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This commit is contained in:
Jakub Valtar
2017-07-20 17:29:22 +02:00
parent 97b8c06763
commit b0b75e3c32
1 changed files with 5 additions and 2 deletions
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7
core/src/processing/opengl/shaders/LineVert.glsl
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@@ -52,7 +52,8 @@ void main() {
// formula to convert from clip space (range -1..1) to screen space (range 0..[width or height])
// screen_p = (p.xy/p.w + <1,1>) * 0.5 * viewport.zw
// prevent dividing by W by transforming the tangent formula
// prevent division by W by transforming the tangent formula (div by 0 causes
// the line to disappear, see https://github.com/processing/processing/issues/5183)
// t = screen_q - screen_p
//
// tangent is normalized and we don't care which direction it points to (+-)
@@ -66,7 +67,8 @@ void main() {
// t = +- normalize( ((q.xy*p.w - p.xy*q.w) / (p.w*q.w)) * 0.5 * viewport.zw )
//
// remove the common scalar divisor/factor, not needed due to normalize and +-
// (keep viewport - can't remove because it has different components for x and y)
// (keep viewport - can't remove because it has different components for x and y
// and corrects for aspect ratio, see https://github.com/processing/processing/issues/5181)
// t = +- normalize( (q.xy*p.w - p.xy*q.w) * viewport.zw )
vec2 tangent = normalize((q.xy*p.w - p.xy*q.w) * viewport.zw);
@@ -79,6 +81,7 @@ void main() {
// Perspective ---
// convert from world to clip by multiplying with projection scaling factor
// to get the right thickness (see https://github.com/processing/processing/issues/5182)
// invert Y, projections in Processing invert Y
vec2 perspScale = (projectionMatrix * vec4(1, -1, 0, 0)).xy;