Fix DebugAxis helper; Increase the sensitivity to prevent loss of color in debug axis (closes #1560)

modules/base/rendering/renderablecartesianaxes.cpp

@@ -118,14 +118,7 @@ void RenderableCartesianAxes::initializeGL() {
     );
 
     glGenVertexArrays(1, &_vaoId);
-    glGenBuffers(1, &_vBufferId);
-    glGenBuffers(1, &_iBufferId);
-
     glBindVertexArray(_vaoId);
-    glBindBuffer(GL_ARRAY_BUFFER, _vBufferId);
-    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iBufferId);
-    glEnableVertexAttribArray(0);
-    glBindVertexArray(0);
 
     std::vector<Vertex> vertices({
         Vertex{0.f, 0.f, 0.f},
@@ -140,7 +133,7 @@ void RenderableCartesianAxes::initializeGL() {
         0, 3
     };
 
-    glBindVertexArray(_vaoId);
+    glGenBuffers(1, &_vBufferId);
     glBindBuffer(GL_ARRAY_BUFFER, _vBufferId);
     glBufferData(
         GL_ARRAY_BUFFER,
@@ -149,8 +142,10 @@ void RenderableCartesianAxes::initializeGL() {
         GL_STATIC_DRAW
     );
 
+    glEnableVertexAttribArray(0);
     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), nullptr);
 
+    glGenBuffers(1, &_iBufferId);
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iBufferId);
     glBufferData(
         GL_ELEMENT_ARRAY_BUFFER,
@@ -158,6 +153,7 @@ void RenderableCartesianAxes::initializeGL() {
         indices.data(),
         GL_STATIC_DRAW
     );
+    glBindVertexArray(0);
 }
 
 void RenderableCartesianAxes::deinitializeGL() {
@@ -201,9 +197,9 @@ void RenderableCartesianAxes::render(const RenderData& data, RendererTasks&){
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     glEnablei(GL_BLEND, 0);
     glEnable(GL_LINE_SMOOTH);
+    glLineWidth(3.0);
 
     glBindVertexArray(_vaoId);
-    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _iBufferId);
     glDrawElements(GL_LINES, NVertexIndices, GL_UNSIGNED_INT, nullptr);
     glBindVertexArray(0);
 

modules/base/shaders/axes_fs.glsl

@@ -33,17 +33,20 @@ uniform vec3 yColor;
 uniform vec3 zColor;
 
 Fragment getFragment() {
-    Fragment frag;
+  Fragment frag;
 
-    vec3 colorComponents = step(0.01, vs_positionModelSpace);
+  // We compare against a small value as the first vertex doesn't have a positional
+  // information (or rather it is 0) and we don't want to miss out on the color close to
+  // the origin
+  vec3 colorComponents = step(2e-32, vs_positionModelSpace);
 
-    frag.color.rgb = colorComponents.x * xColor +
-        colorComponents.y * yColor +
-        colorComponents.z * zColor;
-    frag.color.a = 1.0;
+  frag.color.rgb = colorComponents.x * xColor +
+    colorComponents.y * yColor +
+    colorComponents.z * zColor;
+  frag.color.a = 1.0;
 
-    frag.depth = vs_screenSpaceDepth;
-    frag.gPosition = vs_positionViewSpace;
-    frag.gNormal = vec4(0.0, 0.0, 0.0, 1.0);
-    return frag;
+  frag.depth = vs_screenSpaceDepth;
+  frag.gPosition = vs_positionViewSpace;
+  frag.gNormal = vec4(0.0, 0.0, 0.0, 1.0);
+  return frag;
 }

modules/base/shaders/axes_vs.glsl

@@ -34,13 +34,13 @@ uniform mat4 modelViewTransform;
 uniform mat4 projectionTransform;
 
 void main() {
-    vec4 positionViewSpace = modelViewTransform * vec4(in_position, 1.0);
-    vec4 positionClipSpace = projectionTransform * positionViewSpace;
-    vec4 positionScreenSpace = positionClipSpace;
-    positionScreenSpace.z = 0.0;
-    vs_positionModelSpace = in_position;
-    vs_screenSpaceDepth  = positionScreenSpace.w;
-    vs_positionViewSpace = positionViewSpace;
+  vec4 positionViewSpace = modelViewTransform * vec4(in_position, 1.0);
+  vec4 positionClipSpace = projectionTransform * positionViewSpace;
+  vec4 positionScreenSpace = positionClipSpace;
+  positionScreenSpace.z = 0.0;
+  vs_positionModelSpace = in_position;
+  vs_screenSpaceDepth  = positionScreenSpace.w;
+  vs_positionViewSpace = positionViewSpace;
 
-    gl_Position = positionScreenSpace;
+  gl_Position = positionScreenSpace;
 }