notice and this permission notice shall be included in all copies *
* or substantial portions of the Software. *
* *
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, *
* INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A *
* PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT *
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF *
* CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE *
* OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. *
****************************************************************************************/
#version __CONTEXT__
uniform mat4 modelViewProjection;
uniform mat4 modelTransform;
uniform vec3 cameraViewDir;
in vec4 vs_color[];
out vec4 gs_color;
out vec4 gs_position;
out vec3 gs_normal;
#include "PowerScaling/powerScaling_vs.hglsl"
layout(lines_adjacency) in;
layout(triangle_strip, max_vertices = 4) out;
vec4 prismoid[4];
// Calculate the correct powerscaled position and depth for the ABuffer
void ABufferEmitVertex(vec4 pos) {
// calculate psc position
vec4 tmp = pos;
vec4 position = pscTransform(tmp, modelTransform);
gs_position = tmp;
// project the position to view space
position = modelViewProjection*position;
gl_Position = position;
EmitVertex();
}
// Original code from http://prideout.net/blog/?p=61
void main() {
gs_color = vs_color[0];
// Get the current and adjacent vertex positions and calculate help vectors u and v
vec3 p0, p1, p2, p3;
p0 = gl_in[0].gl_Position.xyz; p1 = gl_in[1].gl_Position.xyz;
p2 = gl_in[2].gl_Position.xyz; p3 = gl_in[3].gl_Position.xyz;
vec3 n0 = normalize(p1-p0);
vec3 n1 = normalize(p2-p1);
vec3 n2 = normalize(p3-p2);
vec3 u = normalize(n0+n1);
vec3 v = normalize(n1+n2);
float EARTH_RADIUS = 6371000.0;
float width = 0.1*EARTH_RADIUS;
// Calculate normals for all 4 new vertices
vec3 normals[4];
normals[0] = normalize(cross(cameraViewDir,u));
normals[1] = -normals[0];
normals[3] = normalize(cross(cameraViewDir,v));
normals[2] = -normals[3];
// Calculate positions for the new vertices
prismoid[0] = vec4(p1 + normals[0]*width, 0);
prismoid[1] = vec4(p1 + normals[1]*width, 0);
prismoid[2] = vec4(p2 + normals[2]*width, 0);
prismoid[3] = vec4(p2 + normals[3]*width, 0);
// Send normals and verticies to fragment shader
gs_normal = normals[0];
ABufferEmitVertex(prismoid[0]);
gs_normal = normals[1];
ABufferEmitVertex(prismoid[1]);
gs_normal = normals[3];
ABufferEmitVertex(prismoid[3]);
gs_normal = normals[2];
ABufferEmitVertex(prismoid[2]);
EndPrimitive();
}