Repo created

libs/shaders/GL/shaders_lib.glsl

@@ -0,0 +1,49 @@
+// This is a library of functions which we are use in our shaders.
+// Common (DO NOT modify this comment, it marks up block of common functions).
+
+// Scale factor in shape's coordinates transformation from tile's coordinate
+// system.
+const float kShapeCoordScalar = 1000.0;
+
+// VS (DO NOT modify this comment, it marks up block of vertex shader functions).
+
+// This function applies a 2D->3D transformation matrix |pivotTransform| to |pivot|.
+vec4 applyPivotTransform(vec4 pivot, mat4 pivotTransform, float pivotRealZ)
+{
+  vec4 transformedPivot = pivot;
+  float w = transformedPivot.w;
+  transformedPivot.xyw = (pivotTransform * vec4(transformedPivot.xy, pivotRealZ, w)).xyw;
+  transformedPivot.z *= transformedPivot.w / w;
+#ifdef VULKAN
+  transformedPivot.y = -transformedPivot.y;
+  transformedPivot.z = (transformedPivot.z  + transformedPivot.w) / 2.0;
+#endif
+  return transformedPivot;
+}
+
+// This function applies a 2D->3D transformation matrix to billboards.
+vec4 applyBillboardPivotTransform(vec4 pivot, mat4 pivotTransform, float pivotRealZ, vec2 offset)
+{
+  float logicZ = pivot.z / pivot.w;
+  vec4 transformedPivot = pivotTransform * vec4(pivot.xy, pivotRealZ, pivot.w);
+  vec4 scale = pivotTransform * vec4(1.0, -1.0, 0.0, 1.0);
+  vec4 position = vec4(transformedPivot.xy / transformedPivot.w, logicZ, 1.0) + vec4(offset / scale.w * scale.x, 0.0, 0.0);
+#ifdef VULKAN
+  position.y = -position.y;
+  position.z = (position.z  + position.w) / 2.0;
+#endif
+  return position;
+}
+
+// This function calculates transformed position on an axis for line shaders family.
+vec2 calcLineTransformedAxisPos(vec2 originalAxisPos, vec2 shiftedPos, mat4 modelView, float halfWidth)
+{
+  vec2 p = (vec4(shiftedPos, 0.0, 1.0) * modelView).xy;
+  vec2 d = p - originalAxisPos;
+  if (dot(d, d) != 0.0)
+    return originalAxisPos + normalize(d) * halfWidth;
+  else
+    return originalAxisPos;
+}
+
+// FS (DO NOT modify this comment, it marks up block of fragment shader functions).